Naveen Rathi, Derek Chang, Claire Lu, MD; Mohammed Alghammass, MD
Identification: Patient is a 51-year-old female. Chief Complaint: fatigue, abnormal lab findings History: Patient with history of hypertension, severe mitral regurgitation, and ventricular tachycardia status post ICD placement in 2016, who presents after a nephrology visit for abnormal labs including hemoglobin of 5.7 g/dl and creatinine >6 mg/dl. She presents with increased fatigue, weight loss, excessive nasal mucus with occasional blood, edema of bilateral lower extremities, and a worsening petechial rash over bilateral upper and lower extremities.
She had a similar admission three months ago, at which time she was treated for urinary tract infection (UTI), acute kidney injury (AKI), and anemia which were thought to be secondary to splenic laceration. During that stay, a c-ANCA was obtained and returned positive and c3/c4 levels returned low after she discharged. Notably, several months ago, she was treated with antibiotics for a tooth abscess. Physical Abnormalities: Our exam showed marked petechiae over bilateral upper and lower extremities, 3/6 systolic murmur best heard at cardiac apex, and 2+ lower extremity edema. CBC was notable for hemoglobin of 5.7 g/dl, normal WBC, and platelets of 102 k/mcl. CMP was significant for Potassium of 6 mmol/L, Creatinine of 7.6 mg/dl. Other notable labs showed TSH of 13.15 mcIU/mL, positive HIV antigen test, and positive hepatitis C antibody test. Differential Diagnosis: Presumed diagnosis was Granulomatosis with Polyangiitis (GPA given renal failure, positive c-ANCA, and bilateral ground glass opacities on chest CT. A transthoracic echocardiogram (TTE) showed large vegetations present on the mitral, these findings were confirmed with transesophageal echocardiogram (TEE) (Figure 1). Blood cultures tested positive for streptococcus mutans. Finally, her kidney biopsy showed infectious glomerulonephritis. Treatment: The final diagnosis of infective endocarditis (IE) was most likely seeded from her tooth infection secondary to streptococcus mutans. This was likely subacute since her presentation months before had probable impacts to her kidneys. Patient was treated with IV ceftriaxone, dialysis was initiated, infected tooth was extracted, and ICD hardware was removed. Confirmatory testing of HIV and HCV RNA was negative.
While patient's constellation of symptoms and positive c-ANCA was highly concerning for GPA, her IE was the root cause that led to infectious glomerulonephritis. HIV, HCV, and c-ANCA positivity could be explained by her immune response to her IE. Conclusion: Infective Endocarditis has been shown to induce the production of ANCA, as well as mimic ANCA-associated vasculitis. It is integral to consider a broad differential and exclude infection before pursuing the vasculitis diagnosis, where treatment includes immunosuppression.
Ying CM, Yao DT, Ding HH, et al. Infective endocarditis with antineutrophil cytoplasmic antibody: report of 13 cases and literature review. PLoS One. 2014;9:e89777. [PMID: 24587028] doi:10.1371/journal.pone.0089777
Shi XD, Li WY, Shao X, et al. Infective endocarditis mimicking ANCA-associated vasculitis: does it require immunosuppressive therapy?: A case report and literature review. Medicine (Baltimore). 2020;99:e21358. [PMID: 32702934] doi:10.1097/MD.0000000000021358
Branson BM, Owen SM, Wesolowski LG, et al. Laboratory Testing for the Diagnosis of HIV Infection: Updated Recommendations. Centers for Disease Control and Prevention and Association of Public Health Laboratories; 27 June 2014. Accessed at https://stacks.cdc.gov/view/cdc/23447 on 27 April 2019.
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