Abstract: PUB148
C3 Glomerulonephritis: Diagnostic Challenges and Overlap Syndromes
Session Information
Category: Trainee Case Report
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Agarwal, Krishna A., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Sula Karreci, Esilida, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Kruger gomes, Larissa, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Schulman, Ruth, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Stillman, Isaac Ely, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Lecker, Stewart H., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Steinman, Theodore I., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
- Denker, Bradley M., Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States
Group or Team Name
- BIDMC
Introduction
C3-glomerulonephritis (C3GN) is a rare complement-mediated GN, with an incidence of 1-3:1,000,000. Spectrum of presentation can range from asymptomatic hematuria and proteinuria to a full blown acute GN with hypertension, hematuria, and renal insufficiency. Serum C3 levels are typically low. Diagnosis is confirmed by renal biopsy. The underlying mechanism appears to be dysregulated alternate complement pathway, triggered by genetic, environmental or a combination of both factors. Medical management addresses blood pressure, proteinuria, and dyslipidemia. Immunosuppression with glucocorticoids, antimetabolites, and anti-complement agents is used alone or in combination. Here we present 2 cases of biopsy-proven C3GN, mimicking infection-associated GN (IAGN) and TTP/HUS.
Case Description
Case 1: A 49-year-old man presented with 4-5 days of fevers, chills, nausea, vomiting and diarrhea. Labs revealed mild thrombocytopenia, proteinuria, microscopic hematuria and a low C3 level. Blood cultures revealed Streptococcus pyogenes. His hospital course was marked by rapidly progressive pancytopenia and hemodialysis-requiring acute renal failure. He received a single dose of eculizumab empirically due to concern for atypical HUS, but platelet counts improved too rapidly to be consistent with eculizumab benefit. Kidney biopsy revealed acute tubular injury with glomerular C3 deposition. EM did not reveal immune deposits. Subsequent renal recovery followed 4 hemodialysis sessions. One-month post-discharge, he had normal renal function and hematologic cell counts.
Case 2: A 74-year-old man with CKD III was admitted with altered mental status, septic shock, and acute kidney injury. Extensive workup did not detect infection or altered autoimmune status. His course was complicated by worsening renal failure, proteinuria, and hematuria. Renal biopsy demonstrated acute tubular injury and glomerular C3 deposition without immune deposits on EM. Eculizumab was deferred due to normal C3 and C4 levels. A steroid pulse was associated with an improvement in creatinine beginning on day 4 and return to baseline kidney function by day 17.
Discussion
Our cases highlight the variable presentation and complexity associated with accurate diagnosis of C3GN, including considerable overlap with IAGN and TTP/HUS.