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Abstract: FR-PO713

Wrist Drop: An Unusual Initial Presentation of ANCA-Negative Pauci-Immune Glomerulonephritis

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Aamer, Sameen, Allegheny Health Network, Pittsburgh, Pennsylvania, United States
  • Soundranayagam, Sheahahn V., Allegheny Health Network, Pittsburgh, Pennsylvania, United States
  • Dunmyre, Brandon T., Allegheny Health Network, Pittsburgh, Pennsylvania, United States
Introduction

Pauci-immune glomerulonephritis (PING) is often associated with the presence of antineutrophil cytoplasmic antibodies (ANCA). ANCA-negative PING is a rare variant, which primarily affects the kidneys, with fewer extrarenal manifestations as compared to ANCA-positive PING. Our case highlights the initial presentation of progressive neurological weakness in ANCA negative PING.

Case Description

A 77-year-old male with medical history of hypertension and monoclonal gammopathy of undetermined significance (MGUS) presented with acute left wrist drop and progressive muscle weakness for six months. The weakness started in the lower extremities, and gradually involved the upper extremities. He denied numbness, tingling, rash, fever and gastrointestinal symptoms. Vital signs were stable. Neurological exam was positive for bilateral foot drop, left wrist drop, decreased sensation in all extremities, decreased deep tendon reflexes, and an unsteady steppage gait. Laboratory tests showed elevated creatinine 1.82 mg/dL (baseline 0.7-0.9), low albumin 1.9 g/dL, and elevated CRP 7.5 mg/dL. Lumbar puncture and MRI spine was normal. Electromyography showed moderate acute-on-chronic symmetrical sensory motor polyneuropathy and left radial mononeuropathy. Subsequent sural nerve biopsy revealed marked axonal neuropathy. Patient’s kidney function continued to worsen with creatinine peaking at 2 g/dL. 24 hour urine collection revealed 2.5 g proteinuria, with an elevated urine albumin-creatinine ratio of 1300. Therefore, a renal biopsy was performed revealing pauci-immune proliferative and necrotizing glomerulonephritis with crescent formation, negative immunofluorescence with no amyloid and immune deposits. Treatment with intravenous steroids followed by rituximab was initiated, resulting in improved renal function with creatinine of 1.77 at discharge. He demonstrated further renal recovery on outpatient follow up with serum creatinine down to 1.32.

Discussion

ANCA-negative PING is a severe vasculitis with high morbidity and mortality.This is the first case to report severe neurological weakness as the initial presentation of ANCA-negative PING. It highlights the importance of considering PING in the differential diagnosis for patients presenting with neurological weakness and elevated creatinine, as prompt diagnosis and treatment can prevent adverse patient outcomes.