Abdominal obstruction will be one of your major challenges. It is a common abdominal emergency, and in some communities the most common one. Some patients with simple obstruction resolve spontaneously, for example those with ascariasis (often) or tuberculous peritonitis (often) or non-specific adhesions (less often). When you operate, you may only need to divide adhesions, or massage a ball of Ascaris from a child's ileum on into his colon. But if you find that his small gut is gangrenous, you will have to excise it and anastomose its ends. You cannot safely do this with the large gut, because an unprotected anastomosis of the large gut is dangerous. So you will have bring its ends to the surface temporarily in some form of ostomy (9.6). Or, you can resect the gangrenous part, join cut ends of his large gut, and protect the anastomosis you have made with a proximal colostomy (9.6).
Unfortunately, a patient with intestinal obstruction often presents late, so that by the time you see him he may be severely dehydrated, hypovolaemic, oliguric, and shocked. You will have little difficulty deciding that he is obstructed, but will he withstand an operation? Deciding why he is obstructed may have to wait until you do a laparotomy. When you look inside his abdomen, it may not be easy to recognize what has happened, to decide what to do, or to do it.
One of the many ways in which the industrial and the developing worlds differ is the way in which the guts of their inhabitants obstruct. In the industrial world intestinal obstruction is caused about equally by adhesions, hernias, and carcinoma of the colon. In the developing world adhesions and carcinoma of the colon are unusual. Their place is taken by ascariasis, volvulus of the sigmoid colon or small intestine, and by intussusception. Although developing countries differ, their similarities are more striking than their differences.
THE CAUSES OF INTESTINAL OBSTRUCTION vary geographically. Find out the common causes in your area.
Common causes. Incarcerated or irreducible external hernias (inguinal and femoral). Volvulus of the sigmoid colon. Ascariasis. Intussusception. Obstruction due to ileus due to sepsis; for example, when a patient presents late with sepsis resulting from a perforated typhoid ulcer, a tubo-ovarian abscess, appendicitis, or a perforated duodenal ulcer. Adhesions or bands following previous surgery, or abdominal sepsis. Adhesions or fibrosis due to abdominal tuberculosis.
Uncommon causes. Volvulus of the small gut. Carcinoma of the colon. Carcinomatosis of the peritoneum. Amoebic granuloma or stenosis.
Rare causes. Primary tumours of the small gut. Congenital bands. Crohn's disease. Mesenteric vascular occlusion. Gall- stone ileus. Diverticulitis. Lymphogranuloma.
WHAT IS THE PATTERN OF INTESTINAL OBSTRUCTION IN YOUR AREA? Fig. 10-5 INTESTINAL OBSTRUCTION. A, B, and C, small gut obstruction. In A, the obstruction is high, there is frequent vomiting, no distension, and intermittent pain, which is not of the classical type. In B, the obstruction is in the middle of the small gut. There is moderate vomiting, moderate distension, and intermittent pain of the classical, colicky, crescendo type with free intervals. In C, obstruction is low in the small gut. Vomiting is late and faeculent, and distension is marked. Pain may or may not be classical.
In D, and E, the large gut is obstructed. In D, the ileocaecal valve is competent, and prevents distension spreading to the small gut, so that there is a closed loop. In E, the valve is incompetent, so that there is reflux into the small gut which distends. After Dunphy and Way, ''Current Surgical Diagnosis and Treatment' Figs, 33-5 and 34-5. With the kind permission of Jack Lange.