Reversible choroidal ischemia as a rare sight-threatening manifestation of microscopic polyangiitis presenting with crescentic glomerulonephritis

BACKGROUND: Ocular involvement in ANCA-associated vasculitis is uncommon and usually affects the anterior segment. Posterior segment ischemic involvement, particularly choroidal perfusion disturbance, is extremely rare. We report a patient with microscopic polyangiitis (MPA) who developed bilateral visual impairment due to choroidal perfusion impairment demonstrated by fluorescein angiography (FFA), along with severe crescentic glomerulonephritis. CASE PRESENTATION: A 53-year-old woman presented with acute kidney injury, proteinuria, hematuria, elevated inflammatory markers, and p-ANCA positivity. Kidney biopsy demonstrated pauci-immune crescentic glomerulonephritis. She was treated with pulse steroids, cyclophosphamide, and plasma exchange. Ten days later, she developed bilateral visual loss. Fundus examination revealed preserved retinal vasculature without hemorrhage or exudates. FFA showed normal retinal vessel filling without vascular leakage but diffuse patchy background hypofluorescence, predominantly at the posterior pole, consistent with choroidal perfusion impairment. Immunosuppression was continued, leading to complete visual recovery and partial renal improvement. CONCLUSION: Recognition of this entity and prompt immunosuppressive treatment may prevent irreversible vision loss.