Irritable Bowel Syndrome Biol E-163 TA session 12/18/06

IBS Recurring upper and lower GI symptoms Variable degrees of abdominal pain, constipation or diarrhea, and abdominal bloating

Etiology Cause unknown No anatomic reasons found Symptoms aggravated by emotional factors, diet, drugs, or hormones –But, stress and emotional conflicts don’t always coincide with symptom onset

Pathophysiology No consistent motility abnormalities Possible abnormalities –Abnormal gastro-colonic reflex = delayed, prolonged colonic activity –Reduced gastric emptying –Disordered gastric motility –Transit time through small bowel varies Hyperactive (constipation) or delayed (diarrhea) –Excess mucus production –Hypersensitivity to intestinal gas –Hypersensitivity to gastrin and cholecystokinin But do not necessarily correlate with symptoms

Symptoms Usually begins in teens and 20s Symptoms recur at irregular periods, can be triggered by food or stress Features –Abdominal pain related to or relieved by defecation –Change in stool frequency or consistency –Abdominal distention –Mucus in stool –Sensation of incomplete evacuation Extra-intestinal symptoms –Fibromyalgia (widespread pain) –Headaches –Dyspareunia (painful sexual intercourse) –Temporomandibular joint syndrome (TMJ)

Clinical Types of IBS 1.Constipation-predominant IBS Pain over at least one area of colon Periods of constipation alternating with more normal frequency Stool containing clear or white mucus Pain comes in bouts or continuous dull ache, may be relieved by bowel movement Eating is common trigger Bloating, flatulence, nausea, dyspepdia, heartburn 2.Diarrhea-predominant IBS Precipitous diarrhea occuring immediately on rising or eating Pain, bloating, rectal urgency, and (less commonly) incontinence

Diagnosis 1.Patient history 2.Physical exam 3.Testing 4.Concurrent disease

Treatment 1.Diet 2.Drug therapy