Topic: Horner's Syndrome
Subject: Medicine
A 54-year-old white male presents with drooping of his right eyelid for 3 weeks. On examination, he has ptosis of the right upper lid, miosis of the right pupil, and decreased sweating on the right side of his face. Extraocular muscle movements are intact. In addition to a complete history and physical examination, which one of the following would be most appropriate at this point?

The clinical triad of Horners syndromeipsilateral ptosis, miosis, and decreased facial sweating suggests decreased sympathetic innervation due to involvement of the stellate ganglion, a complication of Pancoasts superior sulcus tumors of the lung. Radiographs or MRI of the pulmonary apices and paracervical area is indicated. Horners syndrome may accompany intracranial pathology, such as the lateral medullary syndrome (Wallenbergs syndrome), but is associated with multiple other neurologic symptoms, so MRI of the brain is not indicated at this point. The acetylcholine receptor antibody level is a test for myasthenia gravis, which can also present with ptosis, but not with full-blown Horners syndrome. Diabetes mellitus and thyroid disease do not commonly present with Horners syndrome.