Pearls & Oy-sters: Arteriovenous Malformation With Sinus Thrombosis and Thalamic Hemorrhage: Unusual Cause of Parkinsonism and Dementia.

Deep cerebral venous thrombosis is an uncommon condition, which usually produces headache, altered consciousness, and ocular movement abnormality. Parkinsonism occasionally occurs when there is basal ganglia involvement. We report a case of a 78-year-old man who presented with a rapidly progressive parkinsonism with poor response to dopaminergic therapy. The patient had bilateral and symmetrical hypokinesia, rigidity, and marked gait impairment with festination. Brain MRI showed bilateral thalamic hyperintensity on T2-weighted and FLAIR sequences, with right thalamic and intraventricular hemorrhage due to straight sinus thrombosis. Angiography revealed an arteriovenous malformation in the quadrigeminal cistern with afferent supply from the posterior cerebral arteries, as well as partial thrombosis of the vein of Galen and half of the straight sinus. No predisposing factor for thrombosis was found. Given the location and size of the malformation, and the substantial amount of thalamic and intraventricular hemorrhage, conservative management was decided, with slow but progressive gait improvement. The presence of deep cerebral venous thrombosis should be suspected in cases of rapidly progressive parkinsonism with cognitive decline. As in this case, thrombosis may be secondary to a deep arteriovenous malformation, a very rare occurrence that may require specific therapy.