PROBLEM

A 24-year-old Mexican man who recently immigrated to the United States presents to the emergency department complaining of pain in his left shoulder. He reports that the pain began after he had a generalized tonic-clonic seizure while he was still in Mexico. Examination reveals that his left shoulder has a severely limited range of motion secondary to pain. Otherwise, that extremity is within normal limits. The remainder of the exam is unremarkable. What is your interpretation of this view of the patient’s shoulder?

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ANSWER

The image shows abnormal alignment of the glenohumeral joint with internal rotation of the left humerus, indicating that this patient suffered a posterior dislocation of his left shoulder as a result of his seizure. Seizure and electrocution are the two most common causes of posterior shoulder dislocation. Noteworthy on the plain film are small, linear, calcific densities that raise concern for soft-tissue parasitic infection. Because the patient had recently arrived from Mexico, the possibility of neurocysticercosis had to be entertained in light of his antecedent seizure.

After successful closed reduction of his shoulder with procedural sedation, the patient underwent additional diagnostic testing including a non-contrast computed tomography (CT) scan of his head. The CT scan demonstrated multiple discrete areas of high attenuation consistent with the diagnosis of neurocysticercosis (see image). The patient was admitted to the neurology service for further management of his disease.