CN IX/X Palsy: A Fact Hard to Swallow

We discussed in clinic a case of possible CNIX/X (gossopharyngeal/vagus nerve) palsy presenting with dysphagia and weight loss. Here’s a quick review of the functionalities of these cranial nerves, how to examine for abnormalities, and differential diagnosis.

CNIX is responsible for swallowing, taste and sensation over the posterior 1/3 of the tongue and palate, promoting salivation from parotid, and it forms the afferent limb of the gag reflex (Walker,1990). CNX is important for  swallowing, phonation, and articulation (as it contributes to the movement of the palate, pharynx, larynx, and esophagus), and forms the efferent limb of the gag reflex. CNX also has autonomic functions such as gastric acid secretion, gallbladder emptying and heart rate regulation.

Physical exam in the context of possible CNIX/X palsy should include a full neurological and head&neck examination (Erman, 2009). Assess the patient’s voice including pattern, loudness, and articulation (e.g. the “ee” sound is hard to hold for more than a few  seconds with vocal cord paralysis). The gag reflex, palate elevation, and swallowing should be evaluated.

Differential for CNIX/X dysfuntion involving systematically thinking about different pathology from the cortex to the neuromuscular junction (Erman, 2009).

§      cortex (contribute to CN IX and X): acute stroke, tumor
§      extrapyramidal tracts (contribute to CN IX and X): extrapyramidal movement disorders
§      brainstem (nuclei): amyotrophic lateral sclerosis, syringomyelia, Arnold-Chiari malformation, tumor
§      peripheral nerve (CN IX and X): cerebellopontine angle tumor, skull base osteomyelitis, skull base fracture, glossopharyngeal neuralgia, diptheria
§      neurmuscular junction: myasthenia gravis

-Jenny