A 74-year-old man comes to the office due to several months of choking spells, dysphagia, and cough. He has also had recurrent episodes of pneumonia. His other medical problems include hypertension and osteoarthritis. Blood pressure is 130/70 mm Hg. The patient has foul-smelling breath, but his oropharyngeal and neck examinations are normal. Cardiopulmonary examination is also normal. A barium swallow study is performed and reveals an abnormality in the upper esophagus, as shown in the image below.
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Which of the following mechanisms is the most likely cause of his symptoms?
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Deglutition (swallowing) is a complex process that involves 3 phases:
In the voluntary oral phase, the food bolus is collected in the back of the mouth and lifted upward to the posterior wall of the pharynx.
This initiates the pharyngeal phase, which consists of involuntary pharyngeal muscle contractions that propel the food bolus to the esophagus.
During the esophageal phase, food stretches the walls of the esophagus, stimulating peristalsis just above the site of distension and moving the food downward. Relaxation of the lower esophageal sphincter (LES) follows, allowing the food bolus to enter the stomach.
Abnormal spasm or diminished relaxation of the cricopharyngeal muscles during swallowing (cricopharyngeal motor dysfunction) is thought to be the underlying mechanism of Zenker diverticulum formation. This process results in early oropharyngeal dysphagia with a feeling of food obstruction at the level of the neck and coughing/choking. Increased oropharyngeal intraluminal pressure eventually results in herniation of the pharyngeal mucosa through a zone of muscle weakness (false diverticulum) in the posterior hypopharynx (Killian triangle). Patients consequently develop food retention with halitosis/regurgitation. Pulmonary aspiration of diverticular contents may also lead to recurrent pneumonia. As the diverticulum enlarges, it may become palpable as a lateral neck mass, and dysphagia can worsen due to luminal narrowing caused by extrinsic esophageal compression.
(Choice B) Degenerative changes of the myenteric plexus with impaired LES relaxation result in achalasia. Barium swallow typically shows esophageal dilation with esophagogastric junction narrowing ("bird's beak").
(Choice C) Mucosal tears around the gastroesophageal junction can be caused by increased intraluminal pressure in the stomach during prolonged or recurrent retching/vomiting (Mallory-Weiss syndrome).
(Choice D) Retention cysts form due to accumulation of trapped secretions following obstruction of a gland's duct. Chronic rhinosinusitis frequently causes mucus retention cysts in the maxillary sinus.
(Choice E) Mediastinal lymphadenitis (eg, due to tuberculosis, fungal infections) can cause scarring/traction of the mid-portion of the esophagus, resulting in the formation of true diverticula (containing all gut wall layers).
Educational objective:
Diminished relaxation of cricopharyngeal muscles during swallowing results in increased intraluminal pressure in the oropharynx. This may eventually cause the mucosa to herniate through a zone of muscle weakness in the posterior hypopharynx, forming a Zenker (false) diverticulum, which presents in elderly patients with oropharyngeal dysphagia, halitosis, regurgitation, and recurrent aspiration.