A 43-year-old man presents to your office complaining of periodic involuntary head turning and head fixation to the right side. Physical examination reveals a hypertrophied left sternocleidomastoid muscle. What is the most likely diagnosis?

Question

A 43-year-old man presents to your office complaining of periodic involuntary head turning and head fixation to the right side.  Physical examination reveals a hypertrophied left sternocleidomastoid muscle.  What is the most likely diagnosis?

Quizplus · Accepted Answer

This patient suffers from torticollis, a focal dystonia of the sternocleidomastoid muscle. Dystonia is defined as sustained muscle contraction resulting in twisting, repetitive movements, or abnormal postures. It may be focal (affecting only one muscle) or diffuse. Torticollis can be congenital, idiopathic, secondary to trauma or local inflammation, or drug-induced. Medications commonly responsible include the typical antipsychotics, metoclopramide, and prochlorperazine. (Choice A) Parkinson's disease is characterized by resting tremors, bradykinesia, rigidity, and postural instability. It is not associated with focal dystonia. (Choice B) Essential tremor is a form of intention tremor affecting the upper extremities, head, voice, and other body parts. Essential tremor resolves during sleep and often improves with alcohol consumption. Rigidity and dystonia are absent. (Choice C) Chorea is a movement disorder characterized by brief, irregular, unintentional muscle contractions. Movements tend to flow from one to another but are not repetitive or rhythmic. (Choice D) Akathisia is a sensation of restlessness that causes the patient to move frequently. (Choice F) Athetosis refers to slow, writhing movements that typically affect the hands and feet. Athetoid movements are characteristic of Huntington's disease. Chorea and athetosis often occur together. (Choice G) Tourette syndrome is a disorder characterized by involuntary, stereotyped, repetitive movements and vocalizations called tics. Common tics include shoulder shrugging, blinking, grimacing, and coprolalia (swearing). (Choice H) Hemiballismus is unilateral, violent arm flinging caused by damage to the contralateral subthalamic nucleus. Hemiballismus is very disruptive but tends to be self-limited. (Choice I) Myoclonus is the involuntary jerking of a muscle or muscle group. Unlike chorea, it can be rhythmic or patterned and is usually initiated by contraction or relaxation. Educational Objective: Torticollis is a common form of focal dystonia involving the sternocleidomastoid muscle. It can occur idiopathically but is very often medication-related. Discontinuation of the causative agent(s) may improve symptoms.

A 43-Year-Old Man Presents to Your Office Complaining of Periodic