Functional Bowel Disorders


Patients and doctors differ greatly in their understanding and use of the word constipation. For many people, it is used for the infrequent passage of stools. For others it can refer to the passage of very hard stools. There is huge variation in bowel habits and many patients go several days without opening their bowels. This is not necessarily abnormal.

There are a number of causes of constipation, including problems like an underactive thyroid and Parkinson’s disease. Constipation may be due to other causes and these can often be considered to be a transit problem or an evacuatory problem (obstructed defaecation syndrome). Patients with a transit problem have a slow or lazy colon that does not propel food through the bowel at the proper speed. Patients with an evacuatory problem may have difficulty with the actual process of emptying the bowels.

Patients with constipation often complain of hard or infrequent stools. Sometimes they also have symptoms of obstructed defaecation syndrome.

A flexible sigmoidoscopy or colonoscopy will excluded serious disease. A combination of a proctogram and transit studies distinguishes between a transit and a defaecatory problem

Faecal Incontinence

Faecal incontinence ranges from lack of control of wind to a complete loss of control of stool. It is a common condition with around 10-15% of people.

The three main causes are damage to the sphincter muscle, damage to the nerves to the sphincter / pelvic floor or a weak pelvic floor with prolapse. These are often related to damage from childbirth. Incontinence may not come to light until many years later, as the muscles get weakened further with ageing.

Patients may experience different patterns of incontinence. Some patients suffer from leakage of stool from the anal canal without them being aware that it is happening (passive incontinence). Other patients know that they need to open their bowels but cannot get to the toilet in time (urge incontinence).

A colonoscopy or flexible sigmoidoscopy will exclude a cause higher up the bowel. Anorectal physiology and an endoanal ultrasound examine the structure and function of the anal sphincter. If there is a suspicion that bowel prolapse may be causing the symptoms, then we may suggest a proctogram.

Chronic Anorectal Pain

Anorectal pain is commonly associated with ODS (about 50%). Less commonly (5%) patients complain of isolated anorectal pain. Its symptoms can be relatively non-specific and varied and it can sometimes be difficult to treat.

There are many causes of anorectal pain. Some people will have specific causes such as an anal fissure or abscess. Others might have a pelvic floor problem such as anismus, prolapse or an enterocoele. Nerve entrapment is a rare cause. Sometimes, no obvious cause for the symptoms is found and this is called proctalgia fugax or chronic idiopathic anal pain. The pain these patients feel is real but treatment, in the absence of a structural cause, is mainly symptomatic.

The nature of the pain varies between patients and may give a clue to its cause.

After an examination, tests will usually involve anorectal physiology and endoanal ultrasound. A proctogram and transit study is also often performed to check for any evidence of internal or external prolapse or an enterocoele. We may suggest investigations to rule out a back problem.