Clonus after a Stroke
A 55-year-old man with a history of high blood pressure and ischemic stroke 2 years before admission presented with bleeding in the upper gastrointestinal tract. On admission, the patient had had two melenic stools without hemodynamic compromise. On examination, he was found to have right hemiparesis, right Babinski's sign, hyperreflexia, and motor aphasia. Dorsiflexion of the right foot produced sustained clonus, as a result of the previous stroke (video). Clonus is a series of rhythmic, unidirectional contractions and relaxations of the gastrocnemius and soleus muscles, induced by a sudden and maintained dorsiflexion of the foot. Clonus is seen following interruption of the descending cortical fibers, as in multiple sclerosis, amyotrophic lateral sclerosis, and stroke. However, the metabolic disturbances of renal failure, hepatic failure, and hepatic encephalopathy can also result in findings of clonus. Treatment requires addressing the underlying cause. The patient underwent upper endoscopy, which showed chronic gastritis. His clinical condition stabilized, but the neurologic findings persisted.