A case of aortic abscess and acute kidney injury caused by chronic Q fever

A case of aortic abscess and acute kidney injury caused by chronic Q fever | 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 A case of aortic abscess and acute kidney injury caused by chronic Q fever Zhouning Liao, Haiping Zhen, RuiPing Zhang, Pearl Pai, Yiping Lu, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7111704/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Nov, 2025 Read the published version in BMC Infectious Diseases → Version 1 posted 13 You are reading this latest preprint version Abstract Q fever, caused by Coxiella burnetii, is a global zoonosis characterized by acute self-limiting influenza-like syndrome, pneumonia, hepatitis, or chronic infection. We present a rare case of chronic Q fever complicated by an aortic root abscess and acute kidney injury to highlight diagnostic challenges and therapeutic strategies for such complex presentations. Case description : A 62-year-old farmer previously healthy, presented with fever and heart failure which was alleviated with appropriate antimicrobial treatment, but later developed recurrent fever with hematuria and acute kidney injury. Renal biopsy showed diffuse proliferative glomerulonephritis with exudative features. Immunohistochemical analysis and electron microscopy were negative. A usual infection screen and blood culture failed to determine the source of infection. However, a cardioesophageal ultrasound showed the formation of a pus cavity at the root of the ascending aorta. The Polymerase Chain Reaction (PCR) and serology of Coxiella burnetti turned out positive indicative of Q fever infection. Conclusion : Q fever can be complicated by aortic abscess and acute kidney injury. It is rare for chronic Q fever infection to cause major vascular abscess along with acute kidney injury, and the diagnosis and treatment are often more difficult. The combination of molecular detection, imaging and pathology may be necessary to clinch to diagnosis. In patients with recurrent fever accompanied by multiple organ injuries, Q fever should not be neglected in the differentials. Doxycycline is the first-line treatment for Q infection, but the presence of a perivascular abscess may require surgical intervention. In addition, long-term follow-up of renal function and the risk of recurrence of endocarditis is advised. Q fever acute kidney injury aortic abscess Figures Figure 1 Figure 2 Background Q fever is a zoonotic infection caused by Coxiella burnetii. It is spread globally by contact with infected animals (such as cattle and sheep) or by inhalation of contaminated aerosols [ 1 ] . Its clinical manifestations are biphasic: acute infection is mostly manifested as self-limiting influenza-like syndrome (fever, myalgia, headache), while chronic infection is characterized by the development of infective endocarditis, vasculitis, and large vascular abscess, which is most likely to occur in patients with underlying immune deficiency, heart valve disease, or artificial valve replacement [ 2 ] . It is interesting that Q fever heart-related kidney injury is more common in chronic infection, and the pathological mechanism is closely related to immune complex deposition (such as C3 and IgM mediated glomerulonephritis). However, due to the lack of specific biomarkers and specific pathological features, clinical diagnosis may pose a challenge [ 3 ] .</p Case Description The patient, a 62-year-old male farmer with long-term contact with livestock, was admitted to our hospital due to one week history of facial swelling and abdominal distension. The patient had been in good health with no family history or past contact with infectious diseases. Physical examination showed fine crepitations in both lungs, and pitting edema of both lower limbs. Laboratory examination showed that N-telencephalic natriuretic peptide (NT-BNP) of 9554pg/ml (range), white blood cell: 6.95×10 9 /L, CRP: 31.99 mg/L, serum creatinine: 106umol/L, albumin: 30.5g/L. Hepatitis B, hepatitis C, syphilis, HIV serology was all negative. Sputum culture and blood culture were negative. Anti-cyclic citrullinated peptide antibody, Extractable nuclear antigen (ENA), Anti-Neutrophil Cytoplasmic Antibodies (ANCA), anti-GBM antibody were also negative. Serum immunofixation electrophoresis showed suspected abnormal monoclonal bands in the IgG and κ lanes. Serum protein electrophoresis, urine protein negative. IgG4 was 0.4510 g/L, anti-dsDNA was negative, normal anticardiolipin. Chest CT scan showed interstitial pulmonary edema, with pericardial and pleural effusion. Echocardiography showed left ventricular wall and septal hypertrophy and small pericardial effusion. There was no thrombosis in deep veins of both lower limbs. Abdominal color ultrasound scan showed small amount of fluid in the abdominal cavity. The patient was treated for heart failure with furosemide, irbesartan and atorvastatin. On day 6, the patient developed recurrent fever, hematuria, and worsening renal function (serum creatinine increased to 297 µmol/L). White blood cells and C-reaction protein (CRP) did not change significantly (Table 1 and Table 2 ). Renal ultrasound scan showed increased echogenicity of both kidneys, and a small left kidney stone. An abdomen CT scan showed little fluid accumulation in the abdominal pelvic cavity with subcutaneous edema of the abdominal pelvic wall. A possible diagnosis of infective endocarditis secondary to chronic Q fever was made after consulting our hospital clinical microbiologist. Empirically, 0.1g of doxycycline was administered to the patient once daily for anti-infective treatment. Subsequent transesophageal echocardiography showed a two-lobe aortic valve with stenosis (moderate to severe), and insufficiency (moderate). There was cystic structure of the wall of the retro valvular junction at the level of the aortic ring to the sinus which raised the possibility of appearances that followed collapse and liquefaction of an interwall abscess or hematoma. There were also aortic sinus and ascending aorta dilatation and thickening, mitral valve and tricuspid valve regurgitation and their chordae tendineae thickening. Table 1 Laboratory Parameters test/ Date Reference Value 6.16 6.20 6.23 6.24 6.27 6.29 7.3 WBC(10 9 /L) 3.89–9.93 6.95 6.98 7.23 6.99 7.73 7.76 6.57 HB(g/L) 133–171 125 119 126 123 113 114 110 PLT(×10 9 /L) 162–341 94 78 92 99 87 99 84 Neut (×10 9 /L) 2.01–7.42 4.57 4.81 4.94 4.42 5.28 5.37 4.55 Creatinine (uoml/L) 62–106 106 168 233 243 297 290 297 Urea nitrogen (mmol/L) 2.76–8.07 8.5 11.2 11.6 11.6 12.4 12.8 14.4 CRP(mg/L) 0–5 31.99 35.37 39.38 33.03 35.76 33.06 29.49 Table 2 Urine analysis and microscopy test/ Date Reference Value 6.16 6.18 6.20 6.22 6.24 6.29 6.30 7.2 red cell <30 150 50 160 160 160 40 50 200 colour Yellow light red light red light red colourless colourless colourless colourless Yellow protein(g/L) <0.1 0.7 0.3 0.3 0.3 0.3 0.3 0.3 0.3 morphology None N hybridism hybridism hybridism hybridism hybridism N N hematuria negative 3+ 3+ 3+ 3+ 2+ 3+ 3+ 3+ There was hypertrophy of ventricular septum and left ventricular wall and small amount of pericardial effusion. left ventricular systolic function was preserved (Fig. 1 ). Renal biopsy showed diffuse glomerular spherical or segmental intracapillary hyperplasia, extensive and mild C3, IgM, C1q antibody staining of mesangium and arteriole. IgA, IgG, C4 and fibrin staining were negative (Fig. 2 ). Coxiella burnetii antibodies and PCR were positive. Combined with clinical and laboratory results, the diagnosis of Q fever infection was confirmed. After 1 week of doxycycline, the patient's temperature was normalized, hematuria was less, and edema of both lower limbs resolved. Discussion and conclusion Coxiella burnetii is the pathogen of Q fever. Chronic Q fever impacts the patients' quality of life, and making a clinical diagnosis is challenging. Most Q fever infections are diagnosed at the stage of chronic infection [ 1 ] . According to the literature, about 5% of Q fever cases developed severe infective endocarditis, and diagnosis of Q fever artificial valve infection is often difficult, resulting in higher morbidity and mortality [ 2 , 3 ] . A small proportion of Q fever can lead to large vessel abscesses, such as abdominal aortic abscess or aortic root abscess. These can be diagnosed through bacterial testing or through surgical pathology [ 4 , 5 ] . It is not uncommon to with acute glomerulonephritis associated with acute Q fever [ 6 ] , there have also been case reports of Q fever causing infectious endocarditis accompanied by kidney damage [ 7 ] , 15% of the patients suffered from renal damage due to Q fever-induced infective endocarditis upon admission [ 8 ] . Q fever heart-related kidney injury is usually manifested as chronic infection or endocarditis, associated with secondary immune complex deposition, and presented with hematuria, proteinuria and sterile pyuria [ 9 , 10 , 11 ] . Some cases have reported on generalized swelling, hepatosplenomegaly, and anemia [ 1 ] . Renal biopsies have revealed focal segmental intravascular proliferative glomerulonephritis with C3, C1q, and IgM immune complex deposition, intravascular proliferative glomerulonephritis, crescentic glomerulonephritis, and immune complex mesangioproliferative glomerulonephritis [ 12 , 13 ] . It is not clear whether Coxiella burnetii directly invades the kidneys [ 10 , 11 ] . We have presented a case with aortic root abscess detected on transesophageal cardiac ultrasound, but routine blood culture and serology failed to identify any common pathogens. During hospitalization, the patient who was a farmer, developed recurrent fever, persistent hematuria, and acute kidney injury. The renal biopsy was consistent with an acute proliferative glomerulonephritis secondary to infective endocarditis. Using PCR, Q fever virus was detectable in the serum of the patient. On further enquiry the patient had intermittent fever and received symptomatic treatment including oral antibiotics for more than a month before hospitalization. Being a farmer and with exposure to livestock on a long-term basis put him at risk of Q fever infection. The patient responded to oral doxycycline. The acute kidney injury was secondary to chronic Q fever infection associated ascending aorta abscess. In this case, acute kidney injury caused by Q fever combined with aortic abscess is rare and may be caused by direct pathogen invasion or inflammatory factor storm, but the specific mechanism needs further study. The patient was subsequently evaluated for aortic abscess surgery, but the patient refused and was treated, of doxycycline therapy. At the three-month follow-up, the patient was reported in good condition. In conclusion, Q fever infective endocarditis or aortic abscess is rare. In patients with recurrent fever and acute kidney injury, and history of contact with livestock, Q fever infection should be suspected. The detection of Q fever viral infection requires serological examination, Metagenomics(M-ngs), and real-time PCR that detects targeting Cox's body markers. Multi-disciplinary collaboration involving Cardiology, Clinical Microbiology, Radiology, Nephrology are essential for successful management of such patients. Abbreviations PCR: Polymerase Chain Reaction; NT-BNP: N-telencephalic natriuretic peptide; ENA: Extractable nuclear antigen; ANCA :Anti-Neutrophil Cytoplasmic Antibodies; CRP:C-reaction protein; M-ngs: Metagenomics. Declarations Ethics approval and consent to participate Not applicable. Clinical Trial Clinical trial number: not applicable Consent for publication Written informed consent for publication of their clinical details along with any identifying images was obtained from the patient. Availability of data and materials The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding No funding was received for this study. Authors’ contributions ZNL wrote the manuscript. HPZ, RPZ, PP, MXL and YPL participated in the clinical care of the patient. CXX and LGZ assisted in interpreting the results under clinical prospective. All authors assisted the results interpretation and manuscript revision. All authors read and approved the final manuscript. Acknowledgements Not applicable. References Anderson A, Bijlmer H, Fournier PE, et al. Diagnosis and management of Q fever–United States, 2013: recommendations from CDC and the Q Fever Working Group. [J]MMWR Recomm Rep 2013; 62: 1–30。 Mohamed W, Dihmis O, Thirukumaran D,et al. Q-Fever endocarditis: Prosthetic valve infection in the absence of zoonotic exposure. [J]Perfusion.2024 Nov 22;1-16 Alshukairi AN, Morshed MG, Reiner NE. Q Fever Presenting as Recurrent, Culture-negative Endocarditis with Aortic Prosthetic Valve Failure: A Case Report and Review of the Literature.[J] Can J Infect Dis Med Microbiol. 2006 Nov;17(6):341-4. Yahav D, Kuznitz I, Reisfeld S,et al. Polymicrobial Q Fever and enterococcal aortic prosthetic valve endocarditis with aortic root abscess.[J] Vector Borne Zoonotic Dis. 2015 May;15(5):326-8. Kloppenburg GT, van de Pavoordt ED, de Vries JP. Endograft-preserving therapy of a patient with Coxiella burnetii-infected abdominal aortic aneurysm: a case report. [J] Med Case Rep. 2011 Dec 6;5:565-569. Yao Y, Zhao H, Lu H et al. Crescentic Glomerulonephritis and Portal Hypertension with Chronic Q Fever: A Case Report and Comprehensive Literature Review. [J]Infect Drug Resist. 2024 Oct 23;17:4599-4605 Uff JS, Evans DJ. Mesangio-capillary glomerulonephritis associated with Q-fever endocarditis. [J]Histopathology. 1977 Nov;1(6):463-72. Agrawal A, Virk HUH, Riaz I,et al. Predictors of 30-day re-admissions in patients with infective endocarditis: a national population based cohort study. [J]Rev Cardiovasc Med. 2020 Mar 30;21(1):123-127 Coorey CP, James W, Manickavasagam V,et al. Endocapillary proliferative glomerulonephritis associated with Q fever endocarditis: A case report. [J]Clin Case Rep. 2024 Oct 21;12(10):e9473. Stewart AG, Broom J, Sowden D,et al. Acute kidney injury in acute Q fever. [J]Intern Med J. 2019 Oct;49(10):1326-1329. Li Y, Shen Y, Yang H,et al. Q Fever-Related Glomerulonephritis Unveiled by Metagenomic Next-Generation Sequencing. [J]Kidney Int Rep. 2024 Aug 3;9(10):3062-3066. Ismayilov R, Acar BN, Kapar B,et al. Q Ateşi Endokarditi İlişkili İmmün Kompleks Aracılı Proliferatif Glomerülonefrit: Türkiye’den Dördüncü Olgu [Q Fever Endocarditis-Associated Immune Complex-Mediated Proliferative Glomerulonephritis: Fourth Case from Türkiye]. [J]Mikrobiyol Bul. 2023 Apr;57(2):293-300. Thanamayooran A, Tennankore K, Geldenhuys L,et al. Q-uestioning the Diagnosis: An Educational Case Report.[J] Can J Kidney Health Dis. 2022 May 2;9:1-7. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 28 Nov, 2025 Read the published version in BMC Infectious Diseases → Version 1 posted Editorial decision: Revision requested 10 Sep, 2025 Reviews received at journal 21 Aug, 2025 Reviews received at journal 20 Aug, 2025 Reviewers agreed at journal 19 Aug, 2025 Reviewers agreed at journal 19 Aug, 2025 Reviewers agreed at journal 18 Aug, 2025 Reviews received at journal 17 Aug, 2025 Reviewers agreed at journal 09 Aug, 2025 Reviewers invited by journal 08 Aug, 2025 Editor invited by journal 17 Jul, 2025 Editor assigned by journal 16 Jul, 2025 Submission checks completed at journal 16 Jul, 2025 First submitted to journal 13 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. 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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-7111704","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":498353606,"identity":"5a8997b2-9eea-437d-b13a-45f25aaffdc7","order_by":0,"name":"Zhouning Liao","email":"","orcid":"","institution":"The University of Hong Kong-Shenzhen Hospital","correspondingAuthor":false,"prefix":"","firstName":"Zhouning","middleName":"","lastName":"Liao","suffix":""},{"id":498353608,"identity":"63b37a22-057d-4e93-925f-3d0a00c4bb4f","order_by":1,"name":"Haiping Zhen","email":"","orcid":"","institution":"The University of Hong Kong-Shenzhen 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This suggests a change due to the rupture and liquefaction of an intramural abscess or hematoma. with the echoless area within it, measuring 31×10mm, the sac wall was thickened and echogenic and a rupture was observed on the left ventricular outflow tract. LA: Left Atrium, LV: Left Ventricle; AO：Ascending Aorta）\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7111704/v1/20cc2b8d00197c5fa1f9c142.png"},{"id":89230791,"identity":"fabb97d3-ff2f-4a97-b14e-bfeb74c7f2b6","added_by":"auto","created_at":"2025-08-17 14:15:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":431943,"visible":true,"origin":"","legend":"\u003cp\u003eA. PAS stain shows diffuse proliferative glomerulonephritis with diffuse global endocapillary hypercellularity and lobular mesangial expansion (x 400). B. PASM stain shows diffuse global endocapillary hypercellularity and segmental diffusion GBM (x 400).\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7111704/v1/fa69a0dc32de63023ed9d2c0.png"},{"id":97178543,"identity":"bb276f2e-6b26-425e-92cc-bb9be1c30809","added_by":"auto","created_at":"2025-12-01 16:10:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1240728,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7111704/v1/88e3b539-a183-4f6d-a63d-1e7495aee5e2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A case of aortic abscess and acute kidney injury caused by chronic Q fever","fulltext":[{"header":"Background","content":"\u003cp\u003eQ fever is a zoonotic infection caused by Coxiella burnetii. It is spread globally by contact with infected animals (such as cattle and sheep) or by inhalation of contaminated aerosols \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Its clinical manifestations are biphasic: acute infection is mostly manifested as self-limiting influenza-like syndrome (fever, myalgia, headache), while chronic infection is characterized by the development of infective endocarditis, vasculitis, and large vascular abscess, which is most likely to occur in patients with underlying immune deficiency, heart valve disease, or artificial valve replacement \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. It is interesting that Q fever heart-related kidney injury is more common in chronic infection, and the pathological mechanism is closely related to immune complex deposition (such as C3 and IgM mediated glomerulonephritis). However, due to the lack of specific biomarkers and specific pathological features, clinical diagnosis may pose a challenge \u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e.\u003c/p"},{"header":"Case Description","content":"\u003cp\u003eThe patient, a 62-year-old male farmer with long-term contact with livestock, was admitted to our hospital due to one week history of facial swelling and abdominal distension. The patient had been in good health with no family history or past contact with infectious diseases. Physical examination showed fine crepitations in both lungs, and pitting edema of both lower limbs. Laboratory examination showed that N-telencephalic natriuretic peptide (NT-BNP) of 9554pg/ml (range), white blood cell: 6.95×10\u003csup\u003e9\u003c/sup\u003e/L, CRP: 31.99 mg/L, serum creatinine: 106umol/L, albumin: 30.5g/L. Hepatitis B, hepatitis C, syphilis, HIV serology was all negative. Sputum culture and blood culture were negative. Anti-cyclic citrullinated peptide antibody, Extractable nuclear antigen (ENA), Anti-Neutrophil Cytoplasmic Antibodies (ANCA), anti-GBM antibody were also negative. Serum immunofixation electrophoresis showed suspected abnormal monoclonal bands in the IgG and κ lanes. Serum protein electrophoresis, urine protein negative. IgG4 was 0.4510 g/L, anti-dsDNA was negative, normal anticardiolipin. Chest CT scan showed interstitial pulmonary edema, with pericardial and pleural effusion. Echocardiography showed left ventricular wall and septal hypertrophy and small pericardial effusion. There was no thrombosis in deep veins of both lower limbs. Abdominal color ultrasound scan showed small amount of fluid in the abdominal cavity. The patient was treated for heart failure with furosemide, irbesartan and atorvastatin. On day 6, the patient developed recurrent fever, hematuria, and worsening renal function (serum creatinine increased to 297 µmol/L). White blood cells and C-reaction protein (CRP) did not change significantly (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Renal ultrasound scan showed increased echogenicity of both kidneys, and a small left kidney stone. An abdomen CT scan showed little fluid accumulation in the abdominal pelvic cavity with subcutaneous edema of the abdominal pelvic wall. A possible diagnosis of infective endocarditis secondary to chronic Q fever was made after consulting our hospital clinical microbiologist. Empirically, 0.1g of doxycycline was administered to the patient once daily for anti-infective treatment. Subsequent transesophageal echocardiography showed a two-lobe aortic valve with stenosis (moderate to severe), and insufficiency (moderate). There was cystic structure of the wall of the retro valvular junction at the level of the aortic ring to the sinus which raised the possibility of appearances that followed collapse and liquefaction of an interwall abscess or hematoma. There were also aortic sinus and ascending aorta dilatation and thickening, mitral valve and tricuspid valve regurgitation and their chordae tendineae thickening.\u003c/p\u003e\u003cdiv class=\"gridtable\"\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\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\u003e\u003cb\u003eLaboratory Parameters\u003c/b\u003e\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"9\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003etest/ Date\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eReference Value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.16\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.20\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6.23\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.24\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e6.27\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6.29\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003e7.3\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWBC(10\u003csup\u003e9\u003c/sup\u003e/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.89–9.93\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e7.73\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e7.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e6.57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHB(g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e133–171\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e125\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e119\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e126\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e123\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e113\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e114\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e110\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePLT(×10\u003csup\u003e9\u003c/sup\u003e/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e162–341\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e92\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e87\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNeut (×10\u003csup\u003e9\u003c/sup\u003e/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.01–7.42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4.94\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.42\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e5.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e5.37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e4.55\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCreatinine (uoml/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e62–106\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e106\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e168\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e233\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e243\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e297\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e290\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e297\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUrea nitrogen (mmol/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.76–8.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e11.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e11.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e12.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e12.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e14.4\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCRP(mg/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0–5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e35.37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e39.38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e33.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e35.76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e33.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e29.49\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\u003c/div\u003e\u003cdiv class=\"gridtable\"\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\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\u003eUrine analysis and microscopy\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003etest/\u003c/p\u003e\u003cp\u003eDate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eReference Value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.16\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.18\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6.20\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.22\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e6.24\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6.29\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003e6.30\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003e7.2\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ered cell\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e150\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e160\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e160\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e160\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ecolour\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYellow\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003elight red\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003elight red\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003elight red\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ecolourless\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ecolourless\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003ecolourless\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003ecolourless\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eYellow\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eprotein(g/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u0026lt;0.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003emorphology\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eN\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003ehybridism\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ehybridism\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003ehybridism\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003ehybridism\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003ehybridism\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003eN\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003eN\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ehematuria\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003enegative\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3+\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/table\u003e\u003c/div\u003e\u003cp\u003eThere was hypertrophy of ventricular septum and left ventricular wall and small amount of pericardial effusion. left ventricular systolic function was preserved (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Renal biopsy showed diffuse glomerular spherical or segmental intracapillary hyperplasia, extensive and mild C3, IgM, C1q antibody staining of mesangium and arteriole. IgA, IgG, C4 and fibrin staining were negative (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Coxiella burnetii antibodies and PCR were positive. Combined with clinical and laboratory results, the diagnosis of Q fever infection was confirmed. After 1 week of doxycycline, the patient's temperature was normalized, hematuria was less, and edema of both lower limbs resolved.\u003c/p\u003e"},{"header":"Discussion and conclusion","content":"\u003cp\u003eCoxiella burnetii is the pathogen of Q fever. Chronic Q fever impacts the patients' quality of life, and making a clinical diagnosis is challenging. Most Q fever infections are diagnosed at the stage of chronic infection \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. According to the literature, about 5% of Q fever cases developed severe infective endocarditis, and diagnosis of Q fever artificial valve infection is often difficult, resulting in higher morbidity and mortality \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. A small proportion of Q fever can lead to large vessel abscesses, such as abdominal aortic abscess or aortic root abscess. These can be diagnosed through bacterial testing or through surgical pathology \u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIt is not uncommon to with acute glomerulonephritis associated with acute Q fever \u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e, there have also been case reports of Q fever causing infectious endocarditis accompanied by kidney damage\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e, 15% of the patients suffered from renal damage due to Q fever-induced infective endocarditis upon admission\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. Q fever heart-related kidney injury is usually manifested as chronic infection or endocarditis, associated with secondary immune complex deposition, and presented with hematuria, proteinuria and sterile pyuria\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Some cases have reported on generalized swelling, hepatosplenomegaly, and anemia \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Renal biopsies have revealed focal segmental intravascular proliferative glomerulonephritis with C3, C1q, and IgM immune complex deposition, intravascular proliferative glomerulonephritis, crescentic glomerulonephritis, and immune complex mesangioproliferative glomerulonephritis \u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. It is not clear whether Coxiella burnetii directly invades the kidneys \u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eWe have presented a case with aortic root abscess detected on transesophageal cardiac ultrasound, but routine blood culture and serology failed to identify any common pathogens. During hospitalization, the patient who was a farmer, developed recurrent fever, persistent hematuria, and acute kidney injury. The renal biopsy was consistent with an acute proliferative glomerulonephritis secondary to infective endocarditis. Using PCR, Q fever virus was detectable in the serum of the patient. On further enquiry the patient had intermittent fever and received symptomatic treatment including oral antibiotics for more than a month before hospitalization. Being a farmer and with exposure to livestock on a long-term basis put him at risk of Q fever infection. The patient responded to oral doxycycline. The acute kidney injury was secondary to chronic Q fever infection associated ascending aorta abscess. In this case, acute kidney injury caused by Q fever combined with aortic abscess is rare and may be caused by direct pathogen invasion or inflammatory factor storm, but the specific mechanism needs further study. The patient was subsequently evaluated for aortic abscess surgery, but the patient refused and was treated, of doxycycline therapy. At the three-month follow-up, the patient was reported in good condition.\u003c/p\u003e\u003cp\u003eIn conclusion, Q fever infective endocarditis or aortic abscess is rare. In patients with recurrent fever and acute kidney injury, and history of contact with livestock, Q fever infection should be suspected. The detection of Q fever viral infection requires serological examination, Metagenomics(M-ngs), and real-time PCR that detects targeting Cox's body markers. Multi-disciplinary collaboration involving Cardiology, Clinical Microbiology, Radiology, Nephrology are essential for successful management of such patients.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003ePCR: Polymerase Chain Reaction; NT-BNP: N-telencephalic natriuretic peptide; ENA: Extractable nuclear antigen; ANCA :Anti-Neutrophil Cytoplasmic Antibodies; CRP:C-reaction protein; M-ngs: Metagenomics.\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClinical trial number: not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent for publication of their clinical details along with any identifying images was obtained from the patient.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZNL wrote the manuscript. HPZ, RPZ, PP, MXL and YPL participated in the clinical care of the patient. CXX and LGZ assisted in interpreting the results under clinical prospective. All authors assisted the results interpretation and manuscript revision. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAnderson A, Bijlmer H, Fournier PE, et al. Diagnosis and management of Q fever\u0026ndash;United States, 2013: recommendations from CDC and the Q Fever Working Group. [J]MMWR Recomm Rep 2013; 62: 1\u0026ndash;30。\u003c/li\u003e\n\u003cli\u003eMohamed W, Dihmis O, Thirukumaran D,et al. Q-Fever endocarditis: Prosthetic valve infection in the absence of zoonotic exposure. [J]Perfusion.2024 Nov 22;1-16 \u003c/li\u003e\n\u003cli\u003eAlshukairi AN, Morshed MG, Reiner NE. Q Fever Presenting as Recurrent, Culture-negative Endocarditis with Aortic Prosthetic Valve Failure: A Case Report and Review of the Literature.[J] Can J Infect Dis Med Microbiol. 2006 Nov;17(6):341-4. \u003c/li\u003e\n\u003cli\u003eYahav D, Kuznitz I, Reisfeld S,et al. Polymicrobial Q Fever and enterococcal aortic prosthetic valve endocarditis with aortic root abscess.[J] Vector Borne Zoonotic Dis. 2015 May;15(5):326-8.\u003c/li\u003e\n\u003cli\u003eKloppenburg GT, van de Pavoordt ED, de Vries JP. Endograft-preserving therapy of a patient with Coxiella burnetii-infected abdominal aortic aneurysm: a case report. [J] Med Case Rep. 2011 Dec 6;5:565-569.\u003c/li\u003e\n\u003cli\u003eYao Y, Zhao H, Lu H et al. Crescentic Glomerulonephritis and Portal Hypertension with Chronic Q Fever: A Case Report and Comprehensive Literature Review. [J]Infect Drug Resist. 2024 Oct 23;17:4599-4605\u003c/li\u003e\n\u003cli\u003eUff JS, Evans DJ. Mesangio-capillary glomerulonephritis associated with Q-fever endocarditis. [J]Histopathology. 1977 Nov;1(6):463-72.\u003c/li\u003e\n\u003cli\u003eAgrawal A, Virk HUH, Riaz I,et al. Predictors of 30-day re-admissions in patients with infective endocarditis: a national population based cohort study. [J]Rev Cardiovasc Med. 2020 Mar 30;21(1):123-127 \u003c/li\u003e\n\u003cli\u003eCoorey CP, James W, Manickavasagam V,et al. Endocapillary proliferative glomerulonephritis associated with Q fever endocarditis: A case report. [J]Clin Case Rep. 2024 Oct 21;12(10):e9473. \u003c/li\u003e\n\u003cli\u003eStewart AG, Broom J, Sowden D,et al. Acute kidney injury in acute Q fever. [J]Intern Med J. 2019 Oct;49(10):1326-1329.\u003c/li\u003e\n\u003cli\u003eLi Y, Shen Y, Yang H,et al. Q Fever-Related Glomerulonephritis Unveiled by Metagenomic Next-Generation Sequencing. [J]Kidney Int Rep. 2024 Aug 3;9(10):3062-3066.\u003c/li\u003e\n\u003cli\u003eIsmayilov R, Acar BN, Kapar B,et al. Q Ateşi Endokarditi İlişkili İmm\u0026uuml;n Kompleks Aracılı Proliferatif Glomer\u0026uuml;lonefrit: T\u0026uuml;rkiye\u0026rsquo;den D\u0026ouml;rd\u0026uuml;nc\u0026uuml; Olgu [Q Fever Endocarditis-Associated Immune Complex-Mediated Proliferative Glomerulonephritis: Fourth Case from T\u0026uuml;rkiye]. [J]Mikrobiyol Bul. 2023 Apr;57(2):293-300.\u003c/li\u003e\n\u003cli\u003eThanamayooran A, Tennankore K, Geldenhuys L,et al. Q-uestioning the Diagnosis: An Educational Case Report.[J] Can J Kidney Health Dis. 2022 May 2;9:1-7.\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-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Q fever, acute kidney injury, aortic abscess","lastPublishedDoi":"10.21203/rs.3.rs-7111704/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7111704/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eQ fever, caused by Coxiella burnetii, is a global zoonosis characterized by acute self-limiting influenza-like syndrome, pneumonia, hepatitis, or chronic infection. We present a rare case of chronic Q fever complicated by an aortic root abscess and acute kidney injury to highlight diagnostic challenges and therapeutic strategies for such complex presentations.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCase description\u003c/b\u003e: A 62-year-old farmer previously healthy, presented with fever and heart failure which was alleviated with appropriate antimicrobial treatment, but later developed recurrent fever with hematuria and acute kidney injury. Renal biopsy showed diffuse proliferative glomerulonephritis with exudative features. Immunohistochemical analysis and electron microscopy were negative. A usual infection screen and blood culture failed to determine the source of infection. However, a cardioesophageal ultrasound showed the formation of a pus cavity at the root of the ascending aorta. The Polymerase Chain Reaction (PCR) and serology of Coxiella burnetti turned out positive indicative of Q fever infection.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e: Q fever can be complicated by aortic abscess and acute kidney injury. It is rare for chronic Q fever infection to cause major vascular abscess along with acute kidney injury, and the diagnosis and treatment are often more difficult. The combination of molecular detection, imaging and pathology may be necessary to clinch to diagnosis. In patients with recurrent fever accompanied by multiple organ injuries, Q fever should not be neglected in the differentials. Doxycycline is the first-line treatment for Q infection, but the presence of a perivascular abscess may require surgical intervention. In addition, long-term follow-up of renal function and the risk of recurrence of endocarditis is advised.\u003c/p\u003e","manuscriptTitle":"A case of aortic abscess and acute kidney injury caused by chronic Q fever","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-17 14:15:43","doi":"10.21203/rs.3.rs-7111704/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-10T20:22:49+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-21T09:44:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-20T05:50:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"45531106221827490728614750746458947966","date":"2025-08-19T06:59:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"23913893102042342466255911956566608784","date":"2025-08-19T04:28:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"87305355414307724610846860816641755746","date":"2025-08-19T03:40:52+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-17T18:44:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"228937511148462665323006423613565307585","date":"2025-08-09T11:24:48+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-08T14:11:20+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-07-17T05:54:43+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-16T10:02:09+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-16T09:58:54+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Infectious Diseases","date":"2025-07-13T07:06:26+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-infectious-diseases","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"infd","sideBox":"Learn more about [BMC Infectious Diseases](http://bmcinfectdis.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/infd","title":"BMC Infectious Diseases","twitterHandle":"#bmcinfectdis","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"35be10f8-3b0c-4b28-a0b8-96d7784e314a","owner":[],"postedDate":"August 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-01T16:03:38+00:00","versionOfRecord":{"articleIdentity":"rs-7111704","link":"https://doi.org/10.1186/s12879-025-12102-y","journal":{"identity":"bmc-infectious-diseases","isVorOnly":false,"title":"BMC Infectious Diseases"},"publishedOn":"2025-11-28 15:57:20","publishedOnDateReadable":"November 28th, 2025"},"versionCreatedAt":"2025-08-17 14:15:43","video":"","vorDoi":"10.1186/s12879-025-12102-y","vorDoiUrl":"https://doi.org/10.1186/s12879-025-12102-y","workflowStages":[]},"version":"v1","identity":"rs-7111704","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7111704","identity":"rs-7111704","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}