Sigmoid sinus thrombosis presenting with posterior alexia in a patient with Behçet's disease and polycythaemia: a case report

A 59-year-old Caucasian woman presented with an acute onset of alexia, noticed whilst driving. She described how while she could read car number plates, she had lost the ability to read and understand words on roadside advertisements and car window stickers.

Neurological examination was unremarkable apart from the inability to read full words or sentences. Imaging of the brain, initially computed tomography, followed by magnetic resonance venography, confirmed a diagnosis of sigmoid sinus thrombosis with associated venous infarction. The patient's past medical history revealed that she had suffered an ischemic stroke and following investigation for this, had undergone a nephrectomy for renal cell carcinoma. This was complicated by postoperative deep venous thrombosis. She had a persistent polycythaemia that was managed with venesection, and recently she had been diagnosed with Behçet's disease. Prior to this presentation, she had recently stopped her prophylactic antiplatelet medication as she was due to undergo a total knee replacement for osteoarthritis. She was managed with weight-adjusted, low molecular weight heparin followed by oral anticoagulation, and made a good recovery from her symptoms.

This case illustrates a classical neurological syndrome, highlights the importance of cerebral venous and sinus thrombosis as a cause of stroke, and the importance of remaining vigilant to a person's changing risk of venous thrombosis with evolving comorbidity.