Constipation

Differential Overview

❑ Lifestyle

❑ Drugs

❑ Depression

❑ Irritable bowel syndrome

❑ Pelvic floor dysfunction

❑ Hypothyroidism

❑ Hypokalemia

❑ Colon cancer

❑ Anorectal pathology

❑ Voluntary retention

❑ Megacolon

❑ Mechanical obstruction

❑ Spinal cord pathology

❑ Hypercalcemia

❑ Scleroderma

Diagnostic Approach

Determine what the patient means by constipation. Patients are bothered by straining, excessively hard stools, unproductive urges, infrequency, and a feeling of incomplete evacuation.

With recent-onset constipation, seek an obstructing lesion, such as colon cancer, stricture, diverticular disease, inflammatory bowel disease, or foreign body. Hard stool in the vault rules out mechanical obstruction and suggests impaired emptying of the rectal vault. A change in stool caliber is more often caused by a tight sphincter than an “apple core” lesion.

Clinical Findings

Lifestyle  Lack of exercise, low intake of fluids, and dietary fiber contribute to constipation.

Drugs  Laxatives (chronically used), opiates, iron, calcium- or aluminum-
containing antacids, calcium-channel blockers, and anticholinergic
medications, such as tricyclic antidepressants, are common sources. Dark
pigmentation of the colonic mucosa on anoscopy suggests surreptitious
laxative abuse with anthraquinone laxatives such as castor oil or senna.

Depression  Constipation is a common presenting somatic manifestation, associated with altered mood and cognition, and other “vegetative” signs.

Irritable bowel syndrome  There is a longstanding history, beginning in young age, of abdominal cramps followed by bowel movements, bloating, flatulence, and constipation. Excessive nonpropulsive contractions produce small, hard “rabbit pellet” stools. Symptoms increase with psychological stress.

Pelvic floor dysfunction  Suspect when there is prolonged or excessive straining before elimination, or vaginal or perineal pressure needed to assist evacuation.

Hypothyroidism  Constipation is seldom the main symptom. Other symptoms such as fatigue, weight gain, and cold intolerance, and findings such as enlarged thyroid, coarse hair and facial features, loss of lateral eyebrows, and delayed relaxation of ankle reflexes suggest the diagnosis.

Hypokalemia  Suspect in patients taking diuretics or chronically using laxatives.

Colon cancer  Consider cancer in patients older than 50 years of age, especially when a family history of colon cancer exists or when a recent onset of constipation, a change in stool caliber, or rectal bleeding (including occult blood) has occurred.

Anorectal pathology  Inflamed or thrombosed hemorrhoids, fissures, strictures, or proctitis may contribute.

Voluntary retention  Retention of stool may down-regulate the usual physiologic feedback.

Megacolon  An atonic, hugely dilated colon is indicated by abdominal distension with an empty rectal vault. A psychogenic form is associated with encopresis (soiling at night).

Mechanical obstruction  Symptoms include lack of passage of stool or air, vomiting (especially with small bowel obstruction), visible peristalsis with loud borborygmi, progressive abdominal distension, and severe, colicky abdominal pain.

Spinal cord pathology  Constipation is caused by colonic dilation, which is associated with multiple sclerosis, tabes dorsalis, or spinal cord tumors. It may be suggested by decreased anal sensation with an absent anal reflex or a flaccid anal sphincter.

Hypercalcemia  Serum calcium is usually greater than 12; therefore, other manifestations such as CNS effects are present.

Scleroderma  Constipation is associated with dysphagia and tight, shiny skin.

Book Source Details

• Book Title: Field Guide to Bedside Diagnosis
• Author(s): David S. Smith
• Year of Publication: 2007
• Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2007 Lippincott Williams & Wilkins.

Other Book Chapters Related to Bowel movements

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Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2008 Williams & Wilkins.

More About Causes of Bowel movements

• Back to symptom: Bowel movements: Introduction (review 2132 causes)
• Next Book Extract About Bowel movements: Rectal Pain (Field Guide to Bedside Diagnosis)
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More About This Book: Title: Field Guide to Bedside Diagnosis Authors: David S. Smith Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 0-78178-165-5

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