Irritable Bowel Syndrome

Symptoms

IBS is a disease of no obvious pathological abnormalities. It is a disorder that primarily affects the young. Until recently, IBS was thought to be somatic manifestations of psychological stress. Typically, patients with IBS are young and present symptoms before the age of 45. Symptoms of IBS include abdominal pain, altered bowel habits, gas and flatulence, and upper gastrointestinal symptoms. The most consistent clinical feature of IBS is the alteration in bowel habits. The most common pattern is the alternation of constipation and diarrhea and with one being the dominant symptom.

Initially, constipation occurs on an occasional basis progressing to a steady phase in which laxative treatments are no longer effective. Due to the prolonged retention of the stool in the colon, the stool is dehydrated and is usually hard. The constipation phase of IBS may last for weeks or months interrupted by brief episodes of diarrhea. If diarrhea is the predominating symptom, small, loose stools of volume less than 200 mL is the norm and the patients may also pass large amounts of mucus. Emotional stress and eating can aggravate diarrhea. Blood in the stool is not a feature of IBS unless it comes from hemorrhoids. Even though IBS patients present with constipation and diarrhea, they generally do not present with weight loss as a consequence of malabsorption.

IBS patients also frequently complain of increased passing of gas or belching and complain of distended abdomen. Although some IBS patients may actually have increased production of gas, studies have actually shown that most IBS patients generate normal amount of intestinal gas. Rather, IBS patients have impaired transit and tolerance of intestinal gas leading to indicated symptoms. Up to 50 percent of IBS patients also complain of symptoms in the upper gastrointestinal region. These include heartburn, nausea, dyspepsia, and vomiting. Abdominal pain in IBS patients is highly variable in location and quality. The pain is frequently described as crampy and/or a constant ache.

Risks

IBS accounts for up to 3.5 million physician visits a year in the United States. It is estimated that up to 50 percent of those with symptoms consistent with a diagnosis of IBS never seek a doctor's care. Those who do seek medical advice often had a major life event prior to seeking help (e.g., death in the family). Although IBS is a global disease, social and cultural factors affect the presentation and the diagnosis of IBS. In the West, it is estimated that up to 20 percent of adults show symptoms consistent with diagnosis of IBS. In the Western hemispheres, women have a higher incidence of the condition and are more likely to consult a physician. In south Asia, men in India have a higher incidence of IBS. In South Africa, IBS symptoms are more prevalent in black, urban dwellers than black, rural dwellers. In the United States, prevalence is equal between blacks and whites.

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