One Pill Can Kill: The Case of the Hotheaded Toddler

Welcome to the third case in the One Pill Can Kill series. Children account for nearly half of the 2.6 million poisoning calls received by poison-control centers in the U.S. each year, and while many of the ingestions reported are benign, this column focuses on substances that can kill children in small doses. In 2017 25 children died of poisons reported to poison call centers.

Wednesday, 20:12

Your call is to a residence for 4-year-old girl who “drank a bottle of diffuser oil.” You arrive to a skyscraper condo in a ritzy part of town and are granted access to the lobby by a security guard trying his best not to be nosy. He points you toward the elevator, and you proceed to Penthouse #3 on the 33rd floor. You travel to the end of the hall—yes, even penthouses needing your assistance are located at the very end of the hall—and find the door slightly ajar. A woman screams for you to come in.

You are now standing in a large open-concept room that on first glance seems the size of an airport. The near-panoramic views of the sun setting over the city distract you for a moment before you turn your attention to a 30-year-old woman holding a small girl. The girl weighs 18 kilograms (40 pounds) and appears agitated and is pushing her mother away. She is flushed and dry, and when you feel her forehead, she is burning hot. You quickly don a mask, worried the child may have bacterial meningitis.

The mother speed-talks at you in spite of your structured line of questioning. Who could blame her? The child, perfectly healthy and fully immunized, was seen to drink a bottle of oil for a diffuser. Minty Mist is the name on the bottle, and it smells strongly of wintergreen. The bottle holds 30 mL (1 oz.), though the mother tells you it was only half full. A few drops remain. The ingestion occurred just before she called 9-1-1.

Now that you have pieced together a story, the child is flushed, dry, and spontaneously breathing. Capillary refill peripherally is quick, and her extremities are warm. Pupils are equal and reactive at 3 mm. Heart rate is 118, sinus rhythm, respiratory rate 40, BP 90/52, SpO₂ 97%. The condo is remarkably clean, scantly organized, and has a slight scent of something that reminds you of the Christmas sleigh ride you took annually as a child.

Prep time:

• List five toxic differential diagnoses for this hot, agitated child.
• List five nontoxic differential diagnoses for this hot, agitated child.
• What is your approach to the child who is hot and agitated?
• What are your next three steps once arriving at the patient’s side?

You look carefully at the fine print on the bottle while your partner checks a glucose reading: Contains 100% oil of wintergreen (methyl salicylate). Do not ingest. Keep out of reach of children.

The child has a capillary glucose reading of 6.7 mmol/L (120 mg/dL). You recall from your toxicology lectures that even small amounts of methyl salicylate can be deadly—anything more than a lick should be evaluated in the ER.

You promptly load the child into the ambulance and, along with mom, head straight to the pediatric emergency room. The child complains about the sounds of the sirens; your partner takes it easy on the switch, but she continues to complain about ringing in her ears. By the time you get to the emergency bay, she seems a little less agitated and a little more obtunded. You drop her in the resuscitation bay, where two nurses hustle to attach her to monitors and repeat a bedside glucometer check. To your surprise her glucose has dropped to 2.2 mmol/L (40 mg/dL). An emergency physician arrives and requests a dextrose bolus and infusion as well as a bicarbonate infusion.

Methyl Salicylate

Methyl salicylate is closely related to acetylsalicylic acid (aspirin). It is toxic to children at very small doses (measured in milliliters). It has many toxic mechanisms, primarily:

• It stimulates the respiratory center, causing respiratory alkalosis;
• It disrupts cellular metabolism, causing metabolic acidosis;
• It increases pulmonary vascular permeability, causing pulmonary edema;
• It inhibits gluconeogenesis, leading to hypoglycemia.

But of all the toxic properties, its most concerning one is this: It rapidly crosses the blood-brain barrier, causing neuroglycopenia (low glucose in brain cells). This causes cerebral edema.

Further, methyl salicylate is rapidly absorbed in the GI tract, yet the effects of cerebral edema can be delayed by many hours, making the initial presentation falsely reassuring.

The Aspirin Toxidrome

Salicylates present in a toxidrome that can be mistaken for anticholinergic activity. Patients are typically hot, flushed, and tachypneic. They begin agitated and progress to becoming confused and then comatose. The often complain of tinnitus, or ringing in the ears. They can have nausea and bloody vomit. In severe overdose they have hypotension, cardiovascular collapse, and seizure.

In addition to aspirin and oil of wintergreen, salicylates can be found in Pepto-Bismol, muscle rubs, and shampoos, among other household things.

Treatment of Salicylate Overdose

In the field, watch out for these sequelae of salicylate overdose: hypoglyemia, hypotension, and seizure.

Treatment is the same as for nonoverdose patients. In periarrest and arrested patients, consider sodium bicarbonate. Be aware the respiratory alkalosis helps balance the metabolic acidosis, and intubation that leads to decreased minute ventilation can precipitate cardiac arrest.

In the emergency room, the main principle of management is to alkalinize the blood and urine using sodium bicarbonate. Aspirin can either be ionized or not ionized. If it’s ionized, it is more difficult to pass across membranes like the blood-brain barrier and nephron. By alkalinizing the urine, salicylates are trapped in the nephron, unable to be reabsorbed into the body, and are excreted in urine. By alkalinizing the blood, salicylates are less able to cross the blood-brain barrier, where they have their most deadly consequences. A more basic (higher) pH keeps aspirin ionized, keeping patients safer.

Initiate dialysis rapidly in patients whose measured aspirin level is high or in people with end-organ damage such as cerebral edema, pulmonary edema, or acute kidney injury.

Wrap-Up

There are about 20,000 salicylate poisonings in children every year in the United States. Mortality in severe toxicity is 15%, and 39 people died in 2011 of salicylate poisoning (that’s the last year I could find data for). While it’s important to think about this chemical in children, elderly people can present with chronic salicylate toxicity that often presents as delirium. The bottom line? Respect salicylates. Despite being cheap and readily available, they can be debilitating and deadly.

After a decade working as a helicopter paramedic, Blair Bigham, MD, MSc, EMT-P, completed medical school. He is now an attending emergency physician in Ontario and critical care fellow in California. E-mail him at blair.bigham@medportal.ca; on Twitter follow @BlairBigham.