Clinical features

The classical presentation is of a pain situated in the left iliac fossa that is usually relieved by defaecation or the passage of wind. The pain is unrelated to meals or other precipitating factors.

Another presenting feature is an erratic bowel habit. The patient complains of periods of constipation with small stools that look like rabbit pellets alternating with the passage of loose stools. There may be a feeling of incomplete emptying of the rectum. An organic disease is suggested by true watery diarrhoea.

Other features of IBS:

• the symptoms are very variable between patients. A patient may complain of pain from any site in the abdomen and may have a normal bowel habit. Also patients may complain of abdominal distension and excess flatus
• patient with this condition looks well. This is despite frequent painful episodes and perhaps several acute hospital admissions with a suspected acute abdominal pathology
• symptoms of this condition may be associated with times of increased 'stress'
• there are few signs but may include abdominal distension, tenderness over the colon and mucus on PR examination.
• air insufflation on sigmoidoscopy may reproduce the pain.

NICE (1) note that:

• healthcare professionals should consider assessment for IBS if the person reports having had any of the following symptoms for at least 6 months:
  • abdominal pain or discomfort
  • bloating
  • change in bowel habit
• all people presenting with possible IBS symptoms should be asked if they have any of the following 'red flag' indicators and should be referred to secondary care for further investigation if any are present:
  • unintentional and unexplained weight loss
  • rectal bleeding
  • a family history of bowel or ovarian cancer
  • a change in bowel habit to looser and/or more frequent stools persisting for more than 6 weeks in a person aged over 60 years
• all people presenting with possible IBS symptoms should be assessed and clinically examined for the following 'red flag' indicators and should be referred to secondary care for further investigation if any are present:
  • anaemia
  • abdominal masses
  • rectal masses
  • inflammatory markers for inflammatory bowel disease. If there is significant concern that symptoms may suggest ovarian cancer, a pelvic examination should also be considered

Formal definition of symptoms of irritable bowel syndrome are provided in the linked item.

Reference:

• (1) NICE (February 2015).Irritable bowel syndrome in adults - diagnosis and management of irritable bowel syndrome in primary care.