Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by abdominal pain and altered bowel habits without any organic cause. It affects 3-22% of the population worldwide. While the exact cause is unclear, it is believed to involve altered gut motility, hypersensitivity, and psychosocial factors. Diagnosis is made based on symptoms according to the Rome criteria and excludes other conditions. Treatment involves dietary modifications, medications to target predominant symptoms such as fiber for constipation or alosetron for diarrhea, and treatment of accompanying psychiatric conditions like anxiety or depression.

1. Irritable Bowel Syndrome
Hossam GHONEIM, MD

3. What is IBS
• Irritable bowel syndrome (IBS) is a
gastrointestinal syndrome characterized by
chronic abdominal pain and altered bowel
habits in the absence of any organic cause.

4. Epidemiology
• Affects between 3-22% of persons worldwide
• Account for up to 50% of gastroenterology
referrals
• $8 billion dollars/yr. spent related to IBS

5. Epidemiology
• 70% are women
• 50% develop symptoms prior to age 35
• 20% between ages 35 and 50.
• Psychiatric illness frequently accompanies it,
but no clear causal link has been established.

6. Etiology
• Remains unclear
• Biopsychosocial model best describes it
– Altered GI motility
– GI hypersensitivity
– Psychosocial factors

7. Is IBS truly psychological
12% 88%

8. Recently
• Proposal of post-
infectious hypothesis
• Proposed association
with serotonin which
may stimulate intestinal
secretion and peristalsis
in addition to visceral
pain receptors via 5-
HT3 and 5-HT4
pathways
– Target of new therapies

9. Diagnosis
• Wide array of
symptoms
• Chronic abdominal pain
and altered bowel
habits remain the
central characteristic of
IBS.
• There are no
biochemical markers
• Symptom-based criteria

10. Diagnosis
• Consensus Statement of the American
Gastroenterological Association (AGA):
– Diagnosis of IBS should be based upon the
identification of positive symptoms consistent
with the condition and excluding in a cost-
effective manner other conditions with similar
clinical presentation.

12. Diagnosis
• ACG review on diagnosis and treatment of IBS
recommends the following labs:
– CBC
– Chemistry panel
– TSH
– FOBT
• In persistent diarrhea type:
– Celiac testing, Lactose intolerance testing, Gluten
free diet trial

13. Diagnosis
• Symptomatically, IBS has been divided into 3
subcategories.
– Constipation Predominant … IBS-C
– Diarrhea Predominant … IBS-D
– Pain Predominant (Alternate) … IBS-A

15. Diagnosis
• The Rome Criteria
– Provides a framework for identifying these
conditions.
– Originally created in 1992 and later revised in
1999 and 2006.

16. Rome Criteria
• 12 or more weeks out
of the last 12 months
with abdominal pain or
discomfort
• Can be continuous or
recurrent
• PLUS >>>
• At least 2 of the
following:
– Pain relieved by
defecation
– Associated with change
in stool frequency
– Associated with a
change in stool
form/appearance

18. Diagnosis
Red Flags .. strongly consider further testing
– Anemia
– FMH of CRC or IBD
– Fever
– Bloody stool
– Nocturnal symptoms
– Large volume diarrhea
– greasy stools
– Onset age >50
– Palpable rectal mass
– Persistent severe
diarrhea or constipation
– Recent Antibiotic use
– Rectal bleeding
– Weight Loss

19. Differential Diagnosis
• IBD- CD, UC
• Medications- Laxatives, Constipating agents
• Infection- Parasitic, Bacterial, Viral, Opportunistic
• Malabsorption- Celiac, Pancreatic Insuff, Lactose
intolerance, NON-coeliac gluten sensitivity
• Endocrine- Hypo/Hyperthyroidism, Diabetes, Addison’s
disease
• Malignancy

20. Lymphoma Crohn’s Disease
VCE

22. Therapeutic Approach
• Establish an empathetic physician-patient
relationship

23. Therapeutic Approach
• Identify associated factors and treat
– Anxiety
– Stress
– Social Phobias
– Depression/Dysthymia
– Panic Disorder
– Substance Abuse
– Previous sexual or physical abuse

24. Therapeutic Approach
Dietary Recommendations
– No specific advice has been shown to be efficacious
in trials
– Expert opinion recommends limiting:
• Alcohol
• Caffeine
• Fat
• Gas producing food
• Exacerbating items known to the patient, ? food allergy
• FODMAP

26. Therapeutic Approach
• Diarrhea-Predominant
– Loperamide 2-4mg up to QID
• Can be used prophylactically with anticipated stress
– Cholestyramine 4g 1-6x/day
• Second line, Level C evidence
– Alosetron
• Restricted use in US, Only women, central and peripheral
5-HT3 receptor antagonist

27. Therapeutic Approach
• Constipation-Predominant
– Fiber 20-30g/day
• Start slow and titrate up/may worsen bloating
– Osmotic Laxatives
• Magnesium Citrate
• Lactulose
• Polyethelyne Gylcol
– Tegaserod 6mg bid
• Selective partial 5-HT4 receptor antagonist
• FDA approved in women for short term use (6 weeks)
• Diarrhea most common side effect
• Ischemic Colitis has been reported

28. Therapeutic Approach
• Pain-Predominant
– Jailwala and colleagues conducted a review of RCT
on pharmacotherapy in Annals of Internal Medicine
in 2000
• Showed smooth muscle relaxants effective for pain-
predominant, however none of them used in the studies
have been FDA approved.

29. Therapeutic Approach
• Pain-Predominant
– Dicyclomine 10-20mg bid to qid
• PRN usage only
• Antispasmotic
– Amitryptyline 10-25mg qhs
• TCA
• Steinhart and colleagues showed in 1 RCT of 14 pts that
amitriptyline showed global improvement in pts. with IBS
• Anticholinergic Side Effects limiting
– Tegaserod

30. Therapeutic Approach
• Antibiotics, There is a growing body of
evidence supporting the role of antibiotics
– Rifaximin
– Ciprofloxacin
– Metronidazole

31. Therapeutic Approach
• Probiotics
– Probiotics are not routinely recommended in
patients with IBS.
– Although they have been associated with an
improvement in symptoms, the magnitude of
benefit and the most effective species and strain
are uncertain

32. Take Home message
• Use a symptom based approach and reasonable lab
approach to diagnose IBS
• Identify red flags
• Tailor your ttt to the patients’ predominant symptom
• Treat coexisting factors depression & anxiety
• IBS-C osmotic laxatives are preferred
• IBS-D Alosetron
• IBS-A TCA
• FODMAP is worth a trial
• Antibiotic and probiotic increasing role in the future

33. Thank You