Summary

A woman aged 26 years was referred by her GP to the eye casualty department with sudden-onset left homonymous hemianopia and right-sided headache. Full ophthalmic examination was normal with the exception of a left homonymous hemianopia confirmed with automated perimetry. Urgent CT imaging revealed a non-haemorrhagic cerebral infarct in the right parieto-occipital region. Subsequent blood tests confirmed a diagnosis of antiphospholipid syndrome with positivity in IgG anticardiolipin antibody, IgG anti-β2-GP1 antibody and the Lupus anticoagulant screen. MRI revealed extensive congenital abnormality at the Circle of Willis, affecting the right half of circulation. The unique dual pathologies may explain her predisposition to right-sided cerebral infarctions. This case highlights a rare but potentially fatal cause of visual disturbance in a young patient, and the importance of the multidisciplinary team approach in diagnosis and management.