Etiology

Chronic intestinal obstruction may be caused by the same factors which produce acute ileus if they do not occlude the entire lumen of the bowel but leave part of the canal open. Besides, obstruction of the intestine is frequently occasioned by strictures resulting from preceding ulcers or from new growths. The latter, benign as well as malignant, are liable to give rise to occlusion even if they do not occupy the entire circumference of the bowel, by simply obtruding part of the canal at the site of their greatest development. Strictures caused by ulcers much more frequently involve the large than the small intestine. According to Treves, they are found six times as often in the large bowel as in the small one.

While formerly dysentery was believed to be the cause of a large number of these intestinal strictures, Woodward 1 has shown that this view is not supported by facts. Among the many autopsies on patients with chronic dysentery which the latter had an opportunity to observe, there was not one case of dysenteric stricture of the intestine. Nothnagel agrees with Woodward. On the other hand, tuberculous ulcers of the intestine which were regarded as only rare causes of intestinal stricture have recently been found to produce strictures quite frequently. Koenig2 laid stress upon the frequency of constricting tuberculosis of the intestines. The latter may exist even if tuberculosis in other organs is absent. Ulcers of typhoid fever very rarely if ever cause strictures, and this also applies to the small follicular ulcers. Syphilitic ulcers on the contrary produce strictures quite often. All kinds of strictures are met with most frequently in the lower portion of the colon, principally in the rectum.

Sometimes they lie just above the anal region and can then be very easily discovered.

Symptomatology

The symptoms and the course of the disease vary considerably, and greatly depend upon the cause of the obstruction. Thus, clinically, the benign growths must be differentiated from the malignant ones (in which the obstruction is caused by cancer). The picture which the intestinal obstruction as such produces will, however, be pretty much the same. A stenosis which is not very much pronounced may give rise to no symptoms whatever. It is therefore quite evident that the disease may exist for some length of time before manifesting its presence.

In typical cases of chronic intestinal obstruction the onset is slow and insidious. The patient at first notices slight digestive disturbances, some discomfort in the abdomen which gradually changes into real pain, and slight constipation. The latter as a rule quickly becomes worse. Mild aperients which a short while before were efficient refuse to act, and the patient is obliged to resort to stronger cathartics; at times even these will fail to work. Frequently constipation suddenly alternates with an attack of severe diarrhoea, which may last several days and be followed by another period of obstinate constipation. In some instances the color and form of the fecal matter will be an indication of the seat of the stenosis. It is generally believed that pipestem-like or tape-like motions indicate a stricture in the colon. According to Treves,1 however, this sign is of very little value, as in the great majority of cases the sphincter muscle is the originator of these peculiar shapes. Diarrhoea may also occasionally occur. It is sometimes quite obstinate, especially if the stenosis is situated in the large bowel.

An admixture of blood or pus in the dejecta is occasionally met with and is due to ulcerative processes taking place at the seat of the stricture or immediately above it.

1 Woodward: Loc. cit.

2 Koenig: Deutsche Zeitschrift fur Chirurgie, 1891.

Vomiting is not a very marked feature at first, but later on occurs more frequently. When the obstruction, however, becomes complete, vomiting is a prominent symptom and may assume a stercoraceous character.

The situation of the obstruction has much influence upon the clinical picture of the disease. If the stenosis is situated in the duodenum above Vater's papilla, the symptoms will resemble those of stricture of the pylorus. Ischochy-mia, vomiting, nausea will be the prominent features. A stenosis of the duodenum below Vater's papilla, although presenting symptoms similar to those of stricture of the pylorus, will be recognized by the more or less constant presence of large amounts of bile in the stomach. The farther down in the small intestine the obstruction is situated, the less pronounced are the gastric symptoms and the more marked the intestinal manifestations (less vomiting or nausea, more constipation, colicky pains). If the stenosis is situated in the lower portion of the ileum or in the colon no gastric symptoms are as a rule present. The appetite is good, there is no nausea, and the principal features are obstinate constipation, sometimes alternating with diarrhoea and frequent attacks of colicky pains.

1 Treves: Loc. cit., p. 395.

Condition of the Abdomen. The abdomen may present a normal appearance when the stenosis is situated in the upper portion of the small intestine, although in some of these cases there may be a protrusion of the upper part of the abdomen. If the site of obstruction is in the lower portion of the small intestine or in the large bowel, then some distention of the abdomen is usually noticeable, especially after the disease has advanced considerably. Above the obstruction there is always distention and hypertrophy of the bowel. The latter is a manifestation of the attempt which nature makes in order to overcome the difficulty. The intestines above the stenosis act with greater force in order to propel the contents through the narrow passage.

The contraction of the bowel above the affected area often assumes a tetanic type and is then painful. Such violent tetanic contractions are often visible through the abdominal wall, and by propelling large amounts of liquids and gases through the narrowed lumen, give rise to gurgling and bubbling sounds audible at a distance. Treves thus describes the picture which this violent peristalsis manifests: "The surface of the abdomen becomes uneven, a rounded elevation appears in one place and depressions appear in another. They produce an aspect comparable to that of a relief map of a hilly country. Slowly the hill-like elevation sinks and vanishes and out of the shallow valley appear fresh eminences which rise up and move along beneath the skin. The movements are slow and attended by colicky pains, and by more or less of rumbling and gurgling sounds." . . . "The same coil appears again and again and can often be quite definitely recognized. Although as a rule the contracting coils of the small intestine are of considerably smaller size than those of the large bowel, occasionally even the small intestine may assume such dimensions that it cannot be differentiated from the large bowel."

Meteorism is often present. If the obstruction is situated in the lower portion of the colon or in the rectum, the meteorism is at first restricted to the large bowel, the distention then being pronounced along the course of the colon at both sides of the abdominal wall and in the epigastric region. The lower part of the abdomen and also the region of the navel may be free from meteorism. If the stricture is situated in the lower portion of the ileum or caecum, the lumbar regions of the abdomen are quite lax, while the distention is more or less pronounced in the me-sogastric and hypogastric regions.

After having described the symptoms of chronic intestinal obstruction in a general way it will be useful to point out separately the characteristics of some special forms which occur more or less frequently.

Chronic intussusception may develop either after an acute attack or begin slowly and insidiously without at first giving rise to any marked symptoms. It is most frequently found in the ileo-caecal portion. Pain occurs during the progress of the disease and is usually of a paroxysmal character. Attacks of pain may appear several times a day or once in twenty-four hours. Occasionally days and even weeks elapse between the paroxysms. As a rule the intervals between the attacks grow shorter as the disease advances. In some cases there is almost continuous suffering with occasional exacerbations. Vomiting seldom occurs and is certainly not a marked feature. A tendency to diarrhoea very often exists. The bowels may be normal or constipated for a while and then become loose, or there may be persistent diarrhoea. Blood is very often passed with the stools and tenesmus is occasionally present.

On examination of the abdomen by palpation a tumor is. found in almost half of the cases. The nature of the tumor corresponds to that found in acute intussusception described above. Occasionally a tumor can be felt in the rectum when the intussusception involves the lower portion of the large bowel. In rare instances the invaginated portion is separated from the bowel by necrotic processes, and may then appear in the movement. While this event may in rare instances lead to perfect recovery (the other portions of the bowel growing together and the lumen thus being restored), in the greater majority it causes death through perforation, rupture of the intestinal walls, and general peritonitis.