A 55-year-old woman with no previous history of thyroid disease developed posterior reversible encephalopathy syndrome driven by severe autoimmune hyperthyroidism consistent with Graves’ disease. The patient initially presented with acute encephalopathy, fever, and hypoxia.
Her clinical course was complicated by recurrent focal and generalised seizures and profound bilateral visual loss. Initial neuroimaging demonstrated only chronic infarcts, but subsequent MRI revealed right occipital cortical and subcortical abnormalities with diffusion restriction that were initially interpreted as an acute posterior cerebral artery territory infarction. However, a combination of encephalopathy, seizures, visual loss, and interval radiological improvement prompted a tertiary neuroradiological review, after which the imaging abnormalities were considered consistent with posterior reversible encephalopathy syndrome.
Clinical Presentation and Diagnosis
Posterior reversible encephalopathy syndrome is a clinico-radiological syndrome characterized by acute encephalopathy, seizures, headache, and visual disturbance, with neuroimaging typically demonstrating predominantly posterior vasogenic oedema. While severe hypertension, renal dysfunction, sepsis, and exposure to cytotoxic or immunosuppressive therapies are well-recognized precipitants, cases associated with autoimmune thyroid disease are uncommon.
No alternative infectious or inflammatory etiology was uncovered through comprehensive infectious, neuronal, and paraneoplastic antibody evaluations, alongside cerebrospinal fluid examination. The patient’s condition highlighted the diagnostic challenge posed by occipital posterior reversible encephalopathy syndrome with diffusion restriction mimicking posterior circulation infarction.
Management and Patient Outcome
Management involved treating severe thyrotoxicosis with carbimazole, administering antiepileptic therapy, and treating concurrent systemic infection and acute kidney injury. As therapy progressed, her eyesight slowly recovered from merely perceiving light to distinguishing objects and colours, though notable cognitive and visual deficits remained during subsequent evaluations.
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