Management of Constipation in Adults Grace Lee May 2018

Objectives Learn how to define constipation Learn the causes of constipation Learn how to manage constipation

Case A 76 year old woman with HTN, DMII, HLD presents to your clinic to be evaluated for constipation, which has been ongoing for the past year. She’s complaining of having stools only twice a week and has to strain for nearly all of her bowel movements. She has been eating more vegetables, drinking more water, and increasing her physical activity. She has also recently included Metamucil in her diet. Her last colonoscopy one year ago was normal. What would you offer next for her constipation? A. Miralax B. Senna C. Docusate D. Weekly tap water enemas E. Either A. or B.

Definition Rome IV criteria (Need 2 of the following): Straining* Lumpy or Hard Stools* Sensation of Incomplete Evacuation* Use of Manual Maneuvers (digital evacuation)* Sensation of Anorectal Obstruction/Blockage* < 3 Bowel Movements per week -Those with * next to them, need to be associated with >25% of defecations * Need to be associated with >25% of defecations

Causes Primary/Functional Secondary Causes -A thorough history is needed to elicit the etiology of constipation -You always want to rule out secondary causes of constipation first

Primary/Functional There are 3 subtypes: Normal transit/Psychiatric Slow transit = due to enteric nerve plexus dysfunction Dyssynergic defecation = inability to relax muscles to allow bowel movements out from rectum -Normal transit: Normal colonic motility = This is often due to the belief of having decreased bowel movements, i.e. psychiatric -Slow transit: Patients have little or no increase in motility after eating

Secondary Causes Neurogenic Non-neurogenic Irritable Bowel Syndrome Central: Multiple Sclerosis, Parkinson Disease Peripheral: DM II, Hirschsprung Disease Irritable Bowel Syndrome Drugs Analgesics: NSAIDs Anti-cholinergics: Anti-histamines, antipsychotics, anti-depressants (TCA) Cation-containing agents: Iron, Antacids Neurally active: Opiates, Serotonin Antagonists (Zofran), Antihypertensives (CCB, Beta-blockers) Non-neurogenic Hypothyroidism, metabolic (i.e. hypokalemia, hypercalcemia), CKD, Rheum disorders, IBD Other Examples: Neurogenic: a) Central – Spinal cord injury b) Peripheral – Autonomic neuropathy, Chagas Disease, Intestinal Pseudo-obstruction Drugs: - Anti-cholinergics: Anti-histamines (Claritin, Zyrtec, Allegra), Antidepressants (TCA), Anti-epileptics - Cation-containing agents: Sucralfate, Barium - Neurally active agents: Ganglionic blockers, Vinca alkaloids Non-neurogenic: Rheumatologic disorders (dermatomyositis, scleroderma), anorexia nervosa, pregnancy, panhypopituitarism, myotonic dystrophy, obstructing lesions of GI tract (colon CA)

Management

Steps in Management Lifestyle Changes & Bulk-Forming Laxatives Other Laxatives: Surfactants, Osmotic or Stimulant Laxatives Suppositories -Order of management of constipation Fecal Disimpaction & Enemas Other Pharmacologic Agents

Step 1: Lifestyle Changes & Bulk-Forming Laxatives Lifestyle modification Increase fluids, fiber, and physical activity Bulk-forming laxatives: Absorb water & soften stool Psyllium (Metamucil) Methylcellulose (Citrucel) Polycarbophil (FiberCon) Wheat Dextrin (Benefiber) -Lifestyle changes and bulk-forming laxatives are the first step in management of constipation -Recommended daily dietary fiber: 20-35 grams/day

Step 2: Other Laxatives Mush or Push Osmotic Laxatives Stimulant Laxatives Surfactants

Step 2: Surfactants Decrease surface tension of stool, allowing water to enter stool more easily Example: Docusate/Colace -There is little evidence to support use of surfactant agents in chronic constipation -> in other words, don’t use it -Less effective than other laxatives

Step 2: Osmotic Laxatives Draw water into lumen by osmosis & soften stool (mush) Examples: Polyethylene glycol (PEG) Synthetic Disaccharides Lactulose, Sorbitol Saline Milk of Magnesium, Magnesium Citrate -PEG examples: Golytely, Miralax -PEG based laxatives are superior to synthetic disaccharide based laxatives as lactulose & sorbitol can lead to abdominal bloating & flatulence

Step 2: Stimulant Laxatives Increase intestinal motor activity by activating enteric nerves (push) Examples: Senna Bisacodyl -Good for slow-transit constipation

Step 3: Suppositories Liquify stool at rectum, allowing it to pass easier Examples: Bisacodyl Glycerin -If laxatives fail, then suppositories can be trialed

Step 4: Fecal Disimpaction & Enemas 1st Step: Manual disimpaction 2nd Step: Use mineral oil enema for lubrication 3rd Step: Cleanse bowel with other enemas Warm water Soap Suds Sodium phosphate (Fleet) 4th Step: Administer water-soluble contrast enema (in fluoroscopy suite) -If the patient has failed diet/lifestyle changes, laxatives, and suppositories, then think of fecal disimpaction as a reason for constipation -1st step: manual disimpaction should be attempted first -2nd step: once manual disimpaction is completed, then a mineral oil enema can be given to provide lubrication & soften the stool -3rd step: once a mineral oil enema is given, then you want to cleanse the bowel with other enemas (preferred regimen: warm water enema x3 days) = Avoid sodium phosphate enemas in the elderly as it can lead to dehydration -4th step: If fecal impaction is unsuccessful or partially successful, then a water-soluble contrast enema is used (Gastrografin or Hypaque) to identify other reasons why a patient is constipated -> shows you the entire colon & rectum = How it works: 1) An X-ray is taken prior to administration of enema 2) Then, the enema is administered 3) Then, additional x-rays are taken in real-time as the enema fills your colon to see any abnormalities in your colon or rectum

Suppositories & Enemas: Where do they work? Lactulose Enema Tap Water Enema Soap Sud Enema -Diagram depicting where suppositories and enemas work -Water-soluble contrast enema is the only one that reaches the right side of the colon Fleet Enema Water-soluble Contrast Enema Suppositories Mineral oil Enema

Step 5: Other pharmacologic agents Increase fluid secretion into lumen & motility Guanylate cyclase C receptor agonists Linaclotide Plecanatide Cl channel activator Lubiprostone -Some examples of other pharmacologic agents available for severe constipation if previous regimens fail -Both Guanylate cyclase C receptor agonists and Cl channel activators work by increasing secretion of fluid into lumen of GI tract and increase motility

Back to the Case A 76 year old woman with HTN, DMII, HLD presents to your clinic to be evaluated for constipation, which has been ongoing for the past year. She’s complaining of having stools only twice a week and has to strain for nearly all of her bowel movements. She has been eating more vegetables, drinking more water, and increasing her physical activity. She has also recently included Metamucil in her diet. Her last colonoscopy one year ago was normal. What would you offer next for her constipation? A. Miralax B. Senna C. Docusate D. Weekly tap water enemas E. Either A. or B. 1) Does this patient have constipation? = Yes since she fulfills at least 2 of Rome IV criteria: <3 bowel movements/week and has to strain for >25% of defecations 2) What has she done to try to relieve her constipation? = Increased fluids, fiber (vegetables) in her diet, and physical activity = Added Metamucil (bulk-forming laxative)

The Answer A 76 year old woman with HTN, DMII, HLD presents to your clinic to be evaluated for constipation, which has been ongoing for the past year. She’s complaining of having stools only twice a week and has to strain for nearly all of her bowel movements. She has been eating more vegetables, drinking more water, and increasing her physical activity. She has also recently included Metamucil in her diet. Her last colonoscopy one year ago was normal. What would you offer next for her constipation? A. Miralax B. Senna C. Docusate D. Weekly tap water enemas E. Either A. or B. Answer is E. After the patient increases her fluid intake, changes her diet, increases her physical activity, and has added bulk-forming laxatives, either osmotic or stimulant laxatives can be added to her regimen Why not the other choices? A. Miralax is an osmotic laxative and is a good option to add to her current regimen, but Senna can also be added as the next choice B. Senna is a stimulant laxative and is a good option to add to her current regimen, but Miralax can also added as the next choice C. Docusate is a surfactant/stool softener with minimal effects on chronic constipation, so this would not be a good option to add to her current regimen D. Tap water enemas would be given only after both osmotic and stimulant laxatives have been trialed with no improvement

Summary A thorough history must be obtained to rule out secondary causes of constipation Dietary/lifestyle changes & Bulk-forming laxatives should be used first Then, osmotic/stimulating laxatives can be used If all laxatives fail, then suppositories and enemas are used Finally, other pharmacologic agents are used if all else fails

References Text: Wald, A. Etiology and evaluation of chronic constipation in adults. Uptodate.com. May 2018. Wald, A. Management of chronic constipation in older adults. Uptodate.com. May 2018.

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