Irritable Bowel Syndrome

Question 1

What is irritable bowel syndrome (IBS)?

Answer 1

gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits in the absence of any organic cause - no specific abnormality

Question 2

What are the causes of IBS?

Answer 2

gastrointestinal motility and visceral hypersensitivity

Question 3

What are common symptoms of IBS?

Answer 3

chronic abdominal pain (crampy with variable intensity and periodic exacerbations), distention, bloating, gas, altered bowel habits (constipation or diarrhea)

Question 4

What are immune system mediators associated with IBS?

Answer 4

increased numbers of lymphocytes (stimulate the enteric nervous system leading to abnormal motor and visceral responses), increased numbers of mast cells, elevated levels of plasma proinflammatory interleukins (cytokines - proteins that are mediators of immune responses)

Question 5

What are some psychosocial dysfunctions associated with IBS?

Answer 5

more lifetime/daily stress, anxiety, depression, phobias, somatization

Question 6

Who is most likely to experience IBS?

Answer 6

younger patients and women

Question 7

What are the Rome criteria?

Answer 7

recurrent abdominal pain at least one day per week in the last three months associated with at least two of the following: related to defecation, change in stool frequency, change in stool form

Question 8

Which alarm symptoms are NOT associated with IBS?

Answer 8

rectal bleeding, nocturnal symptoms, progressive abdominal pain, weight loss, laboratory abnormalities

Question 9

What are the diagnostic evaluations necessary for IBS?

Answer 9

diarrhea predominant: stool cultures, celiac disease screening, 24 hour stool collection, colonoscopy/sigmoidoscopy, biopsy; constipation predominant: radiography, colonoscopy/sigmoidoscopy

Question 10

How is IBS classified?

Answer 10

25% of bowel movements threshold: constipation predominant: > 25% constipation, diarrhea predominant: > 25% diarrhea, mixed: > 25% constipation and > 25% diarrhea

Question 11

What are the Manning criteria for diagnosis of IBS?

Answer 11

pain relieved with defecation, more frequent stools at onset of pain, looser stools at onset of pain, visible abdominal distention, passage of mucus, sensation of incomplete evacuation