AUTHOR INFORMATION

Section 1 of 12

Authored by Dave A Holson, MD, MPH, Assistant Professor of Emergency Medicine, Mount Sinai School of Medicine; Director, Department of Emergency Medicine, Queens Hospital Center, Jamaica, NY

Coauthored by Sekuleo Gathers, MD, Staff Physician, Department of Emergency Medicine, Mount Sinai Medical Center

Dave A Holson, MD, MPH, is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, National Medical Association, and Society for Academic Emergency Medicine

Edited by William K Chiang, MD, Associate Professor, Department of Emergency Medicine, New York University School of Medicine; Consulting Staff, Department of Emergency Medicine, Bellevue Hospital Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Eugene Hardin, MD, FACEP, FAAEM, Chair and Associate Professor, Department of Emergency Medicine, Charles R Drew University of Medicine and Science; Chair, Department of Emergency Medicine, Martin Luther King, Jr/Drew Medical Center; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Barry Brenner, MD, PhD, FACEP, Professor of Emergency Medicine, Professor of Internal Medicine, and Professor of Anatomy and Neurobiology, Research Director, Department of Emergency Medicine, University of Arkansas for Medical Sciences

Author's Email:	Dave A Holson, MD, MPH
Editor's Email:	William K Chiang, MD

eMedicine Journal, October 2 2006, VOLUME 7, Number 10

INTRODUCTION

Section 2 of 12

Background: Constipation is a symptom rather than a disease and is the most common digestive complaint in the United States. A standard set of criteria has been suggested that includes at least 2 of the following symptoms present for at least 3 months:

• Hard stools

• Straining at defecation

• Sensation of incomplete evacuation at least 25% of the time

• Two or fewer bowel movements per week

Pathophysiology: Constipation results from a colonic or anorectal functional disorder.

Frequency:

• In the US: More than 4 million people have frequent constipation, a prevalence of about 2%. Constipation accounts for an estimated 2.5 million physician visits per year.

Mortality/Morbidity: Most patients with constipation can be treated medically, resulting in complete success or improvement. However, a small percentage of patients are quite debilitated as a result of constipation. Some patients with functional constipation (ie, colonic inertia) require total abdominal colectomy with ileorectal anastomosis.

Race: Constipation appears to affect people of color 1.3 times more frequently than whites.

Sex: Male-to-female ratio is approximately 1:3.

Age: Constipation can occur in all ages, from newborns to elderly persons. An age-related increase in the incidence of constipation exists, with 30-40% of adults older than 65 years citing constipation as a problem.

CLINICAL

Section 3 of 12

History:

• History is most relevant regarding the etiology of constipation. Understanding the type and degree of disability caused by the symptoms is important. Disability may include the following:

• Length of time attempting rectal evacuation

• Number of bowel movements per week

• Presence of chronic straining and/or hard stools

• The patient may be totally asymptomatic or complain of the following:

• Abdominal bloating

• Pain on defecation

• Rectal bleeding

• Spurious diarrhea

• Low back pain

• The following also suggest that the patient may have difficult rectal evacuation:

• Feeling of incomplete evacuation

• Digital extraction

• Tenesmus

• Enema retention

• However, the following signs and symptoms should be concerning:

• Rectal bleeding

• Abdominal pain

• Vomiting

• Unexplained weight loss

Physical:

• General physical examination often is of no benefit in determining etiology or deciding on treatment. The following are exceptional findings:

• A localized mass on abdominal examination

• Local anorectal lesions, which can cause or contribute to constipation (eg, anal fissures, fistulae, strictures, cancer, thrombosed hemorrhoids)

• Visible intussusception during straining

• Digital rectal examination provides information about the following:

• Anorectal masses

• Tone of the internal anal sphincter

• Strength of the external anal sphincter and puborectalis muscle

• Presence of gross blood or occult bleeding by checking the stool guaiac

• Stool amount and consistency: In pelvic outlet dysfunction, more stool is present in the rectal vault than in colonic inertia or irritable bowel syndrome, in which little or no stool remains in the rectum between defecations. Pelvic floor dysfunction manifests by failure of descent of the examining finger and contraction of the upper segment of the sphincter during straining.

Causes: The cause of constipation is usually multifactorial.

• Secondary constipation

• Dietary - Low fiber

• Structural - Anal fissures, thrombosed hemorrhoids, strictures, and tumors

• Endocrinopathic and metabolic - Hypercalcemia, hypokalemia, hypothyroidism, diabetes mellitus, and pregnancy

• Neurologic - Stroke, Hirschsprung disease, Parkinson disease, multiple sclerosis, spinal cord lesion, Chagas disease, and familial dysautonomia

• Connective-tissue disorders - Scleroderma, amyloidosis, and mixed connective-tissue disease

• Drugs
  • Antidepressants (cyclic antidepressants, monoamine oxidase inhibitors [MAOIs])
  • Metals (iron, bismuth)
  • Anticholinergics (benztropine, trihexyphenidyl)
  • Opioids (codeine, morphine)
  • Antacids (aluminum, calcium compounds)
  • Calcium channel blockers (verapamil)
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or diclofenac
  • Sympathomimetics (pseudoephedrine)
  • Cholestyramine and stimulant laxatives (long-term use)
  • Antipsychotics

• Psychologic - Depression

• Functional constipation

• Simple constipation - Repressed defecatory urge

• Irritable bowel syndrome

• Constipation with colonic dilatation - Idiopathic megacolon or megarectum

• Constipation without colonic dilatation - Idiopathic slow transit constipation

• Chronic intestinal obstruction

• Rectal outlet obstruction - Anismus, solitary rectal ulcer, intussusception

• Weak pelvic floor - Descending perineum, rectocele

• Ineffective straining

DIFFERENTIALS

Section 4 of 12

Obstruction, Large Bowel

Other Problems to be Considered:

Diabetes mellitus
Hyperparathyroidism
Hypothyroidism
Lead poisoning
Neuropathy
Parkinson disease
Scleroderma

WORKUP

Section 5 of 12

Lab Studies:

• Serum chemistry may exclude any metabolic causes of constipation, such as hypokalemia and hypercalcemia.

• Complete blood count (CBC) may reveal any anemia that might be associated with rectal bleeding (gross or occult).

• Thyroid function tests may be helpful with patients suspected of having hypothyroidism.

Imaging Studies:

• Plain film of the abdomen (upright and flat)

• This study underscores the amount of stool present in a patient's colon. Differentiation of fecal impaction, bowel obstruction, and fecalith is possible.

• Diagnosis of fecaliths is important because of the dreaded complication of stercoral ulcers, which can lead to colonic perforation.

• Diabetic gastropathy, as well as fecal impaction, may be seen in patients with diabetic neuropathy.

• Residual barium (from barium enemas) can be visualized.

• Scleroderma and other connective-tissue diseases may be complicated by motor disturbances that mimic colonic obstruction on plain film.

• Myxedema ileus is a consequence of hypothyroidism.

Other Tests:

• An extensive workup of the constipated patient is performed on an outpatient basis and usually occurs after approximately 3-6 months of failed medical management.

• These tests are either anatomic (eg, Gastrografin enema, proctosigmoidoscopy, colonoscopy) or physiologic (eg, colonic transit study, defecography, manometry, electromyography).

Procedures:

• Anoscopy: Routinely perform anoscopy on all constipated patients to visualize anal fissures, ulcers, hemorrhoids, and local anorectal malignancy.

• Digital disimpaction: A well-lubricated gloved finger might be required in patients with lower anorectal impactions.

• Warm water enemas: These usually are unpopular among the nursing staff and probably are not necessary within the ED.

TREATMENT

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Emergency Department Care:

• Most patients have chronic constipation, which does not lend itself to a specific etiology at time of presentation.

• A comprehensive history should readily identify the most common causes of fecal impaction including (1) postoperative constipation, (2) prolonged bed rest, (3) residual barium from barium enemas, or (4) medication-related constipation (eg, opioids, anticholinergics).

• In elderly bedridden patients, it is important to exclude severe dehydration and electrolyte abnormalities.

• Exclude any life-threatening complication of constipation (eg, volvulus) and remember that the patient might present with intestinal perforation after tap water enemas performed at home.

• Specifically focus therapeutic interventions on facilitating rectal evacuation rather than increasing bowel movement.

Consultations:

• Consult a general surgeon if you suspect intestinal obstruction or volvulus.

MEDICATION

Section 7 of 12

The mainstay of treatment is a high-fiber diet. Bulking agents usually are the next line of treatment. Enemas can be used to assist in complete stool evacuation. Avoid irritant or peristaltic stimulants (eg, senna). Chronic use has been reported to induce damage to the myenteric plexus, which may eventually impair bowel motility.

Drug Category: Bulk-forming agents -- These agents are used to increase fecal mass, which stimulates peristalsis.

Drug Name	Psyllium (Metamucil, Fiberall) -- Promotes bowel evacuation by forming a viscous liquid and promoting peristalsis.
Adult Dose	1 tsp PO qd/tid with 8 oz of liquid
Pediatric Dose	<6 years: Not established 6-12 years: Administer half of adult dose with 8 oz of liquid >12 years: Administer as in adults
Contraindications	Documented hypersensitivity; fecal impaction, intestinal obstruction, colonic atony, undiagnosed abdominal pain
Interactions	May decrease absorption and effects of salicylates, nitrofurantoin, tetracyclines, and diuretics
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Caution in intestinal adhesions, ulcers, or stenosis

Drug Name	Methylcellulose (Citrucel) -- Promotes bowel evacuation by forming a viscous liquid and promoting peristalsis.
Adult Dose	1 tbsp PO qd/tid with 8 oz of liquid
Pediatric Dose	<6 years: Not established 6-12 years: Administer half of adult dose with 8 oz of liquid >12 years: Administer as in adults
Contraindications	Documented hypersensitivity; fecal impaction, colonic atony, intestinal obstruction, undiagnosed abdominal pain
Interactions	May decrease absorption and effects of salicylates, nitrofurantoin, tetracyclines, and diuretics
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in intestinal adhesions, ulcers, or stenosis

Drug Category: Emollients or softeners -- Lower surface tension of stool and allow mixing of aqueous and fatty substances, thereby softening stool.

Drug Name	Docusate (Colace, Surfak) -- Allows the incorporation of water and fat into stool causing softening of stool.
Adult Dose	100 mg PO qd/bid
Pediatric Dose	<3 years: 10-40 mg/d PO qd or divided bid/qid >3-6 years: 20-60 mg/d PO qd or divided bid/qid 6-12 years: 40-150 mg/d PO qd or divided bid/qid >12 years: Administer as in adults
Contraindications	Documented hypersensitivity; nausea, vomiting, acute abdominal pain
Interactions	Decreases effects of warfarin and increases effects of phenolphthalein
Pregnancy	A - Safe in pregnancy
Precautions	Prolonged use of medication may result in electrolyte imbalance

Drug Category: Emollient stool softeners in combination with stimulants -- Emollient stool softeners cause stool to soften. Stimulants increase peristaltic activity in the GI.

Drug Name	Docusate sodium and casanthranol combination (Peri-Colace, Diocto C, Silace-C) -- Docusate sodium allows incorporation of water and fat into stool causing stool to soften. Casanthranol is an anthraquinone stimulant hydrolyzed by colonic bacteria into active compound. Usually produce action 8-12 h after administration.
Adult Dose	1-4 cap or tab PO qd Alternatively, 5-60 mL PO qd if syrup or emulsion given
Pediatric Dose	<6 years: Not recommended >6 years: Administer as in adults
Contraindications	Documented hypersensitivity; nausea, vomiting, GI bleeding, appendicitis, GI bleeding, congestive heart failure, fecal impaction, appendicitis, nausea, vomiting, acute abdominal pain
Interactions	Decreases effects of warfarin and increases effects of phenolphthalein
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Excessive use may lead to electrolyte imbalance, osteomalacia, steatorrhea, and cathartic colon

Drug Category: Osmotic laxatives -- These agents act by retaining fluid in the bowel, osmosis, or altering the pattern of water distribution in feces.

Drug Name	Magnesium hydroxide (Phillips' Milk of Magnesia) -- Causes osmotic retention of fluid, which distends colon and increases peristaltic activity. This in turn promotes emptying of the bowel.
Adult Dose	5-15 mL PO q6h prn
Pediatric Dose	2.5-5 mL PO prn up to qid
Contraindications	Documented hypersensitivity; colostomy, ileostomy, renal failure, fecal impaction, appendicitis
Interactions	Decreases effects of tetracyclines, digoxin, indomethacin, and iron salts
Pregnancy	A - Safe in pregnancy
Precautions	Caution in severe renal impairment

Drug Name	Sodium phosphate (Fleet enema) -- Through osmotic effects, these agents draw water from the intestine into the lumen of the gut, producing distention and promoting bowel emptying.
Adult Dose	1 adult (4.5 fl oz) enema PR
Pediatric Dose	1 pediatric (2.25 fl oz) enema PR
Contraindications	Documented hypersensitivity; hypernatremia, hyperphosphatemia, renal failure, hypocalcemia, fecal impaction
Interactions	Do not administer aluminum, magnesium antacids, or sucralfate
Pregnancy	A - Safe in pregnancy
Precautions	Hypocalcemia, hyperphosphatemia, hypernatremia, and acidosis in patients with renal difficulties; caution in congestive heart failure and cirrhosis

Drug Name	Polyethylene glycol solution (MiraLax) -- For treatment of occasional constipation. In theory, less risk of dehydration or electrolyte imbalance with isotonic polyethylene glycol compared with hypertonic sugar solutions. Laxative effect generated because polyethylene glycol is not absorbed and continues to hold water by osmotic action through small bowel and colon, resulting in mechanical cleansing. Supplied with measuring cap marked to contain 17 g of laxative powder when filled to indicated line. May require 2-4 d (48-96 h) to produce bowel movement.
Adult Dose	Dissolve 17 g in 8 oz of water and drink daily prn for up to 2 wk
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; colitis, ileus, megacolon, bowel perforation, gastric retention, GI obstruction
Interactions	May decrease absorption of oral medications, thereby reducing effectiveness
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in ulcerative colitis and hot loop polypectomy; not for use > 2 wk

Drug Name	Lactulose (Cephulac, Cholac, Constilac) -- Produces an osmotic effect in the colon, resulting in distention and promoting peristalsis. Action may take up to 48 h.
Adult Dose	15-30 mL PO qd/bid
Pediatric Dose	<1 year: 2.5 mL PO bid 1-5 years: 5 mL PO bid 6-12 years: 10 mL PO bid >12 years: Administer as in adults
Contraindications	Documented hypersensitivity; galactosemia, intestinal obstruction
Interactions	Decreases effects of neomycin, laxatives, and antacids
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Adverse effects include flatulence, cramps, and abdominal discomfort; caution in diabetes mellitus; monitor for electrolyte imbalance

Drug Category: Gastrointestinal agent, miscellaneous -- These agents may assist in increasing GI motility.

Drug Name	Lubiprostone (Amitiza) -- Locally acting chloride channel activator that enhances a chloride-rich intestinal fluid secretion without altering sodium and potassium concentrations in the serum. Specifically activates C1C-2, an apical membrane in the human intestine. Increases intestinal fluid secretion to assist in GI motility, thereby decreasing symptoms of chronic idiopathic constipation (eg, abdominal pain, bloating, straining, hard stools).
Adult Dose	24 mcg PO bid with food
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; history of mechanical GI obstruction; severe diarrhea
Interactions	Data limited, none reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Common adverse effects include headache, nausea, diarrhea, abdominal pain, and abdominal distension; discontinue if diarrhea persists

Drug Category: 5-HT4 Receptor partial agonists -- These agents may stimulate peristaltic activity by partially activating serotonin type 4 receptors.

Drug Name	Tegaserod (Zelnorm) -- Serotonin type 4 (5-HT4) receptor partial agonist with no affinity for 5-HT3 receptors. May trigger peristaltic reflex via 5-HT4 activation, which enhances basal motor activity and normalizes impaired GI motility. Research studies have shown inhibitory activity of the drug on visceral activity in the GI tract.
Adult Dose	6 mg PO bid ac
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; moderate or severe renal impairment; history of bowel obstruction, symptomatic gallbladder disease, suspected sphincter of Oddi dysfunction, or abdominal adhesions
Interactions	None reported
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Diarrhea may occur (do not give to patients with diarrhea); discontinue if new or sudden worsening of abdominal pain or diarrhea occurs (do not give to patients with diarrhea); ischemic colitis and other forms of intestinal ischemia have been reported rarely (causality has not been established); discontinue immediately if ischemic colitis (eg, rectal bleeding, bloody diarrhea, new or worsening abdominal pain) occurs and evaluate immediately, do not resume treatment if findings consistent with ischemic colitis

FOLLOW-UP

Section 8 of 12

Further Inpatient Care:

• Patients with the following warrant admission and surgical evaluation:

• Obstructive symptoms

• Nonrectal impactions

• Fever and dehydration

Further Outpatient Care:

• Further outpatient care should include contact with the primary care physician to ensure follow-up.

• Referral to a gastroenterologist is warranted for patients with the following:

• Constipation of recent onset

• Chronic constipation associated with weight loss, anemia, or change in stool consistency

• Refractory constipation

• Constipation requiring chronic laxative use

• Future directions

• Prokinetic agents that stimulate serotonergic enteric nervous system receptors
  • Tegaserod
  • Prucalopride

• Enteric nervous system neurotrophin and opiate
  antagonists

• Electrical stimulation of the colon

• Stem cells to repopulate dysfunctional neurons

In/Out Patient Meds:

• Bulk-forming agent: Psyllium (eg, Metamucil) increases frequency and softens stool consistency.

• Emollient: Docusate sodium (eg, Colace) improves hard bowel movements.

• Lukewarm tap water enema: This treatment facilitates rapid relief of symptoms and may help regulate further bowel movements.

Deterrence/Prevention:

• Adequate fluid intake (ie, eight 8-oz glasses of water per day)

• Regular exercise

• High-fiber diet

• Avoidance or decreased use of constipating medications

• Regular bowel habits with attempted bowel movements at the same time daily may help symptoms, especially after meals when the gastrocolic reflex is strongest.

Complications:

• Anal fissures

• Fecal impaction

• Bowel obstruction

• Fecal incontinence

• Stercoral ulceration

• Megacolon

• Volvulus

• Rectal prolapse

• Urinary retention

• Syncope

Prognosis:

• Most active patients do well with medical management.

• Constipation is an ongoing problem for patients who are bedridden or otherwise debilitated.

• Colectomy usually is reserved for patients with slow transit constipation who fail to respond to 6 months of medical management with good patient compliance.

Patient Education:

• Listening to patients' concepts of normal bowel activity is important.

• Instituting a behavior modification program allows patients to become more aware of and responsive to normal urges to defecate.

• Emphasize the importance of a high-fiber diet.

• Emphasize adequate fluid intake.

• Emphasize regular exercise.

• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education articles Constipation in Adults and Constipation in Children.

MISCELLANEOUS

Section 9 of 12

Medical/Legal Pitfalls:

• Failure to discover an obstructing lesion of the colon (eg, tumor, volvulus) as the cause of constipation

• Failure to consider intestinal perforation in the patient who has been self-administering enemas at home

• Failure to treat an underlying systemic illness (eg, hypothyroidism)

• Failure to adequately hydrate or correct any underlying electrolyte imbalance

TEST QUESTIONS

Section 10 of 12

CME Question 1: An 80-year-old man is brought to the ED from his nursing home with a 5-day history of constipation. Which of the following signs and symptoms is not an indication for admission?

A: Rectal impaction
B: Dehydration
C: Fever
D: Abdominal distention
E: Vomiting

The correct answer is A: Patients with obstructive symptoms, nonrectal impaction, fever, and dehydration warrant admission and surgical consultation.

CME Question 2: A constipated 30-year-old man is discharged from the ED with instructions to increase dietary fiber intake and to start a bulk-forming agent. Which of the following is not an example of a bulk-forming agent?

A: Methylcellulose (Citrucel)
B: Psyllium (Metamucil)
C: Calcium polycarbophil (FiberCon)
D: Docusate sodium (Colace)
E: Malt soup extract (Maltsupex)

The correct answer is D: Colace is an emollient or stool softener that works by lowering surface tension of stool to allow mixing of aqueous and fatty substances, thereby softening the stool.

Pearl Question 1 (T/F): Diagnostic tests provide the most useful information about the etiology of constipation.

The correct answer is False: History provides the most useful information in these cases.

Pearl Question 2 (T/F): Elderly, bedridden, and constipated patients require further workup.

The correct answer is True: Severe dehydration, electrolyte abnormalities, intestinal obstruction, and carcinoma should be excluded.

Pearl Question 3 (T/F): The mainstay of treatment for constipation is preventative.

The correct answer is True: A high-fiber diet, exercise, adequate fluid intake, and decreased use of constipating medications are mainstays of treatment.

Pearl Question 4 (T/F): A 60-year-old man with a past medical history significant for a stroke with left hemiparesis presents with constipation for 3 days and vomiting once today. Vital signs are stable and the patient is afebrile. Rectal examination reveals a large amount of stool in the vault, no masses, and guaiac-negative stool. CT scan is the diagnostic test of choice.

The correct answer is False: Plain films of the abdomen (upright and flat) should be performed first.

PICTURES

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Caption: Picture 1. Large amount of stool throughout the colon.
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Caption: Picture 2. Large stool mass in hepatic flexure of the colon.
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Caption: Picture 3. Colon distension secondary to fecal impaction.
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Caption: Picture 4. Pseudo-obstruction secondary to fecal impaction.
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Caption: Picture 5. Distended transverse colon.
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Caption: Picture 6. Distended rectum.
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	eMedicine Zoom View (Interactive!)
Picture Type: CT

BIBLIOGRAPHY

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• Halligan S, Bartram CI: The radiological investigation of constipation. Clin Radiol 1995 Jul; 50(7): 429-35[Medline].
• Harari D, Gurwitz JH, Avorn J, et al: How do older persons define constipation? Implications for therapeutic management. J Gen Intern Med 1997 Jan; 12(1): 63-6[Medline].
• Johanson JF, Sonnenberg A, Koch TR: Clinical epidemiology of chronic constipation. J Clin Gastroenterol 1989 Oct; 11(5): 525-36[Medline].
• Martin H, Slyk MP, Deymann S, Cornacchione MJ: Safety profile assessment of risperidone and olanzapine in long-term care patients with dementia. J Am Med Dir Assoc 2003 Jul-Aug; 4(4): 183-8[Medline].
• Mezwa DG, Feczko PJ, Bosanko C: Radiologic evaluation of constipation and anorectal disorders. Radiol Clin North Am 1993 Nov; 31(6): 1375-93[Medline].
• Rantis PC, Vernava AM, Daniel GL, Longo WE: Chronic constipation--is the work-up worth the cost?. Dis Colon Rectum 1997 Mar; 40(3): 280-6[Medline].
• Schiller LR: New and emerging treatment options for chronic constipation. Rev Gastroenterol Disord 2004; 4 Suppl 2: S43-51[Medline].
• Shafik A: Constipation. Pathogenesis and management. Drugs 1993 Apr; 45(4): 528-40[Medline].
• Sonnenberg A, Koch TR: Epidemiology of constipation in the United States. Dis Colon Rectum 1989 Jan; 32(1): 1-8[Medline].
• Velio P, Bassotti G: Chronic idiopathic constipation: pathophysiology and treatment. J Clin Gastroenterol 1996 Apr; 22(3): 190-6[Medline].

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