Irritable bowel syndrome

What is it?

According to the NIDDK: a group of symptoms that occur together, including recurrent abdominal pain and altered bowel habits, with no visible signs of damage or disease in the digestive tract, and a functional disorder of gut-brain interaction. It affects about 12% of people in the United States. The NHS describes it as a common condition affecting the digestive system that often lasts for life, but lifestyle changes and medicines ease the symptoms.

Subtypes according to the NIDDK (on days with abnormal bowel movements): IBS-C when hard stools exceed 25% and loose stools are under 25%; IBS-D the reverse; and IBS-M when each exceeds 25%.

Causes

Doctors do not know the specific cause; the NIDDK points to problems in gut-brain interaction that may affect the speed of digestion and the perception of pain.

Risk factors

Associated factors according to the NIDDK: painful early-life experiences, depression, anxiety and somatic symptom disorder, bacterial gastrointestinal infections, small intestinal bacterial overgrowth, food sensitivities, and genetic predisposition. Women are up to twice as likely to be affected, and people under 50 more than older people.

Symptoms

Abdominal pain often related to bowel movements, a change in bowel habits (diarrhoea, constipation or both), bloating, a feeling of incomplete evacuation, and white mucus in the stool. Symptoms may worsen in women during their period. The disease is chronic but the symptoms fluctuate (NIDDK). The NHS lists cramps, bloating and diarrhoea.

The NIDDK stresses that irritable bowel syndrome can be painful but does not lead to other health problems or damage to the digestive tract.

How is it diagnosed?

The doctor diagnoses irritable bowel syndrome when there is abdominal pain with two or more of: pain that improves or worsens after a bowel movement, a change in stool frequency, and a change in stool form, provided symptoms occur at least once a week over the last 3 months and began at least 6 months earlier (the doctor may diagnose with a shorter period). Assessment includes reviewing symptoms and the medical and family history (coeliac disease, colon cancer and inflammatory bowel disease) and an abdominal examination (NIDDK).

“In most cases doctors do not use tests to diagnose it”. When they are requested they are to rule out others: blood tests (anaemia and infection), stool tests, a hydrogen breath test, upper endoscopy with biopsy to rule out coeliac disease, and colonoscopy to rule out cancer and inflammatory bowel disease. Warning signs: anaemia, rectal bleeding, bloody or black tarry stools, weight loss (NIDDK).

Treatment

The treatment categories usually used are listed here; this is not a prescription. The doctor chooses the plan according to each person's condition; do not change any medicine or dose without a specialist.

Dietary changes according to the NIDDK: increasing fibre, avoiding gluten, and following the low-FODMAP diet. Lifestyle: more physical activity, reducing stress-causing situations, and enough sleep. The doctor may recommend probiotics although research on their effectiveness is still ongoing.

Medicines by symptom (chosen with the doctor): for diarrhoea loperamide, rifaximin, eluxadoline and alosetron; for constipation fibre supplements, laxatives, lubiprostone, linaclotide and plecanatide; for pain antispasmodics, antidepressants (tricyclic and SSRI) and enteric-coated peppermint oil capsules. Psychological therapies: cognitive behavioural therapy, gut-directed hypnotherapy, and relaxation training.

The NHS says lifestyle changes and medicines help ease the condition.

Living with it

The disease is often chronic with fluctuating symptoms; most people learn to control it by tracking what triggers symptoms (food, stress, menstrual cycle) and discussing it with the doctor. This page does not cover specific improvement rates.

Common questions