Diarrhea

Diarrhea is the passage of frequent, loose stool.  This is less common a problem than constipation. If persistent, diarrhea can lead to dehydration, malabsorption, fatigue, hemorrhoids, and perianal skin breakdown.  If duration of diarrhea is greater than 3 weeks, it is defined as chronic.

CAUSES

The most common cause of diarrhea at the end of life is overuse of laxatives followed by infection including overgrowth by Candida. 

Other causes include:

  • drugs (i.e. laxative, antibiotics, antacids)
  • radiation therapy
  • intestinal obstruction
  • diet
  • tumour (colon or retum, pelvic, pancreatic, carcinoid, fistula)
  • malabsorption (pancreatic carcinoma, gastrectomy, ileal resection, colectomy)
  • overflow incontinence
  • emotional and psychological stress
  • gastrointestinal bleeding.

ASSESSMENT

Diarrhea is typically defined as the passage of more than 3 unformed stool /24 hour period. Consideration must be given to the underlying cause of diarrhea. 

Measure stool osmolality and electrolyte content and calculate anion gap: [osm - 2 (Na+ K)].

  • If gap > 50 mmol/l , diarrhea is osmotic
  • If < 50 mmol/l diarrhea is secretory diarrhea

If diarrhea is due to ileal resection, a mixed secretory/osmotic picture will be seen and diarrhea will become secretory if fasted. 

If laxatives are to blame may be due to irregular or too high dosing. Usually resolves in 24-48 hours once stopped and should then restart at a lower dose.

MANAGEMENT

Non-Pharmacological Interventions

  • Rehydration, electrolyte correction: encourage oral intake of clear fluids
  • Avoid milk, gas-forming foods
  • Hold laxatives
  • Consider bulk agents such as bran but see comments above in section on constipation

Pharmacological Interventions

Adsorbent
Non-specifically adsorb dissolved or suspended substances like bacteria, toxins, water onto surface.

Consider:
Attapulgite

Mucosal prostaglandin inhibitors
Blocks prostaglandin mediated increases intestinal water and electrolyte secretions.
Bismuth salts have added benefit as antimicrobial against E coli.

Consider:
Bismuth salts

Opioids
Opioids are the most important class of drugs used for diarrhea in palliative care and act by decreasing peristalsis in the colon. However, they preserve fasting peristalsis and increase anal sphincter tone.

Should be avoided if there are signs of infection, fever, or blood. 

Do not use opioids in cases of Clostridium difficile or Shigella as they increase risk of toxic megacolon.

Consider:
Loperamide
Diphenoxylate

Somatostatin
Inhibits secretion and peristalsis. Works in cryptosporidial diarrhea, carcinoid, Zollinger-Ellison syndrome, Verner Morrison, ileostomy or enterocolic fistulas.

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This page was last updated: March 10th, 2005 at 2:59pm.