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Clinical Case 054: Just a sip…

Mother of a 15 month old boy (weighs 11 kg) presents to the clinic with a bottle of massage liniment.

 

A quick glance at the label tells you the active ingredients are;

 

Per 50 milliliter:

 

 

Mum says she just popped out to hang the washing and left him playing on the floor.  She was not aware that her teenage son had left the bottle on the couch after going to footy practice.

 

When she came back inside she immediately smelled the menthol and found the little guy on the floor, playing with the bottle, it was dripping down his chin and he was making a disgusted face – like he had a bad taste in his mouth.  She picked him up and could smell the scent on his breath.  But he was fine, happy and she gave hi a bottle of milk to settle him and get the taste out of his mouth.
Ok, now you are seeing him 45 minutes later – he still looks fine, he is playing happily, smells like a gymnasium.  His obs are all normal and Mum says:
“I am sure it is fine – but I just thought I should bring him in for a quick once over…”
After examining him you agree that he is normal, no signs of respiratory distress, no chest or abdo signs.  Now here are the questions:
As a special treat we have expert opinion and learning from Dr Leon Gussow – Master of Tox, author of the Poison review blog @poisonreview on twitter
Leon says: Although we can estimate the volume of liniment this child might have swallowed, it is important to keep in mind that this is only an estimate, and it’s always possible that the child ingested more than we thought. The average volume of a swallow in a young child is about 0.2 ml/kg of liquid, or about 2.2 ml in this patient. Since the child seems to have found the taste of this product rather unpleasant, it is likely (but not certain) that he actually ingested less than a swallow. Casey says: always assume the worst and act conservatively in this scenario – the alternative is bad for you and the kid!

Casey says: Everything is toxic in big enough doses! In this case there are 2 ingredients that can cause serious badness with really small doses. Methylsalicylic acid – this is metabolised to aspirin – but is more potent. A small sip could be toxic. Camphor – this was once used to induce seizures in psych patients prior to ECT. Camphor can be toxic at doses of 30 – 50 mg/kg – so 300 – 500 mg for this kid – that is about a mouthful of our liniment.
Leon says: My primary concern in this product would be with methyl salicylate and camphor. Methyl salicylate is concentrated, readily absorbed through the gastrointestinal tract, and can cause severe early-onset salicylate toxicity. Since there is 15 g methyl salicylate per 50 ml liniment, a 2.2 ml ingestion would involve 660 mg or 60 mg/kg. In general, ingestions of less than 150 mg/kg of salicylate are considered nontoxic, ingestions of 150-300 mg/kg are considered moderately toxic, and greater than 500 mg/kg potentially lethal. Although I would not expect the amount ingested by this child to produce significant toxicity, it is always possible that the ingested more than 1 swallow, and I observe him for at least 6 hours.
Camphor is a rapidly acting neurotoxin, producing both excitation and depression. As little as 1 g has produced fatality in an 18-month-old child. Major toxicity has not been associated with ingestions less than 30 mg/kg. Since there is 4.5 g camphor per 50 ml liniment, 2.2 ml would contain approximately 200 mg camphor, or 18 mg/kg. Again, since he patient may have ingested more than one swallow, I would observe him for a least 6 hours for onset of seizure activity.
Oil of turpentine is a low-viscosity hydrocarbon that can cause significant aspiration or inhalational injury. It can also cause CNS depression. It is reassuring that the child seems to have no respiratory symptoms on presentation, but again careful observation is essential.
Menthol rarely causes significant toxicity, but can cause neurological and gastrointestinal effects.

/EXPAND]

Leon says:  I would expect this child to do well and be discharged home after 6 hours in the ED, but pediatric toxicology is full of unpleasant surprises. During observation, I would look for any signs of respiratory distress, coughing, wheezing, tachypnea, mental status changes, ataxia, or seizure activity.
[EXPAND Q4: What resources can you use to help you manage this case?]Leon says: In the States, the best resource would be the local poison control center, 1-800-222-1222. Casey : In WA the Poisons line is truly awesome – you can talk to a senior toxicologist 24/7. They give good practical advice and that is what I do every time
Casey

Comments

  1. Realistically this case is all about the methyl salicylate.
    Camphor, menthol and turpentine oil would all be expected to present symptomatically early – 45 minutes down the line and a completely happy kid is reassuring.
    Obviously I concur with Leon’s advice though 😉
    A tip about salicylism – you won’t necessarily see tachypnoea, but rather hyperpnea. The patient may breathe deeply not fast.
    Cheers,
    Chris

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