AJKD Atlas of Renal Pathology: Subacute Bacterial Endocarditis-Associated Glomerulonephritis.

Abstract

Antibiotic therapy has decreased the incidence of glomerulonephritis related to subacute bacterial endocarditis (SBE). Kidney involvement may be the initial manifestation of SBE in about 20% of patients. Hematuria and mild proteinuria are commonly present. Hypertension and nephrotic syndrome are rare. Serum complement levels may be low. Gross hematuria may be present in patients with renal infarctions related to embolic events. The degree of GFR loss correlates with the severity of glomerulonephritis; diffuse glomerulonephritis causes moderate GFR loss, and necrotizing glomerulonephritis with crescents can cause a rapid GFR decline. More extensive glomerulonephritis is commonly associated with high-titer ANCA positivity. Antibiotic therapy can result in partial to complete resolution of kidney disease. Light microscopy: Glomerular lesions show variable and often mixed active and chronic lesions. Focal or diffuse proliferative glomerulonephritis is present in about half of cases, and may have neutrophils within the glomerular tuft. Focal necrotizing lesions with crescents may be present. Chronic lesions include segmental glomerulosclerosis, as well as fibrocellular and fibrous crescents. Renal infarction related to an embolic event can occur. Necrotizing glomerulonephritis with crescents without endocapillary hypercellularity can occur. Immunofluorescence microscopy: Mesangial and capillary wall irregular, granular staining for IgG, IgM, C3, and sometimes IgA are usually present in cases with proliferative glomerulonephritis. IgM staining is usually greater than IgG and IgA. IgA may be dominant in cases with staphylococcal infection. However, there is typically little or no staining in