A case report of PR-3-ANCA-positive glomerulonephritis with histological features of GPA associated with infectious endocarditis

RATIONALE: Several renal diseases are associated with infectious endocarditis. However, there are few reports on patients with granulomatosis with polyangiitis (GPA) associated with infectious endocarditis, and there is no consensus for appropriate treatment. PATIENTS CONCERNS: A 35 -years-old man with congenital ventricular septal defect presented severe anemia, hematuria and proteinuria. The blood and urine examinations showed elevated white blood cells (12,900 cells/μL), C-reactive protein level (13.1 mg/dL) and proteinase 3-anti-neutrophil cytoplasmic antibody (PR3-ANCA) level (11.0 IU/mL), severe anemia (hemoglobin: 6.1 g/dL) and renal dysfunction [estimated glomerular filtration rate (eGFR): 12.7 ml/min.1.78 m(2) with hematuria and proteinuria]. DIAGNOSES: The patient was diagnosed with crescentic glomerulonephritis with histological features of GPA associated with infectious endocarditis by renal biopsy and transthoracic echocardiography. INTERVENTIONS: Antibacterial drugs (ampicillin-sulbactam) were administrated. No immunomodulating agents were used because immunosuppressive drugs may worsen infectious endocarditis. Subsequently, renal function and urinary findings improved. However, infectious endocarditis was not improved. Therefore, valve replacements and ventricular septal closure surgery were conducted. OUTCOMES: Thereafter, his postoperative course was uneventful, renal function improved (eGFR: 64.3 ml/min.1.78 m(2)), and PR3-ANCA level normalized. LESSONS: We reported a case report of PR3-ANCA positive glomerulonephritis with histological features of GPA associated with infectious endocarditis. Physicians might note this renal complication when they manage infectious endocarditis.