Irritable Bowel Syndrome

Ailments, illnesses, and syndromes of unknown etiologies.

Irritable Bowel Syndrome

In medicine ( gastroenterology ), irritable bowel syndrome ( IBS ) is a group of functional bowel disorders which are fairly common and make up 20-50% of visits to a specialist.

Features

Symptoms of IBS are abdominal pain or discomfort associated with changes in bowel habits in the absence of any structural abnormality. Colonic hypersensitivity is a sensitive but less specific sign of IBS. Depending on the kind of discomfort and bowel habits, IBS is also known as spastic colon , and can be subclassified into diarrhea-predominant (IBS-D), constipation-predominant (IBS-C) and IBS with alternating stool pattern (IBS-A). Typical is the overlap of IBS with chronic pelvic pain (this is probably due to misdiagnosis by the gynaecologist), fibromyalgia and mental disorder .

Diagnosis

According to the Rome II consensus conference of the American Gastroenterological Association and international medical societies on functional bowel disorders , the diagnosis of IBS can be made when the following criteria are fulfilled: At least 12 weeks, which need not be consecutive, in the preceding 12 months of abdominal discomfort or pain that has 2 of 3 features:

Relieved with defecation; and/or
Onset associated with a change in frequency of stool; and/or
Onset associated with a change in form (appearance) of stool.

Symptoms that cumulatively support the diagnosis of IBS

Abnormal stool frequency (for research purposes, "abnormal" may be defined as greater than 3 bowel movements per day and less than 3 bowel movements per week);
Abnormal stool form (lumpy/hard or loose/watery stool);
Abnormal stool passage (straining, urgency, or feeling of incomplete evacuation);
Passage of mucus ;
Bloating or feeling of abdominal distention.

(Source: AGA .)

The diagnosis of a functional bowel disorder always presumes the absence of a structural or biochemical explanation for the symptoms. This has to be excluded carefully via:

colonoscopy
esophagogastroduodenoscopy (EGD)
abdominal ultrasound
blood tests : full blood count , liver enzymes , electrolytes , renal function
stool chemistry (e.g. tests for exocrine pancreas insufficiency and other malabsorption conditions), stool microbiology , fecal fat
H 2 -tests for lactose intolerance and fructose malabsorption
deep duodenal biopsy or blood tests for celiac disease

A diagnostic test for IBS via assessment of colonic/rectal hypersensitivity using a barostat is currently being discussed. However, sensitivity and specificity are not yet high enough to render the method widely applicable.

Pathophysiology

Research on the etiology of IBS has not yet brought forth unanimous results. Changes in colonic motility and immunologic causes have been discussed. Hypersensitivity of the gut is a major finding in IBS patients. The association of IBS with stress is less clear. Studies have shown that there may be a correlation between IBS and prior sexual or physical abuse.

About 25% of patients develop symptoms after a hefty enteritis (partially after use of antibiotics , see also diarrhea ). In these cases, a prolonged immune reaction is currently discussed as pathogenetic . So far, this is mainly based on experiments in the animal model .

IBS is widely regarded as a conglomeration of disorders with similar symptoms but a different etiology (" trash can "). As with many other medical conditions, there is a lot of speculation about causes, including in the field of alternative medicine .

Treatment and Prognosis

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