A 31-year-old woman has a 6-year history of abdominal pain and bloating. She has had an irregular bowel habit with periods of increased bowel actions up to four times a day and periods of constipation. Opening her bowels tends to relieve the pain which has been present in both iliac fossae at different times. She had similar problems around the age of
17 years which led to time off school. She thinks that her pains are made worse after eating citrus fruits and after some vegetables and wheat. She has tried to exclude these from her diet with some temporary relief but overall there has been no change in the symptoms over the 6 years. One year previously she was seen in a gastroenterology clinic and had a
sigmoidoscopy which was normal. She found the procedure very uncomfortable and developed similar symptoms of abdominal pain during the procedure. She is anxious about the continuing pain but is not keen to have a further endoscopy.
She has a history of occasional episodes of headache which have been diagnosed as migraine and has irregular periods with troublesome period pains but no other relevant medical history. She is a non-smoker who does not drink alcohol. Her paternal grandmother died of carcinoma of the colon aged 64 years. Her parents are alive and well. She works as
Examination of the cardiovascular and respiratory systems is normal. She has a palpable, rather tender colon in the left iliac fossa.
• What is the most likely diagnosis and what investigations should be performed?
The pattern of the pain, the absence of physical signs, normal investigations and reproduction of the pain during sigmoidoscopy all make it likely that this is irritable bowel syndrome (IBS). This is a very common condition accounting for a large number of referrals to gastroenterology clinics. IBS is often episodic, with variable periods of relapse and
remission. Periods of frequent defaecation alternate with periods of relative constipation.
Relapses are often associated with periods of stress. In IBS it is common to have a history of other conditions such as migraine and menstrual irregularity. Under the age of 40 years with a history of 6 years of similar problems, it would be reasonable to accept the diagnosis and reassure the patient. However, the family history of carcinoma of the colon
raises the possibility of a condition such as familial polyposis coli. The family history, the circumstances of the grandmother’s death and the patient’s feelings about this should be explored further. Anxiety about the family history might contribute to the patient’s own symptoms or her presentation at this time. If there are living family members with polyposis coli, DNA probing may be used to identify family members at high risk. If any doubt remains in this woman it would be sensible to proceed to a barium enema or a colonoscopy to rule out any significant problems.
The diagnosis of IBS relies on the exclusion of other significant conditions such as inflammatory bowel disease, diverticular disease or large-bowel malignancy. In patients under the age of 40 years it is usually reasonable to do this on the basis of the history, examination and a normal full blood count and ESR. In older patients, sigmoidoscopy and barium enema or colonoscopy should be performed. A plan of investigation and management should be clearly established. The symptoms tend to be persistent and are not helped by repeated normal investigations looking for an underlying cause. Symptoms may be helped by antispasmodic drugs or tricyclic antidepressants. Some patients will benefit from the
consumption of a high-fibre diet.
• Irritable bowel syndrome is a common disorder and difficult to treat.
• Explanation of the condition to the patient is an important part of the management.
• Sigmoidoscopy with air insufflation often reproduces the symptoms of IBS.