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Medical Mystery

Quillen College of Medicine

Medical Mystery of the Week

    You are sent a video of a neurologic test on a 66-year-old man (see below). What is your diagnosis, what test(s) would you order to confirm your suspicions, and what treatment, if any, do you recommend?

Click on picture to start video.

DIAGNOSIS: sustained ankle (gastrocnemius/soleus) clonus. Sustained clonus (≥ 7 beats) is a sign of upper motor neuron disease in which central inhibition of the stretch reflex arc is released. Clonus should be tested for at thre ankle (with the knee flexed, dorsiflex the foot), the knee (with the patient supine grasp the patella and push it quickly distad) and wrist (grasp the patient's fingers and forcibly hyperextend the wrist). Any disease involving the pyramidal tract can cause clonus (e.g., stroke, multiple sclerosis, cancer, trauma, paraneoplastic syndromes, prion disease, encephalitis, etc.).
   Frontal release signs found normally in new born infants but abnormal when found in children and adults include the grasp reflex (involuntary grasping of examiner's fingers), the palmar-mental reflex (contraction of the ipsilateral mentalis muscle when the palm is stroked), the glabellar reflex (sustained blinking when the supraorbital region is tapped), and the snout reflex (puckering of the lips when stroked).In elderly adults, positive frontal signs often indicate a diagnosis of dementia.











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