Clinical and neuroimaging characteristics in mild-type infantile acute subdural hematoma: a report of four cases

Clinical and neuroimaging characteristics in mild-type infantile acute subdural hematoma: a report of four cases | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Clinical and neuroimaging characteristics in mild-type infantile acute subdural hematoma: a report of four cases Nobuhiko Aoki This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2733567/v2 This work is licensed under a CC BY 4.0 License Status: Posted Version 2 posted You are reading this latest preprint version Show more versions Abstract Purpose Infantile acute subdural hematoma (IASDH) has a limited age distribution and mostly benign clinical features. Mild-type IASDH has a stereotypical clinical course that, however, has been described in only a few studies. Methods Four male infants (aged 6–10 months; mean age: 7.5 months) were diagnosed with mild-type IASDH associated with retinal hemorrhage (RH) after suffering from occipital impact in a fall. The present case series reviews their clinical features and neuroimaging findings, including CT and MRI findings. Results All infants fell backwards from a standing or sitting position onto a soft surface, striking the occipital region. They began crying on impact and then soon afterwards exhibited seizure-like activity or recurrent vomiting. CT and MRI revealed a thin, unclotted subdural hematoma (SDH) without mass effect or brain parenchymal abnormality. Various degrees of bilateral retinal hemorrhage (RH) were observed. On the day of symptom onset, all infants returned to baseline, and follow-up for more than 5 years revealed normal development with no deficits. Conclusions Mild-type IASDH with retinal hemorrhage presents with seizure-like activity or recurrent vomiting preceded by crying after an occipital impact on a soft surface. The clinical course of IASDH is followed by rapid recovery on the day of symptom onset. CT and MRI findings reveal a small, unclotted subdural hematoma (SDH) without a mass effect or cerebral parenchymal abnormality. Abusive head trauma Infantile acute subdural hematoma Mild type Retinal hemorrhage Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Infantile acute subdural hematoma (IASDH) has been reported since the 1960s in Japan [4]. However, because most cases were published in Japanese-language journals, coupled with the frequent criticism that the diagnosis was being used to conceal cases of child abuse, the concept of IASDH is not widely accepted in the English-speaking world [8]. Recent Japanese reports demonstrate that patients suffering from IASDH, particularly the mild form, can be distinguished from those with abusive head trauma (AHT) through multidisciplinary assessment, including evaluation by a child abuse pediatrician [1, 9]. Mild-type IASDH is the most common form, constituting more than half of IASDH cases, and is recognized as a benign clinical entity in Japan. No previous studies have examined the neuroimaging features characteristic of mild-type IASDH. The present study therefore aimed to clarify the characteristics of IASDHs, particularly the mild type, to address this omission. Materials & Methods Between 2013 and 2022, 38 patients under the age of 2 years were referred to the Department of Neurosurgery at Bethlehem Garden Hospital with symptoms attributable to an acute subdural hematoma (SDH). The full clinical data on the patients, their CT (in some cases also MRI) findings, and interview records were analyzed. Fifteen of the patients received the diagnosis of IASDH, which was originally defined as an acute subdural hematoma in infants caused by minor head trauma without loss of consciousness or any associated cerebral contusion [2]. Patients thought to have AHT based on an evaluation by a multidisciplinary team, including a child abuse pediatrician, were excluded. Mild-type IASDH was diagnosed in eight of the 15 infants based on their normal consciousness status, absence of motor disturbances, and the presence of vomiting and/or irritability on admission [2]. After excluding four patients who were not evaluated by MRI, the remaining four patients with long-term follow-up (> 5 years) were analyzed. Table 1 shows the details of their history. Case 1 An 8-month-old male patient with no significant medical history fell backward while trying to stand and struck his occipital area against a carpeted floor. The infant immediately began crying. While holding him in her arms, his mother noted signs of altered consciousness, seizure-like activities, including an upward gaze, and tremor of the left arm followed by generalized tonic convulsion. The infant was taken to a nearby emergency room. When the physician began to examine the patient, he cried again and displayed purposeful movement in all his extremities. A standard, general physical examination revealed no abnormalities. Although the patient returned to baseline on the same day, emergency CT revealed SDH on the left side (Fig. 1), prompting an ophthalmological examination, which found bilateral multiple, multilayered retinal hemorrhages (RH). The infant was admitted for further observation and underwent MRI on hospital day 12, which revealed a thin, film-like, high-intensity SDH on the left cerebral convexity. (Fig. 1) No mass effect or parenchymal abnormality was observed. At his ten-year follow-up examination, the patient had normal development with no deficits. Case 2 A 10-month-old male infant who began walking fell and struck his occipital region on a floor covered by a 15 mm-thick carpet while trying to steady himself by grabbing a table leg. The scene was witnessed by his mother and grandparents who were sitting in front of the patient at the time. The infant immediately began crying. While his mother held him in her arms to comfort him, he lost consciousness and exhibited seizure-like activity, including an upward gaze and tremor of the left upper extremities followed by a generalized tonic seizure. He was taken to an emergency room where he seemed alert and noted to return to baseline. Although no neurological abnormalities or external signs of trauma were observed, CT revealed a thin SDH with mixed density on the right side. Fundoscopy on the same day found bilateral multiple, multilayered RH. The infant was admitted for further observation for ten days without presenting any neurological abnormalities. MRI on day 3 revealed an SDH on the left side and a posterior interhemispheric fissure. No mass effect or parenchymal abnormality was noted. (Fig. 3) During the observation at the hospital, the infant was asymptomatic. The subsequent outpatient follow-up for 9 years showed normal development. Case 3 A 7-month-old male infant with no significant medical history fell backwards from a seated position and struck his occipital region on a cushion mattress. The event was witnessed by his parents, who happened to be in front of the patient. The infant began crying immediately upon striking his head. His father held him in his arms and noted altered consciousness, upward deviation of both eyes, cyanosis and flaccidity of the body. The infant was taken by ambulance to the emergency department. Enroute to the hospital, he regained consciousness and returned to baseline. In the emergency room, a pediatrician identified a thin SDH with a maximum thickness of 2 mm on CT (Fig. 4) and decided to admit the patient for continued observation. No neurological abnormalities or external signs of trauma were noted. Two days after admission, fundoscopy revealed multiple multilayered RH on both sides. A full skeletal survey, including a 3-D cervical spinal CT, revealed no abnormalities. MRI performed 19 days after symptom onset revealed a thin, film-like, high-intensity SDH on the right side. No mass effect or parenchymal abnormality was observed. His clinical course was unremarkable, and the patient showed normal development at regular follow-up visits over six years. Case 4 A 6-month-old male infant with no significant medical history fell backward while trying to stand up in the living room and hit the occipital region on a carpeted floor. The infant began crying on impact and soon thereafter had vomiting incessantly. After signs of irritability appeared, the infant was taken to a nearby hospital where a physical examination failed to find any abnormalities. However, the physician referred the infant to a pediatric hospital where CT was performed at the mother’s request, and an acute, low-density SDH on the left side was disclosed. (Fig. ５) Although no neurological abnormalities or external signs of trauma were noted, the infant was admitted for continued observation. On the day of admission, vomiting and irritability subsided, and the subsequent clinical course was uneventful. Two days after admission, fundoscopy revealed multiple, multilayered RH on both sides. MRI performed 11 days after symptom onset revealed a thin, high-intensity SDH on the right side. No mass effect or parenchymal abnormality was noted. (Fig. ５) The patient achieved normal developmental milestones over 5 years of regular follow-up visits. Discussion IASDH has a limited age distribution, occurring chiefly between 6 months and 10 months of age, when infants normally begin sitting or standing [1, 9]. As in previous Japanese cases, all the infants in the present report immediately began crying upon striking their head, indicating the presence of a lucid interval. Most patients with IASDH present a benign clinical course. Infants with mild-type IASDH typically return to baseline on the day of arrival at the emergency room, and follow-up visits demonstrate normal development. These clinical features of IASDH do not coincide with those of AHT, which has its peak incidence at ages 2 to 4 months and a generally poor prognosis [5, 7, 10]. Neuroimaging findings of mild-type IASDH include a thin SDH with heterogeneous density, indicating the presence of a small, unclotted hematoma mixed with cerebrospinal fluid overlying a large surface area of the cerebral convexity. MRI is useful for confirming the absence of cerebral edema and primary brain injury. However, infants with mild-type IASDH are not always evaluated by MRI. Since the patients become alert and asymptomatic on admission, their parents are reluctant to ask for MRI, which requires sedation. No surgical intervention or autopsy studies have been performed in infants with mild-type IASDH, so the mechanism of injury involved in this condition is a matter of speculation. Zouros et al. proposed that during infancy, tearing of the loosely adherent arachnoid envelope at the main arachnoid granulation site along the superior sagittal sinus may result in a considerable amount of CSF mixing with acute blood in the subdural space [11]. In the present series, the CT and MRI findings demonstrating thin, unclotted, widely diffused SDH in the cerebral convexity may be explained by cleavages in the dural border cell layer [6]. In this context, a traumatic rupture in the arachnoid granulation connecting columns of arachnoid cells to the venous sinuses might explain the mechanism inducing mild-type IASDH. Tearing of the bridging veins, which commonly causes symptomatic SDH with mass effect, could be followed by progressive hemorrhage through the cleavages in the dural border cell layer. The clinical severity of IASDH depends on the volume of the subdural hematoma; thus, surgery is not indicated for mild-type IASDH. However, as seen in cases 2 and 4 in the present series, tiny or low-density SDH on CT might be overlooked, potentially resulting in the development of subacute or chronic SDH [3]. Conclusions Infants with mild-type IASDH present with crying followed by seizure-like activity or vomiting/irritability after striking the occipital region on a soft surface. On arrival at the emergency room, they are asymptomatic, presenting only retinal hemorrhage. CT and MRI findings are characterized by the presence of a thin, unclotted SDH without a mass effect or any cerebral parenchymal abnormality. CT findings may be overlooked if the physician is not aware of the possibility of the unique association of this type of SDH. The basic differences in SDH with RH associated with AHT in the English-speaking world and with IASDH in Japan may reside in the absence or presence of a primary cerebral parenchymal injury. Further studies are needed to elucidate the mechanism and predisposition of infants with IASDH. The present study has several limitations. The population of Japan is racially homogeneous. In the present series, the patients were all Japanese infants who were referred to the study center for a second opinion. The small number of cases were all mild-type IASDH only, thus potentially introducing a selection bias. Declarations Author contribution: Nobuhiko Aoki (corresponding author with no coauthors) conceived the idea of the study, conducted the literature search, and drafted the original manuscript. The author reviewed the manuscript draft and revised it critically on intellectual content and approved the final version of the manuscript to be published. Availability of data and material: This article does not include any data or material to be provided. Ethics approval and consent to participate: This article was approved by the Ethics Committee of Bethlehem Garden Hospital and Tokyo Metropolitan Tama Medical Center. No funding was obtained for this study. Consent of publication: The author gives my consent for the publication of identifiable details, which can include photographs and/or case history and/or details within the text to be published in this journal. Conflict of interest: None Additional Declarations Ethics approval and consent to participate: This article was approved by the Ethics committee in Bethlehem Garden Hospital and Tokyo Metropolitan Tama Medical Center. No funding was obtained for this study. The author provides a statement indicating that the parents/legal guardians provided consent to publish identifiable details and case histories of infant patients described in this case series. References 1. Akutsu N, Nonaka M, Narisawa A, Kato M, Harada A、Park YS（2022） Infantile subdural hematoma in Japan: a multicenter, retrospective study by the J-HITs (Japanese head injury of infants and toddlers study) group. PLoS ONE 25 (17): e0264396 2. Aoki N, Masuzawa H (1984) Infantile acute subdural hematoma. Clinical analysis of 26 cases. J Neurosurg 61: 273-280 3. Aoki N (1990) Chronic subdural hematoma in infancy. Clinical analysis of 30 cases in the CT era. J Neurosurg 73:201-205 4. Aoki N (2011) Infantile acute subdural hematoma: Caused by abuse or mild head trauma? Nervous System in Children 36 : 326-330. (Japanese) 5. Keenan HT, Runyan DK, Marshall SW, Nocera MA, Merten DF, Sinai SHA ( 2003) A population-based study of inflicted traumatic brain injury in young children. JAMA 290:621-26 6. Mack J, Squier W, Eastman JT (2009) Anatomy and development of the meninges: implications for subdural collections and CSF circulation. Pediatr Radiol 391 : 200-210 7. Nuno M、Pelissier L, Varshneya K, Adamo MA、Drazin D （2015） Outcomes and factors associated with infant abusive head trauma in the US. J Neurosurg Pediatr. 16:515-22 8. Rekate HL (1985) Subdural hematomas in infants. J Neurosurg 61: 316-317 9. Shimoji K, Suehiro E, Matsuno A, Araki T（2022）: Abusive head trauma in Japan. Childs Nerv Syst Oct4.https://doi.org/10.1007/s00381-022-05692-4 10. Thompson LW, Bass KD, Agvei JO, Borngraber E, Naseem HUR, Wang J, Reynolds RM（2019） Incidence of nonaccidental head trauma in infants: a call to revisit prevention strategies. J Neurosurg Pediatr 20 : 1-8, 2019 11. Zouros A, Bhargava R, Hoskinson M, et al （2004 ） Further characterization of traumatic subdural collections of infancy. Report of five cases. J Neurosurg Pediatr 100 :512-518 Tables Table1. Clinical and neuroimaging summary of four cases with mild-type IASDH Case No Age (mos), Sex Presenting history Site of impact/ Surface Presenting sign & symptom Opthalmological examination CT findings on admission MRI findings (days after onset) Management Outcome Follow up (Yrs) 1 8 M Fall while trying to stand Occiput/ carpeted floor Generalized tonic convulsion Bilateral multilayered retinal hemorrhage Thin SDH mixed density T1 12days thin film-like high-intensity SDH observation Normal development 10 2 10 M Fall while standing Occiput/ Carpeted floor Generalized tonic convulsion Bilateral multilayered retinal hemorrhage Thin SDH mixed density with sediment formation FLAIR 3days thin film-like high-intensity SDH observation Normal development 9 3 7 M Fall from sitting position Occiput/ cushion mattress Flaccid posture, Floppy Bilateral multilayered retinal hemorrhage Thin SDH high &iso- density FLAIR 19 days thin film-like high-intensity SDH observation Normal development 6 4 6 M Fall after trying to stand Occiput/ carpeted floor Recurrent vomiting & irritability Bilateral multilayered retinal hemorrhage Thin SDH low density T1 11 days thin, irregular shaped high-intensity SDH observation Normal development 5 Additional Declarations Ethics approval and consent to participate: This article was approved by the Ethics committee in Bethlehem Garden Hospital and Tokyo Metropolitan Tama Medical Center. No funding was obtained for this study. The author provides a statement indicating that the parents/legal guardians provided consent to publish identifiable details and case histories of infant patients described in this case series. Cite Share Download PDF Status: Posted Version 2 posted You are reading this latest preprint version Show more versions 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-2733567","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":188154214,"identity":"1da41d46-3ed9-4b97-bb61-b5f5902ef4ba","order_by":0,"name":"Nobuhiko Aoki","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAklEQVRIiWNgGAWjYFACHhCRwMPP3tj+4wOQBRVmI6xFsudwg+QMUrQwGMxIb5DmQWjBDczZe49J/KhIkzFgSGwwtm2zy+Nnb2D88IGBLw+XFsuec2mSPWdyeMwZDjYk57YlF0v2HGAGupCtGJcWgxs5ZhK8bRU8lo2NDYdz25gTN9xIYGPmYWBLbMCjRfIvUIvBYcbGZsu2euK0SPO25fAYHGNsZmZsO0yEljPnkq1lzqQBA5mxjbHn3PHEmT0HmyVnGODxy/HegzffVCTb88s/f8bwo6w6sZ+9+eCHDxXHcIYYKmAERyAj0EkGxxKI08LwB86qIVbLKBgFo2AUDH8AAEWnV8OaiI0UAAAAAElFTkSuQmCC","orcid":"","institution":"1)\tDepartment of Neurosurgery, Bethlehem Garden Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Nobuhiko","middleName":"","lastName":"Aoki","suffix":""}],"badges":[],"createdAt":"2023-03-24 20:07:55","currentVersionCode":2,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":true,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":true,"humanSubjectCaseReport":true,"vertebrateSubjectEthicalGuidelines":false,"coiExplicitlySet":false},"doi":"10.21203/rs.3.rs-2733567/v2","doiUrl":"https://doi.org/10.21203/rs.3.rs-2733567/v2","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":35218789,"identity":"ba5ae89b-a9c6-41e1-a3a3-990b25c7f42b","added_by":"auto","created_at":"2023-04-03 17:35:07","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":187654,"visible":true,"origin":"","legend":"\u003cp\u003eCase 1, male aged 8 months\u003c/p\u003e\n\u003cp\u003eLeft: CT on arrival showing thin, irregularly shaped SDH, indicating an unclotted SDH on the left side. (arrow)\u003c/p\u003e\n\u003cp\u003eRight: MRI (FLAIR) 12 days after symptom onset demonstrating a thin, film-like, high-intensity SDH on the left convexity. (arrow) No mass effect or parenchymal abnormality was observed on the other sequences. (not shown)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-2733567/v2/541908f6c900fa13c1ca0f3e.png"},{"id":35218792,"identity":"0aa75d44-8851-4e0e-8bd8-c04420cbca35","added_by":"auto","created_at":"2023-04-03 17:35:08","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":510742,"visible":true,"origin":"","legend":"\u003cp\u003eCase 1, Fundoscopy on arrival demonstrating multiple, bilateral, multilayered retinal hemorrhages.\u003cbr\u003e\n \u0026nbsp;Left: Right eye \u0026nbsp;Right: Left eye\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-2733567/v2/68f29baac23b74f15b858333.png"},{"id":35218791,"identity":"26d5c3e9-49b9-4fe0-bf03-168cfafba9b2","added_by":"auto","created_at":"2023-04-03 17:35:08","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":365694,"visible":true,"origin":"","legend":"\u003cp\u003eCase 2, male aged 10 months\u003c/p\u003e\n\u003cp\u003eLeft: CT on arrival demonstrating a thin SDH with heterogeneous density on the right side. (arrow)\u003c/p\u003e\n\u003cp\u003eNote the low-density sediment formation in the upper part and high- density sediment formation in the lower part.\u003c/p\u003e\n\u003cp\u003eRight: MRI (FLAIR) 3 days after symptom onset demonstrating a thin, film-like, high-intensity SDH on the right side. (arrow)\u003c/p\u003e\n\u003cp\u003eNo mass effect or parenchymal abnormality was observed on the other sequences. (not shown)\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-2733567/v2/fd1d136d4d89b6e80090a6cd.png"},{"id":35218793,"identity":"0cfd5a61-aee7-4d4f-b34b-690e38914d5c","added_by":"auto","created_at":"2023-04-03 17:35:08","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":207324,"visible":true,"origin":"","legend":"\u003cp\u003eCase 3, male aged 7 months\u003c/p\u003e\n\u003cp\u003eLeft: CT on arrival demonstrating tiny, high- and iso-dense SDH on the right cerebral convexity. (arrow) Note the bilateral enlargement of the lateral ventricles and subarachnoid spaces.\u003c/p\u003e\n\u003cp\u003eRight: MRI (FLAIR) 19 days after symptom onset demonstrating thin, film-like, high-intensity SDH on the right side. (arrow) No mass effect or parenchymal abnormality was observed on the other sequences. (not shown)\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-2733567/v2/e4cffc8363a468747d3900d8.png"},{"id":35218931,"identity":"f6b60aaa-b4ea-4634-9deb-cc0f80ebc05f","added_by":"auto","created_at":"2023-04-03 17:43:07","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":179426,"visible":true,"origin":"","legend":"\u003cp\u003eCase 4, male aged 6 months\u003c/p\u003e\n\u003cp\u003eLeft: CT on arrival demonstrating thin, low-density SDH on the right side. (arrow)\u003c/p\u003e\n\u003cp\u003eNote that the density of the SDH is higher than that of the cerebrospinal fluid in the lateral ventricles and subarachnoid spaces on the left side.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-2733567/v2/7d982f52150623edb1ff7525.png"},{"id":35218932,"identity":"1232eb68-f2a6-4b42-a208-ccbea6812a1f","added_by":"auto","created_at":"2023-04-03 17:43:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1604837,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2733567/v2/2a2db9c4-f82d-4209-88a5-6b7895dc368a.pdf"}],"financialInterests":"\u003cp\u003eEthics approval and consent to participate: This article was approved by the Ethics committee in Bethlehem Garden Hospital and Tokyo Metropolitan Tama Medical Center. No funding was obtained for this study. The author provides a statement indicating that the parents/legal guardians provided consent to publish identifiable details and case histories of infant patients described in this case series.\u003c/p\u003e","formattedTitle":"\u003cp\u003e\u003cstrong\u003eClinical and neuroimaging characteristics in mild-type infantile acute subdural hematoma: a report of four cases\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eInfantile acute subdural hematoma (IASDH) has been reported since the 1960s in Japan [4]. However, because most cases were published in Japanese-language journals, coupled with the frequent criticism that the diagnosis was being used to conceal cases of child abuse, the concept of IASDH is not widely accepted in the English-speaking world [8].\u003c/p\u003e\n\u003cp\u003eRecent Japanese reports demonstrate that patients suffering from IASDH, particularly the mild form, can be distinguished from those with abusive head trauma (AHT) through multidisciplinary assessment, including evaluation by a child abuse pediatrician [1,\u0026nbsp;9].\u003c/p\u003e\n\u003cp\u003eMild-type IASDH is the most common form, constituting more than half of IASDH cases, and is recognized as a benign clinical entity in Japan. No previous studies have examined the neuroimaging features characteristic of mild-type IASDH. The present study therefore aimed to clarify the characteristics of IASDHs, particularly the mild type, to address this omission.\u003c/p\u003e"},{"header":"Materials \u0026 Methods","content":"\u003cp\u003eBetween 2013 and 2022, 38 patients under the age of 2 years were referred to the Department of Neurosurgery at Bethlehem Garden Hospital with symptoms attributable to an acute subdural hematoma (SDH). The full clinical data on the patients, their CT (in some cases also MRI) findings, and interview records were analyzed. Fifteen of the patients received the diagnosis of IASDH, which was originally defined as an acute subdural hematoma in infants caused by minor head trauma without loss of consciousness or any associated cerebral contusion [2]. Patients thought to have AHT based on an evaluation by a multidisciplinary team, including a child abuse pediatrician, were excluded. Mild-type IASDH was diagnosed in eight of the 15 infants based on their normal consciousness status, absence of motor disturbances, and the presence of vomiting and/or irritability on admission [2]. After excluding four patients who were not evaluated by MRI, the remaining four patients with long-term follow-up (\u0026gt;\u0026thinsp;5 years) were analyzed. Table\u0026nbsp;1 shows the details of their history.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase 1\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAn 8-month-old male patient with no significant medical history fell backward while trying to stand and struck his occipital area against a carpeted floor. The infant immediately began crying. While holding him in her arms, his mother noted signs of altered consciousness, seizure-like activities, including an upward gaze, and tremor of the left arm followed by generalized tonic convulsion. The infant was taken to a nearby emergency room.\u003c/p\u003e\n\u003cp\u003eWhen the physician began to examine the patient, he cried again and displayed purposeful movement in all his extremities. A standard, general physical examination revealed no abnormalities. Although the patient returned to baseline on the same day, emergency CT revealed SDH on the left side (Fig.\u0026nbsp;1), prompting an ophthalmological examination, which found bilateral multiple, multilayered retinal hemorrhages (RH). The infant was admitted for further observation and underwent MRI on hospital day 12, which revealed a thin, film-like, high-intensity SDH on the left cerebral convexity. (Fig.\u0026nbsp;1)\u003c/p\u003e\n\u003cp\u003eNo mass effect or parenchymal abnormality was observed. At his ten-year follow-up examination, the patient had normal development with no deficits.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase 2\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 10-month-old male infant who began walking fell and struck his occipital region on a floor covered by a 15 mm-thick carpet while trying to steady himself by grabbing a table leg. The scene was witnessed by his mother and grandparents who were sitting in front of the patient at the time. The infant immediately began crying. While his mother held him in her arms to comfort him, he lost consciousness and exhibited seizure-like activity, including an upward gaze and tremor of the left upper extremities followed by a generalized tonic seizure. He was taken to an emergency room where he seemed alert and noted to return to baseline. Although no neurological abnormalities or external signs of trauma were observed, CT revealed a thin SDH with mixed density on the right side. Fundoscopy on the same day found bilateral multiple, multilayered RH. The infant was admitted for further observation for ten days without presenting any neurological abnormalities. MRI on day 3 revealed an SDH on the left side and a posterior interhemispheric fissure. No mass effect or parenchymal abnormality was noted. (Fig.\u0026nbsp;3)\u003c/p\u003e\n\u003cp\u003eDuring the observation at the hospital, the infant was asymptomatic. The subsequent outpatient follow-up for 9 years showed normal development.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase 3\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 7-month-old male infant with no significant medical history fell backwards from a seated position and struck his occipital region on a cushion mattress. The event was witnessed by his parents, who happened to be in front of the patient. The infant began crying immediately upon striking his head. His father held him in his arms and noted altered consciousness, upward deviation of both eyes, cyanosis and flaccidity of the body. The infant was taken by ambulance to the emergency department. Enroute to the hospital, he regained consciousness and returned to baseline. In the emergency room, a pediatrician identified a thin SDH with a maximum thickness of 2 mm on CT (Fig.\u0026nbsp;4) and decided to admit the patient for continued observation. No neurological abnormalities or external signs of trauma were noted. Two days after admission, fundoscopy revealed multiple multilayered RH on both sides. A full skeletal survey, including a 3-D cervical spinal CT, revealed no abnormalities. MRI performed 19 days after symptom onset revealed a thin, film-like, high-intensity SDH on the right side. No mass effect or parenchymal abnormality was observed. His clinical course was unremarkable, and the patient showed normal development at regular follow-up visits over six years.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase 4\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 6-month-old male infant with no significant medical history fell backward while trying to stand up in the living room and hit the occipital region on a carpeted floor. The infant began crying on impact and soon thereafter had vomiting incessantly. After signs of irritability appeared, the infant was taken to a nearby hospital where a physical examination failed to find any abnormalities. However, the physician referred the infant to a pediatric hospital where CT was performed at the mother\u0026rsquo;s request, and an acute, low-density SDH on the left side was disclosed.\u0026nbsp;(Fig.\u0026nbsp;５) Although no neurological abnormalities or external signs of trauma were noted, the infant was admitted for continued observation.\u003c/p\u003e\n\u003cp\u003eOn the day of admission, vomiting and irritability subsided, and the subsequent clinical course was uneventful. Two days after admission, fundoscopy revealed multiple, multilayered RH on both sides. MRI performed 11 days after symptom onset revealed a thin, high-intensity SDH on the right side. No mass effect or parenchymal abnormality was noted.\u0026nbsp;(Fig.\u0026nbsp;５)\u003c/p\u003e\n\u003cp\u003eThe patient achieved normal developmental milestones over 5 years of regular follow-up visits.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIASDH has a limited age distribution, occurring chiefly between 6 months and 10 months of age, when infants normally begin sitting or standing [1,\u0026nbsp;9]. As in previous Japanese cases, all the infants in the present report immediately began crying upon striking their head, indicating the presence of a lucid interval. Most patients with IASDH present a benign clinical course. Infants with mild-type IASDH typically return to baseline on the day of arrival at the emergency room, and follow-up visits demonstrate normal development. These clinical features of IASDH do not coincide with those of AHT, which has its peak incidence at ages 2 to 4 months and a generally poor prognosis [5,\u0026nbsp;7,\u0026nbsp;10].\u003c/p\u003e\n\u003cp\u003eNeuroimaging findings of mild-type IASDH include a thin SDH with heterogeneous density, indicating the presence of a small, unclotted hematoma mixed with cerebrospinal fluid overlying a large surface area of the cerebral convexity. MRI is useful for confirming the absence of cerebral edema and primary brain injury. However, infants with mild-type IASDH are not always evaluated by MRI. Since the patients become alert and asymptomatic on admission, their parents are reluctant to ask for MRI, which requires sedation.\u003c/p\u003e\n\u003cp\u003eNo surgical intervention or autopsy studies have been performed in infants with mild-type IASDH, so the mechanism of injury involved in this condition is a matter of speculation.\u003c/p\u003e\n\u003cp\u003eZouros et al. proposed that during infancy, tearing of the loosely adherent arachnoid envelope at the main arachnoid granulation site along the superior sagittal sinus may result in a considerable amount of CSF mixing with acute blood in the subdural space [11]. In the present series, the CT and MRI findings demonstrating thin, unclotted, widely diffused SDH in the cerebral convexity may be explained by cleavages in the dural border cell layer [6]. In this context, a traumatic rupture in the arachnoid granulation connecting columns of arachnoid cells to the venous sinuses might explain the mechanism inducing mild-type IASDH. Tearing of the bridging veins, which commonly causes symptomatic SDH with mass effect, could be followed by progressive hemorrhage through the cleavages in the dural border cell layer.\u003c/p\u003e\n\u003cp\u003eThe clinical severity of IASDH depends on the volume of the subdural hematoma; thus, surgery is not indicated for mild-type IASDH. However, as seen in cases 2 and 4 in the present series, tiny or low-density SDH on CT might be overlooked, potentially resulting in the development of subacute or chronic SDH [3].\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eInfants with mild-type IASDH present with crying followed by seizure-like activity or vomiting/irritability after striking the occipital region on a soft surface. On arrival at the emergency room, they are asymptomatic, presenting only retinal hemorrhage. CT and MRI findings are characterized by the presence of a thin, unclotted SDH without a mass effect or any cerebral parenchymal abnormality. CT findings may be overlooked if the physician is not aware of the possibility of the unique association of this type of SDH.\u003c/p\u003e\n\u003cp\u003eThe basic differences in SDH with RH associated with AHT in the English-speaking world and with IASDH in Japan may reside in the absence or presence of a primary cerebral parenchymal injury. Further studies are needed to elucidate the mechanism and predisposition of infants with IASDH.\u003c/p\u003e\n\u003cp\u003eThe present study has several limitations. The population of Japan is racially homogeneous. In the present series, the patients were all Japanese infants who were referred to the study center for a second opinion. The small number of cases were all mild-type IASDH only, thus potentially introducing a selection bias.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contribution:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNobuhiko Aoki (corresponding author with no coauthors) conceived the idea of the study,\u0026nbsp;conducted\u0026nbsp;the\u0026nbsp;literature search, and drafted the original manuscript.\u003c/p\u003e\n\u003cp\u003eThe author reviewed the manuscript draft and revised it critically on intellectual content and approved the final version of the manuscript to be published.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis article does not include any data or material to be provided.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;This article was approved by\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003ethe\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eEthics\u0026nbsp;Committee of\u0026nbsp;Bethlehem Garden Hospital and Tokyo Metropolitan Tama Medical Center.\u003c/p\u003e\n\u003cp\u003eNo funding was obtained for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent of publication:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe author gives my consent for the publication of identifiable details, which can include photographs and/or case history and/or details within the text\u0026nbsp;to be published in this journal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest:\u003c/strong\u003e None\u003cstrong\u003e\u0026nbsp;\u003cbr\u003e\u0026nbsp;Additional Declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate: This article was approved by the Ethics committee in Bethlehem Garden Hospital and Tokyo Metropolitan Tama Medical Center. No funding was obtained for this study. The author provides a statement indicating that the parents/legal guardians provided consent to publish identifiable details and case histories of infant patients described in this case series.\u003c/p\u003e"},{"header":"References","content":"\u003cp\u003e1. Akutsu N, Nonaka M, Narisawa A, Kato M, Harada A、Park YS（2022） Infantile subdural hematoma in Japan: a multicenter, retrospective \u0026nbsp;study by the J-HITs (Japanese head \u0026nbsp;injury of infants and toddlers study) group. PLoS ONE 25 (17): e0264396\u003c/p\u003e\n\u003cp\u003e2. Aoki N, Masuzawa H\u0026nbsp;(1984) Infantile acute subdural hematoma.\u0026nbsp;Clinical analysis of 26 cases.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eJ Neurosurg 61: 273-280\u003c/p\u003e\n\u003cp\u003e3. Aoki N (1990) Chronic subdural hematoma in infancy. Clinical analysis of 30 cases in the CT era. J Neurosurg 73:201-205\u003c/p\u003e\n\u003cp\u003e4. Aoki N (2011) Infantile acute subdural hematoma: Caused by abuse or mild head trauma? Nervous System in Children 36\u003cstrong\u003e:\u003c/strong\u003e326-330. (Japanese)\u003c/p\u003e\n\u003cp\u003e5. Keenan HT, Runyan DK, Marshall SW,\u0026nbsp;Nocera MA, Merten DF, Sinai SHA\u0026nbsp;( 2003) A population-based study of inflicted traumatic brain injury in young children. JAMA\u0026nbsp;290:621-26\u003c/p\u003e\n\u003cp\u003e6. Mack J, Squier W, Eastman JT (2009) Anatomy and development of the meninges: implications for subdural collections and CSF circulation. Pediatr Radiol 391\u003cstrong\u003e\u0026nbsp;:\u003c/strong\u003e200-210\u003c/p\u003e\n\u003cp\u003e7. Nuno M、Pelissier L, Varshneya K, Adamo MA、Drazin D （2015） Outcomes and factors associated with infant abusive head trauma in the US. J Neurosurg Pediatr. 16:515-22\u003c/p\u003e\n\u003cp\u003e8. Rekate HL (1985) Subdural hematomas in infants. J Neurosurg 61: 316-317\u003c/p\u003e\n\u003cp\u003e9. Shimoji K, Suehiro E, \u0026nbsp;Matsuno A, Araki T（2022）: Abusive head trauma in Japan. Childs Nerv Syst\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eOct4.https://doi.org/10.1007/s00381-022-05692-4\u003c/p\u003e\n\u003cp\u003e10. Thompson LW, \u0026nbsp;Bass KD, Agvei JO,\u003csup\u003e\u0026nbsp;\u003c/sup\u003eBorngraber E, Naseem HUR, Wang J, Reynolds RM（2019） Incidence of nonaccidental head trauma in infants: \u0026nbsp;a call to revisit prevention strategies. J Neurosurg Pediatr 20 \u003cstrong\u003e:\u003c/strong\u003e1-8,\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e2019\u003c/p\u003e\n\u003cp\u003e11. Zouros A, Bhargava R, Hoskinson M, et al （2004\u003cstrong\u003e）\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u0026nbsp;\u003c/strong\u003eFurther characterization of traumatic subdural collections of infancy. Report of five cases. J Neurosurg Pediatr 100\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e:512-518\u003c/p\u003e"},{"header":"Tables","content":"\u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-size:21px;font-family:\"Times New Roman\",serif;color:black;'\u003eTable1. \u0026nbsp;Clinical and neuroimaging summary of four cases with\u003c/span\u003e\u003c/strong\u003e\u003cspan style='font-size:21px;font-family:\"Century\",serif;color:black;'\u003e\u0026nbsp;\u003cstrong\u003emild-type\u003c/strong\u003e\u003c/span\u003e\u003cstrong\u003e\u003cspan style='font-size:21px;font-family:\"Times New Roman\",serif;color:black;'\u003e\u0026nbsp;IASDH\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003ctable style=\"width: 7.1e+2pt;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 35.45pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eCase\u003c/span\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cspan style='font-family:\"MS PGothic\",sans-serif;color:black;'\u003e \u003c/span\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eNo\u003c/span\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cspan style='font-family:\"MS PGothic\",sans-serif;color:black;'\u003e \u003c/span\u003e\u003c/strong\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.55pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eAge\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e(mos),\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eSex\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ePresenting\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ehistory\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.7pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eSite of impact/\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eSurface\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ePresenting sign \u0026amp; symptom\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eOpthalmological\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eexamination\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77.95pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eCT findings\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eon admission\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eMRI findings\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e(days after onset)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eManagement\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eOutcome\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.5pt;border-color: windowtext currentcolor;border-style: solid none;border-width: 1.5pt medium;padding: 0in 5.4pt;height: 47pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFollow up\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cstrong\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e(Yrs)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 35.45pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e1\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.55pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e8\u003c/span\u003e\u003cspan style='font-family:\"MS PGothic\",sans-serif;color:black;'\u003e \u003c/span\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eM\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFall while trying \u0026nbsp;to stand\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.7pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eOcciput/\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ecarpeted floor\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eGeneralized\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003etonic convulsion\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eBilateral\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003emultilayered\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eretinal \u0026nbsp;hemorrhage\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77.95pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eThin SDH\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003emixed density\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eT1 \u0026nbsp;12days\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ethin film-like high-intensity \u0026nbsp;SDH\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eobservation\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eNormal\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003edevelopment\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.5pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e10\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 35.45pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e2\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.55pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e10 M\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFall while standing\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.7pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eOcciput/\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eCarpeted\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003efloor\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eGeneralized\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003etonic convulsion\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eBilateral\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003emultilayered\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eretinal \u0026nbsp;hemorrhage\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77.95pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eThin SDH\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003emixed density with\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003esediment formation\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFLAIR \u0026nbsp;3days\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ethin film-like high-intensity SDH\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eobservation\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eNormal\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003edevelopment\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.5pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e9\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 35.45pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e3\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.55pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e7\u003c/span\u003e\u003cspan style='font-family:\"MS PGothic\",sans-serif;color:black;'\u003e \u003c/span\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eM\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFall from sitting position\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 56.7pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eOcciput/\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ecushion mattress\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFlaccid posture,\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFloppy\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu 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0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eNormal\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003edevelopment\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.5pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 65.2pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu 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5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e6 M\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 63.75pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1.5pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eFall after trying to\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu 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floor\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70.9pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1.5pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eRecurrent vomiting\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e\u0026amp;\u003c/span\u003e\u003cspan style='font-family:\"MS PGothic\",sans-serif;color:black;'\u003e \u003c/span\u003e\u003cspan style='font-family:\"Times New 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Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eretinal \u0026nbsp;hemorrhage\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77.95pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1.5pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eThin SDH\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003elow density\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92.15pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1.5pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003eT1 \u0026nbsp; 11 days \u0026nbsp; \u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003ethin, irregular shaped high-intensity SDH\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n 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style='font-family:\"Times New Roman\",serif;color:black;'\u003eNormal\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003edevelopment\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42.5pt;border-color: currentcolor currentcolor windowtext;border-style: none none solid;border-width: medium medium 1.5pt;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 68.05pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;text-align:justify;font-size:14px;font-family:\"Yu Mincho\",serif;margin-bottom:0in;line-height:normal;vertical-align:baseline;'\u003e\u003cspan style='font-family:\"Times New Roman\",serif;color:black;'\u003e5\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Bthlehem Garden Hospital","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Abusive head trauma, Infantile acute subdural hematoma, Mild type, Retinal hemorrhage","lastPublishedDoi":"10.21203/rs.3.rs-2733567/v2","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2733567/v2","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInfantile acute subdural hematoma (IASDH) has a limited age distribution and mostly benign clinical features. Mild-type IASDH has a stereotypical clinical course that, however, has been described in only a few studies.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFour male infants (aged 6–10 months; mean age: 7.5 months) were diagnosed with mild-type IASDH associated with retinal hemorrhage (RH) after suffering from occipital impact in a fall. The present case series reviews their clinical features and neuroimaging findings, including CT and MRI findings.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll infants fell backwards from a standing or sitting position onto a soft surface, striking the occipital region. They began crying on impact and then soon afterwards exhibited seizure-like activity or recurrent vomiting. CT and MRI revealed a thin, unclotted subdural hematoma (SDH) without mass effect or brain parenchymal abnormality. Various degrees of bilateral retinal hemorrhage (RH) were observed. On the day of symptom onset, all infants returned to baseline, and follow-up for more than 5 years revealed normal development with no deficits.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMild-type IASDH with retinal hemorrhage presents with seizure-like activity or recurrent vomiting preceded by crying after an occipital impact on a soft surface. The clinical course of IASDH is followed by rapid recovery on the day of symptom onset. CT and MRI findings reveal a small, unclotted subdural hematoma (SDH) without a mass effect or cerebral parenchymal abnormality.\u003c/p\u003e","manuscriptTitle":"Clinical and neuroimaging characteristics in mild-type infantile acute subdural hematoma: a report of four cases","msid":"","msnumber":"","nonDraftVersions":[{"code":2,"date":"2023-04-03 17:35:03","doi":"10.21203/rs.3.rs-2733567/v2","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}},{"code":1,"date":"2023-03-31 14:40:06","doi":"10.21203/rs.3.rs-2733567/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a372fa4a-cfba-4a41-9b2c-d2fd55a33edc","owner":[],"postedDate":"April 3rd, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-03-31T14:40:06+00:00","versionOfRecord":[],"versionCreatedAt":"2023-04-03 17:35:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v2","identity":"rs-2733567","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2733567","identity":"rs-2733567","version":["v2"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}