Bowel

Irritable Bowel Syndrome

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Irritable Bowel Syndrome, Functional Chronic Diarrhea

  • Epidemiology
  1. Prevalence
    1. Overall in U.S.: 5-10%
    2. Lifetime Prevalence: 10-22%
  2. Slightly more common in women (1.5 fold increased risk over men)
  3. Prevalence for elderly same as for young (however, peak time of diagnosis at 20-39 years old)
  4. Most common condition seen by Gastroenterologists
  • Pathophysiology
  1. Organic factors
    1. Gastrointestinal hypersensitivity
    2. Altered motility
    3. Neurohormonal factors
    4. Mucosal barrier dysfunction
  2. Provoked by psychosocial risk factors
    1. Prior physical or sexual abuse significantly increases risk
  3. Severe Gastroenteritis episode may be associated (Odds Ratio 5.9)
    1. Antibiotics (Rifamaxin, Neomycin) have reduced symptoms in some cases
  4. Familial association
    1. Risk increases 3 fold with Family History of Irritable Bowel Syndrome
  • Associated Conditions
  1. Gastroesophageal Reflux Disease
  2. Dysphagia
  3. Globus Hystericus
  4. Fatigue
  5. Non-cardiac Chest Pain
  6. Urologic dysfunction
  7. Gynecologic disease (e.g. Chronic Pelvic Pain)
  8. Fibromyalgia
  9. Chronic Fatigue Syndrome
  10. Temperomandibular joint syndrome
  11. Food Allergy
  12. Low-fiber diet
  • Risk Factors
  • Psychosocial
  1. Anxiety Disorder
  2. Major Depression
  3. Somatization Disorder
  4. Sexual abuse or physical abuse
  5. Stressful life events
  6. Substance Abuse
  • Types
  1. Alternating Diarrhea and Constipation
  2. Nervous Diarrhea
  3. Predominant Constipation
  4. Upper Abdominal Bloating and discomfort
  • Symptoms
  1. Altered bowel habits
    1. Diarrhea
    2. Constipation
    3. Scybalous stools (hard, pellet-like stools)
    4. Mucus per Rectum (40% of cases)
    5. Incomplete evacuation sensation (69% of cases)
  2. Recurrent and Chronic Abdominal Pain (73% of cases)
    1. Upper abdominal discomfort after eating
    2. Left Lower Quadrant Abdominal Pain
    3. Right Lower Quadrant Abdominal Pain
    4. Abdominal Pain relieved with Defecation (52% of cases)
  3. Gaseousness
    1. Excessive Flatulence or Eructation
    2. Normal patients experience about 13 farts per day
    3. Abdominal Distention (32% of cases)
  4. Nausea or Vomiting
  5. References
    1. Ford (2008) JAMA 300(15): 1793-805 [PubMed]
  • Diagnosis
  • Rome III Criteria
  1. Abdominal symptoms persistent or recurrent for 6 months or more
    1. Symptoms occur on at least three days per month for at least 3 months
    2. Abdominal Pain, bloating or discomfort
    3. Marked change in bowel habits
      1. Change in stool frequency
      2. Change in stool consistency (Constipation or Diarrhea)
      3. Altered stool passage
        1. Straining for normal consistency stool
        2. Urgency of Defecation
        3. Incomplete evacuation
  2. Two or more below
    1. Pain relieved with Defecation
    2. Onset of pain is related to a change in frequency of stool
    3. Onset of pain is related to a change in appearance of stool
  • Diagnosis
  • Manning Criteria
  1. Onset of pain linked to more frequent Bowel Movements
  2. Looser stools associated with onset of pain
  3. Pain relieved by stool passage
  4. Noticeable Abdominal Bloating
  5. Sensation of incomplete evacuation more than 25% of the time
  6. Diarrhea with mucus more than 25% of the time
  • Red Flags
  • Symptoms and signs suggestive of other diagnosis
  1. Nighttime Diarrhea
  2. Nocturnal Stool Incontinence
  3. Nocturnal awakening due to abdominal discomfort
  4. Abdominal Pain that interferes with normal sleep
  5. Visible or occult blood in stool
  6. Weight loss
  7. Recurrent Fever
  8. Family History of Colon Cancer
  9. Family History of Inflammatory Bowel Disease
  10. Elderly
  11. Diarrhea without pain suggests alternative diagnosis
  12. Laboratory abnormality
    1. Leukocytosis
    2. Anemia
    3. Increased Erythrocyte Sedimentation Rate (ESR)
  • Differential Diagnosis
  1. Colonic Adenocarcinoma
  2. Inflammatory Bowel Disease
    1. Ulcerative Colitis
    2. Crohn's Disease
  3. Abdominal Angina (Ischemic Colitis)
  4. Pseudo-obstruction (Diabetes Mellitus, Scleroderma)
  5. Intermittent Sigmoid Volvulus
  6. Toxic Megacolon or Bacterial overgrowth syndrome
  7. Endocrine causes
    1. Hypothyroidism or Hyperthyroidism
    2. Diabetes Mellitus
    3. Addison's Disease
  8. Malabsorption
    1. Celiac Sprue (strongly consider if Diarrhea with red flags)
    2. Lactose Intolerance
    3. Pancreatic insufficiency
  9. Giardiasis
  10. Endometriosis
  11. Psychiatric illness
    1. Depression
    2. Somatization
    3. Anxiety Disorder or Panic Disorder
  12. Medications
    1. Laxatives
    2. Constipating medications
  • Evaluation
  1. General
    1. Avoid a piecemeal work-up
      1. Perform a complete evaluation the first time
      2. Avoid over-investigation
    2. Irritable bowel is no longer diagnosis of exclusion
      1. Diagnostic criteria above are sufficient to treat
      2. Lab and imaging are typically low yield in cases otherwise suggestive of Irritable Bowel Syndrome
    3. Indications for full evaluation and Gastroenterology
      1. Red flags present (see above) or
      2. Onset over age 50 years
  2. Careful History
    1. History of Gastrointestinal Symptoms
    2. Family History of gastrointestinal disease
    3. Marital History
    4. Sexual Abuse (strong correlation)
  3. Reasonable exam
    1. Thorough abdominal examination
    2. Also focus on possible endocrine causes
  4. Look for Food Intolerance (consider diet diary)
    1. Lactose Intolerance
    2. Sorbitol
    3. Wheat (Gluten Sensitive Enteropathy)
  • Labs
  • Initial, based on predominant symptom
  1. Constipation dominant
    1. Complete Blood Count (CBC)
    2. Serum Electrolytes or Chemistry panel (chem8)
    3. Thyroid Stimulating Hormone (TSH)
  2. Diarrhea predominant
    1. Evaluation in absence of negative red flags
      1. Complete Blood Count (CBC)
      2. Tissue transglutaminase IgA for Celiac Sprue
    2. Other tests to consider if indicated by history (previously recommended as part of standard default protocol)
      1. Stool Ova and Parasites
      2. Fecal Leukocytes
      3. Serum Electrolytes or chemistry panel
      4. Thyroid Stimulating Hormone (TSH)
      5. Erythrocyte Sedimentation Rate (ESR) or C-Reactive Protein (C-RP)
  3. Pain Dominant
    1. Complete Blood Count (CBC)
  4. Reference
    1. Fass (2001) Arch Intern Med 161:2081-8 [PubMed]
  • Diagnostics
  1. Colonoscopy of Flexible Sigmoidoscopy
    1. More uncomfortable in Irritable Bowel Syndrome
    2. Not absolutely indicated if remainder of evaluation suggests Irritable Bowel Syndrome
      1. Consider if red flags or age over 50 years
  2. Consider additional studies as indicated (to evaluate differential diagnosis)
    1. CT Abdomen with contrast
    2. Right upper quadrant Ultrasound
    3. Upper GI Study
    4. Barium Enema
  • Management
  • General Measures
  1. See the patient frequently
    1. Maintain a strong doctor-patient relationship
    2. Offer frequent reassurance
    3. Identify and treat emotional stressors
    4. Answer patients questions in unhurried environment
  2. Do not downplay symptoms as psychiatric
    1. Irritable Bowel is a real functional bowel problem
    2. Explain physiology and absence of serious illness
  3. Reduce stressors
    1. Teach Relaxation Techniques
    2. Teach coping mechanisms for chronic illness
  4. Exercise
  5. Consider Probiotics (weak evidence)
    1. Bifidobacterium infantis
    2. Bifidobacterium bifidum MIMBb75
      1. Decreases overall irritable bowel symptoms
      2. Guglielmetti (2011) Aliment Pharmacol Ther 33(10): 1123-32 [PubMed]
  6. General Diet recommendations
    1. Get adequate fluid intake (>64 ounces/day)
    2. Bulk agents (gradually increase)
      1. Metamucil
      2. Citrucel
      3. High fiber-bran or other soluble Dietary Fiber (absorbs water)
    3. Avoid FODMAPS (Fementable Oligo- di and mono saccharides and polyols)
      1. Avoid fructose (e.g. apples, pears, high fructose corn syrup)
      2. Avoid Fructans (fructooligosaccharides, inulins, levans - e.g. high fiber bars)
      3. Avoid Lactose (consider challenge with quart of skim milk)
      4. Avoid Polyols (sugar Alcohols: Sorbitol, xylitol, mannitol, malitol
      5. Avoid Galactooligosaccharides (e.g. brussel sprouts, onions)
    4. Consider avoiding other provocative agents
      1. Consider Elimination Diet (although no evidence to support this)
      2. Avoid Caffeine
      3. Avoid Alcohol
      4. Avoid Legumes and other gas producing foods (see FODMAPS above)
      5. Avoid Artificial Sweeteners and carbonated beverages (see Polyols above)
      6. Avoid Fatty meals
      7. Corn, wheat and citrus may also exacerbate Irritable Bowel Syndrome
      8. Some fiber can also exacerbate symptoms
  7. Avoid Provocative or addictive medications
    1. Stimulant Laxatives (except brief use)
      1. Correctol
      2. Dulcolax
      3. Cascara
    2. Sedatives or Tranquilizers (Benzodiazepines)
    3. Narcotics
  1. Consider eliminating lactose, Caffeine from diet
  2. Exclude Gluten Sensitive Enteropathy as cause
  3. Cholestyramine 4 grams qhs to 6 times daily
    1. Limited evidence
  4. Loperamide (Imodium) 2-4 mg qid prn
    1. Before meals
    2. As needed in stressful social situations
  5. Ondansetron (Serotonin antagonist)
    1. Reduces rapid transit
  6. Rifaximin (Xifaxan)
    1. Small improvements in symptoms (NNT 10) at a high cost ($1300 for a 14 day course)
    2. Relapse by 6 months is common
  7. Eluxadoline (Viberzi)
    1. Schedule IV Opioid agonist similar to Imodium, but taken daily at $1000/month
    2. Marginal efficacy (NNT 11) for decreased Diarrhea and Abdominal Pain at 6 months
    3. Risk of serious Pancreatitis (deaths have occurred) due to sphincter of odi spasm
      1. Contraindicated in prior Cholecystectomy, prior Pancreatitis or >3 Alcohol drinks per day
      2. https://www.fda.gov/safety/medwatch/safetyinformation/safetyalertsforhumanmedicalproducts/ucm546771.htm
    4. (2016) Presc Lett 23(6):32
    5. (2017) Presc Lett 24(5):27
  8. Alosetron (Lotronex)
    1. Risk of Constipation and Ischemic Colitis
      1. Iatrogenic deaths have occured
      2. Black box warning: Signed Informed Consent needed
    2. FDA controlled prescriptions only for women with IBS with Diarrhea
      1. Requires special Informed Consent and must be part of a prescriber program
    3. Dose: 1 mg daily (may advance to bid)
  9. Peppermint
    1. Pittler (1998) Am J Gastroenterol 93:1131-5 [PubMed]
  • Management
  • Pain dominant Irritable Bowel
  1. Chronic Pain
    1. Tricyclic Antidepressants
      1. Amitriptyline (Elavil) 25 mg orally at bedtime
      2. Desipramine (Norpramin) 50 mg orally three times daily
    2. Tegaserod (Zelnorm)
      1. Withdrawn from market in 2007 due to cardiovascular risks (but still available for limited use)
      2. Nyhlin (2004) Scand J Gastroenterol 39:119-26 [PubMed]
    3. SSRI medications may be effective as adjunct (e.g. Zoloft)
      1. However, not first-line agents due to insufficient evidence
      2. Tabas (2004) Am J Gastroenterol 99:914-20 [PubMed]
  2. Post-prandial pain: Anticholinergic
    1. Avoid chronic, frequent use
    2. Trial for 2 weeks and stop if no effect
    3. Dicyclomine (Bentyl) 10-20 mg, 15 min before meal
    4. Hyoscyamine (Levsin) 0.125 to 0.25 mg before meal
    5. Peppermint Oil (see reference below)
  1. Use gastro-colic response
    1. Wake-up, eat breakfast and anticipate stool in AM
  2. First line: Bulk agents (e.g. Fiber, Psyllium, bran)
    1. Titrate to 20-30 grams per day
    2. Risk of bloating initially (requires adequate hydration)
    3. Evidence to support is lacking, but remains a central tool in IBS management
  3. Second line (use at bedtime for AM stool)
    1. Improves stool frequency, but may not alter Abdominal Pain
    2. Osmotic agents
      1. Polyethylene glycol (Miralax) 1 capful in 8 ounces at bedtime (preferred)
      2. Lactulose 1-2 teaspoons at bedtime
      3. Milk of Magnesia 1-2 tablespoons at bedtime
    3. Consider Stimulant Laxatives if osmotic agents fail
      1. Senna or Cascara
      2. Bisacodyl
  4. Third line (prescription agents that increase GI transit and intestinal fluid)
    1. Amitiza (Lubiprostone)
      1. Drossman (2009) Aliment Pharmacol Ther 29(3): 329-41 [PubMed]
    2. Linzess (Linaclotide)
      1. Expensive ($7 per pill) for minimal efficacy (NNT 5-8) for decreased pain
      2. (2012) Prescr Lett 19(12): 68-9
    3. Trulance (Plecanatide)
  5. Restricted Use agent (emergency use only due to risk)
    1. Tegaserod (Zelnorm): 5-HT4 agonist
      1. Cardiovascular event risk prompted removal from U.S. market in 2007
      2. Dose: 6 mg bid 30 minutes before meals
  6. Other agents potentially useful
    1. Guar-Gum
      1. Parisi (2002) Dig Dis Sci 47:1696-704 [PubMed]
    2. Peppermint
      1. Pittler (1998) Am J Gastroenterol 93:1131-5 [PubMed]
    3. Loxiglumide (cholecystokinin-A receptor antagonist)
  • Management
  • Other specific symptoms or comorbidities
  1. Excessive Flatus (gas)
    1. See General dietary recommendations (including FODMAP avoidance) as above
    2. Simethicone 40 to 125 mg up to qid
    3. Beta-galactosidase (Beano)
  2. Comorbid Mood Disorders
    1. Major Depression
      1. SSRI Medications or other Antidepressants
    2. Anxiety
      1. See Anxiety Management
  • Resources
  1. International Foundation for Functional GI Disorders
    1. http://www.iffgd.org
  2. American College of Gastroenterology
    1. http://www.ACG.GI.org