Table of Contents
Definition and Pathogenesis of Diverticula
True and false diverticula
Diverticula are wall protrusions in hollow organs. A distinction must be made between ‘true’ and ‘false’ diverticula. Medical students should learn the definitions and differences, as they usually appear on medical student exams, particularly Zenker’s diverticulum.
In the case of a true diverticulum, all wall layers are affected, even the muscularis. The protrusion often occurs due to tension from outside, such as scarring or inflammatory changes (with tuberculosis or lymphadenitis, for example).
In the case of a false diverticulum (or pseudo-diverticulum), only mucosa and submucosa evert to the outside through a weak spot in the muscle layer. The reason for this is increased intraluminal pressure.
With respect to the esophagus, diverticula can be classified on the basis of location, as well as whether they are true or false.
Traction diverticula are true diverticula and are usually found on the level of the tracheal bifurcation. Therefore, they also are referred to as bifurcation diverticula or parabronchial diverticula.
Pulsion diverticula are false diverticula. Predilection sites include the following points of the esophagus that have weak muscle:
- Laimer triangle (longitudinal muscle-free zone on the upper esophagus)
- Killian triangle (muscle-weak area between the pars obliqua and the pars fundiformis of the cricopharyngeal muscle of the dorsal hypopharynx). Strictly speaking, this is really a diverticulum of the hypopharynx, although it is usually dealt within the context of the esophagus. Diverticula in the area of the Killian triangle are also known as Zenker’s diverticula.
- Above the diaphragm: called an epiphrenic diverticulum
Epidemiology of Zenker’s Diverticulum
Zenker’s diverticulum is the most common type. It represents 70% of all cases of diverticula, followed by traction diverticula (20%) and epiphrenic diverticula (10%). Zenker’s diverticulum affects mostly older men.
Symptoms of Esophageal Diverticula
Dysphagia and regurgitation
Large diverticula are accompanied by symptoms. Patients complain of dysphagia, retrosternal pain, feelings of pressure, and nightly regurgitation of undigested food residue. The latter is associated with risks of aspiration and pneumonia. The deposition of food residue in the bulges may lead to halitosis. Some patients describe a ‘gurgling’ sound when they drink.
Diverticula rarely become inflamed, bleed, perforate, or form fistulas.
Diagnosis of Esophageal Diverticula
Esophageal bolus swallow test is the method of choice
The diagnostic method of choice is an esophageal bolus swallow test. X-ray images often clearly show the accumulation of contrast agents in protuberances, allowing precise differentiation of diverticula according to their location. Traction diverticula usually feature ‘ear-like’ outgrowths, whereas pulsion diverticula are mainly sack-shaped.
Due to the possible presence of a perforation, in the United States, it is recommended that healthcare professionals use a water-soluble contrast medium, as barium poses the risk of mediastinitis or peritonitis upon exit from the esophagus.
In order to exclude other possible causes of symptoms, endoscopy always should be performed as well. However, care must be taken because the mucous membranes near diverticula are particularly prone to perforation.
In terms of differential diagnoses, healthcare practitioners should consider esophageal carcinoma.
Therapy of Zenker’s Diverticulum
Surgical measures for Zenker’s diverticula
Diverticula can be treated surgically. However, surgery is usually indicated only for Zenker’s diverticula—rarely for larger and symptomatic epiphrenic diverticula.