ANCA-Negative Pauci-Immune Crescentic Glomerulonephritis in a 26-Year-Old Postpartum Woman Treated with Oral Steroid and Azathioprine

Introduction: Pauci-immune crescentic glomerulonephritis (PICGN) is a rapidly progressive condition leading to rapid loss of kidney function within days to weeks and potentially life threatening. PICGN is an idiopathic form of crescentic GN that typically lacks significant immune deposits within glomeruli and often associated with antineutrophil cytoplasmic antibody (ANCA). However, some patients with PICGN are ANCA negative. Treatment for PICGN with or without ANCA includes IV methylprednisolone pulse therapy followed by tapering of oral steroid and cyclophosphamide either IV or orally. Case Description: A 26 year old Filipina presented with anuria, jaundice and elevated creatinine hours after an emergency cesarian section secondary to arrest of labor. She had BP elevation, edema and blurring of vision. No other signs and symptoms. Her D-dimer, phosphorus and triglycerides were high. Coomb's test are negative, C3/C4 are normal. She underwent hemodialysis (HD) for couple of sessions until her clinical status improved. Renal biopsy showed PICGN with cellular crescents and global glomerulosclerosis. P and C-ANCA were negative. She was given oral steroid and azathioprine (AZA) for 6 months which showed remarkable clinical improvement. Serum creatinine fall to 5mg/dL from 10mg/dL, UPCR to 0.8mg/dL from 3.9 mg/dL. HD was discontinued with stable kidney function and continuously monitored as outpatient. Discussion: PICGN is the most common cause of RPGN in adults and often associated with the presence ANCA’s. Around 10-30% of patients with PICGN lack the ANCA's. The mechanisms of ANCA-negative PICGN are still vague. Neutrophils (PMNs) are the major effector cells in ANCA-positve PICGN. PMNs are also thought to be the major effector cells in ANCA-negative PICGN. The presence of PMNs in pathological lesions exist separately from circulating ANCA’s and may include other autoantibodies or T-cell dependent mechanisms. Treatment of patients with ANCA-negative PICGN are usually based on those patients who are ANCA-positive. In our patient, oral steroid and AZA have shown excellent results.