Recurrent Hemorrhagic Venous Infarctions Caused by Thrombosis of a Pontine Developmental Venous Anomaly and Protein S Mutation

A 34-year-old man presented with an acute onset of upbeat nystagmus, slurred speech, and limb and truncal ataxias. The patient had a history of limb ataxia and gait disturbance previously treated as brainstem encephalitis with corticosteroids 3 years previously. Brain magnetic resonance imaging showed pontine developmental venous anomaly (DVA) and hemorrhagic infarction within the drainage territory of the DVA. Three months later, the patient exhibited recurrent limb ataxia, double vision, and numbness of the left side of the body. The brain magnetic resonance imaging revealed recurrent hemorrhagic venous infarction within the same territory of the pontine DVA. Laboratory tests disclosed a hypercoagulable state owing to a decrease of protein S activity despite the normal antigen level. Genetic testing indicated that the patient was a homozygous carrier of protein S Tokushima. The patient's severe disability remained unchanged in spite of treatment with anticoagulation therapy using warfarin. We propose that further research on hereditary coagulopathy be carried out in patients with recurrent episodes of DVA-related infarction.