Simple constipation: low-fibre diet, poor fluid intake, lifestyle and bad habit
Slow transit (idiopathic) constipation
Normal transit (irritable bowel syndrome)
Serious disorders not to be missed
Intrinsic neoplasia: colon, rectum or anus, especially colon cancer
Extrinsic malignancy (e.g. lymphoma, ovary)
Local anal lesions (e.g. anal fissure)
Drugs (opiates, iron, others)—see list
Thyroid disorder (hypothyroidism)
Spinal dysfunction (severe only)
Is the patient trying to tell me something?
May be functional (e.g. depression, anorexia nervosa).
Define what exactly the patient means by constipation. The history should include stool consistency, frequency, ease of evacuation, pain on defecation and the presence of blood or mucus. A dietary and drug history is important.
Basic tests are FBE/ESR, occult blood in stool
Consider serum calcium, potassium, CEA and TFTs
If appropriate refer for sigmoidoscopy or colonoscopy and radiological studies (e.g. CT colonography, bowel transit studies)
Alarm symptoms are rectal bleeding, recent constipation in those >40 years and family history of cancer.
Bleeding suggests cancer, haemorrhoids, diverticular disorder and inflammatory bowel disease.
Beware of hypokalaemia causing constipation in the elderly patient on diuretic treatment. Drugs selected associated with constipation: analgesics, opioids esp. codeine, TCAs, antacids esp. aluminium hydroxide, Ca channel blockers, SSRIs, cough mixtures, anti-cholinergics, benzodiazepines.