Intramedullary hemorrhage caused by arteriovenous malformation: a case of mixed lateral and medial medullary syndrome.

A 48-year-old man with no known risk factor for cerebrovascular disease, other than cigarette smoking, experienced the sudden onset of a mixed lateral and medial medullary syndrome. Computed tomography scan failed to show any definite abnormality. Magnetic resonance imaging scans revealed hemorrhage restricted to the left dorsolateral medulla. Angiography showed abnormal arteries originating from the left vertebral artery with small niduses located on the surface of the medulla and contralateral cerebellum. Small brain-stem hemorrhages are a contraindication to thrombolytic or anticoagulant therapy, and therefore must be recognized in the acute stage.