Constipation resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mugilan Poongkunran M.B.B.S [2]

Definition

Constipation is a syndrome that is characterized by difficulty in passing stool, by infrequent bowel movements, by hard stool, or by a feeling of incomplete evacuation that occurs either in isolation or secondary to another underlying disorder.

Clinical subgroups	Definitions
Normal transit constipation	Normal transit constipation refers to constipation in patients with normal anorectal function and normal colonic transit, with or without abnormal colonic motor disturbances and abnormal (ie, reduced or increased) colonic sensations.
Slow transit constipation	Slow transit constipation refers to constipation in patients with normal anorectal function but slow colonic transit, with or without abnormal colonic motor disturbances and abnormal (ie, reduced or increased) colonic sensations.
Defecatory disorders (Outlet obstruction, obstructed defecation, dyschezia, anismus, or pelvic floor dyssynergia)	Defecatory disorders refer to constipation in patients with impaired rectal evacuation from inadequate rectal propulsive forces and/or increased resistance to evacuation during defecation, with or without structural disturbances like rectocele and intussusception, reduced rectal sensation, and slow colonic transit. Increased resistance to evacuation might follow high anal resting pressure (anismus) and/or incomplete relaxation or paradoxical contraction of the pelvic floor and external anal sphincters (dyssynergia).
Combination disorders	Combination disorders refer to patients with combination or overlap of disorders (eg, STC with defecatory disorders), perhaps even an association with features of irritable bowel syndrome.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Atropine poisoning
• Hypokalemia
• Lead poisoning
• Opium poisoning
• Severe dehydration
• Spinal cord injury
• Superior mesenteric artery occlusion

Common Causes

• Hardening of the feces: Improper mastication, low dietary fiber, dehydration and medications (aluminium, calcium, diuretic, iron).
• Paralysis or slowed transit: Hypothyroidism, hypokalemia, injured anal sphincter, medications (loperamide, codeine, morphine, tricyclic antidepressants) and severe systemic illness due to other causes.
• Constriction, where part of the intestine or rectum is narrowed or blocked: Diverticulosis, pelvic masses and stenosis.
• Psychosomatic constipation: Functional constipation and irritable bowel syndrome.
• Smoking cessation
• Abdominal surgery and childbirth

Management

Diagnostic Approach

Shown below is an algorithm depicting the diagnostic approach of constipation in adults based on the American Gastroenterological Association (AGA) guideline.

Characterize the symptoms: Symptoms suggestive of constipation: ❑ Difficulty in passing stool ❑ Desire to defecate but an inability to pass stool ❑ Straining to begin and/or to end defecation ❑ Prolongation in time to pass stool ❑ Sensation of incomplete emptying of bowel ❑ Sensation of anal blockage during defecation ❑ Difficulty in passing soft stool and/or enema fluid ❑ Difficulty in passing stool postprandial ❑ Direct digital manipualtion to pass stool ❑ Perineal or vaginal pressure to pass stool ❑ Sudden or gradual in onset ❑ ≥3 months ❑ Infrequency in passing stool ❑ Hard or lumpy stools ❑ Use of laxatives to pass stool ❑ Type of laxative ❑ Frequency of usage ❑ Dosage ❑ Use of enemas to pass stool ❑ Use of suppositories to pass stool Symptoms associated with constipation: ❑ Abdominal pain or abdominal discomfort: ❑ Associated with change in frequency of stool ❑ Associated with change in consistency of stool ❑ Improves with passage of stool ❑ During straining ❑ Persisting between bowel movements ❑ Abdominal distention ❑ Abdominal bloating ❑ Diarrhea alternating with constipation ❑ Blood in stools ❑ Fever ❑ Nausea and vomiting ❑ Loss of appetite ❑ Loss of weight ❑ Fatigue ❑ Malaise ❑ Fibromyalgia ❑ Psychosocial distress Obtain a detailed history: ❑ Diet: ❑ Dietary pattern change ❑ Low fiber diet ❑ Food intolerance ❑ Medications: ❑ Anticholinergics ❑ Anticonvulsants ❑ Antidepressants ❑ Antihistamines ❑ Antihypertensives ❑ Antiparkinsonian drugs ❑ Antipsychotics ❑ Antispasmodics ❑ Bile acid sequestrants ❑ Chemotherapeutic agents ❑ Endocrine medications (pamidronate or alendronic acid) ❑ Miscellaneous compounds (barium sulfate or oral contraceptives) ❑ Opioid analgesics ❑ Sympathomimetics ❑ Systemic illness: ❑ Diabetes ❑ Hypothyroidism ❑ Gastrointestinal disorders ❑ Neuromuscular disorders ❑ Surgical history: ❑ Abdominal surgeries ❑ Caesarean section ❑ Post surgical extended bed rest ❑ Trauma history: Spinal cord injury ❑ Family history: ❑ Colorectal cancer ❑ Pelvic masses ❑ Neuromuscular diseases ❑ Personal history: ❑ Smoking cessation ❑ Drug abuse ❑ Travel history

Examine the patient: ❑ General examination: ❑ Pulse rate ❑ Blood pressure ❑ Respiratory rate ❑ Weight ❑ Thyroid ❑ Signs of dehydration ❑ Perineal/rectal examination: ❑ Observe perianal skin for evidence of fecal soiling ❑ During stimulated evacuation observe ❑ Anal verge for any patulous opening or prolapse of anorectal mucosa ❑ Descent of the perineum ❑ During a squeeze aimed at retention observe the elevation of perineum ❑ Test anal reflex by a light pinprick or scratch ❑ During digital evaluation ❑ Evaluate the resting tone of the sphincter ❑ Look for puborectalis muscle tenderness ❑ Look for rectocele, hemorrhoids or anal fissure ❑ Abdominal examination: ❑ Abdominal mass ❑ Abdominal distension ❑ Abdominal tenderness ❑ Increased or decreased bowel sounds ❑ Neurological examination: ❑ Neuropathy ❑ Spinal cord injury

Order laboratory tests: ❑ Complete blood count (CBC) ❑ TSH ❑ Serum calcium ❑ Serum glucose ❑ Creatinine When secondary causes are suspected: ❑ Colonoscopy ❑ Flexible sigmoidoscopy ❑ Barium enema ❑ Computed tomographic colonography

Consider the diagnostic criteria of constipation Rome III criteria: Symptoms for ≥6 months and ≥2 of the following for the past 3 months: ❑ Straining during defecation ❑ Hard or lumpy stools ❑ Sensation of incomplete evacuation during defecation ❑ Sensation of anorectal obstruction/blockade during defecation ❑Manual maneuvers to facilitate defecations with <3 defecations/week ❑ Absence of loose stools Pharmacologic studies based criteria: Spontaneous bowel movements <3 per week and ≥1 of the following for at least 12 weeks during the past 12 months: ❑ Straining during more than one-fourth of defecation ❑ Lumpy or hard stools in more than one-fourth of defecation ❑ Sensation of incomplete evacuation in more than one-fourth of defecation ❑ Absence of loose stools or watery spontaneous bowel movements

❑ Adjust or discontinue medications causing constipation ❑ Administer a trial of fiber and/or laxatives Secondary constipation: ❑ Consider treating secondary causes of constipation if uncovered during evaluation (due to metabolic conditions, myopathies, neuropathies, or other conditions) Organic constipation: ❑ Consider treating organic causes of constipation if uncovered during evaluation (due to mechanical obstruction or adverse drug effect) Irritable bowel syndrome: ❑ Consider treating irritable bowel syndrome

Adequate response to trial of fiber and/or laxatives

Inadequate response to trial of fiber and/or laxatives

❑ Anorectal manometry ❑ Balloon expulsion test

Normal

Inconclusive

Abnormal

❑ Barium defecography or ❑ MR defecography

Normal

Abnormal

Colonic transit

Defecatory disorder

Slow

Normal

Slow transit constipation

Normal transit constipation

Therapeutic Approach

Shown below are algorithms depicting the therapeutic approaches of clinical subgroups of constipation in adults based on the American Gastroenterological Association (AGA) guideline.

Refractory Constipation

Chronic constipation who have not responded to a high-fiber diet and/or over-the-counter laxatives after organic disorders have been excluded

Order specific tests: ❑ Rectal Balloon Expulsion Test (BET) ❑ Anorectal Manometry (ARM) ❑ Barium, Scintigraphic, and Magnetic Resonance Defecography (BD) ❑ Colonic Transit Test (CTT)

Normal BET, ARM, BD, CTT

Abnormal CTT Normal BET, ARM, BD

Abnormal BET, ARM, BD Normal CTT

Abnormal BET, ARM, BD, CTT

Normal transit constipation

Slow transit constipation

Pelvic floor dysfunction

Combined slow transit constipation and pelvic floor dysfunction

Normal Transit Constipation

Normal transit constipation

Fiber ❑ Psyllium: 1 tsp up to 3 times daily OR ❑ Methylcellulose: 1 tsp up to 3 times daily OR ❑ Calcium polycarbophil: 2-4 tablets OD ❑ Insoluble fiber (wheat bran) is not preferred PLUS Saline laxative ❑ Milk of magnesia: 15-30 ml OD or BID

Response to treatment

Yes

No

Continue the same regimen

Add stimulant laxative ❑ Bisacodyl: 10 mg suppositories or 5-10 mg orally up to 3 times/wk OR ❑ Glycerin: Suppository OD

Response to treatment

No

Yes

Add hyperosmolar agents ❑ PEG: 8-32 oz once daily OR ❑ Lactulose: 15-30 ml OD or BID

Continue the same regimen

Response to treatment

Yes

No

Continue the same regimen

Adjust and change medications periodically

Slow Transit Constipation

Slow transit constipation

Fiber ❑ Psyllium: 1 tsp up to 3 times daily OR ❑ Methylcellulose: 1 tsp up to 3 times daily PLUS Saline laxative ❑ Milk of magnesia: 15-30 ml OD or BID PLUS Stimulant laxative ❑ Bisacodyl: 10 mg suppositories or 5-10 mg orally up to 3 times/wk

Response to treatment

Yes

No

Continue the initial therapeutic regimen ❑ Fiber ❑ milk of magnesia

Add hyperosmolar agent ❑ PEG: 8-32 oz once daily OR ❑ Lactulose: 15-30 ml OD or BID

Response to treatment

No

Yes

Repeat colonic transit test with medications

Continue the initial therapeutic regimen

Response to treatment

Normal

Delayed

Adjust medications as needed

Repeat BET and BD

Normal

Abnormal

Consider illeo rectal anastamosis or subtotal colectomy

Manage for pelvic floor dysfunction

Pelvic Floor Dysfunction

Pelvic floor dysfunction

Abnormal BET or BD ❑ Define rectoanal angle ❑ Define preineal descent ❑ Define rectal emptying High resting pressure ❑ Rule out anal fissure first Abnormal reflex ❑ Absence of rectoanal inhibitory reflex ❑ Rule out adult Hirschsprung's disease

Fiber ❑ Psyllium: 1 tsp up to 3 times daily OR ❑ Methylcellulose: 1 tsp up to 3 times daily PLUS Stimulant laxative ❑ Bisacodyl: 10 mg suppositories or 5-10 mg orally up to 3 times/wk OR ❑ Glycerin: Suppository OD

Biofeedback ❑ Anorectal and pelvic floor muscle activity are recorded by surface electromyographic sensors ❑ Patients are taught to increase intraabdominal pressure and relax the pelvic floor muscles during defecation ❑ Patients practice by expelling an air filled balloon or through external traction to a catheter attached to the balloon ❑ Patients are taught to recognize weaker sensations of rectal filling ❑ Patients are taught Kegel exercises

Response to treatment

Yes

No

Follow clinically

Repeat balloon expulsion test

Abnormal

Normal

Perform defecating proctogram

Manage as normal transit constipation

Normal

Abnormal

Reassess biofeedback + medications if needed

Define anatomic rectal defect

No response

Clinically significant

Insignificant

Consider surgery

Surgical repair and follow up

No surgery needed

Combined Pelvic Floor Dysfunction and Slow Transit Constipation

Combined pelvic floor dysfunction and slow transit constipation

Biofeedback PLUS Dietary fiber: Psyllium/methylcellulose PLUS Stimulant laxative: Bisacodyl PLUS Saline laxative: Milk of magnesia

Response to treatment

Yes

No

Perform colonic transit test without medications

Repeat balloon expulsion test

If delayed manage as slow transit constipation

If normal follow clinically

Abnormal

Normal

Perform defecating proctogram

Manage as slow transit constipation

Normal

Abnormal

Reassess biofeedback + add hyperosmolar agents (lactulose/PEG)

Define anatomic rectal defect

No improvement

No response

Clinically significant

Insignificant

Repeat colonic transit test on medications

Continue therapeutic regimen

Surgical repair and follow up

No surgery needed

Normal

Delayed

Adjust medications as needed

Consider surgery

Consider surgery if no improvement

Do's

• Do begin evaluation of constipation with a detailed history and physical examination that includes a rectal examination.
• Do perform a colonoscopy in patient's presenting with the recent onset of constipation without an obvious explanation, hematochezia, weight loss of ≥10 pounds, a family history of colon cancer or inflammatory bowel disease, anemia and positive fecal occult blood test.
• Do perform a trial of conservative management of lifestyle and dietary modification in patients without any of the above alarm symptoms.

Dont's

• Dont use insoluble fiber like wheat bran for the intial managment of constipation in adults.

References

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