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Laxative Abuse
Matthew E. Bryant, MD
image BASICS
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)
  • Psychologic 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., magnesiumcontaining 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.
image DIAGNOSIS
PHYSICAL EXAM
  • No specific findings but may include cachexia, evidence of dehydration, abdominal pain or distension, and edema; fever may be due to self-infected wounds or thermometer manipulation (2).
  • Bulimics or anorexics who purge may have Russell sign (excoriation of fingers from repeated selfinduced retching) (4); clubbing, cyclic edema, skin pigmentation changes, parotid hypertrophy
  • Rarely, severe cases may be associated with renal failure, cardiac arrhythmias, skeletal muscle paralysis, anemia from blood-letting or self-induced skin wounds.
DIFFERENTIAL DIAGNOSIS
Any etiology of chronic diarrhea, especially in high-risk groups
DIAGNOSTIC TESTS & INTERPRETATION
If patient has not had an initial workup for chronic diarrhea, rule out infectious, inflammatory, and malignant causes based on patient demographics and risk factors.
Initial Tests (lab, imaging)
  • Serum electrolytes hypokalemia, hypernatremia, hyperphosphatemia
    • Acute diarrhea: metabolic acidosis (hypovolemia)
    • Chronic diarrhea: metabolic alkalosis secondary to hypokalemia-induced inhibition of chloride uptake with inhibited bicarbonate secretion
  • CBC, stool cultures, Clostridium difficile polymerase chain reaction (PCR) to rule out infectious cause if history is suspicious (fecal leukocytes, ova and parasites (O&P)—check for giardia, isospora, and cryptosporidia specifically) (2,3).
  • Colonoscopy, small-bowel endoscopy, or imaging studies are not usually necessary but help to evaluate other causes of chronic diarrhea (2).
  • Melanosis coli on sigmoidoscopy or colonoscopy indicate overuse of anthracene laxatives.
Follow-Up Tests & Special Considerations
The following algorithm can be used to confirm diagnosis and determine what laxative is being used (1,5)[B].
  • Collect 24-hour stool: If stool is solid, workup is over.
  • Obtain stool osmolality, stool electrolytes, and calculate osmolal gap [-290 -2 (Na+ + K+)], Na+ and K+ are stool concentrations.
    • If osmolality >400 mOsm/kg, rule out urine contamination of stool. Measure urea and creatinine of sample.
    • If osmolality <250 to 400 mOsm/kg, rule out water added to stool (colon cannot dilute stool to osmolality of plasma).
    • If osmolality = 250 to 400 mOsm/kg, measure osmolal gap.
      • Gap >50: unmeasured solute; check fecal fat and stool magnesium levels.
      • Gap <50: Rule out use of secretory laxative; urinalysis and stool analysis for laxative titers. Do not obtain serum laxative titers, as they peak 1 to 2 hours after ingestion. Urine titers can be 10 times as high as plasma titers.
  • Confirm diagnosis with multiple stool analyses before addressing patient with concern for intentional abuse.
image TREATMENT
GENERAL MEASURES
  • Behavioral support is essential in intentional use.
  • Wean patient off laxatives and supplements; substitute high-fiber diet and bulk preparations or short-term saline enemas
  • Treat secondary constipation (3)[C].
  • Treat metabolic abnormalities.
P.593

MEDICATION
Replace needed fluid, vitamins, electrolytes, and minerals.
First Line
  • Patient education on normal bowel habits
  • Nonstimulant laxatives (if needed) to treat constipation (3)[C]
    • Polyethylene glycol (3)[C]
    • Lactulose (3)[C]
    • High-fiber diet
  • Precautions: Patients may be manipulative to deny problem; may hide laxatives in hospital rooms.
  • Significant possible interactions
    • Increased rate of intestinal motility may affect rate of absorption of medications (e.g., antibiotics, hormones).
    • Docusate sodium may potentiate hepatotoxicity of other drugs.
    • Consider loperamide to improve anal tone and promote rectal inhibitory reflex (6)[C].
ISSUES FOR REFERRAL
In cases of Münchausen syndrome by proxy, legal proceedings must be considered, because most victims are children. Behavioral health support for patients with significant psychological comorbidities
SURGERY/OTHER PROCEDURES
Avoid exploratory surgery and repetitive evaluations or invasive procedures.
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
  • Persistent diarrhea with hemodynamic instability
  • Electrolyte/metabolic complications, including lactic acidosis
  • Cardiac arrhythmias
IV Fluids
Resuscitate based on clinical presentation. If patient is hemodynamically stable and without significant abnormalities in serum sodium, give normal saline boluses or oral replacement to correct metabolic alkalosis (chronic) or acidosis (acute) as needed. If patient is hemodynamically unstable, treat volume status as in hypovolemic shock, while monitoring serum electrolytes closely (especially sodium, potassium, and bicarbonate (6,7)[C].
Nursing
If stable, patient does not need continuous telemetry. Depending on psychiatric history, patient may need one-on-one or line-of-sight observation. Special care must be taken to ensure adequate nutrition and control access to laxatives. If surreptitious laxative ingestion is suspected, do not perform unauthorized room searches due to legal constraints.
Discharge Criteria
  • Psychological evaluation, support, and follow-up
  • Diet and bowel programs
  • Resolution of electrolyte abnormalities/dehydration
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
  • Ongoing behavioral counseling
  • Careful medical support; frequent visits as needed
  • Assess serum electrolytes.
DIET
Ensure good nutritional habits.
  • Increase fiber intake.
  • Avoid constipating substances.
  • Adequate calories, especially with bulimia
PROGNOSIS
  • Natural history is unclear and varied depending on underlying cause.
  • Prognosis is related to underlying behavioral disorders in intentional abuse or underlying organic disease (if present).
  • Prognosis is poor with anorexia nervosa; very poor in Münchausen syndrome.
  • Cathartic colon is commonly refractory to treatment (7)[C].
REFERENCES
1. Thomas PD, Forbes A, Green J, et al. Guidelines for the investigation of chronic diarrhoea, 2nd edition. Gut. 2003;52(Suppl 5):v1-v15.
2. Schiller LR. Definitions, pathophysiology, and evaluation of chronic diarrhoea. Best Pract Res Clin Gastroenterol. 2012;26(5):551-562.
3. Roerig JL, Steffen KJ, Mitchell JE, et al. Laxative abuse: epidemiology, diagnosis and management. Drugs. 2010;70(12):1487-1503.
4. Sim LA, McAlpine DE, Grothe KB, et al. Identification and treatment of eating disorders in the primary care setting. Mayo Clin Proc. 2010;85(8):746-751.
5. Fine KD, Santa Ana CA, Fordtran JS. Diagnosis of magnesium-induced diarrhea. N Engl J Med. 1991;324(15):1012-1017.
6. Kent AJ, Banks MR. Pharmacologic management of diarrhea. Gastroenterol Clin North Am. 2010;39(3):495-507.
7. Neims DM, McNeill J, Giles TR, et al. Incidence of laxative abuse in community and bulimic populations: a descriptive review. Int J Eat Disord. 1995;17(3):211-228.
Additional Reading
&NA;
  • Abraham BP, Sellin JH. Drug-induced, factitious, and idiopathic diarrhea. Best Pract Res Clin Gastroenterol. 2012;26(5):633-648.
  • Bytzer P, Stokholm M, Andersen I, et al. Prevalence of surreptitious laxative abuse in patients with diarrhoea of uncertain origin: a cost benefit analysis of a screening procedure. Gut. 1989;30(10):1379-1384.
  • Shelton JH, Santa Ana CA, Thompson DR, et al. Factitious diarrhea induced by stimulant laxatives: accuracy of diagnosis by a clinical reference laboratory using thin layer chromatography. Clin Chem. 2007;53(1):85-90.
  • Sweetser S. Evaluating the patient with diarrhea: a case-based approach. Mayo Clin Proc. 2012;87(6):596-602.
  • Tozzi F, Thornton LM, Mitchell J, et al. Features associated with laxative abuse in individulals with eating disorders. Psychosom Med. 2006;68(3):470-477.
See Also
&NA;
Algorithm: Diarrhea, Chronic
Codes
&NA;
ICD10
F55.2 Abuse of laxatives
Clinical Pearls
&NA;
  • Laxative abuse may be intentional or unintentional.
  • When associated with eating disorders, laxative abuse is associated with more severe disease.
  • Consider laxative abuse in patients with watery diarrhea, especially if unexplained or refractory.
  • As many as 15% of patients referred to tertiary care centers for unexplained chronic diarrhea abuse laxatives.
  • Presentation is diverse and nonspecific including weight loss, weakness, and hypotension.
  • Patients often won't acknowledge diarrhea if laxative abuse is intentional.