Description

• A chronic watery diarrhea caused by intentional or unintentional misuse of laxatives due to self-medication or provider error
• System(s) affected: gastrointestinal, nervous, psychiatric, skin, and renal
• Synonym(s): factitious diarrhea; cathartic colon; as part of Münchausen syndrome (self or by proxy)—most dramatic form

Epidemiology

• Predominant age: 18 to 40 years associated with bulimia or anorexia nervosa
• Common in the elderly as a result of treatment for constipation, either by health care professional or self-directed (unintentional)
• Associated with athletes in sports with weight limits (wrestling)
• Predominant sex (intentional abuse): female (90%) > male
• More common in upper socioeconomic classes

Prevalence
Laxative abuse in different groups

• 0.7–5.5% in the general population
• As many as 15% undergoing evaluation for chronic diarrhea
• Unexplained chronic diarrhea after routine investigations: 4–7%
• Up to 70% of patients with binging/purging anorexia and bulimia nervosa abuse laxatives but rarely as the sole method of purging.
• Chronic use of constipating medications (opioids)

Pediatric Considerations
Children may be given excess laxatives by caregivers (Münchausen syndrome by proxy).

Geriatric Considerations
Elderly in nursing homes are at increased risk for laxative overuse (usually inadvertent).

Etiology and Pathophysiology

• Four types of chronic diarrhea: secretory, osmotic, inflammatory, and fatty. Rule out other causes; laxative abuse is a diagnosis of exclusion (1).
• Chronic ingestion of any laxative agent
  • Stimulant (most common, rapid onset of action)
    • Diphenylmethane (bisacodyl)
    • Anthraquinones (senna cascara, castor oil)
  • Saline and osmotic products (sodium phosphate, magnesium sulfate/citrate and hydroxide, lactulose, polyethylene glycol)
  • Bulking agents (psyllium)
  • Surfactants (docusate)
• Psychological factors
  • Bulimia or anorexia nervosa (associated with behavioral pathology)
  • Secondary gain (attention-seeking): disability claims or need for concern, caring from others
  • Inappropriate perceptions of “normal” bowel habits

Risk Factors

In patients with eating disorders

• Longer duration of illness
• Comorbid psychiatric diagnoses (e.g., major depression, obsessive-compulsive disorder, posttraumatic stress disorder, anxiety, borderline personality disorder)
• Early age of eating disorder symptoms

General Prevention

• Educate patients about proper nutrition, normal bowel function, potential adverse effects of excessive laxative use, and medications (e.g., magnesium-containing antacids) that can cause diarrhea.
• Ask patients specifically about laxative use; inadvertent overuse is common.

Commonly Associated Conditions

• Anorexia nervosa, bulimia nervosa
• Use of constipating medications (opioids, iron supplements)
• Any chronic disorder associated with constipation
• Depression and anxiety
• Borderline personality
• Self-injurious behaviors/suicidal ideation
• Impulsive behavior
• Münchausen syndrome/Münchausen syndrome by proxy (children) may have associated factitious symptoms involving diverse organ systems.
• Fictitious disorders
• Patient is dependent on a caregiver.