OROPHARYNGEAL DYSPHAGIA DUE TO IATROGENIC NEUROLOGICAL DYSFUNCTION

Oropharyngeal dysphagia due to iatrogenic neurological dysfunction may relate to either medication side effects or surgical complications. There are several general mechanisms by which neurological side effects of medications can cause or aggravate oropharyngeal dysphagia. These include decreased level of arousal, direct suppression of brainstem swallowing regulation, movement disorders (dyskinesias, dystonias, and parkinsonism), neuromuscular junction blockade, myopathy, oropharyngeal sensory impairment, and disturbance of salivation. Postsurgical oropharyngeal dysphagia due to neurological dysfunction has been described in association with carotid endarterectomy, esophageal cancer surgery, anterior cervical fusion, and ventral rhizotomy for spasmodic torticollis. A potential explanation for oropharyngeal dysphagia following these surgical procedures is intraoperative mechanical disruption of the innervation of the pharyngeal constrictor muscles by the pharyngeal plexus. Posterior fossa and skull base surgery can lead to dysphagia as a result of intraoperative damage to brainstem centers and/or cranial nerves involved in swallowing. Perioperative stroke is the most likely explanation for oropharyngeal dysphagia appearing acutely following surgery, especially if the type of surgery predisposes to embolism or hypoperfusion.