A Delayed Onset of Lateral Medullary Syndrome: A Case Report.

Lateral medullary syndrome (LMS), also known as Wallenberg syndrome, is a rare stroke that commonly affects the posterior inferior cerebellar artery and, less commonly, the vertebral arteries. LMS presents with a common constellation of posterior circulation stroke symptoms. In this case, we are discussing a 72-year-old male patient who has been diagnosed with left LMS. While the patient's presentation at the time of the suspected diagnosis included classic symptoms of Wallenberg syndrome, his initial visit to the emergency room five days before did not, as he only presented with vertigo symptoms: dizziness, a spinning sensation, and balance issues. Therefore, the delayed presentation of the patient's symptoms will be discussed in this case report. It took five days for typical lateral medullary symptoms to occur, which is unusual for ischemic strokes, especially LMS. While it is unusual for symptoms to occur gradually, it raises an important concept of stroke evolution, which describes how strokes can progress over a period of time either due to worsening ischemia or extension of the infarct. Stroke evolution is clinically significant because it emphasizes that stroke symptoms are not always forthcoming and direct, as highlighted in our patient's case. Even with initial negative diagnostic studies, clinicians should not completely rule out LMS or other types of ischemic strokes given the idea of stroke progression. Our patient was diagnosed with LMS initially on the basis of physical examination alone and later confirmed by a repeat diffusion-weighted MRI.