IRRITABLE BOWEL SYNDROME (IBS)

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IRRITABLE BOWEL SYNDROME (IBS)

• Dr. Mohamed Shekhani
• MBChB-CABM-FRCP

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IBS Epidemiology

• A common disorder, with a 7 prevalence .
• Women are 1.5 times more likely to be affected
  than men, most commonly between ages 20-40 years.
• Onset after the age of 50 years is uncommon.

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IBSPathophysiology

• Not well understood,may vary depending on the
  subtype include
• Abnormal GIT motility
• Visceral afferent hypersensitivity
• Autonomic innervation abnormalities.
• Altered mucosal immune system activation may
  occur, particularly in patients with diarrhea who
  develop symptoms after an acute gastroenteritis
  (postinfectious IBS).
• Depression, anxiety, a H/O sexual abuse, phobias,
  somatization are commonly associated, but not
  psychosocial factors.
• Health-related quality of life (HRQOL) scores are
  lower in IBS than in unaffected persons, but ?
  Cause or effect.
• IBS patients who seek evaluation treatment are
  more likely to have comorbid psychiatric illness
  psychological stress is likely to exacerbate
  symptoms.

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IBSburden

• IBS is costly, with direct indirect (including
  decreased work productivity) costs estimated at
  20 billion, with IBS patients consuming gt 50
  more in health care resources than matched
  controls.
• Increased health care utilization in IBS patients
  is directly related to somatization levels.

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IBD Diagnosis

• Based solely on clinical grounds.
• As no biochemical, radiographic, endoscopic or
  histologic marker exists, the dignosis depends on
  Rome criteria.
• Now depends on Rome 3, but only Rome I criteria
  have been evaluated for accuracy, with a
  sensitivity of 71 specificity of 85.
• The ACG task force on IBS has recommended a
  simpler definition
• Abd pain associated with altered bowel habits
  (change in stool form or frequency) over a period
  of at least 3 months.

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Diagnosis Rome 3

• Recurrent abd pain or discomfort (abn sensation
  not described as pain) at least 3 days a month in
  past 3 months (with onset gt 6 months prior)
  associated with two or more of the following
• Improvement with defecation
• Onset associated with change in frequency of
  stool
• Onset associated with change in form (appearance)
  of stool
• Absence of alarm indicators that suggest other
  diseases
• Age gt50 years
• Male
• Short history of symptoms
• Documented weight loss
• Nocturnal symptoms
• Family history of colon cancer
• Rectal bleeding
• Recent antibiotic use

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IBD Diagnosis

• Rome III criteria describes 4 subtypes of IBS
• Constipation-predominant
• Diarrhea-predominant
• Mixed
• Unsubtyped.
• Supportive symptoms may include
• Abnormal stool frequency (gt3/d, lt3ds/week)
• Abnormal stool form (lumpy/hard or loose/watery)
• Straining or urgency or a sensation of incomplete
  evacuation, mucus
• Bloating.

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IBS Diagnosis

• Meeting the diagnostic Rome criteria for IBS the
  absence of alarm symptoms signs regarded as
  reassuring that the patient does not have organic
  disease such as IBD, CRC or celiac disease.
• Recent review of the literature has suggested
  that nocturnal symptoms as well as rectal
  bleeding in particular are not helpful in
  separating IBS from patients with organic
  disease.
• While other alarm criteria such as anemia weight
  loss lack sensitivity for the diagnosis of
  organic disease, they are specific.
• Affected patients may describe non GIT somatic
  symptoms such as headache, urinary symptoms,
  backache, and fatigue.

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IBS Evaluation

• Patients with potential IBS should not undergo a
  potentially expensive or harmful evaluation that
  may undermine their confidence in the diagnosis
  in the physician.
• Anemia is an alarm sign a complete blood count
  should be performed after the onset of symptoms.
• Patients with IBS with diarrhea mixed IBS
  should have serologic tests for celiac disease,
  which occurs more commonly in patients with these
  IBS subtypes than in the general population.
• A possible link between IBS small intestine
  bacterial overgrowth, but ACG not recommend
  routine testing.
• Testing for lactose intolerance, more common
  among IBS, should be conducted only if this
  diagnosis is unclear on clinical grounds.
• Colonoscopy is indicated only if patients are gt
  50 years.
• In any patient with alarm features, further
  evaluation is mandated should be tailored to
  symptoms i.e patients with constipation need
  imaging to rule out a mechanical obstruction.
• In patients with IBS with diarrhea who undergo
  colonoscopy, biopsies of the colon should be done
  to evaluate for microscopic colitis, particularly
  if there is suggestion of a secretory diarrhea.

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IBS treatmet

• Depends on a patients predominant symptoms.
• Although patients often link diet to symptoms, no
  clear data support elimination diets or food
  allergy testing, but if individual patients
  identify clear food triggers, these can be
  eliminated or reduced.

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IBS treatmet for CP-IBS

• Bulking agents, specially fiber in the form of
  psyllium hydrophilic mucilloid (ispaghula husk)
  calcium polycarbophil, may improve global IBS
  symptoms but can be associated with bloating
  flatulence.
• Laxatives appear to be effective in chronic
  constipation although laxatives appear to
  improve frequency of bowel movements in those
  with constipation, it remains unclear whether
  they have any effect on pain.
• Osmotic laxatives such as milk of magnesia as
  well as nonabsorbable polyethylene glycol,
  sorbitol,lactulose are generally believed to be
  safer than stimulant laxatives, but they may be
  associated with bloating / flatulence so senna /
  bisacodyl may be appropriate for intermittent use
  for constipated patients.
• Tegaserod, a 5-HT4 (serotonin) agonist had been
  previously approved to treat IBS with
  constipation in women improved bowel movements,
  abdominal pain global IBS symptoms.
• Lubiprostone is a chloride channel antagonist
  approved to treat chronic constipation in adults,
  but it does not alleviate abd pain.

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IBS treatmet for CP-IBS
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IBS treatmet for DP-IBS

• In IBS with diarrhea, loperamide improved both
  bowel movement frequency consistency,but it
  had no effect on other IBS symptoms.
• Alosetron, a 5-HT3 antagonist, alleviates
  abdominal pain, global IBS symptoms, and diarrhea
  and urgency in women and men with IBS with
  diarrhea potential serious but uncommon side
  effects include both severe constipation
  ischemic colitis.
• It should be reserved for patients who have
  failed to respond to conventional therapies.

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IBS treatmet for DP-IBS
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IBS treatmet for abd pain

• Antispasmodic agents, including
  Mebeverine,dicyclomine, hyo-scyamine, peppermint
  oil, function as GIT smooth muscle relaxants.
• Reduce abd pain in the short term, but not well
  substantiated, associated with side effects that
  preclude their use may cause constipation.
• Tricyclic antidepressants SSRI have analgesic
  properties tricyclics also have an
  anticholinergic effect may induce constipation.
  
• Smaller doses than are used in the treatment of
  depression are generally recommended.
• Comorbid depression may best be treated with a
  SSRI.
• Psychosocial stressors should also be addressed.

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IBS Bacterial overgrowth trt

• While the link between small intestinal bacterial
  overgrowth IBS remains unclear, the short-term
  (10-14 days) use of the nonabsorbed antibiotic
  rifaximin at doses between 1000-1200 mg/day has
  demonstrated improvement in global IBS symptoms,
  bloating diarrhea in IBSdiarrhea.
• Other antibiotics such as neomycin may be
  effective.
• The efficacy of probiotics is yet to be
  determined adequately.
• Antibiotic /probiotic therapy has been used
  because bacterial overgrowth has been implicated,
  possibly through abnormal motility or as a
  sequela of postinfectious IBS.
• Rifaximin has been effective in relieving
  symptoms in patients with bacterial overgrowth.
• Bifidobacterium infantis is the only probiotic
  that has proven efficacy in the treatment of IBS.

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