Pharyngeal constrictor muscle paralysis rarely occurs in isolation and is often accompanied by paralysis of the esophageal inlet, esophagus, or other muscle groups. The causes of pharyngeal constrictor muscle paralysis are mostly similar to those of soft palate paralysis. In addition, it is often secondary to conditions such as epidemic poliomyelitis and myasthenia gravis.
Clinical Manifestations
Unilateral pharyngeal constrictor muscle paralysis is characterized by difficulty swallowing and a sensation of obstruction, which is particularly pronounced when consuming liquids and often leads to choking. Bilateral paralysis may result in severe dysphagia or even complete inability to swallow. This type of swallowing difficulty differs from that caused by inflammatory or partially mechanical obstruction of the pharynx and larynx. Early-stage symptoms primarily involve difficulty swallowing liquids, often with regurgitation, while solid foods may still be swallowed. If sensory or motor dysfunction of the larynx is also present, food is at high risk of being aspirated into the lower respiratory tract, potentially leading to complications such as aspiration pneumonia.
Diagnosis
Unilateral pharyngeal constrictor muscle paralysis manifests as a drooping of the posterior pharyngeal wall on the affected side, resembling a curtain, which shifts toward the healthy side. In bilateral paralysis, the mucosal folds of the posterior pharyngeal wall disappear. The pharyngeal reflex is absent when the tongue base or pharyngeal wall is palpated. The oropharynx and pyriform sinuses may exhibit significant retention of saliva. Fiberoptic laryngoscopy and imaging studies can assist in ruling out organic lesions of the skull base and the pharyngeal and laryngeal regions.
Treatment
Etiological Treatment
For patients with peripheral nerve paralysis, medications that improve microcirculation and nourish nerves are necessary to promote neural recovery. Options include vitamin B1, vitamin B12, cytidine diphosphate-choline, and murine nerve growth factor. Pyridostigmine bromide is required for patients with myasthenia gravis.
Prevention of Lower Respiratory Tract Complications
Food should be prepared as thickened or paste-like to reduce the risk of aspiration. Assistance may be required to remove retained secretions from the pharynx. In severe cases, nasogastric feeding or gastrostomy may be necessary for nutritional support, while tracheotomy may be performed as needed.
Prognosis
The prognosis of pharyngeal constrictor muscle paralysis depends on its underlying cause and is generally worse than that of isolated soft palate paralysis. Severe paralysis accompanied by swallowing difficulties often leads to aspiration pneumonia, which can be life-threatening.