Suspected overdose

Paracelsus, the Renaissance physician said that "the dose determines that a thing is not a poison", recognizing that most things in excess can be harmful. In the US there are over 2.4 million documented toxin exposures reported to poison control centres, the majority of which occur in children. The leading agents causing death are analgesics, antidepressants, cardiovascular medications, stimulants and illicit drugs.

Your approach to the poisoned patient is two pronged, containing a diagnosis and a treatment are in parallel. The treatment consists of ABC's, D (decontamination/DONT antidotes), E (enhanced elimination), F focused therapy and G (get help). The diagnostic are requires a history, physical exam, search for toxidrome and diagnostic testing.

History is key. How much? When? What? Why? All these can be helpful and alter your approach to the patient. Often patients cant name the medications they're taking or they do so incorrectly (Tylenol vs aspirin). If it is not available, obtaining information from family, work, family physician may be helpful. Specific symptoms to consider include:

protracted coughing - hydrocarbon exposure
inability to swallow/drooling - costic ingestion
hematemesis with iron ingestion
persistent seizures with INH overdose
decreased LOC with carbon monoxide

There are a number of pneumonics to help you remember toxidromes. Below is an article that contains an extensive list. Things to focus on include vital signs (HR, BP, temp, GCS, seizure), pupils (meiosis, mydriasis), odour (garlic-organophosphate, wintergreen - methylsalicylates, almond - cyanide), neurologic exam (rigidity/clonus - SS/NMS), skin (rash, diaphoresis, track markrs, fentanyl patches).

Preliminary labs will include routines, plus toxicology screen, osmolal gap and anion gap. Toxicology can be performed on serum and urine, where urine test tend to identify metabolites and will have positive results for longer duration compared to serum. Quantitative levels should only be performed if it suggests higher toxicity and will alter management. Levels can be performed on: tylenol, ASA, Li, Fe, CO, digoxin, anticonvulsants, toxic alcohols and theophylline. Other aspects of urine testing include any visual change, such as a change in UV light with ethylene glycol, orange with rifampin, pink with ampicillin, green with copper or methylene blue. Microscopy for calcium oxalate crystals also suggests ethylene glycol poisoning (see link below). Imaging tests may include CXR/AXR to look for iron or ingested street drugs (body packing with cocaine). Drugs causing pneumonitis or pulmonary edema can be remembered as MOPS (methadone, opioids, phenobarbitol/phosgene, salicylates).

Today we mentioned that "one pill can kill", although this tends to be targeted more towards children it highlights the potential toxicity of these medications. A top ten list of these drugs includes, but is not limited to:
1. TCA
2. antipsychotics
3. antimalarials
4. anti-arrhythmics
5. camphor
6. oral hypoglycemics - sulfonylureas
7. opioids
8. theophylline/podophylline
9. salicylates
10. calcium channel blockers

Calling poison control is always the right thing to do. You will be put in touch with an experienced nurse and have access to a clinical toxicologist if necessary. They also document each case and follow-up on the patient. For a more detailed approach to therapy see the article below.

Approach to unknown overdose
calcium oxalate cyrstals
fluorescent urine in ethylene glycol ingestion