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Key Features

Essentials of Diagnosis

  • Defined as two or fewer bowel movements per week or excessive difficulty and straining at defecation

General Considerations

Primary constipation

  • Most cases cannot be attributed to any structural abnormalities or systemic disease

  • Colonic transit time is normal in most patients

  • Normal colonic transit time is about 35 hours; > 72 hours is significantly abnormal

  • Slow colonic transit

    • Commonly idiopathic but may be part of a generalized gastrointestinal dysmotility syndrome

    • More common in women, some of whom have a history of psychosocial problems (depression, anxiety, eating disorder, childhood trauma) or sexual abuse

  • Patients may complain of

    • Infrequent bowel movements and abdominal bloating

    • Excessive straining

    • Sense of incomplete evacuation

    • Need for digital manipulation

Causes of secondary constipation

  • Systemic disease

    • Endocrine

      • Hypothyroidism

      • Hyperparathyroidism

      • Diabetes mellitus

    • Metabolic

      • Hypercalcemia

      • Hypokalemia

      • Uremia

      • Porphyria

    • Neurologic

      • Parkinson disease

      • Multiple sclerosis

      • Sacral nerve damage (pelvic surgery, tumor)

      • Paraplegia

      • Autonomic neuropathy

    • Medications

      • Opioids

      • Diuretics

      • Calcium channel blockers

      • Anticholinergics

      • Psychotropics

      • Calcium, iron

      • Nonsteroidal anti-inflammatory drugs

      • Clonidine

      • Cholestyramine

    • Structural abnormalities

      • Anorectal

        • Rectal prolapse

        • Rectocele

        • Rectal intussusception

        • Anorectal stricture

        • Anal fissure

        • Solitary rectal ulcer syndrome

      • Perineal descent

      • Obstructing colonic mass (cancer)

      • Colonic stricture

        • Radiation

        • Ischemia

        • Diverticulosis

      • Hirschsprung disease

      • Idiopathic megarectum

    • Slow colonic transit

      • Idiopathic: isolated to colon

      • Psychogenic

      • Eating disorders

      • Chronic intestinal pseudo-obstruction

    • Dyssynergic defecation

    • Irritable bowel syndrome

Demographics

  • Occurs in 15% of adults and up to one-third of elderly adults

  • More common in women

  • Elderly are predisposed due to comorbid conditions, medical conditions, decreased mobility, medications, poor eating habits, inability to sit on toilet (bed-bound patients)

Clinical Findings

Symptoms and Signs

  • Decreased appetite

  • Nausea and vomiting

  • Abdominal pain and distention

  • Paradoxical "diarrhea"

  • Firm feces palpable on digital rectal examination

Differential Diagnosis

  • Inadequate fiber or fluid intake

  • Poor bowel habits

  • Irritable bowel syndrome

Diagnosis

  • In healthy patients under age 50 without alarm symptoms, it is reasonable to initiate a trial of empiric treatment without diagnostic tests

  • Further diagnostic tests should be performed

    • In patients age > 50 years

    • In patients of any age with

      • Severe constipation

      • Hematochezia

      • Weight loss

      • Positive fecal occult blood or fecal immunochemical tests

      • Positive family history of colon cancer or inflammatory bowel disease

      • No response to empiric treatment

Laboratory Tests

  • Complete blood count

  • Serum electrolytes

  • Serum calcium

  • Serum glucose

  • Serum thyroid-stimulating hormone

  • Fecal occult blood or fecal immunochemical tests

Imaging Studies

  • Colonoscopy or flexible sigmoidoscopy and barium enema

Diagnostic Procedures

  • Diet, fluid, and medication history

  • Physical examination

  • Pelvic floor function studies and colonic transit studies for severe constipation unresponsive to lifestyle changes and laxatives

  • Dyssynergic defecation is assessed with balloon expulsion testing, anal manometry, ...

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