D POTTER1, G LIEW 2, 3, A MAKRIS1, B CLELAND1
1Liverpool Hospital, Liverpool, New South Wales; 2Westmead Hospital, Westmead, New South Wales; 3Sydney University, Camperdown, New South Wales.
Background: Anti-glomerular basement membrane (GBM) disease is a rare disease estimated to affect 0.5-2 cases per million of the population. Autoantibodies against the alpha 3 subunit of type 4 collagen are pathogenic in anti-GBM disease and the subunit is classically considered to be restricted to the basement membrane of the glomerulus and lung. Studies using autoantibodies from anti-GBM patients and mouse monoclonal autoantibodies have demonstrated additional sites of binding within the choroid and retina of the eye, lens capsule, cochlea and choroid plexus. Direct ocular injury in anti-GBM disease, however, has only been reported once.
Case Report: A 45 year old female presented with fever, haematuria and acute renal failure with a creatinine of 254umol/L. Anti–GBM antibodies were detected in serum with a titre of >200IU/ml (reference <20IU/ml). Renal biopsy demonstrated a crescentic glomerulonephritis with linear basement membrane IgG staining on immunofluorescence. She received aggressive treatment with methylprednisolone followed by oral prednisolone, plasma exchange and intravenous cyclophosphamide. Six weeks after diagnosis she developed blurred vision in the left eye. Ophthalmology evaluation with optical coherence tomography demonstrated acute invasion of a choroidal neovascular membrane into the retina of the left eye. This was highly atypical in view of her age and lack of prior eye disease, trauma or macular degeneration. She received anti-vascular endothelial growth factor (VEGF) injections with an excellent response.
Conclusions: Our patient had acute choroidal neo-revascularisation without clear precipitating cause. Deposition of anti-GBM autoantibody within the choroid would induce this pathology and is supported by evidence of the subunit and autoantibody at this site. This case highlights that clinicians should consider other sites beyond the kidney and lung in anti-GBM disease.