Lateral medullary syndrome: uncommon form of brainstem stroke

Lateral medullary syndrome (LMS) is a less common form of a brainstem stroke. It is the result of occlusion of the posterior inferior cerebellar artery (PICA). It is caused by atherosclerosis, thrombosis, or emboli from another source.

A 60-year-old male patient presented to the emergency department with vertigo, vomiting, slurred speech, hiccups, and left-side weakness associated with paresthesia for 1 day. He had a past medical history of uncontrolled hypertension and a smoking habit. The neurological examination revealed ataxia, and left hemiparesis associated with paresthesia. A cranial nerve examination revealed slight right-sided ptosis, mouth deviation, and loss of sensory sensation on the right side of the face. Brain MRI showed right medullary infarct consistent with LMS. Electrocardiogram, echocardiography, and vertebral artery color Doppler were normal. He was admitted to the neurology ward and was treated with low molecular weight heparin 60 mg subcutaneously, aspirin 300 mg, neuroprotective agents, and antihypertensive treatment. After 6 days of medical treatment, his condition has improved massively (dysarthria and dysphagia disappeared). He was discharged for physical rehabilitation.

LMS (Wallenberg syndrome) is one of the brainstem stroke syndromes caused by occlusion of PICA. Vertigo, vomiting, dysphagia, dysarthria, ipsilateral ataxia, Horner's syndrome, and contralateral hemiparesis define this syndrome. Brain MRI is necessary for diagnosis alongside clinical syndrome.

LMS is a rare form of brainstem stroke and carries a favorable prognosis if early hospitalization and treatment is applied. Brain MRI, including diffusion sequence, is the most useful diagnostic tool for detecting LMS.