Annular dilatation is sometimes due to distension just above the seat of a stricture. Sometimes it is due to impaction of a foreign body; sometimes there is no mechanical impediment; occasionally it is observed as a congenital anomaly.
Pouched dilatation (diverticulum) is usually due to retention of food immediately above an impacted foreign body or some obstruction of another character. Some of the muscular fibres of the oesophageal wall become separated and spread asunder, allowing the mucous membrane to be gradually forced through them by repeated efforts of deglutition upon retained masses of food or drink, until finally a pouch is formed, hernia-like, outside of the tube. Another mode of production is said (Rokitansky28) to consist in the subsidence of tumefied glands outside the oesophagus, after adhesions had been contracted with the oesophagus during the inflammatory process. The shrinking of these enlarged glands to their normal volume sometimes draws the tube outward into a funnel-shaped sac constricted at its margin by the muscular coat, which has receded from the pouch or has been stripped loose. The same form of dilatation is likewise an occasional result of rupture of the muscular coat sustained in blows or falls. It occasionally exists, too, as a congenital defect, and this has been attributed (Bardeleben and Billroth29) to partial closing of one of the branchial fissures externally, while the internal opening has remained patent.
28 Archiv. gén. de Méd., 1840, p. 329.
29 Trans. Clin. Soc. London, 1881, p. 130.
SYMPTOMATOLOGY.—The symptoms, at first, are usually those of obstruction to the passage of food, but before this obstruction occurs dilatation may have existed without symptoms. In some cases of diverticulum high up, there is a tumor, usually on the left side of the neck. Rokitansky has reported one the size of the fist situated on the right side of the neck, and Hankel30 and others a tumor upon each side. The tumor varies in bulk from time to time according as it may be empty or may be distended with food, drink, or gas.
30 Rust's Mag., 1833; Dict. Encycl., loc. cit.
Food caught in the pouch can often be forced out into the pharynx by external pressure over the tumor in the neck. The retention of food above a constriction or in a sac is usually accompanied by some distress after indulgence in too much food. This uneasiness becomes relieved upon regurgitation or vomiting. Deglutition is impeded to a less extent when the disease does not implicate the upper portion of the gut.
Complete dilatation is sometimes indicated by long addiction to habits of rumination. In some instances this rumination is an agreeable sensuous process. In pouched dilatation it is very often disagreeable, the regurgitated matters being acrid, owing to acid fermentation of the contents of the sac.
While the dilatation remains moderate there may be little dysphagia or none at all, the muscles continuing sufficiently vigorous to propel the food; but after the muscles become paralyzed by distension the dysphagia gradually increases and may culminate in complete aphagia. One of the special indications of diverticulum is that the regurgitation does not take place until several hours after a meal. As the sac enlarges there may be less and less complaint of dysphagia, because it becomes able to contain larger quantities of food. At the same time it may so compress the main tube as to occlude its calibre and prevent access of food to the stomach.
The symptoms of annular dilatation are similar to those of stricture with retention of food above it, the regurgitation usually following deglutition more quickly.