II. Diagnosis: Chronic Functional Constipation (Rome 4)

  1. Timing Criteria
    1. Symptoms present for the last 3 months
    2. Onset at least 6 months prior to diagnosis
  2. Symptoms affect >25% of stools (two or more present)
    1. Fewer than 3 spontaneous Bowel Movements per week
    2. Straining
    3. Lumpy or hard stools (Bristol Stool Form Scale 1 or 2)
    4. Sensation of incomplete evacuation
    5. Sensation of anorectal obstruction or blockage
    6. Attempts at self disimpaction (manual maneuvers)
  3. Excluding symptoms
    1. No signs Organic Constipation (Acute Constipation)
      1. See Constipation for red flag symptoms
    2. Loose stools are rarely present without Laxatives
    3. Criteria for Irritable Bowel Syndrome are NOT met

III. Types: Primary Constipation

  1. Normal Transit Constipation (Functional Constipation)
    1. Perception of Constipation despite normal stool transit
    2. Provoked by emotional stress and dietary changes
    3. Respond well to hydration, fiber and Osmotic Laxatives
  2. Slow Transit Constipation
    1. Lumpy or hard stools (Bristol Stool Form Scale 1 or 2)
    2. Prolonged stool transit (more common in young women)
      1. Slower than normal transit times on diagnostic testing
      2. Related to decreased meal related peristalsis
      3. Diagnosed with 6 of 24 Sitzmark markers visible on XRay at 120 hours post ingestion
    3. Management
      1. Refractory to dulocolax, Cholinergics, fiber
      2. May respond to biofeedback
  3. Outlet Constipation or Defecation Process Dysfunction (Defecatory Disorders)
    1. Symptoms include excessive straining at soft stool, sometimes requiring disimpaction
    2. Stool not expelled when reaches Rectum
    3. Pelvic Floor Dysfunction (disorganized contraction or relaxation of pelvic floor)
      1. Inadequate rectal propulsion of stool
      2. Increased resistance to evacuation
      3. Incomplete pelvic floor relaxation (or paradoxical contraction)
    4. Contributing Factors
      1. High resting anal tone (anismus)
      2. Mechanical Obstruction
    5. Evaluation by Gastroenterology
      1. Balloon Expulsion Test
      2. Anorectal Manometry
    6. Management
      1. Often refractory to standard Constipation Management (fiber and Laxatives)
      2. Responds to biofeedback-aided pelvic floor therapy and Relaxation Techniques
        1. Visual and auditory feedback of anorectal and pelvic floor activity
        2. Patients learn to coordinate abdominal and pelvic floor activity

IV. Differential Diagnosis: Secondary Constipation

V. Risk Factors

  1. Female gender
  2. Lower socioeconomic status
  3. Comorbid Conditions
  4. Nursing Home Resident
  5. Age over 65 years

VI. Causes: Contributing Factors

  1. See Constipation Causes
  2. Inadequate water intake
  3. Low fiber dietary intake
  4. Sedentary lifestyle
  5. Altered motility
    1. Irritable Bowel Syndrome
    2. Slow transit
    3. Failure to respond to urge to defecate

VII. HIstory

  1. See Constipation
  2. Reconcile medications (including over-the-counter medications)
  3. Consider bowel habit diary for 2 weeks
  4. Consider Constipation Evaluation Scales
    1. Constipation Assessment Scale
    2. Constipation Scoring System
      1. https://thepelvicfloorsociety.co.uk/images/uploads/Cleveland_Clinic_Constipation_Sc.pdf
    3. Patient Assessment of Constipation Scoring System (PAC-SYM)
      1. https://thepelvicfloorsociety.co.uk/images/uploads/PAC_SYM.pdf

VIII. Exam

IX. Findings: Symptoms and Signs Suggestive of Functional Constipation

  1. No red flags suggestive of Organic Constipation
    1. See Constipation for list of red flag symptoms
  2. Chronic duration
  3. No Weight loss
  4. No systemic symptoms

X. Labs

  1. No diagnostic or lab testing is needed in typical primary, Functional Constipation
  2. However, evaluate for red flag findings in history (see Constipation)
    1. If red flag findings, perform Organic Constipation evaluation
  3. Colonoscopy has low yield in primary, Functional Constipation evaluation
    1. However, red flag findings or standard Colorectal Cancer Screening may prompt Colonoscopy

XI. Diagnostics

  1. Indications
    1. Chronic Constipation refractory to standard management
    2. Typically ordered by gastroenterology
  2. Initial Testing
    1. Balloon Expulsion Test
    2. Anorectal Manometry
  3. Later Testing
    1. Colorectal Transit Time
    2. Evacuation Proctography
      1. Colonic Contrast Study (single/double contrast barium)
      2. MR Defecography

XII. Management: Initial Symptomatic Treatment

  1. See below (prevention) for non-pharmacologic measures
  2. Precautions
    1. Disimpact stool first if Fecal Impaction!
    2. Avoid these protocols in Bowel Obstruction, persistent Fecal Impaction
    3. Ensure no preceding Electrolyte disturbance and maintain adequate hydration
  3. Consider bowel evacuation
    1. Evacuation Protocol 1
      1. First: Fleets Enema x1-2 (or pink lady or tap water enema in emergency department)
      2. Next: Magnesium Citrate 1.745 g/30 ml, 10 oz bottle (296 ml) once or divided dosing
    2. Evacuation Protocol 2 (similar to Colonoscopy preparation)
      1. Bisacodyl (Dulcolax) 10 mg (two 5 mg tablets) orally a couple hours before Miralax twice daily for one day
      2. Polyethylene Glycol (Miralax)
        1. Mix 255 g (15 capfuls or 1.25 cups) combined with Gatorade 64 oz (2 quarts)
        2. Drink 8 ounce glass every 15 minutes for one hour (32 oz) twice daily for one day
    3. Evacuation Protocol 3
      1. Enemas (e.g. Fleet Enema) twice daily for 3 days
    4. Evacuation protocol 4
      1. Polyethylene Glycol 4-8 Liters per day until clean
      2. Contraindicated in Bowel Obstruction, fecal impact
      3. Exercise caution with Electrolyte and fluid losses
  4. Protocol recommended by AGA
    1. Step 1
      1. Milk of Magnesia (Magnesium Hydroxide)
      2. Increase Dietary Fiber taken with at least 8 ounces fluid with fluid intake maintained throughout the day
      3. Review prevention as described below
    2. Step 2
      1. Add Bisacodyl (10 mg orally up to twice daily) to Step 1 regimen
    3. Step 3
      1. Add Polyethylene Glycol (e.g. Miralax)
  5. Authors approach
    1. Confirm no Small Bowel Obstruction, Diverticulitis or other contraindication to evacuation
    2. Rectal Exam to check for impaction
    3. Evacuation Protocol 1 (as above)
    4. Miralax 1 capful daily in 8 oz crystal light for 7 days
    5. Maintain fluids >64 ounces daily and avoid Caffeine
    6. When stooling regularly start fiber supplement (e.g. Metamucil, Citrucel) or Dietary Fiber >15 grams daily
  6. Adjunctive Measures when fluids, Osmotic Laxatives and fiber are incompletely effective
    1. See Laxative
    2. Consider short-term daily use of senna or Bisacodyl (<4 weeks)
    3. Kamm (2011) Clin Gastroenterol Hepatol 9(7): 577-83 [PubMed]
    4. Morishita (2021) Am J Gastroenterol 116(1): 152-61 [PubMed]

XIII. Management: Special Circumstances

  1. See Narcotic Related Constipation
  2. See above for management specific to primary Constipation types
  3. Outlet Constipation or Defecation Process Dysfunction
    1. Physical therapy referral for biofeedback-aided pelvic floor therapy
  4. Opioid-Induced Constipation
    1. See Constipation Prophylaxis in Chronic Opioid Use
    2. Peripheral Acting Mu-Opioid Receptor Antagonists (PAMORAs)
      1. Naloxegel (Movantik)
      2. Naldemedine (Symproic)
      3. Methylnaltrexone (Relistor)
        1. Contraindicated in Intestinal Obstruction
        2. Exercise caution in intestinal malignancy
  5. Third-line Agents in refractory cases (FDA Approved Intestinal Secretagogues)
    1. Amitiza (Lubiprostone)
      1. Acts at intestinal chloride channels to increase intestinal fluid secretion and Small Intestine stool transit
      2. Drossman (2009) Aliment Pharmacol Ther 29(3): 329-41 [PubMed]
    2. Linzess (Linaclotide)
      1. Guanylate cyclase-c Agonist
      2. May improve stool frequency, consistency, Abdominal Pain and straining, but risk of Diarrhea
      3. Expensive ($7 per pill) for minimal efficacy (NNT 5-8) for decreased pain
      4. (2012) Prescr Lett 19(12): 68-9
    3. Trulance (Plecanatide)
      1. Guanylate cyclase-c Agonist similar to Linzess (Linaclotide)
    4. Prucalopride (Montegrity)
      1. Serotonin-4 Receptor Agonist that increases Acetylcholine
  6. Other regimens that have been trialed (experimental)
    1. Women with refractory chronic Functional Constipation
      1. Colchicine 0.6 mg PO tid (4 weeks of use in trial)
      2. Verne (2003) Am J Gastroenterol 98:1112-6 [PubMed]

XIV. Prevention

  1. Bowel Retraining: Avoid stool retention
    1. Take the time to go to the bathroom regularly
      1. However, a daily Bowel Movement is not needed for gastrointestinal health
    2. Make use of physiologic bowel cycles (timed stooling when colonic motility is increased)
      1. Plan Bowel Movement soon after waking
      2. Plan Bowel Movement 10-30 minutes after a meal
    3. Positioning can assist with Defecation
      1. Resting feet on a short foot stool while sitting on the toilet may help to straighten the anorectal junction
    4. Consider initiating program with enema or suppository (not for longterm use)
      1. Lukewarm enema within one hour of meal
      2. Bisacodyl suppository immediately after meal
      3. Consider enema for no stool in 3 days
  2. LIfestyle measures
    1. Increase hydration to at least 64 ounces per day
    2. Avoid Caffeine
    3. Participate in regular Exercise (2 to 6 times weekly)
  3. Eliminate all Laxative use
    1. Laxatives (esp. Stimulant Laxatives) cause rebound Constipation
    2. Polyethylene Glycol (Miralax) or Lactulose may be used infrequently as needed
    3. Replace all Laxatives with Bulk-Forming agents (after initial disimpaction protocol)
    4. Anticipate 1-2 week adjustment period
      1. Use Fleet Enema if no stool within 3 days for 1-2 weeks
  4. Increase Dietary Fiber or Bulk-forming agent (Psyllium)
    1. Used with >1.5 L/day fluids to prevent worsening
    2. Increase to 20 grams of Dietary Fiber per day
    3. Anticipate initial bloating with fiber intake
      1. Increase fiber by 5 grams per day per week
    4. May exacerbate atonic colon or slow transit colon
      1. These patients may benefit from low fiber intake

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