The word ostium means «opening» Thus the words ileostomy and colostomy refer to openings into the ileum and colon, respectively, which are the subjects of this chapter. Other ostomies include gastrostomies and jejunostomies, which usually are formed for the purpose of alimentation, and ileal loop urostomies, which are formed to replace the urinary bladder.
An ileostomy is usually the end result of a total proctocolectomy. A colostomy may be formed after a partial colon resection, typically for cancer, diverticulitis, or ischemic disease.
Formation of ostomies
Most ileostomies and colostomies are formed by bringing the bowel out through an incision in the abdominal wall and suturing the mucosa to the skin. Some are «double-barrel» meaning that the bowel leads both to and away from the opening. Two important modifications of ileostomies are available.
The Kock pouch, or continent ileostomy, is a pouch fashioned from ileum just proximal to the ostomy and functions as a reservoir for stool. The stoma is formed in the shape of a nipple, which is cannulated for drainage several times a day. Most patients with Kock pouches remain continent and do not require an ostomy bag.
The second modification is not actually an ileostomy but rather a form of anorectal anastomosis, called an ileorectal pull-through. The entire colon is removed except for the distal rectum. The distal rectum is stripped of mucosa, and the ileum is connected to the anus within the muscular sheath of the rectum, which includes the anal sphincter. To improve continence, a pouch can be formed from the distal ileum.
Consequences and complications of ostomies
Because the colon absorbs water and electrolytes in sufficient amounts to form a firm stool, patients with ileostomies can be expected to lose water and electrolytes more than healthy people do. The normal daily stool of a person whose bowel is intact weighs 100 to 200 g and contains 80% to 85% water. A normally functioning ileostomy discharges 500 to 1,000 g of stool per day, containing 90% to 95% water. Furthermore, whereas healthy people can reduce stool sodium losses to 1 to 2 mEq per day by conserving sodium in the colon, patients with ileostomies have obligatory daily sodium losses of 30 mEq or more.
If the terminal ileum has been removed in addition to the colon, bile salt and vitamin B12 malabsorption may occur. The loss of bile salts may predispose to steatorrhea, which worsens the diarrhea.
Complications of ileostomies and colostomies include irritation of the skin surrounding the ostomy, obstruction of the ostomy, recurrence of inflammatory bowel disease at or proximal to the stoma, and mechanical difficulties with the stoma appliances. Patients also may have psychological and social problems related to the ostomy.
Management of the patient with an ostomy
Preoperative considerations. Ileostomies and colostomies are performed under elective conditions in most instances. Thus, there should be adequate time to discuss the intended surgery with the patient, explain the necessity for the ostomy, explore the patient’s concerns about it, review possible consequences and complications, and reassure the patient that after full recovery from surgery, most patients are able to conduct normal lives, including participation in normal physical, sexual, and social activities.
The physician, surgeon, and ostomy nurse all play important roles in the preoperative preparation of the patient. Patients almost always benefit from talking with another person who has an ostomy. Such people may be well known to the physician or the ostomy nurse or they may be contacted through the local Ostomy Association, which is listed in the telephone book of most medium-to-large communities. The United Ostomy Association is a source for informational material.
The skin surrounding an ostomy is at risk for injury. Patients with an ileostomy are likely to have more skin irritation than patients with a colostomy because ileostomy stool is liquid and contains digestive enzymes. Tape and ill-fitting appliances can also contribute to skin excoriation.
Nondetergent soap and water are the most appropriate peristomal skin-cleansing agents. A variety of skin-conditioning agents and seals for appliances are available. However, an improperly fitting appliance will negate the best skin care.
Fluids, salt, and diet
Fluids and salt.
Because patients with ileostomies may lose up to a liter of water and 30 mEq of sodium in the stool per day, they are encouraged to drink 2 to 3 L of water per day and not to restrict salt. Mild-to-moderate diarrhea may be treated by increasing fluid and sodium intake and by adding bicarbonate of soda and orange juice to provide potassium. More severe diarrhea may require intravenous fluids and electrolytes. Patients with colostomies generally do not have problems with excessive loss of fluid and electrolytes because sufficient colon remains to maintain water- and electrolyte-conserving function.
Patients should be encouraged to eat a normal diet, with some modification. Gas-producing foods may cause discomfort and embarrassment. Fresh fruits may promote loose stools. Most patients discover through trial and error the diet to which they are best suited.
Vitamin and mineral supplements.
Some patients require vitamin and mineral supplements, particularly patients who have steatorrhea or vitamin B12 malabsorption.
Disagreeable odors from the ostomy bag can be distressful. The odors are due to gases that are derived from the action of bacteria on intestinal substrates. The problem is treated by emptying the bag frequently, avoiding gas-forming foods, and adding a deodorant to the bag, such as chlorine tablets or sodium benzoate.
Partial obstruction of the ostomy, usually an ileostomy, may result from recurrent disease, impaction of nondigestible material, or kinking of a loop of bowel just proximal to the stoma. Patients experience abdominal cramping pain and increased ostomy effluent.
Gentle examination of the stoma with the small finger is indicated. This may be followed by endoscopic examination, perhaps with a pediatric sigmoidoscope or fiberoptic gastroscope. Retrograde barium-contrast radiologic studies through the stoma also may be helpful.
Treatment is dictated by the diagnosis
Recurrent inflammatory bowel disease may respond to a course of treatment. Some patients require surgical revision of the stoma.