Abstract: PUB383
ANCA-Associated Vasculitis with Atypical Findings of Renal Medullary Angiitis
Session Information
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Rowe, Heather, Southern Illinois University School of Medicine, Springfield, Illinois, United States
- Rifai, Zeyad Jandali, Southern Illinois University School of Medicine, Springfield, Illinois, United States
- Ramani, Nirali Babubhai, Southern Illinois University School of Medicine, Springfield, Illinois, United States
Introduction
Renal medullary angiitis is a poorly understood marker of systemic vasculitis that is frequently mistaken for acute interstitial nephritis due to the presence of neutrophils on microscopy. Medullary angiitis and the associated systemic vasculitis are rarely documented in the literature.
Case Description
A 71-year-old male presented with constitutional symptoms of malaise, unintentional weight loss, decreased appetite, and worsening renal function. Urinalysis revealed 310 RBCs/high-powered field and a serum creatinine of 3.7 mg/dL. Comprehensive serologic workup revealed an antineutrophil complement antibody titer of 1:640 and proteinase-3 antibody positivity. Given the severity of his constitutional symptoms and the overt suspicion for ANCA vasculitis, the patient was started on prednisone 60mg daily and underwent renal biopsy. Light microscopy showed pauci-immune focal necrotizing crescentic glomerulonephritis with severe medullary angiitis characterized by lymphocytic inflammation and scattered eosinophils surrounding the vasa recta and mild interstitial fibrosis and tubular atrophy. Immunofluorescence confirmed the pauci immune ANCA associated type, while electron microscopy revealed nonspecific mild podocyte effacement. The patient underwent induction with rituximab and was discharged with scheduled maintenance doses of rituximab. The patient continues to follow up with nephrology for his chronic kidney disease (new baseline serum creatinine 1.96 mg/dL).
Discussion
The impressive serologic findings despite vague constitutional symptoms without a rash are an exceedingly rare presentation of this poorly understood diagnosis. We emphasize the necessity of achieving complete immunologic resolution, evidenced by negative serologic markers, via rituximab, to prevent further neutrophil-induced endothelial cell activation and vascular damage. Establishing a standardized guideline for this subset of ANCA vasculitis cases concentrated on serial titer monitoring is an area of interest.