Assessment of constipation in adults
When assessing adults with constipation, take a detailed medication history, including prescription and over-the-counter drugs, complementary and alternative medicines, and laxatives. Constipation is an adverse effect of many commonly used drugs (see Examples of drugs that commonly cause constipation) and changing medication can restore bowel function.
In general, the need for investigation depends on the severity of the symptoms, the patient’s age, and the presence of clinical features that warrant further investigation (see Clinical features that warrant further investigation of gastrointestinal symptoms). Potentially serious medical conditions (such as depression, hypothyroidism, hypercalcaemia, bowel cancer, and obstruction from other causes) must be considered and excluded. Chronic constipation alone does not have a predictive value for bowel cancer, but bowel cancer should be considered if constipation is associated with weight loss, rectal bleeding or new onset of symptoms in a patient older than 50 years.
Physical examination should include a digital rectal examination to determine if the rectum is loaded with faeces, and assessment for dyssynergic defecation. In adults, an abdominal X-ray can be useful to determine the extent and location of faecal loading.