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...

 

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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.

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Pathophysiology

A heightened response to noxious visceral stimuli, such as balloon distension of the rectum or sigmoid colon

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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 suggesting irritable bowel disease or colorectal cancer:

  • weight loss
  • rectal bleeding
  • arthritis, skin rash
  • nighttime symptoms
  • family history of coloroectal cancer or IBD
  • age of onset above 50

Physical Exam

Normal physical exam, including rectal exam

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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.

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Differential Diagnosis

IBS is a diagnosis of exclusion.

 

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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.

 

Medications

for diarrhea: Immodium (loperamide) and fibre

for constipation: high fibre diet and fluids, PEG 3350 powder (osmotic stimulant)

pain: TCAs, SSRIs, pinaverium (Dicetal), trimebutine (Modulon); potential placebo effect

 

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Consequences and Course

 

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The Case of...

 

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Additional Resources

 

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Topic Development

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