Zebras in Adult Dysphagia Workup: Where to Look When You Think You Have Looked Everywhere.

While many patients who present with dysphagia have a clinically identifiable cause of dysphagia, the etiology of swallowing difficulty is oftentimes a diagnostic enigma. The aim of this article is to review possible etiologies of dysphagia when objective evidence of dysphagia is lacking. Included in this discussion are cricopharyngeal spasm, retrograde cricopharyngeal dysfunction, muscle tension dysphagia, dysphagia secondary to medications, and functional dysphagia.