Imaging findings of Balamuthia mandrillaris amoebic encephalitis in 2 cases with different prognosis and literature review

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This study characterizes the imaging manifestations of Balamuthia mandrillaris amoebic encephalitis, yields critical new insights into the intracranial dissemination mechanisms of Balamuthia mandrillaris. Case presentation: We present two cases of Balamuthia mandrillaris amoebic encephalitis confirmed through Next-generation sequencing of cerebrospinal fluid and brain biopsy in our hospital, with different imaging manifestations and prognosis (One death). Meanwhile, we reviewed 16 surviving cases of Balamuthia mandrillarisamoebic encephalitis reported in literatures up to now. Conclusion: Based on 17 surviving patients imaging findings with clinical data and one death case we reported, we proposed that the key imaging features related to the prognosis of Balamuthia mandrillaris amebic encephalitis are hemorrhage within the lesion and centripetal spread through cortical and subcortical brain parenchyma into cerebrospinal fluid circulation along the meninges and ependyms. Ventriculoperitoneal shunt may be superior to ventricular drainage that could provide the patient with a chance of survival. Balamuthia mandrillaris amoebic encephalitis skin lesion hemorrhage prognosis Figures Figure 1 Figure 2 Figure 3 Case Report Case 1 Female, 37 years old, she visited the hospital one week after breast cancer surgery due to dizziness accompanied by nausea and vomiting. On admission, a 10cm×15 cm patchy dark red desquamative infectious lesion was observed on the left lower extremity. This lesion originated from an injury in a landfill two years ago, and pathological examination about eight months ago revealed diffuse inflammatory cell infiltration in the dermis with granuloma formation and multinucleated giant cells, no definite evidence of fungal and tuberculosis infections was found. Next-generation sequencing (NGS) of the skin on the left lower extremity suggested a suspected mycobacterium abscessus infection. Eight months ago, an enlarged lymph node appeared under the left side of neck. The puncture biopsy suggested chronic granulomatous inflammation. Following combination therapy with rifampicin, ethambutol, colabitol, and clarithromycin, the patient exhibited marked symptomatic improvement. Later, the medication was stopped due to a breast surgery. The patient denied any history of residence in or travel to epidemic areas, exposure to freshwater swimming, contact with infected animals or their carcasses, and consumption of raw meat or unpasteurized dairy products. The head MRI examination was completed after admission (Table 1 ), abnormal signal was showed in the right temporal lobe with slightly hypointensity on T1WI, slightly hyperintensity on T2WI with edema surrounding (Fig. 1 a), slightly hyperintensity on DWI along with increased ADC signal. And irregular patchy enhancement was observed, the area of enhanced lesion was approximately 25mm×20mm. Additional multiple patchy abnormal signals were seen in the dorsal brainstem, bilateral pontocerebellar peduncles, left parahippocampal gyrus, and right thalamus, presented as isointense or slightly hypointense on T1WI, slightly hyperintense on T2WI, and high signals on DWI and T2 FLAIR, with no obvious enhancement. However, abnormal leptomeningeal enhancement was founded. The CSF testing on the 5th day of hospitalization revealed the following: 310 nucleated cells per microliter (consisted of 8% neutrophilic granulocytes and 88% lymphocytes), 30 red cells per microliter, 1.515 grams of protein per liter (normal range, 0.150–0.450 g/L), 1.7 millimole of glucose per liter (normal range, 2.5–4.5 mmol/L), 115 millimole of chloride per liter (normal range, 120–131 mmol/L). Intracranial pressure was 330 mmH 2 O. During hospital stay, considering the patient's left lower limb infection and chronic granulomatous lesion under the skin of the neck, the diagnosis-based treatment for mycobacterium abscessus was applied. A follow-up head MRI scan showed multiple patchy significant enhancement in the right temporal lobe, right thalamus, left parahippocampal gyrus, pons, fourth ventricle, and bilateral pontocerebellar peduncles, accompanied by abnormal leptomeningeal enhancement and supratentorial hydrocephalus on the 5th day of hospitalization (Fig. 1 b). Compared with the previous MRI, the lesions had increased and the enhancement was more obvious. The patient's condition worsened and oxygen saturation decreased on the 10th day of hospitalization. Then a head CT scan was performed, which indicated brain swelling and hydrocephalus. Therefore, a lateral ventricle catheter drainage procedure was carried out. Fourteen days later, the MRI performed again and showed new lesions in the periventricular on both sides, the cisterna magna and the deep left frontal lobe (Fig. 1 c). Multiple punctate and patchy hyperintensity on T2WI were newly found in the cervical spinal cord with faint enhancement. Meanwhile, Balamuthia mandrillaris was detected in the cerebrospinal fluid by Next Generation Sequencing (NGS). The treatment was immediately changed to a combination of amphotericin B, flucytosine, fluconazole, sulfamethoxazole and trimethoprim, clarithromycin, pentamidine, and intravenous immunoglobulin for antiamoebic therapy. Amphotericin B and miltefosine were injected intrathecally. However, the patient's condition continued to deteriorate. On the 22th day, the head MRI indicated diffuse abnormal enhancement within the fourth ventricle. Swelling of brain tissue and hydrocephalus were aggravated. New lesions had emerged in both basal ganglia regions (Fig. 1 d). Some lesions showed patchy hyperintensity on T1WI and high density on CT images, which suggested hemorrhage. Unfortunately, she died on the 27th day. Table 1 Clinical and imaging changes of case 1 Timeline Before admission On admission On the 5th day of hospitalization On the 10th day of hospitalization On the 14th day of hospitalization On the 22th day of hospitalization Localization of Lesions the skin of left lower extremity, left neck lymph node cerebral lobe, leptomeningeal, infratentorial brainstem cerebral lobes, leptomeningeal, infratentorial, brainstem, fourth ventricle CT: brain swelling and hydrocephalus cerebral lobes, basal ganglia, leptomeningeal, brainstem, ventricles and cisterns, spinal cord cerebral lobes, both basal ganglia regions, leptomeningeal, brainstem, ventricles and cisterns, spinal cord Pathology granulomatous inflammation not clear not clear not clear Balamuthia mandrillaris amoebic encephalomyelitis Balamuthia mandrillaris amoebic encephalomyelitis Therapy treatment for mycobacterium abscessus treatment for mycobacterium abscessus treatment for mycobacterium abscessus lateral ventricle catheter drainage procedure treatment of anti-amoebic treatment of anti-amoebic Condition improved new lesions in the brain lesions in the brain progressed increased intracranial pressure lesions in the brain progressed, new lesions in the spinal cord lesions in the brain progressed-death Case 2 A 9-year-old male patient was admitted to hospital due to dizziness for 2 days and poor stomach health for 1 day. The patient denied any past medical history and history of obvious open injuries. Cerebrospinal fluid biochemistry showed the following: 2.59 millimole of glucose per liter (normal range, 2.5–4.5 mmol/L), 126.5 millimole of chloride per liter (normal range, 120–131 mmol/L), 491.5 milligram of trace total protein per liter (normal range, 0.150–0.450 g/L). His cerebrospinal fluid culture was negative. The head MRI examination revealed a mass-like abnormal signal in the right occipital lobe, approximately 30.8mm×31.6mm×33.7mm in size with clear boundaries. It showed isointensity on T1WI, a slightly hyperintensity in the center and isointensity at the edge on T2WI and T2 FLAIR, with obvious edema around the lesion (Fig. 2 a ~ c). On DWI, it presented as a hypointensity in the center and slightly hyperintensity at the edge (Fig. 2 d). The lesion showed significant heterogeneous enhancement with marked enhanced edges (Fig. 2 e). Corresponding, the Arterial Spin Labeling (ASL) images showed low perfusion (Fig. 2 f). Due to the obvious space-occupying effect, the lesion in the right occipital lobe was resected on the 4th day of hospitalization. The pathology indicated chronic granulomatous inflammation with necrosis. Two days after the operation, the child developed a fever, which was mainly low-grade fever in the afternoon. On the 12th day after the operation, a mass with pain appeared in the left side of the neck. The ultrasound suggested lymph node enlargement with surrounding soft tissue inflammation. As the patient refused biopsy, a diagnostic anti-tuberculosis treatment (isoniazid + rifampicin + pyrazinamide + linezolid) was given. The following days, the mass subsided significantly. Head MRI reexaminations at 22 days, 30 days and 36 days postoperatively showed new lesions around the surgical area and in the right frontal lobe with rapid progression (Fig. 3 a ~ d). Next day, metagenomic sequencing of the brain tissue was performed and the result indicated the presence of Balamuthia mandrillaris. Anti-amoebic treatment with lincomycin, rifampicin, compound sulfamethoxazole, fluconazole, albendazole tablets, and recombinant human interferon γ was immediately initiated. Multiple MRI reexaminations from 40 to 125 days after the operation showed that the intracranial lesion gradually shrank and the perilesional edema was reduced (Fig. 3 e). Twenty-four months after the operation, the head MRI examination showed that the intracranial lesion was similar to the previous one and no enhancement was observed (Table 2 ). Table 2 Clinical and imaging changes of case 2 Timeline On admission the 12th day after surgery the 22-36th day after surgery the 37th day after surgery the 40-125th day after surgery the 5-24th month after surgery Localization of lesions solid mass in the right occipital lobe with heterogeneous ring enhancement, hypointensity in the center and slightly hyperintensity at the margin on DWI enlarged lymph nodes in the left neck the lesion had progressed with new lesions around the surgical area and in the right frontal lobe / the lesion gradually shrank, and the perilesional edema was reduced the surgical area and the lesion in the right frontal lobe were similar to the previous, and the lesion was stable Pathology intracranial mass secondary to intracranial hypertension ultrasound suggested enlarged lymph nodes with surrounding inflammation in the left neck chronic granulomatous inflammation with necrosis NGS identified Balamuthia mandrillaris amoeba Balamuthia mandrillaris amoeba Balamuthia mandrillaris amoeba Therapy or condition surgery performed 4 days later diagnostic anti-tuberculosis treatment -improved add meropenem and mannitol -progressed anti-amoebic treatment immediately anti-amoebic treatment -improved continuous anti-amoebic therapy -stable Discussion Balamuthia mandrillaris has two forms of life: trophozoites and cysts. It can survive independently in water and soil. It was first isolated from the brain of a pregnant baboon that died of encephalomyelitis at the San Diego Zoo in the United States in 1986 [ 1 ]. Balamuthia mandrillaris mainly affects two organ systems in humans: the skin and the central nervous system [ 2 , 3 ]. The infection routes include direct invasion through skin lesions, the respiratory system, nasal mucosa damage or corneal infection; it can also enter the human body through the digestive system and then spread to other organs via the bloodstream [ 4 ]. In addition, infection can also occur through organ transplantation from infected donors [ 5 ]. The destruction of the blood-brain barrier and subsequent invasion of the central nervous system can lead to granulomatous amoebic encephalitis. Balamuthia mandrillaris phagocytoses the fragments of host tissue and produces tissue-degrading enzymes which trigger an immune response that leading to necrosis, granuloma formation, hemorrhage [ 3 ]. At present, more than 300 cases of human infection with Balamuthia mandrillaris have been reported worldwide with a mortality rate over 90% [ 6 ]. However, there were only 16 cases with complete imaging data and survival in the literature [ 2 , 5 , 7 – 19 ]. In order to improve the diagnostic accuracy of Balamuthia mandrillaris amoebic encephalitis (BAE) and provide effective treatment timely to improve the prognosis, we reviewed and summarized the clinical and imaging data of 17 surviving cases of BAE in the literature and one death case we reported (Table 3 ). Table 3 Clinical and imaging features of 17 surviving cases Gender Age Skin infection Localization of lesions Multiple Enhancement pattern Ependyma and pia mater Edema Calcification Treatment methods Ref M 64y + Right occipital lobe, left parietal lobe + Circular enhancement - + - Surgery (biopsy of 1 of 2 lesions) + medicine 13 1 F 5y - Left temporal lobe, left parietal lobe + Circular enhancement - + + Surgery (partial excisional biopsy of 1 of 2 lesions) + medicine 13 2 F 72y - Right frontal lobe, left temporal lobe + Circular enhancement - NR - Surgery (excisional biopsy of 1 of 2 lesions) + medicine 14 M 35y NR NR + Focal enhancement NR NR NR Surgery (biopsy) 15 M 2y - Third ventricle, fourth ventricle, thalamus, left basal ganglia region, and right semioval center + Nodular and irregular enhancement + + - Surgery (biopsy + VP shunt) + medicine 16 F 21y + Left temporal lobe - Circular enhancement - + - Medicine 17 M 27y - NR + NR - NR - Medicine 9 F 80y + Right frontal lobe - Irregular annular enhancement - + - Surgery (gross total resection) + medicine 18 F 4y - Cerebral hemispheres, cerebellar hemispheres, brainstem, basal ganglia and thalamus + NR - NR - Surgery (craniotomy biopsy + drilling drainage) + medicine 19 M 26y - Left frontal lobe, right temporal lobe + NR - + - Surgery (biopsy of 1 of 2 lesions) + medicine 20 M 84y + Right basal ganglia region, left parieto-occipital lobe, right temporoparietal lobe, bilateral occipital lobes + Circular enhancement - + - Surgery (craniotomy and gross total resection of 1 of the lesions) + medicine 21 F 7y + Left parieto-occipital lobe - NR - NR - Surgery (gross total resection) + medicine 3 M 54y - Right parietal lobe, left parieto-occipital lobe -/+ Infiltrative enhancement - + + Surgery (gross total resection) + medicine 22 M 4y - Right parietal lobe - Circular enhancement - + - Surgery (gross total resection) + medicine 23 M 50y - Left temporal lobe, supratentorial and infratentorial regions -/+ Circular enhancement - + - Surgery (biopsy) + medicine 24 M 59y + Right frontal lobe - NR - + - Surgery (gross total resection) + medicine 25 M 9y - Right occipital lobe, right frontal lobe -/+ Circular enhancement - + - Surgery (gross total resection) + medicine / NR = Not Reported;Ref = Reference 1.Clinical features: gender, age, skin lesions, cervical lymph nodes Gender Among the 17 surviving cases, approximately 65% (11/17) were male and 35% (6/17) were female. This ratio is similar to the male-to-female ratio reported in the literature for Balamuthia mandrillaris infections [ 2 , 6 ]. In China, Wang Lei reported 28 cases of Balamuthia mandrillaris infection with 18 (65%) male patients, and 16 patients developed encephalitis, of which, 69% (11/16) were male patients [ 2 ]. In the United States, a large - scale data statistics with 109 relative cases presented 68% morbidity in male [ 6 ]. Age The age of the 17 survivors was ranged from 2 years old to 84 years old, the median age was 27 years old, and the average age was 35.47 years old. Among the 109 confirmed cases of Balamuthia amebiasis in the United States, patients under 10 years old accounted for 25% (27/109) [ 6 ]. Among 17 survivors, 35% (6/17) were under 10 years old. The majority of survivors are adults, perhaps it was due to the more robust immune system that can fight off infections in adults. Skin lesions Although previous literature reported that most cases of BAE in China were accompanied with skin lesions, which were often the initial symptom with a history of exposure to contaminated soil or water [ 2 ], among all 17 surviving cases, 10 cases accounting for about 59% (10/17) without skin lesions. In addition, we reported case 1 who had skin damage history and died soon in one month after admission, while case 2 had no clear skin damage and survived for a long time. It seemed that patients with skin lesions had worse prognosis here, we speculated that this might be due to the failure to identify the cause early and adopt effective treatment measures in a timely manner, resulting in the continuous proliferation of amoebas in the body and invasion of the central nervous system, exacerbating the condition in case 1 . After questioning the family members, it was found that the child of case 2 liked to swim in the wild, and it was suspected that the pathogen had invaded the brain through the damaged nasal mucosa. Lymphadenitis None of the 16 surviving cases reported in the literature exhibited lymph node enlargement. In contrast, both cases in our center were accompanied with cervical lymph node enlargement. Amoeba can serve as a reservoir or host for bacterial pathogens such as legionella and mycobacterium tuberculosis in the environment. Therefore, the lymph node enlargement might suggest a mixed infection, which was confirmed in death case 1 with mycobacterium abscessus infection of the left knee skin lesion by NGS test. In surviving case 2 , cervical lymph node inflammation occurred 12 days after surgery and improved after anti-tuberculosis treatment. The evidence for mixed infection in case 2 was not sufficient because no pathogen detection was performed on this patient. Whether the lymph node infection in the two cases of this group had any specific features related to BAE remained more cases to verify. 2. Imaging Characteristics The number of lesions 8 cases (47%) had a single lesion in the initial diagnosis, of which 3 cases progressed to multiple lesions. 9 cases (53%) had multiple lesions in the initial diagnosis. More than half of these cases (12/17) had multiple lesions in the course of the disease, which might mean Balamuthia mandrillaris infection prefer to present multiple lesions. Location 11 cases (65%) were located in the superficial cerebral lobes, 3 cases involved the deep brain parenchyma and one case extending to the ependyma. 3 cases with multiple lesions were not mentioned the specific locations. The majority of the cases were located in the superficial cerebral lobes, which was consistent with the hematogenous dissemination route of amoeba [ 20 ]. Lesions tended to appear in the junction of the cortex and medulla at first, and then progress to the deep brain parenchyma and ependymal. Enhanced features 8 cases (47%) showed ring enhancement. 3 cases (18%) presented irregular infiltrative enhancement. 1 case (6%) had multiple focal enhancements, and the remaining lesions were not reported the enhancement in the literatures. The proportion of ring-enhanced lesions was the largest, which might indicate a greater survival when the intracranial infection lesion showed an abscess formation. Edema 12 cases were accompanied with edema around the lesion, while the remaining 5 cases didn’t report whether there was edema in the literature. The edema was consistent with infectious granulomatous lesions. Hemorrhage and Calcification None of the surviving cases had hemorrhage. Case 2 had no hemorrhage and survived after surgical resection of the lesion and active combined multi-drug anti-amoebic treatment for 24 months of follow-up. Nevertheless, case 1 had hemorrhage later and the patient died 27 days after admission, which might mean hemorrhage in lesion was a signal of poor prognosis. In the literatures, 2 cases showed calcification on later reexamination, which might indicate healing phase. 3. Treatment Among the 17 surviving cases, 2 were treated with anti-amoebic drugs alone. 15 cases received surgical intervention combined with drug therapy, among which, 1 case received timely VP shunt surgery plus drug therapy due to the lesion involved the ependymal, another case underwent craniotomy biopsy and drilling drainage. Case 2 we reported underwent surgical resection of the lesion after admission. Although he developed new lesions around the surgical area and in the right frontal lobe, the condition improved after multi-drug anti-amoeba treatment. Conclusion Herein, we reported two cases of Balamuthia mandrillaris amebic encephalitis confirmed by next-generation sequencing. Both patients presented cervical lymph node inflammation, with different imaging manifestations. They received different treatments and had different prognosis. The patient in case 1 was presented with skin lesions. Later, due to breast cancer surgery, the blood-brain barrier was damaged, allowing the pathogen to enter the CNS. Subsequently, the pathogen spread to the spinal cord through the cerebrospinal fluid. Despite aggressive treatment with ventricular drilling and drainage, as well as combined multi-drug anti-amoebic therapy, the rapid progression of the disease caused by amoebic infection and the inherent drug resistance led to the patient's death, as the patient suffered from progressive intracranial hypertension and brain herniation. In the 2-year-old boy’s case listed in the Table 3 , ventricular ependyma and ventricular cisterns were involved, and after timely V-P shunt combined with anti-amoebic drug treatment, he survived [ 16 ]. In case 2 , the patient underwent timely surgical resection after admission, and active anti-amoebic treatment was carried out postoperatively. The patient’s condition had improved after 24 months of follow-up. Early surgical treatment to reduce the lesion burden, combined with anti-amoebic drugs, was the key to successful treatment. Balamuthia mandrillaris amebic encephalitis is not always fatal. When the lesion is localized and resection is feasible, early surgical resection combined with anti-amoebic drug therapy should be the first line for treatment. However, when the lesion is extensive and surgery is not possible, especially when the lesion involves the ependyma, early V-P shunt may offer a glimmer of hope for the patient. ABBREVIATIONS BAE = Balamuthia mandrillaris amoebic encephalitis; NGS = next-generation sequencing; ASL = Arterial Spin Labeling Declarations Ethics approval and consent to participate: The studies involving human participants were reviewed and approved by Research Ethics Committee of the Shengzhou People’s Hospital. The Ethics Committee waived the requirement of written informed consent for participation. Consent for publication: Written informed consent for publication of clinical details and images was obtained from the patients’ next of kin (patient’s husband in case 1 and patient’s parents in case 2). Availability of data and materials: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation. Competing interest: The authors declare no competing interests. Funding: Not applicable. Author contributions: Data collection: Yanjia Chen; data analysis: Tingting Zhang; Writing-original draft preparation: Yanjia Chen and Tingting Zhang; Writing-review and editing: Haiyan Lou. All authors contributed to the article and approved the submitted version. Acknowledgements: The authors thank all the patients who participated in this study and also to everyone who made a contribution to make this research possible. References Visvesvara GS, Martinez AJ, Schuster FL, et al. Leptomyxid ameba, a new agent of amebic meningoencephalitis in humans and animals. J Clin Microbiol. 1990; 28(12):2750-2756. DOI: 10.1128/jcm.28.12.2750-2756.1990 Wang L, Cheng W, Li B, et al. Balamuthia mandrillaris infection in China: a retrospective report of 28 cases. Emerg Microbes Infect. 2020;9(1):2348-2357. DOI: 10.1080/22221751.2020.1835447 Bravo FG, Seas C. Balamuthia mandrillaris amoebic encephalitis: an emerging parasitic infection. Curr Infect Dis Rep. 2012;14(4):391-396. 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Cite Share Download PDF Status: Published Journal Publication published 27 Nov, 2025 Read the published version in BMC Neurology → Version 1 posted Editorial decision: Revision requested 27 Oct, 2025 Reviews received at journal 05 Oct, 2025 Reviewers agreed at journal 26 Sep, 2025 Reviews received at journal 08 Aug, 2025 Reviewers agreed at journal 28 Jul, 2025 Reviewers invited by journal 28 Jul, 2025 Editor invited by journal 28 Jul, 2025 Editor assigned by journal 24 Jul, 2025 Submission checks completed at journal 24 Jul, 2025 First submitted to journal 20 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7168786","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":492285264,"identity":"9c0e780c-09ce-45bc-983e-613ded29a82a","order_by":0,"name":"Yanjia Chen","email":"","orcid":"","institution":"Shengzhou People's Hospital (Shengzhou Branch of the First Affiliated Hospital of Zhejiang University School of Medicine, the Shengzhou Hospital of Shaoxing University)","correspondingAuthor":false,"prefix":"","firstName":"Yanjia","middleName":"","lastName":"Chen","suffix":""},{"id":492285265,"identity":"76366a39-4ed5-4ccf-a9b4-6742b68ac2e2","order_by":1,"name":"Tingting Zhang","email":"","orcid":"","institution":"Zhejiang University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Tingting","middleName":"","lastName":"Zhang","suffix":""},{"id":492285268,"identity":"5fa6bb19-b9e4-40be-8f78-3cd9b1c9d2ef","order_by":2,"name":"Haiyan Lou","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6klEQVRIie3RIQvCQBTA8XcMXJmzviEqfoOTFQU/zInVYBKTCsKlidV9i9mMNwQt07yomAVhySD4psmyzSZ4/3i8H7vbA9DpfjAbgCkArFfMuQJMj1QOKb1n2q7j7cRXZNwL4gF/H+US0+PqvsGe70XJrSOhbseCJcMsYkU8XEToLs1FwB0JrhMLo7rKIjjgqiyx5nuHQBChG4qSYeWQ8CGR0VtOisi0ENnSV5pE2IyI4LnE2g23NYnpT3YBj9jyo/O8mkVog+vzVU7SVV4SHHUb9r4fJlnkIwNfy2SzooBmb8VndTqd7o96AiDhTRE9Jl2EAAAAAElFTkSuQmCC","orcid":"","institution":"Zhejiang University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Haiyan","middleName":"","lastName":"Lou","suffix":""}],"badges":[],"createdAt":"2025-07-20 09:38:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7168786/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7168786/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12883-025-04544-3","type":"published","date":"2025-11-27T15:57:35+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":88038156,"identity":"6ef3d718-d6b0-455c-8cdc-7f24a3fcc005","added_by":"auto","created_at":"2025-07-31 16:37:34","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":22953,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eImage evolution over time of Case 1. \u003c/strong\u003e(a) Initial brain MRI before admission. (b) Brain MRI on the 5th day of hospitalization shows new lesions in the fourth ventricle. (c) Brain MRI on the 14th day of hospitalization shows new lesions in the basal ganglia, ventricles and spinal cord. (d) The brain lesions demonstrate further enlargement, with hemorrhage within some lesions on the 22th day of hospitalization.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7168786/v1/6eae7f324f650b7ebb216c31.jpeg"},{"id":88036064,"identity":"0fd7afe0-eeca-4e03-aaea-49a21b990cc4","added_by":"auto","created_at":"2025-07-31 16:21:34","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":53507,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBrain MRI of case 2 upon admission. \u003c/strong\u003eThere is a mass-like abnormal signal in the right occipital lobe. It shows isointensity on T1WI (a), a slightly hyperintensity on T2WI and T2 FLAIR, with obvious edema around the lesion (b~c) and ring-shaped hyperintensity on DWI (d). (e) The lesion is marked ring-enhanced. (f) The Arterial Spin Labeling (ASL) images show low perfusion.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7168786/v1/9f18c693a279c10b54b70efe.jpeg"},{"id":88036069,"identity":"f8e110ff-3601-46ad-99dc-26d02c9804bc","added_by":"auto","created_at":"2025-07-31 16:21:34","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":32050,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePostoperative image evolution in Case 2. \u003c/strong\u003e(a~c) After 22 days of surgery, there are new symptoms in the surgical area and right frontal lobe. (d) After 36 days of follow-up, the two lesions gradually increase in size. (e) The lesion gradually recedes 125 days after surgery.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7168786/v1/607754e620e115338097c747.jpeg"},{"id":97178703,"identity":"75a689ac-dcfc-4d99-8be7-22ef6c158344","added_by":"auto","created_at":"2025-12-01 16:12:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1113158,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7168786/v1/8990f27b-f609-4e54-a1bf-d7fa198dbe80.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Imaging findings of Balamuthia mandrillaris amoebic encephalitis in 2 cases with different prognosis and literature review","fulltext":[{"header":"Case Report","content":"\u003cp\u003e\u003cstrong\u003eCase 1\u003c/strong\u003e\u003cp\u003eFemale, 37 years old, she visited the hospital one week after breast cancer surgery due to dizziness accompanied by nausea and vomiting. On admission, a 10cm\u0026times;15 cm patchy dark red desquamative infectious lesion was observed on the left lower extremity. This lesion originated from an injury in a landfill two years ago, and pathological examination about eight months ago revealed diffuse inflammatory cell infiltration in the dermis with granuloma formation and multinucleated giant cells, no definite evidence of fungal and tuberculosis infections was found. Next-generation sequencing (NGS) of the skin on the left lower extremity suggested a suspected mycobacterium abscessus infection. Eight months ago, an enlarged lymph node appeared under the left side of neck. The puncture biopsy suggested chronic granulomatous inflammation. Following combination therapy with rifampicin, ethambutol, colabitol, and clarithromycin, the patient exhibited marked symptomatic improvement. Later, the medication was stopped due to a breast surgery. The patient denied any history of residence in or travel to epidemic areas, exposure to freshwater swimming, contact with infected animals or their carcasses, and consumption of raw meat or unpasteurized dairy products.\u003c/p\u003e\u003c/p\u003e\u003cp\u003eThe head MRI examination was completed after admission (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), abnormal signal was showed in the right temporal lobe with slightly hypointensity on T1WI, slightly hyperintensity on T2WI with edema surrounding (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea), slightly hyperintensity on DWI along with increased ADC signal. And irregular patchy enhancement was observed, the area of enhanced lesion was approximately 25mm\u0026times;20mm. Additional multiple patchy abnormal signals were seen in the dorsal brainstem, bilateral pontocerebellar peduncles, left parahippocampal gyrus, and right thalamus, presented as isointense or slightly hypointense on T1WI, slightly hyperintense on T2WI, and high signals on DWI and T2 FLAIR, with no obvious enhancement. However, abnormal leptomeningeal enhancement was founded. The CSF testing on the 5th day of hospitalization revealed the following: 310 nucleated cells per microliter (consisted of 8% neutrophilic granulocytes and 88% lymphocytes), 30 red cells per microliter, 1.515 grams of protein per liter (normal range, 0.150\u0026ndash;0.450 g/L), 1.7 millimole of glucose per liter (normal range, 2.5\u0026ndash;4.5 mmol/L), 115 millimole of chloride per liter (normal range, 120\u0026ndash;131 mmol/L). Intracranial pressure was 330 mmH\u003csub\u003e2\u003c/sub\u003eO.\u003c/p\u003e\u003cp\u003eDuring hospital stay, considering the patient's left lower limb infection and chronic granulomatous lesion under the skin of the neck, the diagnosis-based treatment for mycobacterium abscessus was applied. A follow-up head MRI scan showed multiple patchy significant enhancement in the right temporal lobe, right thalamus, left parahippocampal gyrus, pons, fourth ventricle, and bilateral pontocerebellar peduncles, accompanied by abnormal leptomeningeal enhancement and supratentorial hydrocephalus on the 5th day of hospitalization (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). Compared with the previous MRI, the lesions had increased and the enhancement was more obvious. The patient's condition worsened and oxygen saturation decreased on the 10th day of hospitalization. Then a head CT scan was performed, which indicated brain swelling and hydrocephalus. Therefore, a lateral ventricle catheter drainage procedure was carried out. Fourteen days later, the MRI performed again and showed new lesions in the periventricular on both sides, the cisterna magna and the deep left frontal lobe (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec). Multiple punctate and patchy hyperintensity on T2WI were newly found in the cervical spinal cord with faint enhancement. Meanwhile, Balamuthia mandrillaris was detected in the cerebrospinal fluid by Next Generation Sequencing (NGS). The treatment was immediately changed to a combination of amphotericin B, flucytosine, fluconazole, sulfamethoxazole and trimethoprim, clarithromycin, pentamidine, and intravenous immunoglobulin for antiamoebic therapy. Amphotericin B and miltefosine were injected intrathecally. However, the patient's condition continued to deteriorate. On the 22th day, the head MRI indicated diffuse abnormal enhancement within the fourth ventricle. Swelling of brain tissue and hydrocephalus were aggravated. New lesions had emerged in both basal ganglia regions (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed). Some lesions showed patchy hyperintensity on T1WI and high density on CT images, which suggested hemorrhage. Unfortunately, she died on the 27th day.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical and imaging changes of case \u003cspan refid=\"FPar2\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTimeline\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBefore admission\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eOn admission\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOn the 5th day of hospitalization\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eOn the 10th day of hospitalization\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eOn the 14th day of hospitalization\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eOn the 22th day of hospitalization\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eLocalization of Lesions\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ethe skin of left lower extremity, left neck lymph node\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ecerebral lobe, leptomeningeal, infratentorial brainstem\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ecerebral lobes, leptomeningeal, infratentorial, brainstem, fourth ventricle\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCT: brain swelling and hydrocephalus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ecerebral lobes, basal ganglia, leptomeningeal, brainstem, ventricles and cisterns, spinal cord\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ecerebral lobes, both basal ganglia regions, leptomeningeal, brainstem, ventricles and cisterns, spinal cord\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePathology\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003egranulomatous inflammation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003enot clear\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003enot clear\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003enot clear\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBalamuthia mandrillaris amoebic encephalomyelitis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eBalamuthia mandrillaris amoebic encephalomyelitis\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTherapy\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003etreatment for mycobacterium abscessus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003etreatment for mycobacterium abscessus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003etreatment for mycobacterium abscessus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003elateral ventricle catheter drainage procedure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003etreatment of anti-amoebic\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003etreatment of anti-amoebic\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eCondition\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eimproved\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003enew lesions in the brain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003elesions in the brain progressed\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eincreased intracranial pressure\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003elesions in the brain progressed, new lesions in the spinal cord\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003elesions in the brain progressed-death\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCase 2\u003c/strong\u003e\u003cp\u003eA 9-year-old male patient was admitted to hospital due to dizziness for 2 days and poor stomach health for 1 day. The patient denied any past medical history and history of obvious open injuries. Cerebrospinal fluid biochemistry showed the following: 2.59 millimole of glucose per liter (normal range, 2.5\u0026ndash;4.5 mmol/L), 126.5 millimole of chloride per liter (normal range, 120\u0026ndash;131 mmol/L), 491.5 milligram of trace total protein per liter (normal range, 0.150\u0026ndash;0.450 g/L). His cerebrospinal fluid culture was negative. The head MRI examination revealed a mass-like abnormal signal in the right occipital lobe, approximately 30.8mm\u0026times;31.6mm\u0026times;33.7mm in size with clear boundaries. It showed isointensity on T1WI, a slightly hyperintensity in the center and isointensity at the edge on T2WI and T2 FLAIR, with obvious edema around the lesion (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea\u0026thinsp;~\u0026thinsp;c). On DWI, it presented as a hypointensity in the center and slightly hyperintensity at the edge (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed). The lesion showed significant heterogeneous enhancement with marked enhanced edges (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee). Corresponding, the Arterial Spin Labeling (ASL) images showed low perfusion (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef). Due to the obvious space-occupying effect, the lesion in the right occipital lobe was resected on the 4th day of hospitalization. The pathology indicated chronic granulomatous inflammation with necrosis. Two days after the operation, the child developed a fever, which was mainly low-grade fever in the afternoon. On the 12th day after the operation, a mass with pain appeared in the left side of the neck. The ultrasound suggested lymph node enlargement with surrounding soft tissue inflammation. As the patient refused biopsy, a diagnostic anti-tuberculosis treatment (isoniazid\u0026thinsp;+\u0026thinsp;rifampicin\u0026thinsp;+\u0026thinsp;pyrazinamide\u0026thinsp;+\u0026thinsp;linezolid) was given. The following days, the mass subsided significantly. Head MRI reexaminations at 22 days, 30 days and 36 days postoperatively showed new lesions around the surgical area and in the right frontal lobe with rapid progression (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea\u0026thinsp;~\u0026thinsp;d). Next day, metagenomic sequencing of the brain tissue was performed and the result indicated the presence of Balamuthia mandrillaris. Anti-amoebic treatment with lincomycin, rifampicin, compound sulfamethoxazole, fluconazole, albendazole tablets, and recombinant human interferon γ was immediately initiated. Multiple MRI reexaminations from 40 to 125 days after the operation showed that the intracranial lesion gradually shrank and the perilesional edema was reduced (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ee). Twenty-four months after the operation, the head MRI examination showed that the intracranial lesion was similar to the previous one and no enhancement was observed (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical and imaging changes of case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTimeline\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOn admission\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ethe 12th day after surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ethe 22-36th day\u003c/p\u003e\u003cp\u003eafter surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ethe 37th day after surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ethe 40-125th day\u003c/p\u003e\u003cp\u003eafter surgery\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ethe 5-24th\u003c/p\u003e\u003cp\u003emonth after surgery\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eLocalization of lesions\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esolid mass in the right occipital lobe with heterogeneous ring enhancement, hypointensity in the center and slightly hyperintensity at the margin on DWI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eenlarged lymph nodes in the left neck\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ethe lesion had progressed with new lesions around the surgical area and in the right frontal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ethe lesion gradually shrank, and the perilesional edema was reduced\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ethe surgical area and the lesion in the right frontal lobe were similar to the previous, and the lesion was stable\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePathology\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eintracranial mass secondary to intracranial hypertension\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eultrasound suggested enlarged lymph nodes with surrounding inflammation in the left neck\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003echronic granulomatous inflammation with necrosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNGS identified Balamuthia mandrillaris amoeba\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBalamuthia mandrillaris amoeba\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eBalamuthia mandrillaris amoeba\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTherapy or condition\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003esurgery performed 4 days later\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ediagnostic anti-tuberculosis treatment -improved\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eadd meropenem and mannitol -progressed\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eanti-amoebic treatment immediately\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eanti-amoebic treatment -improved\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003econtinuous anti-amoebic therapy -stable\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eBalamuthia mandrillaris has two forms of life: trophozoites and cysts. It can survive independently in water and soil. It was first isolated from the brain of a pregnant baboon that died of encephalomyelitis at the San Diego Zoo in the United States in 1986 [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Balamuthia mandrillaris mainly affects two organ systems in humans: the skin and the central nervous system [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The infection routes include direct invasion through skin lesions, the respiratory system, nasal mucosa damage or corneal infection; it can also enter the human body through the digestive system and then spread to other organs via the bloodstream [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In addition, infection can also occur through organ transplantation from infected donors [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The destruction of the blood-brain barrier and subsequent invasion of the central nervous system can lead to granulomatous amoebic encephalitis. Balamuthia mandrillaris phagocytoses the fragments of host tissue and produces tissue-degrading enzymes which trigger an immune response that leading to necrosis, granuloma formation, hemorrhage [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. At present, more than 300 cases of human infection with Balamuthia mandrillaris have been reported worldwide with a mortality rate over 90% [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. However, there were only 16 cases with complete imaging data and survival in the literature [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan additionalcitationids=\"CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In order to improve the diagnostic accuracy of Balamuthia mandrillaris amoebic encephalitis (BAE) and provide effective treatment timely to improve the prognosis, we reviewed and summarized the clinical and imaging data of 17 surviving cases of BAE in the literature and one death case we reported (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical and imaging features of 17 surviving cases\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"11\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSkin infection\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLocalization of lesions\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMultiple\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eEnhancement pattern\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eEpendyma and pia mater\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eEdema\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eCalcification\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003eTreatment methods\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003eRef\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e64y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight occipital lobe, left parietal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (biopsy of 1 of 2 lesions)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e13\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLeft temporal lobe, left parietal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (partial excisional biopsy of 1 of 2 lesions)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e13\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e72y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight frontal lobe, left temporal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (excisional biopsy of 1 of 2 lesions)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e35y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eFocal enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (biopsy)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eThird ventricle, fourth ventricle, thalamus, left basal ganglia region, and right semioval center\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNodular and irregular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (biopsy\u0026thinsp;+\u0026thinsp;VP shunt)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLeft temporal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eMedicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e27y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eMedicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e80y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight frontal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eIrregular annular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (gross total resection)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eCerebral hemispheres, cerebellar hemispheres, brainstem, basal ganglia and thalamus\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (craniotomy biopsy\u0026thinsp;+\u0026thinsp;drilling drainage)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e26y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLeft frontal lobe, right temporal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (biopsy of 1 of 2 lesions)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e84y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight basal ganglia region, left parieto-occipital lobe, right temporoparietal lobe, bilateral occipital lobes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (craniotomy and gross total resection of 1 of the lesions)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eF\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLeft parieto-occipital lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (gross total resection)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e54y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight parietal lobe, left parieto-occipital lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-/+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eInfiltrative enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (gross total resection)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e22\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight parietal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (gross total resection)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e50y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLeft temporal lobe, supratentorial and infratentorial regions\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-/+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (biopsy)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e59y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight frontal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eNR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (gross total resection)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e9y\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRight occipital lobe, right frontal lobe\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-/+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eCircular enhancement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eSurgery (gross total resection)\u0026thinsp;+\u0026thinsp;medicine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"11\"\u003eNR\u0026thinsp;=\u0026thinsp;Not Reported;Ref\u0026thinsp;=\u0026thinsp;Reference\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\n\u003ch3\u003e1.Clinical features: gender, age, skin lesions, cervical lymph nodes\u003c/h3\u003e\n\u003cp\u003e\u003cstrong\u003eGender\u003c/strong\u003e\u003cp\u003eAmong the 17 surviving cases, approximately 65% (11/17) were male and 35% (6/17) were female. This ratio is similar to the male-to-female ratio reported in the literature for Balamuthia mandrillaris infections [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In China, Wang Lei reported 28 cases of Balamuthia mandrillaris infection with 18 (65%) male patients, and 16 patients developed encephalitis, of which, 69% (11/16) were male patients [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. In the United States, a large - scale data statistics with 109 relative cases presented 68% morbidity in male [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eAge\u003c/strong\u003e\u003cp\u003eThe age of the 17 survivors was ranged from 2 years old to 84 years old, the median age was 27 years old, and the average age was 35.47 years old. Among the 109 confirmed cases of Balamuthia amebiasis in the United States, patients under 10 years old accounted for 25% (27/109) [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Among 17 survivors, 35% (6/17) were under 10 years old. The majority of survivors are adults, perhaps it was due to the more robust immune system that can fight off infections in adults.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eSkin lesions\u003c/strong\u003e\u003cp\u003eAlthough previous literature reported that most cases of BAE in China were accompanied with skin lesions, which were often the initial symptom with a history of exposure to contaminated soil or water [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], among all 17 surviving cases, 10 cases accounting for about 59% (10/17) without skin lesions. In addition, we reported case \u003cspan refid=\"FPar2\" class=\"InternalRef\"\u003e1\u003c/span\u003e who had skin damage history and died soon in one month after admission, while case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e had no clear skin damage and survived for a long time. It seemed that patients with skin lesions had worse prognosis here, we speculated that this might be due to the failure to identify the cause early and adopt effective treatment measures in a timely manner, resulting in the continuous proliferation of amoebas in the body and invasion of the central nervous system, exacerbating the condition in case \u003cspan refid=\"FPar2\" class=\"InternalRef\"\u003e1\u003c/span\u003e. After questioning the family members, it was found that the child of case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e liked to swim in the wild, and it was suspected that the pathogen had invaded the brain through the damaged nasal mucosa.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eLymphadenitis\u003c/strong\u003e\u003cp\u003eNone of the 16 surviving cases reported in the literature exhibited lymph node enlargement. In contrast, both cases in our center were accompanied with cervical lymph node enlargement. Amoeba can serve as a reservoir or host for bacterial pathogens such as legionella and mycobacterium tuberculosis in the environment. Therefore, the lymph node enlargement might suggest a mixed infection, which was confirmed in death case \u003cspan refid=\"FPar2\" class=\"InternalRef\"\u003e1\u003c/span\u003e with mycobacterium abscessus infection of the left knee skin lesion by NGS test. In surviving case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e, cervical lymph node inflammation occurred 12 days after surgery and improved after anti-tuberculosis treatment. The evidence for mixed infection in case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e was not sufficient because no pathogen detection was performed on this patient. Whether the lymph node infection in the two cases of this group had any specific features related to BAE remained more cases to verify.\u003c/p\u003e\u003c/p\u003e\n\u003ch3\u003e2. Imaging Characteristics\u003c/h3\u003e\n\u003cp\u003e\u003cstrong\u003eThe number of lesions\u003c/strong\u003e\u003cp\u003e8 cases (47%) had a single lesion in the initial diagnosis, of which 3 cases progressed to multiple lesions. 9 cases (53%) had multiple lesions in the initial diagnosis. More than half of these cases (12/17) had multiple lesions in the course of the disease, which might mean Balamuthia mandrillaris infection prefer to present multiple lesions.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eLocation\u003c/strong\u003e\u003cp\u003e11 cases (65%) were located in the superficial cerebral lobes, 3 cases involved the deep brain parenchyma and one case extending to the ependyma. 3 cases with multiple lesions were not mentioned the specific locations. The majority of the cases were located in the superficial cerebral lobes, which was consistent with the hematogenous dissemination route of amoeba [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Lesions tended to appear in the junction of the cortex and medulla at first, and then progress to the deep brain parenchyma and ependymal.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEnhanced features\u003c/strong\u003e\u003cp\u003e8 cases (47%) showed ring enhancement. 3 cases (18%) presented irregular infiltrative enhancement. 1 case (6%) had multiple focal enhancements, and the remaining lesions were not reported the enhancement in the literatures. The proportion of ring-enhanced lesions was the largest, which might indicate a greater survival when the intracranial infection lesion showed an abscess formation.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEdema\u003c/strong\u003e\u003cp\u003e12 cases were accompanied with edema around the lesion, while the remaining 5 cases didn\u0026rsquo;t report whether there was edema in the literature. The edema was consistent with infectious granulomatous lesions.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eHemorrhage and Calcification\u003c/strong\u003e\u003cp\u003eNone of the surviving cases had hemorrhage. Case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e had no hemorrhage and survived after surgical resection of the lesion and active combined multi-drug anti-amoebic treatment for 24 months of follow-up. Nevertheless, case \u003cspan refid=\"FPar2\" class=\"InternalRef\"\u003e1\u003c/span\u003e had hemorrhage later and the patient died 27 days after admission, which might mean hemorrhage in lesion was a signal of poor prognosis. In the literatures, 2 cases showed calcification on later reexamination, which might indicate healing phase.\u003c/p\u003e\u003c/p\u003e\n\u003ch3\u003e3. Treatment\u003c/h3\u003e\n\u003cp\u003eAmong the 17 surviving cases, 2 were treated with anti-amoebic drugs alone. 15 cases received surgical intervention combined with drug therapy, among which, 1 case received timely VP shunt surgery plus drug therapy due to the lesion involved the ependymal, another case underwent craniotomy biopsy and drilling drainage. Case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e we reported underwent surgical resection of the lesion after admission. Although he developed new lesions around the surgical area and in the right frontal lobe, the condition improved after multi-drug anti-amoeba treatment.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eHerein, we reported two cases of Balamuthia mandrillaris amebic encephalitis confirmed by next-generation sequencing. Both patients presented cervical lymph node inflammation, with different imaging manifestations. They received different treatments and had different prognosis. The patient in case \u003cspan refid=\"FPar2\" class=\"InternalRef\"\u003e1\u003c/span\u003e was presented with skin lesions. Later, due to breast cancer surgery, the blood-brain barrier was damaged, allowing the pathogen to enter the CNS. Subsequently, the pathogen spread to the spinal cord through the cerebrospinal fluid. Despite aggressive treatment with ventricular drilling and drainage, as well as combined multi-drug anti-amoebic therapy, the rapid progression of the disease caused by amoebic infection and the inherent drug resistance led to the patient's death, as the patient suffered from progressive intracranial hypertension and brain herniation. In the 2-year-old boy\u0026rsquo;s case listed in the Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, ventricular ependyma and ventricular cisterns were involved, and after timely V-P shunt combined with anti-amoebic drug treatment, he survived [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In case \u003cspan refid=\"FPar3\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the patient underwent timely surgical resection after admission, and active anti-amoebic treatment was carried out postoperatively. The patient\u0026rsquo;s condition had improved after 24 months of follow-up. Early surgical treatment to reduce the lesion burden, combined with anti-amoebic drugs, was the key to successful treatment.\u003c/p\u003e\u003cp\u003eBalamuthia mandrillaris amebic encephalitis is not always fatal. When the lesion is localized and resection is feasible, early surgical resection combined with anti-amoebic drug therapy should be the first line for treatment. However, when the lesion is extensive and surgery is not possible, especially when the lesion involves the ependyma, early V-P shunt may offer a glimmer of hope for the patient.\u003c/p\u003e"},{"header":"ABBREVIATIONS","content":"\u003cp\u003eBAE =\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003cem\u003eBalamuthia mandrillaris\u003c/em\u003e amoebic encephalitis; NGS = next-generation sequencing; ASL = Arterial Spin Labeling\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u0026nbsp;\u003c/strong\u003eThe studies involving human participants were reviewed and approved by Research Ethics Committee of the Shengzhou People\u0026rsquo;s Hospital. The Ethics Committee waived the requirement of written informed consent for participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication:\u0026nbsp;\u003c/strong\u003eWritten informed consent for publication of clinical details and images was obtained from the patients\u0026rsquo; next of kin (patient\u0026rsquo;s husband in case 1 and patient\u0026rsquo;s parents in case 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u0026nbsp;\u003c/strong\u003eThe raw data supporting the conclusions of this article will be made available by the authors, without\u003c/p\u003e\n\u003cp\u003eundue reservation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interest:\u0026nbsp;\u003c/strong\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions:\u0026nbsp;\u003c/strong\u003eData collection: Yanjia Chen; data analysis: Tingting Zhang; Writing-original draft preparation: Yanjia Chen and Tingting Zhang; Writing-review and editing: Haiyan Lou. All authors contributed to the article and approved the submitted version.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u0026nbsp;\u003c/strong\u003eThe authors thank all the patients who participated in this study and also to everyone who made a contribution to make this research possible.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eVisvesvara GS, Martinez AJ, Schuster FL, et al. Leptomyxid ameba, a new agent of amebic meningoencephalitis in humans and animals. J Clin Microbiol. 1990; 28(12):2750-2756. DOI: 10.1128/jcm.28.12.2750-2756.1990\u003c/li\u003e\n\u003cli\u003eWang L, Cheng W, Li B, et al. Balamuthia mandrillaris infection in China: a retrospective report of 28 cases. Emerg Microbes Infect. 2020;9(1):2348-2357. DOI: 10.1080/22221751.2020.1835447\u003c/li\u003e\n\u003cli\u003eBravo FG, Seas C. Balamuthia mandrillaris amoebic encephalitis: an emerging parasitic infection. Curr Infect Dis Rep. 2012;14(4):391-396. DOI: 10.1007/s11908-012-0266-4\u003c/li\u003e\n\u003cli\u003eKiderlen AF, Laube U, Radam E, Tata PS. Oral infection of immunocompetent and immunodeficient mice with Balamuthia mandrillaris amebae. Parasitol Res. 2007;100(4):775-782. DOI: 10.1007/s00436-006-0334-5\u003c/li\u003e\n\u003cli\u003eOrozco LD, Khan MA, Fratkin JD, Hanigan WC. Asymptomatic aneurysm of the cavernous and supraclinoid internal carotid artery in a patient with Balamuthia mandrillaris encephalitis. J Clin Neurosci. 2011;18(8):1118-1120. DOI: 10.1016/j.jocn.2010.11.033\u003c/li\u003e\n\u003cli\u003eCope JR, Landa J, Nethercut H, et al. The Epidemiology and Clinical Features of Balamuthia mandrillaris Disease in the United States, 1974-2016. Clin Infect Dis. 2019;68(11):1815-1822. DOI: 10.1093/cid/ciy813\u003c/li\u003e\n\u003cli\u003eDeetz TR, Sawyer MH, Billman G, Schuster FL, Visvesvara GS. Successful treatment of Balamuthia amoebic encephalitis: presentation of 2 cases. Clin Infect Dis. 2003;37(10):1304-1312. DOI: 10.1086/379020\u003c/li\u003e\n\u003cli\u003eJung S, Schelper RL, Visvesvara GS, Chang HT. Balamuthia mandrillaris meningoencephalitis in an immunocompetent patient: an unusual clinical course and a favorable outcome. Arch Pathol Lab Med. 2004;128(4):466-468. DOI: 10.5858/2004-128-466-BMMIAI\u003c/li\u003e\n\u003cli\u003eSchuster FL, Yagi S, Gavali S, et al. Under the radar: balamuthia amebic encephalitis. Clin Infect Dis. 2009;48(7):879-887. DOI: 10.1086/597260\u003c/li\u003e\n\u003cli\u003eCary LC, Maul E, Potter C, et al. Balamuthia mandrillaris meningoencephalitis: survival of a pediatric patient. Pediatrics. 2010;125(3):e699-703. DOI: 10.1542/peds\u003c/li\u003e\n\u003cli\u003eMart\u0026iacute;nez DY, Seas C, Bravo F, et al. Successful treatment of Balamuthia mandrillaris amoebic infection with extensive neurological and cutaneous involvement. Clin Infect Dis. 2010;51(2):e7-11. DOI: 10.1086/653609\u003c/li\u003e\n\u003cli\u003eDoyle JS, Campbell E, Fuller A, et al. Balamuthia mandrillaris brain abscess successfully treated with complete surgical excision and prolonged combination antimicrobial therapy. J Neurosurg. 2011;114(2):458-462. DOI: 10.3171/2010.10.JNS10677\u003c/li\u003e\n\u003cli\u003eMoriarty P, Burke C, McCrossin D, et al. Balamuthia mandrillaris Encephalitis: Survival of a Child With Severe Meningoencephalitis and Review of the Literature. J Pediatric Infect Dis Soc. 2014;3(1):e4-9. DOI: 10.1093/jpids/pit033\u003c/li\u003e\n\u003cli\u003eVollmer ME, Glaser C. A Balamuthia survivor. JMM Case Rep. 2016;3(3):e005031. DOI: 10.1099/jmmcr.0.005031\u003c/li\u003e\n\u003cli\u003eLehmer LM, Ulibarri GE, Ragsdale BD, Kunkle J. Cutaneous Balamuthia mandrillaris infection as a precursor to Balamuthia amoebic encephalitis (BAE) in a healthy 84-year-old Californian. Dermatol Online J. 2017;23(7):13030/qt8c8720qm.\u003c/li\u003e\n\u003cli\u003ePeng L, Zhou Q, Wu Y, et al. A patient with granulomatous amoebic encephalitis caused by Balamuthia mandrillaris survived with two excisions and medication. BMC Infect Dis. 2022;22(1):54. DOI: 10.1186/s12879-021-07020-8\u003c/li\u003e\n\u003cli\u003eCuoco JA, Klein BJ, LeBel DP, Faulhaber J, Apfel LS, Witcher MR. Successful Treatment of a Balamuthia mandrillaris Cerebral Abscess in a Pediatric Patient With Complete Surgical Resection and Antimicrobial Therapy. Pediatr Infect Dis J. 2022;41(2):e54-e57. DOI: 10.1097/INF.0000000000003418\u003c/li\u003e\n\u003cli\u003eSpottiswoode N, Pet D, Kim A, et al. Successful Treatment of Balamuthia mandrillaris Granulomatous Amebic Encephalitis with Nitroxoline. Emerg Infect Dis. 2023;29(1):197-201. DOI: 10.3201/eid2901.221531\u003c/li\u003e\n\u003cli\u003eQin B, Jia L, Chen J, Liu W. Balamuthia Amebic Encephalitis Cured and Discharged. J Craniofac Surg. 2024. DOI: 10.1097/SCS.0000000000010123\u003c/li\u003e\n\u003cli\u003eYi Z, Zhong J, Wu H, et al. Balamuthia mandrillaris encephalitis in a child: case report and literature review. Diagn Microbiol Infect Dis. 2021;100(4):115180. DOI: 10.1016/j.diagmicrobio.2020.115180\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Balamuthia mandrillaris amoebic encephalitis, skin lesion, hemorrhage, prognosis","lastPublishedDoi":"10.21203/rs.3.rs-7168786/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7168786/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction: \u003c/strong\u003eBalamuthia mandrillaris amoebic encephalitis is a rare granulomatous amoeba encephalitis caused by infection with Balamuthia mandrillaris with a fatality rate over 90%. This study characterizes the imaging manifestations of Balamuthia mandrillaris amoebic encephalitis, yields critical new insights into the intracranial dissemination mechanisms of Balamuthia mandrillaris.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation: \u003c/strong\u003eWe present two cases of Balamuthia mandrillaris amoebic encephalitis confirmed through Next-generation sequencing of cerebrospinal fluid and brain biopsy in our hospital, with different imaging manifestations and prognosis (One death). Meanwhile, we reviewed 16 surviving cases of Balamuthia mandrillarisamoebic encephalitis reported in literatures up to now.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eBased on 17 surviving patients imaging findings with clinical data and one death case we reported, we proposed that the key imaging features related to the prognosis of Balamuthia mandrillaris amebic encephalitis are hemorrhage within the lesion and centripetal spread through cortical and subcortical brain parenchyma into cerebrospinal fluid circulation along the meninges and ependyms. Ventriculoperitoneal shunt may be superior to ventricular drainage that could provide the patient with a chance of survival.\u003c/p\u003e","manuscriptTitle":"Imaging findings of Balamuthia mandrillaris amoebic encephalitis in 2 cases with different prognosis and literature review","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-31 16:21:29","doi":"10.21203/rs.3.rs-7168786/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-27T10:15:48+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-06T03:07:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"29286106938207550056095860612915084205","date":"2025-09-27T02:23:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-09T01:55:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"276839459045881586502685256587895502253","date":"2025-07-29T02:28:21+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-29T02:14:47+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-07-28T09:30:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-24T09:28:31+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-24T09:27:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Neurology","date":"2025-07-20T09:24:54+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e1900491-9c0d-42e7-b287-ba9bec8c2eb5","owner":[],"postedDate":"July 31st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-01T16:05:58+00:00","versionOfRecord":{"articleIdentity":"rs-7168786","link":"https://doi.org/10.1186/s12883-025-04544-3","journal":{"identity":"bmc-neurology","isVorOnly":false,"title":"BMC Neurology"},"publishedOn":"2025-11-27 15:57:35","publishedOnDateReadable":"November 27th, 2025"},"versionCreatedAt":"2025-07-31 16:21:29","video":"","vorDoi":"10.1186/s12883-025-04544-3","vorDoiUrl":"https://doi.org/10.1186/s12883-025-04544-3","workflowStages":[]},"version":"v1","identity":"rs-7168786","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7168786","identity":"rs-7168786","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}