II. Definitions

  1. Functional Gastrointestinal Disorders (FGID)
    1. Includes Functional Dyspepsia, Irritable Bowel Syndrome, Functional Constipation
  2. Bloating
    1. Sensation of gasseousness or distention (with or without abdominal girth changes)
  3. Belching (Eructation, Burping)
    1. Excessive Gas expulsion from the Stomach
    2. Belching is a normal clearance of Stomach gas, typically occurring 25-30 times per day (often unconsciously)
  4. Flatulence (Farting, Abdominal Wind)
    1. Excessive colonic gas expulsion from the anus

III. Pathophysiology

  1. Belching: Gas in Stomach from air Swallowing (Aerophagia)
    1. Hurried Eating or Drinking
    2. Smoking or Chewing gum
    3. Wearing badly fitted dentures
    4. Postnasal drainage
    5. Dry Mouth from anxiety or Anticholinergics
  2. Bloating and Abdominal Distention
    1. Altered intestinal motility and transit typically of the Small Intestine
    2. CNS processing (lower pain threshold)
    3. Visceral Hypersensitivity
    4. Other factors such as gut microflora and immune function may play a role
    5. Typically not related to increased gas production
      1. Not typically related to Flatulence (gas in colon does not cause bloating Sensation in most cases)
      2. Not typically related to Belching (due to swallowed air, not gas generated in Small Intestine)
  3. Flatulence: Gas from Large Intestine
    1. Typically diet related
    2. Bacterial degradation of Large Intestine contents
      1. Indigestible Carbohydrates
      2. Malabsorption (e.g. Lactose Intolerance)

IV. Symptoms

  1. Eructation
  2. Bloating
  3. Borborygmus
  4. Flatulence

V. History

  1. General
    1. Symptoms and their timing
    2. Palliative and provocative measures
    3. Recent illness
    4. Emotional stress
    5. Abdominal surgeries
    6. Gastrointestinal and genitourinary disorders
  2. Localizing symptoms
    1. Able to eat a full plate of food?
    2. Regular, normal Bowel Movements?
  3. Dietary history
    1. Meal patterns (e.g. large meals, rapid eating)
    2. Caffeine
    3. Carbonated drinks
    4. FODMAPs (Fementable Oligosaccharides, Disaccharides, Monosaccharides and Polyols)
      1. See FODMAP
      2. Fructose (e.g. apples, pears, peaches, mangoes, dried fruit, honey, fruit juice, high fructose corn syrup)
      3. Fructans (fructo-Oligosaccharides, inulins, levans - e.g. high fiber bars, onions, leeks, zucchini)
      4. Disaccharides (Lactose): Dairy, cheese, milk
      5. Polyols: Apricots, peaches
        1. Sugar Alcohols (esp. common in sugar-free gum): Sorbitol, xylitol, Mannitol, malitol)
      6. Galactooligosaccharides or Raffinose (brussel sprouts, cabbage, green beans, lentils, legumes, chick peas)

VI. Exam

  1. General examination
  2. Focused abdominal exam
  3. Rectal Exam

VII. Findings: Red Flag Symptoms and signs

  1. Unintentional Weight Loss
  2. Fever
  3. Vomiting
  4. Gastrointestinal Bleeding
  5. Abdominal mass
  6. Dysphagia
  7. Jaundice
  8. Lymphadenopathy
  9. Severe symptoms
  10. Severe Diarrhea
  11. Tenesmus
  12. New onset in over age 55 years
  13. Cancer history

VIII. Associated Conditions

  1. Emotion and Stress exacerbate symptoms (but are not typically the underlying cause)
    1. Anxiety
    2. Depressed mood
    3. Emotional stress
    4. Comorbid illness

IX. Differential Diagnosis

  1. Bloating or Abdominal Distention in general
    1. Abdominal Mass
    2. Pregnancy
    3. Abdominal Wall Hernia (e.g. Umbilical Hernia, Ventral Hernia)
    4. Ovarian Cancer
    5. Ascites
  2. Eructation (Belching, Burping)
    1. Typically aerophagia (see pathophysiology above)
    2. Gastric Belching
      1. Hurried Eating or Drinking
      2. Smoking or Chewing gum
      3. Wearing badly fitted dentures
      4. Postnasal drainage
      5. Xerostomia
      6. Gastroesophageal Reflux Disease
      7. Functional Dyspepsia
    3. Supragastric Belching
      1. Patient ingests air into Esophagus and immediately belches without it reaching the Stomach
      2. Learned repetitive Belching (up to 20/min) in response to stress, anxiety, GERD
      3. Better when distracted, sleeping, and with biofeedback and management of anxiety
  3. Gastric Bloating (symptoms begin <30 minutes after eating)
    1. See Dyspepsia Causes
    2. Functional Dyspepsia
      1. Post-prandial fullness, early satiety and bloating
      2. Epigastric Pain not related to eating may also occur
    3. Gastroesophageal Reflux Disease
    4. Helicobacter Pylori infection
    5. Gastroparesis (post-Viral Gastroenteritis, Diabetes Mellitus, Bariatric Surgery)
    6. Impaired gastric accommodation
    7. Gastric outlet obstruction (esp. chronic Peptic Ulcer Disease with scarring)
    8. Delayed Gastric Emptying
  4. Small Bowel Bloating (symptoms begin >30 minutes after eating)
    1. Pain-Dominant Irritable Bowel Syndrome
    2. Celiac Sprue (Gluten Sensitive Enteropathy)
    3. Dietary intake (see FODMAPs listed above)
    4. Bacterial overgrowth within Small Intestine
  5. Constipation with Bloating
    1. See Constipation Causes
    2. Chronic Constipation (Functional Constipation)
    3. Constipation-Dominant Irritable Bowel Syndrome
    4. Slow transit Constipation
    5. Dyssynergic Defecation (Pelvic Floor Dysfunction)
      1. Lack of coordination between abdominal wall, pelvic floor and anal sphincter on attempted Defecation
      2. Treated with pelvic floor retraining

X. Evaluation: Testing to consider

  1. Eructation (Belching, Burping)
    1. No testing is typically needed, as this is nearly always aerophagia
  2. Gastric Bloating (symptoms begin <30 minutes after eating)
    1. Upper endoscopy
    2. Hemoglobin A1C
    3. Gastric Emptying Study
  3. Small Bowel Bloating (symptoms begin >30 minutes after eating)
    1. Celiac Sprue: IgA Tissue Transglutaminase (TTG) and Total IgA (if low, obtain IgG Gliadin instead of TTG)
    2. Hydrogen Breath Test
  4. Bloating with Constipation
    1. Rectal Exam (impaction, Pelvic Floor Dysfunction)
    2. Thyroid Stimulating Hormone (TSH)
    3. Serum Calcium
    4. Colonoscopy
    5. Colon transit study
    6. Anorectal manometry

XI. Management

  1. General
    1. Avoid discounting patient concerns (as with other functional disorders)
    2. Offer reassurance when findings are consistent with functional gastrointestinal disorder
    3. Manage underlying emotional stress and Mood Disorders (Major Depression, Anxiety Disorder)
    4. Consider Exercise (esp. Irritable Bowel Syndrome, Chronic Constipation)
  2. Exclude secondary causes
    1. Perform testing as indicated based on history including red flag symptoms
  3. Eliminate causative factors
    1. Manage aerophagia in Eructation
    2. Reduce FODMAPs in bloating
  4. Follow specific management strategies for Functional Gastrointestinal Disorders
    1. See Functional Dyspepsia
    2. See Irritable Bowel Syndrome
    3. See Functional Constipation
  5. Consider empiric management for common conditions
    1. Consider Proton Pump Inhibitor for Functional Dyspepsia
    2. Consider antispasmodics (e.g. Hyoscyamine, Dicyclomine, Peppermint Oil) for Irritable Bowel Syndrome
    3. Consider fiber supplementation in Irritable Bowel Syndrome, Chronic Constipation (after initial disimpaction regimen)
  6. Avoid measures without evidence
    1. Simethicone
      1. No evidence that Simethicone is better than Placebo

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