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Abstract: SA-PO861

A Rare Case of ANCA-Negative Pauci-Immune Necrotizing Glomerulonephritis

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Jalal, Abdullah, Washington University in St Louis, St Louis, Missouri, United States
  • Portales Castillo, Ignacio A., Washington University in St Louis, St Louis, Missouri, United States
Introduction

Pauci-immune necrotizing glomerulonephritis (PING) is the most common subtype of crescentic glomerulonephritis accounting for 80% of cases. Among these, 90% have an association with ANCA antibodies. However, 2-3% of patients can have PING in the absence of ANCA Antibodies. Thus far, data on this clinical entity has been limited to few case reports and series. Herein we present a rare case of ANCA-negative Pauci-Immune Glomerulonephritis (AN-PING).

Case Description

47 year old undomiciled male with past medical history of CKD3B, polysubstance use disorder, untreated hepatitis C, presented with lower back pain. Recently had MRSA bacteremia complicated by diskitis/vertebral osteomyelitis and epidural abscess treated non-operatively with daptomycin. Unfortunately patient later left AMA without antibiotics or outpatient follow-up.

On this admission patient’s imaging showed stable vertebral osteomyelitis/diskitis with interval decrease in epidural abscess size. Treated non-operatively with ceftaroline and pain management. During hospitalization patient developed an AKI with Cr 1.65 mg/dL on presentation (recent baseline Cr 1.3-1.5 mg/dL) which rapidly peaked to Cr 3.6 mg/dL over the next 7 days. Initial concern was for acute interstitial nephritis from antibiotics vs infection-related GN. Notable labs include 24 hour UPCR 282 mg; UA: >50 RBCs, 0-5 WBCs. On urine microscopy, numerous isomorphic RBCs seen with few acanthocytes, no RBC/WBC or granular casts. Immunologic workup revealed normal complement levels (C3 94 mg/dL, C4 26 mg/dL), negative ANA, ANCA, Anti-GBM, cryoglobulin levels. Renal biopsy performed revealed pauci-immune focal crescentic glomerulonephritis. There was consideration to starting immunosuppression with corticosteroids; however, patient’s Cr spontaneously down trended on supportive management with IV antibiotics (ceftaroline). On discharge patient’s creatinine was 1.6 and 1.2 on follow-up 3 months later.

Discussion

AN-PING is rare, poorly recognized clinical entity among crescentic glomerulonephritis. Primarily related to its negative serology, AN-PING is often diagnosed late on renal biopsy. This delayed diagnosis has resulted in AN-PING patients having a worse prognosis and higher mortality relative to ANCA-positive GN. Treatment of AN-PING is challenging due to its association with Infection and malignancy (20%), and must be approached on a case-by-case basis.