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Toxicology Rounds: Black Swans: When Routine Cases Morph into the Unexpected

2010; Lippincott Williams & Wilkins; Volume: 32; Issue: 10 Linguagem: Inglês

10.1097/01.eem.0000389826.09598.75

1552-3624

Leon Gussow,

Forensic Toxicology and Drug Analysis

ImageBlack swans are the perfect analogy for much of the risk in emergency medicine practice. A concept that refers to the rarity of the bird in nature, black swans in emergency medicine represent the worrisome possibility that any routine case can unexpectedly morph into an event with poor consequences. If the clinician does not anticipate a black swan event, he can rest assured that the plaintiff's attorney will appear after the fact to make the case seem explainable and predictable. And that is the value of case reports. These describe unusual circumstances and unexpected occurrences. After all, there is little need to publish routine cases. Being aware of these outliers is important, especially in toxicology where there are very few large randomized controlled trials. The bulk of the clinical toxicology literature consists of two types of publications: surveys of clinical registries that often use data reported to poison control centers and emphasize routine cases, and case reports, which emphasize rare occurrences. The astute clinician should be aware of both, and these two unusual cases described recently in clinical literature show why. Acute Ethanol Poisoning in a 4-Year-Old as a Result of Ethanol-Based Hand-Sanitizer Ingestion Engel JS, Spiller HA Pediatr Emerg Care 2010;26(7):508 Several retrospective reviews of regional poison center data have suggested that pediatric ingestion of ethanol-based hand sanitizers rarely causes significant symptoms. Mrvos and Krenzelok looked at such exposures reported to the Pittsburgh Poison Center in children under age 6, identifying 647 cases. None had more than minor symptoms. (Clin Toxicol 2008;31[4]:633.) Miller et al analyzed 1358 similar cases from the Texas Poison Control Network; again there were no moderate or major effects. (Generally, a toxic effect is classified as moderate or major if it requires treatment.) This case report from the Kentucky Regional Poison Center demonstrates that although rare, major sequelae can occur from these ingestions. A 4-year-old girl was brought to the emergency department with ataxia, combativeness, and altered mental status after falling and hitting her head. History revealed recent ingestion of Purell hand sanitizer (62% ethanol). Her bedside glucose level was 165 mg/dL, and a head CT was negative. The child was intubated for airway protection during transfer to a pediatric ICU. The serum ethanol level was 243 mg/dL, corresponding to an estimated ingestion of 1.5 oz to 2.0 oz of the hand sanitizer. Several case reports have made of adults with significant intoxication after deliberate ingestion of these products. One hospital patient who ingested an estimated 450 mL of hand sanitizer became unresponsive with a serum alcohol of 376 mg/dL. When he sobered up, he noted that, “It had a horrible taste, but I was drunk pretty quick.” (Mayo Clin Proc 2007;82[10]:1288.) In the interests of science, I did a simple taste test to see why a child might swallow more than a lick of hand sanitizer. Actually, the product I sampled was slightly sweet and not really unpleasant, somewhat reminiscent of the Italian liqueur Limoncello. Thyroid Storm after Pediatric Levothyroxine Ingestion Majlesi N, et al Pediatrics 2010;126(2):e470-3 Goldfrank's Toxicologic Emergencies states that acute thyroxine overdoses are almost always benign in children because they are usually unintentional and lower doses are ingested, unlike overdoses in adults. (New York: McGraw Hill [8th ed.]; 2006.) Because clinical effects from T4 require conversion to T3 and metabolic activation of protein synthesis, any significant symptoms may not become apparent for up to 10 days. While scattered cases of severe toxicity in children after ingestion of thyroid hormone have been reported, these cases almost always involve ingestion of T3 alone or in combination with T4. This is not unexpected because T3 has much more physiologic activity than T4. This unusual report describes what the authors claim is the first case of thyrotoxicosis in a child after accidental overdose of levothyroxine. A 2-year-old girl ingested up to 40 tablets of 150 mcg (total 6 mg) levothyroxine. In the ED, the child looked well, was given one dose of activated charcoal, and discharged after observation overnight. Total T4 and T3 levels drawn six hours after ingestion were elevated. She continued to do well for several days. On the fifth day after ingestion, she was brought back to the ED with vomiting and diarrhea, lethargy, a heart rate of 220 beats per minute, and a temperature of 101°F. These signs and symptoms responded rapidly to IV fluids and oral propranolol. As clinicians, we need to be aware of all swans, white and black — the many children who ingest drugs and household substances without incident and the rare patient who develops significant toxicity after a similar ingestion. Case reports help us develop that awareness. They should not be ignored.Dr. Gussow: is a voluntary attending physician at the John H. Stroger Hospital of Cook County in Chicago (formerly Cook County Hospital), an assistant professor of emergency medicine at Rush Medical College, and a consultant to the Illinois Poison Center. He is also the editor of his own blog, The Poison Review (www.thepoisonreview.com).Comments about this article? Write to EMN at[email protected]. 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