H&E stain showing a cellular crescent.
H&E stain showing mesangial and endocapillary hypercellularity and proliferation.
Electron micrograph showing a dense subepithelial deposit.
A 30-year-old Asian woman complained of facial fullness and leg edema that developed over the past week. She had no medical history. She was recovering from an upper respiratory illness that began 1 month prior. She had no productive cough, chest pain, or heart disease. She had no dysuria, but did note tea-colored urine through the previous week. She denied any history of nephrolithiasis or nonsteroidal use. There was no vomiting or diarrhea. Her only medication was Tylenol. Family history was unremarkable. Her blood pressure was 150/60 mm Hg, she had 2+ leg edema to the knees, and facial plethora without lymphadenopathy. Her serum creatinine on admission was 1.7 and steadily climbed to 4mg/dl over the next few days. Serum albumin albumin was undetectable, C3 was 118, C4 was 41, and SPEP did not reveal a monoclonal spike. HIV and hepatitis serology were negative.Urine revealed large hemoglobin, > 180 dysmorphic red cells, and random protein to creatinine ratio totaled 7grams. ANA was negative. Further serology was pending.
A renal biopsy was performed and representative images are shown. There was diffuse proliferative glomerulonephritis with numerous neutrophils. Immunofluorescence was positive for IgG and C3. Electron microscopy did show numerous subepithelial deposits and diffuse foot process effacement. There was an occasional cellular crescent noted. A diagnosis of postinfectious glomerulonephritis was made. An ASO eventually resulted positive. Over the next 2 months, her renal function recovered.
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This case was prepared by Kevin T. Harley, MD, Assistant Clinical Professor of Medicine, Division of Nephrology & Hypertension, University of California Irvine.
Nadasdy T, Hebert LA. Infection-related glomerulonephritis: Understanding mechanisms. Semin Nephrol 2011;31:369-375.
Nasr SH, Fidler ME, Valeri AM, et a. Postinfectious glomerulonephritis in the elderly. J Am Soc Nephrol 2011;22:187-195.
The presence of cellular crescents in this case of post-infectious glomerulonephritis could be more generally classified as an immune complex mediated or type 2 rapidly progressive glomerulonephritis. (Type 1 RPGNs would have positive anti-glomerular basement membrane antibodies.) Complement factor H mutation would be a relatively common hereditary defect leading to alternate complement pathway dysregulation and associated glomerulopathies such as atypical post-infectious glomerulonephritis or C3 glomerulopathy.
Indeed, many nephrologists would argue that a case of post-infectious glomerulonephritis that does not eventually recover renal function with normalization of complement levels deserves work up of complement pathway abnormality. The recovery of C3 is not uncommon after the first month of postinfectious glomerulonephritis, though the level is usually low earlier in the course of the disease. Anti-streptolysin antibodies are more commonly detected in respiratory over cutaneous streptococcal infections. In many older patients with an infectious glomerulonephritis, the causative organism may be something other than the classic streptococcus.