Double Positive Anti-PR3 ANCA Vasculitis and Anti-GBM Vasculitis in a Pregnant Woman: Case Report

Pulmonary-renal syndrome (PRS) caused by double-positive ANCA-associated vasculitis and anti-GBM disease is rare, and management is primarily guided by case series evidence. We present an even rarer case of a 36-year-old female who developed PRS in early pregnancy due to double-positive disease. She required intensive care admission for respiratory support and was treated with high-dose steroids and two doses of rituximab (1 g), achieving a good pulmonary response. However, her renal function subsequently deteriorated. Given the high maternal and foetal risks associated with her condition, she chose to terminate her pregnancy at 8 weeks. A subsequent kidney biopsy revealed crescentic glomerulonephritis secondary to anti-GBM disease. She was treated with plasma exchange and cyclophosphamide, leading to normalisation of her kidney function. She was weaned off prednisone and completed a course of intravenous pulsed cyclophosphamide (500 mg ×6 fortnightly). At 1 year post-diagnosis, she remains in biochemical and clinical remission on maintenance rituximab every 6 months. This case highlights the complexity of managing double-positive disease in pregnancy, where evidence is limited, and decisions require careful consideration of maternal and foetal risks. Furthermore, it underscores the importance of early anti-GBM-specific treatment-plasma exchange and cyclophosphamide-in achieving remission.