Annular dilatation is usually due to circumferential distension just above a stricture. When not due to stricture its seat is usually just above the diaphragm, where the oesophagus is normally liable to constriction. The upper portion of the dilatation is larger than the lower portion, and the muscular walls are usually hypertrophied.
Pouched dilatation (diverticulum) is usually formed chiefly of mucous membrane and submucous tissue pushed through gaps in the fibres of the muscular coat, produced by distension. It sometimes involves the entire coat in cases in which the oesophageal wall has become adherent to enlarged lymphatic glands, which subsequently undergo subsidence in volume and drag the adherent portion of the wall after them (Rokitansky). The muscular walls are then usually hypertrophied, the mucous membrane sometimes hypertrophied, sometimes atrophied. The diverticulum is usually located in the upper portion of the oesophagus, just below the inferior constrictor muscle of the pharynx. It may thus be, in part, a pharyngocele also. It may be located behind the point of bifurcation of the trachea or where the oesophagus is crossed by the left bronchus. Its direction may be to the left side in the upper portion of the oesophagus, to the right side, or upon both sides; but when situated lower down it is usually directed backward, between the posterior wall of the tube and the spinal column. Hence its distension with food completely blocks up the calibre of the oesophagus. The orifice by which the oesophageal wall remains in communication with the pouch is round or elliptic in shape and variable in size, sometimes being about an inch in its long diameter, sometimes much smaller. The size of the diverticulum varies; a common size is that of a duck egg, but the size of a fist has been attained. Sometimes the diverticulum drags the oesophagus out of position and forms a sort of blind pouch in the direct line of its axis, so that it becomes filled with food which fails to reach the stomach. Sometimes there are several dilatations.
The dilatations become enlarged by retention of food, and are liable to undergo inflammation, ulceration, and perforation.
DIAGNOSIS.—The diagnosis will depend upon the symptoms of dysphagia, regurgitation, and so on, and upon the evidence furnished by auscultatory indications, palpation with the oesophageal sound, and, in some instances, the existence of a tumor in the neck, enlarging after meals, and from which food or mucus can be forced up into the pharynx by pressure externally.
Stethoscopic auscultation of the oesophagus during the deglutition of water indicates an alteration in the usual form of the gulp, which seems to trickle rapidly in a larger or smaller stream according to the degree of dilatation. If the dilatation be annular and located high up, auscultation is said to give the impression of a general sprinkling of fluid deflected from its course. The peculiar gurgle is often audible without the aid of stethoscopy. Palpation with the oesophageal bougie is competent to reveal the existence of a large sac by the facility with which the terminal extremity of the sound can be moved in the cavity. In the case of a diverticulum, however, the sound may glide past the mouth of the pouch without entering it, although arrested at the bottom of the sac in most instances.
In annular dilatation any constriction below it is usually perceptible to the touch through the sound; but, on the other hand, the ready passage of the bougie into the stomach, while excluding stricture, does not positively disprove the existence of a circumscribed dilatation. If high up, the dilatation may be detected externally by its enlargement when filled with food after a meal, and the subsidence of tumefaction when the sac is emptied by pressure from without, or by regurgitation. If the dilatation occupy a position which exercises compression of the trachea, dyspnoea will ensue when it is distended. The intermittence of the tumefaction serves to differentiate the swelling from abscess or morbid growth. From aneurism of the aorta, which it may simulate (Davy34), it is to be discriminated by absence of the usual stethoscopic and circulatory manifestations. The diagnosis of congenital dilatation is based upon a history of difficulty in deglutition dating from the earliest period of recollection.
34 Irish Hosp. Gaz., 1874, p. 129; Med. Press and Circular, May, 1874.
PROGNOSIS.—The prognosis is not favorable in any given case unless the cause can be removed, and not even then unless food can be prevented from accumulating in the distended portion of the tube. Nevertheless, cases sometimes go on into advanced age. On the other hand, they may terminate fatally within a year (Lindau35). The danger of perforation adds additional gravity to the prognosis, for life may be suddenly lost by this accident. Death usually takes place by inanition. A case of death by suffocation has been recorded, attributed to the pressure of the distended oesophagus upon the intrathoracic vessels (Hannay36).
35 Casper's Wochenschrift, 1840, No. 22; Arch. gén. de Méd., 1841, p. 498; Dict. de Méd et de Chir., xxiv. p. 410.
36 Edinb. Med. and Surg. Journ., July 1, 1833.