It was my first time to meet the 23-year-old woman. Maria was complaining of crampy abdominal pain with alternating diarrhoea and constipation for a number of months. Her tummy often felt full, she said, and when she went to the toilet it felt like she was unable to completely empty her bowel. Although she has not mentioned it as a problem, when I examined her abdomen the most striking feature was how distended it was. It felt like a tight drum, with a percussion sound to match. Yet there was no tenderness and her bowel sounds were normal.
Her main concern was that she might have cancer. A natural worrier, she was the single mother of a toddler and lived with her parents; and although her tummy symptoms were intermittent, they were definitely made worse by stress.
With no family history of cancer or inflammatory bowel disease, no recent weight loss and no blood in her bowel motions, I decided that irritable bowel syndrome (IBS) was the most likely diagnosis.
Readers may be surprised that no investigations were carried out before I came to this conclusion. However, the concept that IBS is a diagnosis made after the exclusion of others is outdated.
If the woman had been older than 50 or if the symptoms had come on acutely, then referral to a gastroenterologist for investigations including a colonoscopy (examination of the bowel using a flexible telescope) would have been the correct course of action. But the diagnosis of IBS in younger people is now made intuitively, with a remarkable degree of safety and reliability.
As well as the typical tummy features described, many patients with IBS experience other symptoms including low backache, constant tiredness and thigh pain. Frequent urination and painful periods are also associated with IBS.
These extracolonic symptoms help make the diagnosis. But it is important that the patient be reassured that they do not represent a separate illness.
Up to 20 per cent of adults are affected by IBS; it is twice as common in women as men. Moreover, while the symptoms of the syndrome can be extremely severe, the good news is that IBS does not shorten a person's life or lead to cancer. In one US study over a 32-year period, death rates were similar among people with IBS compared with a control group without the disease.
The gastrointestinal tract is a long muscular tube that propels food along its length by a process of progressive contraction and relaxation. One theory is that patients with IBS have an altered gut muscle action. Patients with predominant diarrhoea may have longer than normal propulsive contractions. Those with predominant constipation may have fewer and shorter gut movements. And there is evidence that bloating is caused by an abnormal retention of intestinal gas.
A hypersensitivity towards pain and bowel symptoms has been reported in about 60 per cent of patients with IBS. A link has also been established between acute bacterial gastroenteritis and persistent irritable bowel symptoms.
But no reliable prospective studies exist to completely prove or disprove these theories as to the cause of the condition.
Psychosocial factors seem to be important in irritable bowel syndrome. In one study of IBS patients attending a gastroenterology clinic, 42-60 per cent had anxiety or depression as well as the bowel problem. This link has unfortunately led to an element of stigmatisation for IBS patients, who are reluctant to admit to having the condition in case they are labelled as psychologically disturbed. Stress definitely exacerbates IBS, but there is no evidence that it causes it.
Psychological intervention, such as cognitive behavioural therapy, relaxation training and hypnotherapy, have all been shown to be effective in reducing the symptoms of IBS. Patients are instructed how to control their symptoms and taught how to uncouple any previous association of symptoms with feelings of anxiety or distress.
Physical treatments involve the use of antidiarrhoeal drugs or laxatives depending on whether diarrhoea or constipation predominates. Antispasmodic drugs help to reduce abdominal pain.
From a dietary perspective, additional fibre may help constipation but it often worsens abdominal bloating and pain. Coffee, chocolate and sugar substitutes such as sorbitol can make IBS worse. Any food suspected of causing problems should be excluded from the diet for at least a month. The use of probiotics in patients with IBS is currently being investigated.
So how did Maria get on?
She still has IBS but it bothers her less since she underwent cognitive behavioural therapy. She takes peppermint oil and a regular small dose of laxative. And her symptoms have especially improved since she and her daughter moved into their own accommodation some years ago.
mhouston@irish-times.ie
Dr Muiris Houston is pleased to hear from readers but regrets he cannot answer individual queries.