Chronic Constipation

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Chronic constipation - an evidenced based
approach

• Robert A. Baldor, MD, FAAFP
• Professor, Family Medicine Community Health
• UMass Medical School

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Learning Objectives

• by the end of the session, you will have a clear
  understanding of the basic pathophysiology
  related to chronic constipation
• and develop an evidenced based approach for the
  primary care diagnosis and treatment of these
  chronic problems.

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Mrs Z.

• A 34-year-old white female who complains of
  constipation she hasnt discussed it in the past
  as its embarrassing, but states that she has
  been constipated her entire life and has tried a
  variety of OTC products without much relief.
• She further reports that she is very active, runs
  4 days a week, that she always has a bottle of
  water with her and tries to eat salads
  regularly..

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History

• Character of the problem
• Consistency
• Frequency
• Straining, bloating
• Diarrhea
• Medications

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Mrs. Z

• Doesnt have much discomfort, but has to strain
  and has hard stools along with blood occasionally
  on TP she tends to go about twice a week
• She will occasionally have diarrhea but it
  seems related to something she had eaten
• Takes Tums for her bones

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Constipation No Clear Definition

• A group of syndromes with similar findings

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Am College of Gastroenterology

• Unsatisfactory defecation, characterized by
  infrequent stools and/or difficult stool passage
• Brandt 2005

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Pathophysiology

• As food leaves stomach, gastroileal reflex
  relaxes the ileocecal valve and digested food
  (chyme) enters the colon
• Peristaltic contractions move chyme through the
  colon
• Na actively absorbed - water follows because of
  the generated osmotic gradient

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Normal Colonic Transit Time

• A meal reaches the ileo-cecal valve in 4 hours
• the sigmoid colon 12hours later
• then slows to the anus.
• Plastic pellets with a meal ? 70 recovered in 3
  days remainder in a week!

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Defecation

• Food distends the stomach, initiating the
  gastro-colic reflex causing rectal contractions
  a desire to go!
• Urge to defecate occurs as rectal pressures ?
• Defecation reflexes can be inhibited by
  voluntarily contracting the external sphincter or
  facilitated by straining
• Pelvic floor/anal sphincter dysfunction interfere
  with normal defecation

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Most with primary constipation suffer from which
one of the following?

• Slow colonic transit time
• Pelvic floor/anal sphincter dysfunction
• Functional normal transit time and sphincter
  function

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Most with primary constipation suffer from which
one of the following?

• Slow colonic transit time
• Pelvic floor/anal sphincter dysfunction
• Functional normal transit time and sphincter
  function

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Secondary Constipation

• Endocrine dysfunction (DM, hypothyroid)
• Metabolic disorder (? Ca,? K)
• Mechanical (obstruction, rectocele)
• Pregnancy
• Neurologic disorders (Hirschsprungs, multiple
  sclerosis, spinal cord injuries)

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Medication Effect

• Anti-cholinergic effects
• Antidepressants
• Narcotics
• Antipsychotics
• Calcium channel blockers
• Antacids (calcium, aluminum)
• Mrs. Z taking Tums (ca carbonate) for
  osteoporosis - ca phosphate (Posture) and ca
  citrate (Citracal) less constipating.

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IBS ? Rome III Criteria

• Symptoms at least 3 days/month of recurrent
  abdominal pain or discomfort associated with hard
  constipated stools interrupted by brief episodes
  of diarrhea
• Drossman Gastroenterology. 2006

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IBS Treatment

• Multiple RCTs with inconsistent results best
  evidence for treating IBS-C
• Bulking agents
• Psychotropic agents
• DARE review 2001

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Red flags

• Onset after age of 50
• Hematochezia/melena
• Unintentional weight loss
• Anemia
• Neurological defects

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Physical Exam

• Digital rectal examination
• Stool character
• Pain, anal tone
• Masses, fissures, hemorrhoids,
• Abdominal/gynecological exam
• Masses, pain
• Neurological exam

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Treatment Behavioral

• Toileting program to take advantage of natural
  reflexes
• Obey the urge
• Gastro-colic
• Defecation reflex

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Medications - Laxatives

• Bulking agents
• Stool softeners
• Osmotic agents
• Stimulants
• Lubricants
• Other

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Bulking Agents at the Grocery Store

• Vegetables
• Fruits
• Whole grain foods
• Bran (hard outer layer of cereal grains)
• Bloating and gas can be problematic
• Gradually increase intake to 25 grams/day
• Less fermentable fiber like wheat bran tends to
  be better tolerated

Limited evidence for effectiveness
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Food Serving Fiber (Gm)
All Bran cereal 1/3 cup 10
Whole wheat bread 2 slices 4
Wheat bran muffin medium 3
Brown rice 1cup 3
Apple/Pear medium 4
Banana medium 3
Dried figs 5 8
Prune juice 1 cup 3
Sunflower seeds ¼ cup 3
Baked potato w/skin medium 4
Canned baked beans ½ cup 5
Chickpeas ½ cup 5
Lentils/ Kidney beans ½ cup 8
Corn ½ cup 2
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Bulking Agents at the Pharmacy

• Moderate evidence
• Psyllium (Metamucil 2.5gms fiber/dose)
• Limited evidence
• Bran methycellulose (Citrucel 2gms fiber/dose)
• Polycarbophil (Fibercon)
• Fiber needs to be accompanied by adequate
  amounts of liquid to be useful - 8oz/2-3gms of
  added fiber!

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Stool Softeners Limited Evidence

• Contain docusate (Colace), an anionic detergent
  with hydrophilic and hydrophobic ends that
  improves the ability of water to mix with and
  soften the stool
• Helpful to soften stools to make defecation
  easier (post-op, childbirth)
• Helpful for hemorrhoids or anal fissures
• ? dose if no effect is seen after a week
• 40-400mg daily QD-QID

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Stimulants (Irritants)

• Irritate bowel, causing muscle contractions
• often in combination with ducosate
• work in 8-12 hrs (try qhs, increase to BID)
• Senna/ducosate (Senokot-S, Ex-lax - max 4/d)
• Bisacodyl/ducosate (Dulcolax, Correctol- max
  30mg/d)
• Casanthranol/ducosate (Peri-colace max 2/d)

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Stimulant Suppositories

• Contain bisacodyl/ducosate (Dulcolax)
• Glycerin suppositories also believed to have
  their effect by irritating the rectum
• Insertion of the suppository into the rectum may
  itself stimulate a bowel movement

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Osmotic Laxatives

• Polyethylene glycol - PEG (good evidence)
• 17 grams daily
• Saccharines lactulose (moderate evidence)
• flatulence, bloating, cramping
• 15 - 120 ml qhs
• Sorbitol (effective as lactulose in elderly men)
• less bloating than lactulose
• 15 - 120 ml qhs
• Magnesium salts (MOM)
• avoid in renal insufficiency, best for acute
  treatment

Lederle. ACP Journal Club, 1991.
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A Closer Look at Polyethylene Glycol - good
evidence for use

• PEG Large, chemically inert polymer, with
  substantial osmotic activity
• Bowel flora unable to metabolize
• Pulls water into colon to soften and increases
  fecal bulk (takes 2-4 days to work)
• First used in a balanced electrolyte solution for
  colon cleansing (Golytely)
• PEG 3350 (Miralax) or with electrolytes (Movical)

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Lubricant Laxatives

• Contain mineral oil (15-45 ml/day)
• Short-term use only
• Binds fat-soluble vitamins
• May decrease absorption of some drugs
• Avoid lubricants in those at risk for aspiration
  (lipid pneumonia)

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Lubiprostone (Amitiza)

• Selective Chloride channel activator
• ? secretion of Cl- ions into small bowel Na and
  water follow, resulting in a softer, bulkier
  stool
• 24 mcgs BID
• Nausea is common (32)
• Avoid use in pregnancy, breast-feeding

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Methylnaltrexone (Relistor)

• Methyl group reduces lipidophilic properties of
  the opioid antagonist naltrexone - ? ability to
  cross blood-brain barrier
• Peripherally Acting Mu-Opioid Receptor (PAM-OR)
  antagonist
• Indicated for palliative care
• For short-term use (lt 4months)
• Side effects - abdominal pain and flatulence

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Other, Non-FDA Approved Agents, Act to Decrease
Transit Time

• Misoprostol (Cytotec 100-200mcg QID)
• a prostaglandin increases colonic motility1
• Colchicine (0.6mg qd - tid)
• neurogenic stimulation ? colonic motility 2
• 1.Roarty. Alimen pharm Therapeutics. 1997
• 2. Verne. Am J. Gastroenterology. 2003, Frame
  J ABFP, 1998

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A Practical Approach

• R/O treatable secondary causes..
• Am Gastroenterological Assn (AGA) guidelines
• CBC, Glucose, TSH, calcium, creatinine
• Sigmoid/colonoscopy if red flags are present.

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Address Immediate Concerns

• Bloating/discomfort/straining
• Osmotic agent like PEG
• Post-op, childbirth, hemorrhoids, fissures
• Stool softener to make defecation easier
• Stimulants and suppositories acutely
• Manual disimpaction as needed
• then approach the chronic condition.

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Start with Lifestyle Changes

• Exercise, increase fluids and fiber to 25
  grams/day over a period of 6 weeks.
• Fiber must be accompanied by sufficient fluid
• Initial approach fruits and vegetables
• Add commercial bulking agents
• Obey the Urge!
• For children trial of rice vs cows milk

Uncontrolled studies support fiber for normal
transient constipation. Am J Gastroenterol. 1999
G Nutr 4/2010
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If No Improvement

• Add osmotic laxative
• adjust dose slowly until stools are soft
• take several days to work
• caution if CHF or renal insufficiency
• Add stimulant laxatives
• Lubiprostone

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Trial of Other Agents

• Misoprostol (Cytotec)
• Colchicine
• Refractory to empiric approach .

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Pursue Diagnostic Evaluation

• Colonoscopy if not indicated sooner .
• Barium enema for obstruction/megacolon
• Radiopaque Sitz-Markers to measure transit time
• markers ingested, KUB in 5 days
• retention gt20 markers indicates slow transit
• markers seen exclusively in distal colon/rectum
  suggests pelvic floor dysfunction

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Referral to evaluate defecation.

• Balloon expulsion
• Defecography using a barium paste.
• Anorectal manometry with a rectal catheter
• Biofeedback with artificial silicon stool
• Surgery rarely indicated

Enck. Dig Dis Sci. 1993
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Summary.

• Constipation - unsatisfactory defecation, with
  infrequent stools, difficult stool passage or
  both
• Functional constipation (normal transit time and
  sphincter function) seen most often
• Work-up is necessary in the presence of red flags
• onset gt50 yrs hematochezia/melena unintentional
  weight loss anemia neurological defects
• Best evidence for effectiveness is for osmotic
  agents

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Long-term Laxative Concerns

• No evidence for addiction
• No evidence for tolerance
• No evidence for dependence
• No evidence for harm from stimulant use,
  melanosis coli may develop, but it is a benign
  condition
• Muller-Lissner. Am J Gastroenterology. 2005

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The End!
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