[A case of anterior cerebral artery dissection causing enlargement of infarction].

A 46-year-old woman presented with weakness in the right arm and leg. She had developed difficulty in moving the right arm and leg while exercising and had noticed headache simultaneously. On admission, she had hemiparesis of the right side. Angiography on day 1 disclosed irregularity of the left anterior cerebral artery (ACA). We started argatroban and aspirin to prevent exacerbation of ischemia. Diffusion-weighted MR image on day 2 disclosed acute infarction in the territory of the left ACA. When she became able to move her leg against gravity (MMT 3/5), we discontinued antithrobotic therapy on day 3. MRI on day 10 disclosed enlargement of the infarcted area. Angiography on day 16 disclosed stenosis and dilation corresponding to pearl and string sign involving the left ACA. Spontaneous ACA dissection was established based on clinical features and angiographic findings. Antithrombotic therapy in patients with intracranial artery dissection remains controversial because subarachnoidal hemorrhage can complicate the course due to rupture of dissecting aneurysm, for there is no external elastic lamina in intracranial arteries. However, some cases of ACA dissection have showen progression of ischemic symptoms and enlargement of the infarcted area during the acute or subacute phase.