There is a lack of consensus on the definition of ‘chronic idiopathic constipation' (CIC). This makes diagnosis a challenge.
Working definition of chronic idiopathic constipation
A working definition that is used for chronic idiopathic constipation is:-
Persistent constipation of less than three bowel motions per week
Passage of hard and lumpy stools
Straining despite appropriate management for at least 12 months
Absence of any other nerve or other pathology that could have led to the symptoms of constipation
Ruling out other conditions
Deformities and developmental abnormalities of the anus and rectum as well as spinal defects, Hirschsprung's disease and non-retentive fecal soiling should be ruled out before diagnosis of chronic idiopathic constipation is confirmed.
A detailed history of the condition is obtained. Red flags or warning signs that could mean some other more serious conditions also need to be ruled out. Some of the warning signs include:-
Blood in the stool
Onset of symptoms after age 50
Family history of bowel cancer and inflammatory bowel disease like ulcerative colitis and Crohn's disease
Presence of fever and low blood count
Severe constipation not responsive to treatment
Unexplained weight loss
Other details including use and abuse (over-zealous use) of laxatives, doses, duration and results of laxative use, celiac disease, anorectal/spinal malformations etc. are checked for.
This is followed by physical examination. The growth of the patient (if a child), abdomen, spine, testicular reflex, pelvic floor muscles, and rectum and anus anatomy are all checked. Testicular reflex shows a retraction of the testicle of the same side if the inner thigh is stroked.
There may be distension and bloating of the abdomen with bowel sounds and pain and feeling of a hard lumpy mass in the abdomen. In case of spinal abnormalities there may be hairy or pigmented lesions over the spine with flat buttocks or curved and bent spinal column.
After a superficial examination a digital rectal examination is performed. In this a gloved finger is inserted gently into the anus with the help of a local anaesthetic agent to check for tumors, masses, pain and other abnormalities of the anus and rectum.
Investigations for chronic idiopathic constipation
First a plain X-ray film of the abdomen is obtained. This may show the lump of fecal matter. There are other imaging studies like the transit study, Barium contrast enema etc. that show the bowel transit time across the colon and rectum.
A spinal MRI scan is obtained for ruling out spinal defects and injuries.
To check for the tightness and pressure within the rectum and the anus an anorectal manometry is performed. This involves inserting a thin tube like instrument to check for the pressure within the rectum and the anal sphincter. A colonic manometry may also be performed.
A rectal biopsy may be taken while examining the rectum. This involves taking a small tissue sample from the rectum and anus and examining it under the microscope.
A new method of diagnosis is by using a Smartpill that passes thorough the gastrointestinal tract when swallowed and sends signals about the transit, pH, temperature and pressure within the gut to an external receiver.