The causes of disturbances of swallowing

1. Big picture

Disturbance of swallowing is dysphagia; complete inability to swallow is aphagia. In neurology, dysphagia is important because it may be the first sign of a brainstem lesion, bulbar palsy, pseudobulbar palsy, myasthenia gravis, Guillain–Barré syndrome, amyotrophic lateral sclerosis, or another dangerous disorder.

For the exam, the key is not only to list causes, but to decide:

Is the problem oropharyngeal and neurological, or esophageal and mainly gastrointestinal? Neurological dysphagia usually means difficulty initiating swallowing, choking, coughing, nasal regurgitation, wet voice, dysarthria, dysphonia, aspiration, or associated cranial nerve signs.

The most exam-relevant neurological localizations are:

• Nucleus ambiguus / cranial nerves IX–X → dysphagia, dysphonia, palatal weakness, absent gag reflex.

• Hypoglossal nerve / nucleus XII → tongue weakness, deviation, atrophy, fasciculations.

• Bilateral corticobulbar tract lesion → pseudobulbar palsy.

• Neuromuscular junction → fluctuating dysphagia, especially in myasthenia gravis.

• Motor neuron disease → progressive bulbar weakness, dysarthria, dysphagia, tongue fasciculations.