The irritable bowel diseases

Crohn's Disease • Ulcerative Colitis
Similarities between the two diseases appear to overshadow their differences. How they actually differ should be emphasized.

Crohn's disease may affect any part of the bowel from the mouth to the anus. Ulcerative colitis attacks only the colon; Crohn's disease involves the full thickness of the bowel wall. Ulcerative colitis inflames only the inner lining; ulcerative colitis is often cured by surgery, Crohn's disease usually doesn't respond to surgery.

The following questions have been posed to leading scientists in the field of gastrointestinal disorders. Their answers and other information gleaned from medical textbooks and journals are included.

Q: To what extent does irritable bowel disease (IBD) affect other parts of the body?
A: The gastrointestinal tract extends from the mouth to the anus. It is a continuous tube that allows nutrients to enter and wastes to pass out of the body. It also protects the body from infection through the complex network of immunity cells.

The continuous tube that forms the various organs (mouth, esophagus, stomach, small intestine, large intestine, rectum and anus) consists of layers that make up the bowel wall. The inner layer of the bowel wall is called the mucosa, or mucous membrane layer. Inside the bowel wall is the hollow space called the lumen which contains the food we eat in various stages of digestion. Food passes through the lumen. Salivary glands, liver, gall-bladder, and pancreas empty their secretions to aid in digestion.

Q: How does ulcerative colitis begin?
A: The condition is marked by several steps: diarrhea -- and consequent dehydration; fever when the inflammatory process is entrenched; arthritis of the medium-sized joints; eye inflammation; skin lesions; progressively severe bleeding causing anemia; loss of protein and swelling; and development of a toxic megacolon as the severity of inflammation spreads throughout the bowel.

Fortunately, medical treatment by an expert can alleviate these discomforts and control their progress.

Q: Although Crohn's disease and ulcerative colitis are two distinct diseases, confusion exists among both lay people and some doctors. What are the characteristics of Crohn's disease?
A: Crohn's disease usually involves the lower third of the small intestine. Inflammation caused by Crohn's disease is called ileitis if it involves only the ileum and ileocolitis if it involves both the ileum and cecum. Inflammation occurs first, then small ulcers on top of the inflammation. Often these small sores may not cause bowel disorders for several years. Occasionally, a flare-up in the mouth can be the first signs of Crohn's disease. Eventually, patients will notice cramps and dull pain in the right lower part of the abdomen about 60 minutes after a meal.

The discomfort usually lasts for only a few minutes and has been dismissed as "gas." As time passes, the pains and discomfort become more severe. Many patients begin to eat less to avoid the inevitable distress. They also lose about one-fifth of their body weight.

At this stage, diarrhea has not yet become a problem, although inflammation may cause intestinal contents to ooze into the walls of the colon.

Other complications of Crohn's disease include severe bleeding, abscesses, inflammation of the sacroiliac joints, eye problems, such as iritis (blurred vision, redness, and eye pain). Serious skin disorders, such as deep ulcerations on legs and forearms, may erupt. Ulcers in the mouth may recur with intestinal inflammation.

Irritable bowel disease, a disorder of unknown origins, appears in organs along the gastrointestinal tract in various forms and stages but is quite different in appearance when it finally erupts in either the upper (small) colon (Crohn's disease) or the lower (large) colon (ulcerative colitis).

Arthritis is one example of a disorder, seemingly unrelated, that is the result of irritable bowel disease.

Q: How does a gut with a normal appearance turn into the inflamed, painful ulcerated intestine typical of IBD?
A: When the mucosal immune barrier breaks down, harmful bacteria enter the various layers of the intestine. An inflammatory reaction results in swelling (edema), increased blood flow, and ulcerations. Such ulcerations penetrate the bowel wall and affect the full thickness of the intestine. These are typical of ulcerations caused by Crohn's disease.

Eventually, some healing occurs, leaving fibrous scarred tissue around the areas that were previously inflamed. A narrowing of the bowel ensues, causing partial or total obstruction of the intestinal flow.

Q: What causes the intestinal barrier to break down?
A: Some researchers say that the immune response is a chronic state of inflammation, initiated by an unknown antigen, and stimulated by constant leakage of bacterial products through the wounded bowel wall.

Others maintain that the inflammatory cells are reacting to the patient's own tissues as if they were foreign (autoimmunity). The question remains: Are the immune responses observed in IBD the cause of the ailment or overreactive response to a substance not yet defined? Is IBD caused by an infectious agent, or is it an allergic reaction? Medical science, frankly, is baffled.

Q:. Can a diagnosis of IBD be made?
A: No tests are absolute. The following procedures can produce information useful in diagnosing the presence of IBD: blood and urine tests, sedimentation rate, stool examinations, radiologic procedures (barium enema, upper GI, and small bowel inspection, and endoscopic procedures), sigmoidoscopy, colonoscopy, and upper gastrointestinal endoscopy -- including biopsy.

Q: What are the characteristics of ulcerative colitis?
A: Colitis is defined as an inflammation of the colon, or the large intestine. Ulcerative colitis always involves the rectum. The condition can be reviewed easily by a physician while using a sigmoidoscope. Degrees of inflammation can be determined by the appearance of only blood (mild), formation of tiny ulcers and patches of mucus (moderate), or increased blood on the mucosa surface, and narrowing of the lumen of the rectum (severe).

Colitis is often limited to the rectal segment in about 50% of patients. It is then known as ulcerative proctitis. Some people have the disease only in the sigmoid colon and the upper part of the rectum (proctosigmoiditis).

Ulcerative colitis may also be classified as distal or leftsided, in which inflammation extends from the rectum to the descending colon.

Bleeding is a symptom of ulcerative colitis, but it is seldom seen on toilet tissue. The blood is passed into the toilet bowel and comes directly from the rectum.

Ulcerative colitis is often accompanied by rectal discomfort (bowel urgency or tenesmus).

Q: What causes IBD?
A: The exact cause of IBD is not known. Although stress alone is not a direct cause, episodes of anxiety, depression, or excitement may triger IBD or aggravate an existing condition.

Q: What causes IBD? (Second opinion)
A: Because no one has an answer that has been scientifically determined, one should at least give serious thought to the effects of chronic constipation and the use of cathartics.

We know that many parents are impatient with a baby's inability to deliver its waste on time and when convenient to the parents. Few handlers of infants hesitate to administer cathartics. Most of these agents are harsh and habit-forming. Consequently, the infant's intestinal tract can become irritated and highly vulnerable to infection and reinfection.

We also know that the frequent use of laxatives can lead to chronic constipation, another condition in which waste matter and toxins accumulate. Again, the probability is low-grade infection with compounding of waste and toxins clinging to the intestinal walls.

Scientific proof? We have none because little research has been conducted with laxatives and constipation as possible contributors to Crohn's disease and ulcerative colitis.

Why doesn't it happen to everyone so abused? Biologic individuality. The principle is understood when we deal with the questions of contagion; not everyone becomes ill when exposed to the same type of germs.

Q: What are the chances of dying from an attack of irritable bowel disease?
A: Despite the fact that Crohn's disease and ulcerative colitis are chronic disorders, it is unlikely that a person will die from an attack of IBD, from surgery, or from any related illness. Statistics confirm the supposition that IBD patients live as long as other people their own age.

The question of cancer risk arises frequently. The answer is that when IBD is treated in its early stages, the probability of cancer development identified with IBD has become less frequent.

Q: Which parts of the world is IBD most predominant?
A: Countries reporting the highest occurrence rates are the United States, England, Scotland, Scandinavian countries, several in Western and Central Europe, and Israel.

Mysteriously, few cases have been reported from Asia (except Japan), Equatorial Guinea (in Africa), and South America. These are countries where sanitation standards are low and other infections high.

Q: Could environment have an effect on IBD rates?
A: Epidemiologists (scientists who study populations and their health) have found no difference between IBD in rural Communities compared with that in urban dwellers. No environmental contaminant could be found that would contribute to IBD.

Q: Is race a factor in the incidence of IBD?
A: The mystery deepens. IBD seldom appears among Asians, Asiatic Indians, American Indians, or Africans. When these groups migrate to Western societies, however, IBD develops in equal numbers to the society in which they choose to dwell.

Black men and women have IBD at the same rate as whites do in the United States.

Q: Could IBD be a genetic disease?
A: Crohn's disease and ulcerative colitis seem to occur in families. Physicians report that although the diseases can run in families, it is not genetic. A family structure might harbor IBD, but that does not mean that an individual will inherit it.

Q: Since IBD is an infection, what part might viruses and bacteria play?
A: IBD is an infection, yet patients are not infectious. It is not a contagious disease. There are bacterial groups now under suspicion and antibacterial drugs are used to treat inflammations of the intestinal tract. The probability of the immune system having a role in IBD is great. Medical science, however, has not determined just how it responds. Anticolon antibodies have been found in the blood of patients with Crohn's disease.

PHOTO: A caricature of a women in an X-ray showing her "plumbing" breaking apart.

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By Willliam Benaurd, Jr.

IBD NOT THE ONLY CAUSE OF SERIOUS DIARRHEA
Chronic diarrhea is defined as the passage of more than 200 grams of stool per day for more than three weeks. The condition may result from decreased absorption of gastrointestinal contents or increased fluid secretion into the bowel.

Although chronic diarrhea can have many causes, irritable bowel syndrome, lactose intolerance, dietary influences, Crohn's disease and ulcerative colitis are frequently present.

Possible underlying causes of chronic diarrhea can be found in the following categories:

Dietary factors -- excessive use of caffeine (coffee, cola drinks, some pastries, foods that contain sorbitol and other artificial sweeteners).

Prescription drugs and laxatives -- alcohol, magnesium-containing indigestion aids, antibiotics, diuretics (loop), propranolol (Inderal), quinidine, theophyleine, thyroxine.

Infections -- Amebiasis, giardiasis, opportunistic infections associated with overuse of antibiotics, acquired immunodeficiency syndrome (AIDS), inflammatory bowel disease, Crohn's disease, ulcerative colitis.

Metabolic disorders -- Addison's disease, diabetes, hyperthyroidism.

Tumors -- Colon cancer, endocrine tumors, intestinal lymphoma, cancer of the thyroid, pancreatic cancer, villous adenoma.

Emotional disturbance and anxiety attacks which often cause temporary diarrhea, do not qualify for inclusion in chronic states of diarrhea.

Other symptoms, such as Weight loss, heighten the possibility of colon-problems caused by thyroid disorders or malabsorption of food. Arthritis associated with diarrhea, suggests inflammatory bowel disease or Whipple's disease (excessive deposits of fat in the intestinal lymphatic tissue).

Fever and chronic diarrhea may develop from ulcerative colitis, Crohn's disease, amebiasis (a protozoan infection) lymphoma, and tuberculosis.

If diarrhea persists after excessive testing, referral to a gastroenterologist is suggested. A full colonscopy with several biopsies may be necessary to identify the underlying problem.

THE WAR ZONES
The structure of the small intestine (1) consists of a layer of cells, a mucosal lining, a connective tissue support (submucosa) and a fine submucosal smooth muscle layer. The mucosa is surrounded by a circular (annular) smooth muscle layer, followed by a longitudinal smooth muscle layer covered on the outside of the serosal connective tissue.

The colon (2) is structured like the small intestine with both circular and longitudinal smooth muscle. The segmented contractions of the circular muscles cause the divisions of the colon into sausage-like units that slow down the passage of the colonic contents. A decrease in the occurrence or intensity of the segmental contractions of the circular muscles and predominance of the propulsive forces of the longitudinal muscles may lead to diarrhea.

There are about one million neurons in the small intestine nervous system, and they contain a variety of neurotransmitters. One particular neurotransmitter, serotonin, is particularly involved (with acetylcholine) in the genesis of intractable diarrhea.

(3) stomach (4) to anus and rectum

DIAGRAM: The gastro-intestinal system

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