A diagnosis that's hard to swallow: case report of delayed onset lateral medullary syndrome presenting with only dysphagia.

Background: Lateral Medullary Syndrome (LMS) is a posterior circulation stroke (PCS) that has a broad array of manifestations but most classically presents with Horner's syndrome, ipsilateral ataxia, and ipsilateral hyperalgesia. Although dysphagia is also common, isolated and single presentation of this alone is rare and there are only a few case reports of this in the literature. This presentation can bias a clinician's differential diagnosis and delay diagnosis.

Case presentation: A previously healthy 53-year-old-male presented with a complaint of dysphagia. He had no PCS symptoms, a National Institute of Health Stroke Scale (NIHSS) of zero, and an otherwise unremarkable neurological exam. Stroke imaging including non-contrast computed tomography (NCCT) scan of his head and computed tomography angiography (CTA) scan of his head and neck revealed no acute abnormalities. He was found to be positive for Influenza A, but otherwise all other etiologies for his dysphagia were worked up, including consultation with other specialty services, without resolve. Two days later, the patient subsequently developed new right sided sensory deficits and left sided Horner's syndrome, in which a magnetic resonance imaging (MRI) scan of his head revealed an acute infarct of the left lateral medulla with likely thrombus in the left posterior inferior cerebellar artery (PICA).

Conclusions: PCS is frequently missed due to the often-vague symptoms and reassuring negative imaging. This case highlights the variability of presentations that ED physicians may encounter. Nonetheless, a high index of suspicion for PCS should be maintained even in young patients without risk factors. Lastly, dysphagia is never normal, and this case demonstrates the need to reconsider neurogenic origin when other causes have been ruled out.