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 defined by unsatisfactory defecation characterized either by difficult stool passage that includes straining, sense of difficulty passing stool, incomplete evacuation, hard/lumpy stool, prolonged time to passage of stool, need for manual maneuvers to pass stool or by infrequent bowel movement or both.

Rome III Criteria for Functional Constipation

Any 2 of the following
Less than three evacuations per week
Lumpy or hard stools in ≥ 25% of defecations
Straining during ≥ 25% of defecations
Anorectal obstruction sensation for ≥ 25% of defecations
Manual maneuvers to facilitate ≥ 25% of defecations
Incomplete evacuation sensation for ≥ 25% of defecations
Loose stools are not present
Insufficient criteria for irritable bowel syndrome

† Criteria fulfilled for the past 3 months and symptom onset atleast 6 months before diagnosis.

American Gastroenterological Association, however have stopped using the term functional constipation because a subset these patients have slow colonic transit that has been associated with a marked reduction in colonic intrinsic nerves and interstitial cells of Cajal which is against the true definition of functional disorder.

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

The algorithm is based on the American Gastroenterological Association guidelines for management of constipation in adults.

Initial Evaluation

Characterize the symptom: Constipation: ❑ Any desire to defecate but an inability to pass a stool ❑ Any need for straining to begin and/or to end defecation ❑ Any need for prolonged time to pass stool ❑ Any need for direct digital manipualtion to pass stool ❑ Any need for perineal or vaginal pressure to pass stool ❑ Any sensation of incomplete emptying of bowel ❑ Frequency of passage of stools ❑ Consistency of stools (hard or lumpy) ❑ Onset (sudden or gradual) ❑ Duration (chronic ≥ 3 months) ❑ Any use of laxatives to pass stool (what laxative, how often and what dosage) ❑ Any use of additional enemas or suppositories to pass stool Associated symptoms: ❑ Abdominal pain or abdominal discomfort: Onset associated with change in frequency of stool Onset associated with change in consistency of stool Any improvement with passage of stool Onset only during there act of straining Any persistance between bowel movements ❑ Abdominal distention ❑ Diarrhea (Onset, duration, pattern, alternating with constipation) ❑ Blood in stools ❑ Fever ❑ Nausea and vomiting ❑ Loss of appetite ❑ Loss of weight ❑ Fatigue Obtain a detailed history: ❑ Dietary history: Dietary pattern change, low fiber diet, food intolerance, dehydration etc ❑ Medications history: Opioid analgesics, antidepressants, anticholinergics, antispasmodics, antihypertensives, antihistamines etc ❑ Family history: Colorectal cancer, pelvic masses, neuromuscular diseases etc ❑ Systemic illness: Diabetes, hypothyroidism, gastrointestinal disorders, neuromuscular disorders etc ❑ Personal history: Smoking cessation, travel history etc ❑ Surgical history: Abdominal surgeries, childbirth, extended bed rest etc ❑ Trauma history: Spinal cord injury

Examine the patient: ❑ General status: Pulse, blood pressure, respiratory rate, weight, thyroid ❑ Signs of dehydration: Decreased skin turgor, dry mucosa, thirst ❑ Perineal/rectal examination: Observe perianal skin for evidence of fecal soiling Observe anal verge for any patulous opening, prolapse of mucosa Observe the descent of the perineum during simulated evacuation Observe the elevation of perineum during a squeeze aimed at retention Evaluate the resting tone of the sphincter and puborectalis muscle Test anal reflex by a light pinprick or scratch Look for any rectocele, hemorrhoids, anal fissure etc ❑ Abdominal examination: Mass, distension, tenderness and bowel sounds ❑ Neurological examination: Neuropathy, spinal cord injury ❑ Cardiovascular and respiratory examination

Order tests: ❑ Complete blood count (CBC) ❑ TSH ❑ Serum calcium ❑ Serum glucose ❑ Creatinine When secondary causes are suspected: ❑ Colonoscopy ❑ Flexible sigmoidoscopy ❑ Barium enema ❑ Magnetic resonance imaging

Possible etiologies after initial evaluation

Irritable bowel syndrome(IBS)

Unknown etiology

Organic constipation (mechanical obstruction or drug side effect)

Constipation secondary to systemic disease

Rx for IBS

Dietary fiber supplementation and simple laxatives

Treat the underlying etiology

Treat the underlying systemic disease

Refractory constipation if there is no response to initial management

Management of 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

Management of 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 ❑ PEG: 8-32 oz once daily OR ❑ Lactulose: 15-30 ml OD or BID

Response to treatment

No

Yes

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

Continue the same regimen

Response to treament

Yes

No

Continue the same regimen

Adjust and change medications periodically

References

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