Learning Objectives
- Basic principles of managing overdose
- importance of ECGs in toxicology and how to review them
- Identification of common toxidromes and their management
- The use of common antidotes
The study of Medicine Melancholy
Toxicology is the study of how natural or compounded poisons cause undesirable effects in living organisms. A toxic agent is anything the can produce an adverse biological response. This can be chemical (cyanide >.>), Physical (Radiation thanks Okuu) or biological (snake venom).
All medicines are toxic agent, the dose makes the poison - some greek guy
[Acute poisonings are very common, state reports show 33.4 presentations annually per 100,000 people. and account for 10.6% of all injury deaths in Australia][1]
Acute management of poisoning
Someone is brought in with a suspected overdose. What do?
Initial history and investigations
We need to take a good history:
- What agent(s) are suspected reported to be involved? Do some snooping, what did the patient have access to? What have we recently prescribed them? What weird mushrooms has Marisa been selling?
- What dose and formulation was taken? By what route and what time?
- Current and previous symptoms
- Relevant co-morbidities? (Does the patient have other diseases that can impact the pharmacokinetic or pharmacodynamics of the poison i.e( pre-existing renal impairment, cardiovascular issues, obesity and drug tolerance) This might not always be obvious, look for scars, zippers anything you can visually see
- Assess the treatment so far... what on earth did the EMS team or Cir no try doing before they got here
Investigations
- Let's get an ECG, good baseline and to detect toxic QT prolongation or acute arrhythmias.
- Drug levels, our lab in Entei is pretty limited (Thanks Kaguya) but we should always run a paracetamol level in our toxicology patients. Paracetamol is cheap, relatively toxic and available everywhere, so we should throw that in whilst we are taking bloods.
- Checking blood sugar levels to identify potentially fatal insulin overdose
- checking renal function is helpful
- imaging if required
- You can throw in other labs if you want, ketones, pregnancy, urotones but this is guided by symptomatic toxidromes (more on that later)
Examination
- Taking routine observations of GCS, Blood Pressure Heart Rate and Respiratory Rate
- Look for toxidromes (more on that later)
- Otherwise resuscitate as normal, we are still working on many antidotes so working antidotes are only available for some ingestion.
Treatment
Decontamination
Just get rid of the poison udongein!
- If a topical poison or irritant, just wash the skin and/or flush the eye to remove as much of the poison as you can.
- This is very important during protests where tear gas is deployed, if providing aid at demonstrations ensure large amounts of bottled water and eye flush adapters are available to you. This also doubles to aid in dehydration treatment in the field.
- Nemesis (inducing vomiting is not recommended, its traumatic and ineffective whilst complicating the treatment by muddying the dose that was actually absorbed.)
- Lavage (stomach-pumping is not recommended, its traumatic and ineffective whilst complicating the treatment by muddying the dose that was actually absorbed.)
- Activated Charcoal {My Beloved}(recommended if risk of significant toxicity and the poison has been ingested in the last few hours. Exact timing depends on the dose, agent and formulation of poison ingested)
- Whole Bowel irrigation (only on advice from a toxicologist, essentially a macrogol bomb)
Enhanced Elimination
Just make the body get rid of it faster udongein!
- Multi-dose activated charcoal can interrupt intrahepatic circulation acting like a "Gastrointestinal Dialysis" for toxin
References:
[1]: Australian Institute of Health and Welfare. Accidental poisoning [Internet]. Canberra: Australian Institute of Health and Welfare, 2024 [cited 2025 Feb. 9]. Available from: https://www.aihw.gov.au/reports/injury/accidental-poisoning
