Diagnosis of Irritable Bowel Syndrome (IBS)
Since there is no diagnostic marker associated with IBS, the diagnosis is based on symptoms and by excluding other diseases, which may have similar symptoms such as ulcerative colitis, colon cancer, diverticulosis, parasites, dysentery, and other infectious illnesses. To arrive at the diagnosis of IBS positively, the doctor usually will take the following steps:
1. Thorough medical history:
The doctor will take a complete medical history that includes a careful description of symptoms. The symptoms that favor diagnosis of IBS are
- Relief of abdominal pain with defecation
- Looser stools with the onset of pain
- More frequent bowel movements at the onset of pain
- Abdominal bloating or distention
- Feelings of incomplete evacuation, and
- Passage of mucus per rectum.
2. Physical examination:
Most patients, however, will be given a thorough physical exam, which is performed mainly to rule out other medical illnesses. The patient has an overall healthy appearance. The patient may be tense or anxious. The patient may present with sigmoid tenderness or a palpable sigmoid colon.
3. Laboratory test:
A stool sample will be tested for evidence of bleeding by using a special chemical test called Hemoccult slides. This is very important in the evaluation since IBS should not be associated with any bleeding. The stool will also be examined for evidence of microorganisms notorious for producing symptoms of diarrhea or constipation.
Other tests may be done to rule out the deficiency of enzymes required for digestion of milk sugar or check the level of hormones like thyroid, etc.
4. X-ray:
The doctor also may do diagnostic procedures such as x-rays of the lower G.I. series, also called a barium enema. It is a special type of X-ray that uses barium sulfate to outline the lining of the rectum and colon. Barium sulfate is a chalky chemical that shows up as white on X-ray film.
The individual is made to lie on his/her side on an x-ray table, and he/she will be given an enema of barium fluid through a tube that is inserted into the rectum. You will be instructed to 'hold' the fluid inside while an X-ray technician will take a series of X-rays. The procedure is painless.
These studies were done with x-ray to help the doctor rule out conditions like tumor, inflammation, obstruction, Crohn's disease, etc.
5. Endoscopy:
Endoscopy is the process of viewing the inside of the colon and its various parts through a flexible tube inserted through the anus to find out if there is a disease. These examinations are usually performed to rule out other colon disorders, such as colon cancer, ulcers, inflammation, and other problems, that may produce similar symptoms.
The patient is asked to lie on his left side on the exam table. Medication will be given to limit any discomfort experienced during the procedure. Then, the doctor will insert a flexible colonoscope into your rectum. This test uses a colonoscopy, which is a flexible tube with lenses, a tiny TV camera, and a light at the end. Through fiber-optic technology and a video computer chip, the colonoscope can scan the inside of the colon and transmit images to a video screen.
The colonoscopy procedure can take up to 1 1/2 hours and is performed in a hospital as an outpatient procedure.
Since the mainstay of diagnosis of IBS is based on the patient's symptoms and complaints, the medical fraternity has laid down certain criteria for positive confirmation of irritable bowel syndrome. To know more about them, click here.
The Manning criteria to distinguish IBS from organic disease are as follows:
- On set of pain associated with more frequent bowel movements
- On set of pain associated with looser bowel movements
- Pain relieved by defecation
- Visible abdominal bloating
- The subjective sensation of incomplete evacuation more than 25% of the time
- Mucorrhea more than 25% of the time
Recently, a consensus panel updated the Manning Criteria. The result provides a standardized diagnosis for research and clinical practice.
During the past three months, have you experienced continuous or recurrent symptoms of:
- Abdominal pain or discomfort, which is:
- Relieved by defecation? and/or
- Associated with a change in frequency of stool? and/or
- Associated with a change of consistency of stool?
- Two of the following at least 25 percent of occasions or days?
- Altered stool frequency (more than 3 bowel movements/day or fewer than 3 bms/week)
- Altered stool form (lumpy/hard or loose/watery stools)
- Altered stool passage (straining, urgency, or feeling of incomplete evacuation)
- Passage of mucus
- Bloating or feeling of abdominal distension
Diagnosis is usually made after these symptoms have occurred for at least 3 months.
The Rome Criteria for the diagnosis of IBS require that patients have the following continuous or recurrent symptoms for at least 3 months:
Abdominal pain or discomfort characterized by the following:
- Relieved by defecation
- Associated with a change in stool frequency
- Associated with a change in stool consistency
Two or more of the following characteristics at least 25% of the time:
- Altered stool frequency
- Altered stool form
- Altered stool passage
- Mucorrhea
- Abdominal bloating or subjective distention
Written & Approved by-
Dr. Rajesh Shah
M.D. (Hom.)