Stroke causing pure brachial monoparesis.

We studied 15 consecutive patients with acute brachial monoparesis due to stroke. There were 12 men and 3 women aged 45-78 years (mean, 61). Stroke workup included brain imaging, carotid duplex, echocardiography, and blood tests. In nine patients, the arm weakness was mainly distal, and in six it was equal distally and proximally. Tendon reflexes in the affected arm compared to the contralateral arm were symmetrical in 10, increased in 3, and decreased in 2 patients. In 14 patients, brain imaging showed a stroke in the middle cerebral artery branch territory superficially corresponding to the symptoms; and magnetic resonance imaging was negative in 1. Fourteen strokes were ischemic, and 1 was hemorrhagic. Of the 14 patients with ischemic stroke, 6 had > 50% ipsilateral extracranial cartoid artery stenosis, 4 had a serious source of cardiac emboli, and in 4 the cause of stroke was not identified. Our findings suggest that sudden brachial monoparesis should be considered a middle cerebral artery branch territory nonlacunar stroke syndrome. The etiologies of stroke causing pure brachial monoparesis are varied and include carotid artery disease, cardiac embolism, and intracerebral hemorrhage.