Constipation

Constipation
(Gastroenterology 2006;130:1480-91. N Engl J Med 2003;349:1360-68. Gastroenterology 2000;119: 1761-78)
DEFINITION:
  • Historically less than 2-3 bowel movements/week; Excessive difficulty straining at defecation
  • Rome III for functional constipation: see below under Diagnostic Studies
  • Dyschezia: difficulty in defecating
EPIDEMIOLOGY:
  • 5-30% of population report symptoms; Prevalence increases with age
ETIOLOGIES:
  • Causes

    Example

    Idiopathic/Functional

    Chronic idiopathic: Impaired colonic transit, IBS

    Structural

    Colonic or anorectal: cancer, stricture

    Metabolic/Endocrine

    Hypokalemia, Hypercalcemia, Hypocalcemia, Uremia, Hypothyroid, DM

    Collagen vascular disorders

    Scleroderma, Amyloidosis

    Inherited muscular disorders

    Familial visceral myopathy

    Colonic disorders

    Colonic inertia

    Enteric neuro disorders

    Hirschsprung’s, Chronic intestinal pseudo-obstruction

    Nonenteric neuro disorders

    Parkinson’s, Spinal cord injury, MS, Scleroderma (fibrotic/non-contractile)

    Anorectal disorders

    Anal stricture, Rectocele

    Psychological

    Anorexia nervosa

    Medications

    Opiates & antihypertensives such as calcium channel blockers (most common causes), antacids (calcium, aluminum), anticholinergics, antispasmodics, anticonvulsants, antidepressants, diuretics, iron

  • Classification based upon transit time:
    • Normal transit constipation: perception of disordered evacuation; Fiber supplementation may help
    • Slow transit constipation: malfunction of neural network; i.e. infection, endocrine, drug, scleroderma; Fiber may worsen
    • Obstructive defecation: mechanical; i.e. Hirschsprung’s, Pelvic floor dysfunction; Fiber may worsen
  • Anorectal dysfunction:
    • Anismus/spastic pelvic floor syndrome: spasticity of levator ani, abnormal angulated rectoanal axis; Functional problem
    • Impaired rectal sensation: decrease in urge to defecate
    • Megarectum: long-term fecal impaction, often seen in children, physically/mentally impaired elderly; Occasionally with neuro disorder
    • Rectocele: stool directed away from anal canal into rectocele during straining, leading to retention of feces in pouch
PATHOPHYSIOLOGY:
Aug 24, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on Constipation

Full access? Get Clinical Tree

Get Clinical Tree app for offline access