Cláudio Wolff, MD, Gastroenterology Specialist by the Brazilian Federation of Gastroenterology.

Fábio Segal, MD., Ph. D. in Clinical Medicine by the State University Rio Grande do Sul.

Fernando Wolff, MD.


Alternative names:

Spastic colon, nervous stomach, mucous colitis

What is it?

It’s a set of chronic or recurrent gastrointestinal manifestations not associated to any known biochemical or structural change thus far. The number of people affected by this syndrome reaches 10-20% of the population in European countries and in the United States. Among those that seek medical care, the majority is comprised of women, usually in their late adolescence or prior to age 30.

How does it develop?

The cause of irritable bowel syndrome (IBS) is not well known; thus, we don’t know how an individual starts experiencing symptoms from a certain point on.

Changes to the movements conducting the food from the mouth down to the anus (colonic motility) and changes to the electric stimuli, responsible for this intestinal movement, are believed to be involved.

It’s also been observed that individuals with IBS have a lower threshold for pain originating from intestinal distension, that is, smaller volumes of gas or feces inside the intestine are able to give rise to a sensation, interpreted by patients as pain, whereas individuals without the syndrome aren’t likely to be disturbed by similar stimuli.

Psychological changes as depression and anxiety are more frequent in IBS patients that seek medical care. It’s possible that these people perceive and react in a more intense way to lower stimuli.

What does one experience?

The main symptoms are crampy abdominal pain and abdominal distension associated to an increase in daily evacuation frequency and loose stools.

Symptomatic periods can be interposed between asymptomatic periods that last several years, but eventually tend to recur.

Pain is usually crampy, intermittent and more often located in the lower abdomen. It usually alleviates with evacuation and aggravates with stress or at the first hours following meals.

Feces, in most patients, are diarrheic (loose or aquous) and may contain mucus. Other patients complain about constipation (they evacuate less than usual or less than once a week).

Also are common symptoms in IBS patients:

Abdominal distension or bloating,
Shifting periods of diarrhea and constipation,
Excessive flatulence (gases),
Sensation of incomplete emptying after evacuation.

How does the doctor diagnose it?

The diagnosis is made relying on the symptoms presented by the patient. To confirm the diagnosis, no changes should occur in the clinical examination or laboratory tests.

Generally, the doctor requests general blood and stool tests able to detect the most frequent parasitoses.

These tests don’t intend to support the IBS diagnosis, rather, they serve to root out other causes of similar symptoms, as there’s no test that can confirm an IBS diagnosis.

In individuals with onset of symptoms after age 40 and in those with family history of colon cancer, an evaluation by colonoscopy or, less frequently, by dual-contrast barium enema is indicated to root out this possibility.

The presence of fever, bleeding, anemia, weight loss, night symptoms and highly frequent diarrhea of large volume aren’t features of IBS and must prompt an investigation into another cause.

How is it treated?

Initially, it’s necessary that the doctor enlighten the patient about the disease.

Learning that it is a disease of benign course and that it doesn’t result in or progress to a more severe circumstance is a very important step, able alone to tranquilize and get the symptoms to be better tolerated.

The fact that psychological factors may be associated and even trigger more symptomatic periods and that no changes accounting for the condition are found shouldn’t lead us to think they’re imaginary. They do exist; however, their cause and mechanism can’t be explained by today’s scientific knowledge.

A diet rich in fibers is usually useful in patients complaining about constipation, and a better colonic transit can help patients who complain about excessive flatulence.

Some foodstuffs are poorly tolerated by IBS patients. Keeping a dietary journal correlating symptoms with foods previously ingested may detect triggering foods.

Some vegetables such as black beans, cabbage, cauliflower, raw onion, grapes and plums are causes of pain or distension in some patients. Wine, beer, and foods or drinks with caffeine (coffee, tea, etc.) may be poorly tolerated as well.

A large majority of patients get better by understanding their disease and with changes to their diets. In cases in which a particular symptom is especially uncomfortable, symptomatic medications directly directed at treating diarrhea, constipation or abdominal pain can be used.

In some cases, the use of antidepressants is beneficial.

No medication has been proven to be effective in IBS treatment so far. We must be very careful when using largely advertised drugs, of which the actual validity and, especially, safety haven’t been well established.

How is it prevented?

As little is known about the causes and mechanisms of the disease as of yet, nobody can tell how to prevent it.

The search for medical assistance for elucidating the condition and management of specific symptoms avoids the disease to cause further consequences in the patients’ lives.

IBS should be regarded as a disease that is: br> 

Chronic and recurrent,
Without prevention or specific treatment,,
With highly benign characteristics,,
Sensation of incomplete emptying after evacuation.
Without increased risk of progressing into a more severe condition, generally allowing its carriers to maintain their life quality and productivity unchanged.

Questions you can ask your doctor:

Is this that I have a disease?

How come the tests don’t show any changes when I feel pain?


It there any treatment?

Do I always have to take medicine or only when I feel something’s wrong?

Is my psychological state related with my symptoms?