Bartonella henselae infection-mediated shunt nephritis

Abstract

Serum anti-neutrophil cytoplasmic antibody (ANCA) positivity with membranoproliferative pattern on renal biopsy can be due to ANCA-associated vasculitis as well as chronic indolent infections. We present the case of an adolescent boy with congenital heart disease and history of cardiac surgery who presented with severe acute kidney injury requiring hemodialysis. Renal biopsy showed membranoproliferative glomerulonephritis with full-house immunofluorescence pattern. Low serum complements, PR3 ANCA positivity and elevated Bartonella immunoglobulin titers suggested a diagnosis of infective endocarditis-associated glomerulonephritis. Cardiac shunt revision and antibiotic therapy lead to improvement in kidney function. Chronic infections lead to formation of immune complexes that may cause deposit within the renal parenchyma and induce production of ANCA. The distinction of ANCA-associated vasculitis and chronic infections causing acute kidney injury is important in determining therapeutic management. While rare in the pediatric population, we highlight the importance in considering indolent infections in patients with acute glomerulonephritis and ANCA positivity, especially with risk factors.

Keywords: ANCA vasculitis; endocarditis; full-house immunofluorescence; membranoproliferative glomerulonephritis; shunt nephritis.

Figure 1.. Light microscopy: proliferative glomerulus showing lobulation and neutrophilic infiltrate (arrow showing the neutrophilic infiltrate).

Figure 2.. Immunofluorescence staining: positive for C1q, C3, IgA, IgG, and IgM antibodies, consistent with “full-house” pattern.

Figure 3.. Electron microscopy. A: Fusion of podocytes with expansion of mesangial matrix. B: Subendothelial and rare subepithelial deposits with thickened basement membranes. C: Subendothelial deposits.