Irritable Bowel Syndrome
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Introduction
Irritable bowel syndrome (IBS) is very common, affecting 15% of Americans (and Canadians?) on a regular basis and making up 40-50% of referrals to gastroenterologists.
The Case of...
Causes and Risk Factors
As with other functional bowel disorders, stress of various forms is very important.
Different triggers for different people.
Apple juice especially, but others as well, can cause diarrhea, especially in infants.
Pathophysiology
A heightened response to noxious visceral stimuli, such as balloon distension of the rectum or sigmoid colon.
Signs and Symptoms
- history
- physical exam
History
The Manning Criteria includes:
- abdominal pain relieved with defecation
- increased frequency, increased looseness
- mucus in stool (better marker than for colitis)
- abdominal bloating
- sensation of incomplete rectal emptying
Rome III criteria:
Recurrent abdominal pain or discomfort at least once per week in the last 2 months, with symptom onset at least six months ago, associated with 2 or more of the following:
- improvement with defecation
- onset associated with change in frequency of stool
- onset associated with a change in form (appearance) of stool
Red flags require further investigations:
- weight loss
- rectal bleeding
- arthritis, skin rash
- nighttime symptoms
- family history of coloroectal cancer or IBD
- age of onset above 50
- abnormal lab or exam findings
Physical Exam
Normal physical exam, including rectal exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
blood tests normal; abnormal suggests other disease
stool culture and sensitivity, and ova and parasites, if diarrhea
lactose intolerance as contributor to bowel symptoms
tissue transglutaminase is an effective screening tool for celiac disease.
Diagnostic Imaging
Imaging cannot prove IBS, but barium enema or sigmoidoscopy can lean the diagnosis away from more serious conditions.
Differential Diagnosis
IBS is a diagnosis of exclusion.
- inflammatory bowel disease
- colorectal cancer
- lactose intolerance
- celiac disease
- gastroenteritis
- parasitic infection
Treatments
Psychological factors
Identify life stressors and help with anxiety or depression. Reassurance is very important.
Illness behaviour is common. Contract with people about their responsibilities. Frequent follow-up improves coping.
Diet
Ensure appropriate eating habits (Canada's food guide, increased cereal fibres, and fluid.
Breakfast is very important; this helps the bowels to become operational.
Identify and avoid food triggers, along with caffeine and other stimulants, fat, gassy foods, and lactose.
lactose
gluten sensitivity may be seen, even if there is no overt celiac disease
gas-producing foods: beans, onions, carrots, celery, bananas, prunes
Physical activity
Medications
for diarrhea: Immodium (loperamide) and fibre
for constipation: high fibre diet and fluids, PEG 3350 powder (osmotic stimulant)
antispasmotics: pinaverium (Dicetal), hyoscyamine, docyclomine
pain: TCAs, SSRIs, , trimebutine (Modulon); potential placebo effect
probiotics (Gugliemetti et al, 2011).
Consequences and Course
Resources and References
Topic Development
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