Outline the role of decontamination of the digestive tract in the management of patients who present with a drug overdose.
Balance between potential severity of poisoning, time from ingestion and risk to the patient of interventions considered. Most overdoses do not develop significant toxicity but reasonable to use technique with low morbidity and reasonable efficacy in all except clearly non-toxic ingestions (eg. single dose activated charcoal [1g/kg]). Induced emesis with ipecac induces risks without evidence of decreased absorption. Gastric lavage is associated with reasonable decrease in absorption if performed early (e.g. < 1 hour), though it is associated with increased risks (including visceralinjury and aspiration); it may have additional benefit if combined with activated charcoal. Repeat doses of charcoal are usually not of additional benefit except perhaps where a large amount of toxic substance adsorbed by charcoal was ingested (especially slow release preparations). Whole bowel irrigation (using polyethylene glycol e.g. golytely) may have specific benefit with slow release preparations or agents that are poorly absorbed by activated charcoal. Rarely endoscopy or surgical removal is indicated.
This question closely resembles section (b) from Question 1 of the second paper of 2004. However, here it is presented on its own, as a 10-mark question, and so some extra thought should be spent on it.
In brief, decontamination can be critically evaluated in the following manner:
Rationale for decontamination
Techniques of decontamination and their indications
Situations which merit the use of gut decontamination
Criticsm of gut decontamination techniques
The website of the American Academ of Clinical Toxicology has several position statements which might be useful to the fellowship candidate:
Gaudreault, Pierre. "Activated charcoal revisited." Clinical Pediatric Emergency Medicine 6.2 (2005): 76-80.
Andersen, A. Harrestrup. "Experimental Studies on the Pharmacology of Activated Charcoal. III. Adsorption from Gastro‐Intestinal Contents." Acta Pharmacologica et Toxicologica 4.3‐4 (1948): 275-284.
Krenzelok, Edward P. "New developments in the therapy of intoxications." Toxicology letters 127.1 (2002): 299-305.
Eddleston, Michael, et al. "Multiple-dose activated charcoal in acute self-poisoning: a randomised controlled trial." The Lancet 371.9612 (2008): 579-587.
Isbister, Geoffrey K., and Venkata V. Pavan Kumar. "Indications for single-dose activated charcoal administration in acute overdose." Current opinion in critical care 17.4 (2011): 351-357.
Chyka, P. A., and D. Seger. "Position statement: single-dose activated charcoal. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists." Journal of toxicology. Clinical toxicology 35.7 (1996): 721-741.
Daly, F. F. S., M. Little, and L. Murray. "A risk assessment based approach to the management of acute poisoning." Emergency medicine journal 23.5 (2006): 396-399.
Olmedo, Ruben, et al. "Is surgical decontamination definitive treatment of “body-packers”?." The American journal of emergency medicine 19.7 (2001): 593-596.