Drugs. (4)
Opioids.
Tricyclic antidepressants.
Iron containing medication.
Antihypertensive medication.
Colorectal and anal pathology. (3)
Colorectal carcinoma.
Anal Fissure.
Strictures.
Endocrine. (4)
Hypothyroidism.
Hypercalcaemia.
Diabetes Mellitus.
Phaeochromocytoma.
Neurological. (4)
Autonomic neuropathy.
Spinal cord injury.
Multiple sclerosis.
Parkinson’s disease.
Other.
IBS.