Anti-Glomerular Basement Membrane Disease in a Six-year-old Child: A Rare Presentation

Abstract

Antiglomerular basement membrane (anti-GBM) disease is a rare small vessel vasculitis caused by auto-antibodies targeting auto-antigen expressed in basement membranes of capillary beds in lungs and kidneys. A six-year-old male presented with fever, cough, and generalized weakness for three days with respiratory distress for one day. The child had three prior admissions with similar complaints and was treated as a case of lower respiratory tract infection with severe iron deficiency anemia in the past. Multiple packed red cell transfusions were required in these past admissions. In this current admission, he had tachycardia, tachypnea, severe pallor, right-sided lung crepitations & bronchial breath sounds. The hemogram showed severe anemia and leukocytosis. Urine examination showed mild proteinuria and microscopic hematuria. Chest X-ray (current admission) showed right middle and lower zone consolidation. HRCT of the chest revealed an interstitial pattern. A lung biopsy showed pulmonary hemorrhage and positive Prussian blue staining. Raised anti-GBM titers confirmed diagnosis of anti-GBM disease. Renal biopsy revealed normal glomerular morphology on histopathology; with immune fluorescence showing linear positivity for IgG (3+), Kappa (3+), and Lambda (3+). Electron microscopy reported mild effacement of visceral epithelial foot processes and subepithelial/intramembranous electron-dense deposits. He was treated with intravenous methylprednisone for 5 days followed by oral prednisolone for one month, which was thereafter tapered to a lower maintenance dose for 18 months. The child received six cycles of intravenous cyclophosphamide along with a daily low dose of steroids. Currently, the child is asymptomatic after one year of follow-up with seroconversion (antiGBM titers decreased) and normalization of the chest radiograph.