Below is a systematic approach to the poisoned patient derived from the Toxicology Handbook.
Poisoned patients are at risk due to the dynamic nature of toxin metabolism.
- Consider corrosive agents and direct airway injury
- Stridor, dysphagia, dysphonia
- Threats to airway from CNS depression
- Excess secretions from cholinergic agents
- Consider early intubation
- Consider compensatory respiratory alkalosis in tachypnoeic patients in methanol, ethylene glycol, salicylates
- Narcotics causing respiratory depression
- Cholinergic crisis may lead to respiratory failure
- Rate, rhythm, blood pressure, cardiac monitoring
- IV access and fluid resuscitation
Detect & Correct
- Seizures – will be generalised and often self limiting but may be recurrent. May require use of benzodiazipines. Common with sodium channel blockade and serotonin agents.
- Hypoglycaemia – if serum glucose is less than 4.0mmol/L give 50ml of 50% dextrose IV.
- Sodium Bicarbonate (TCA overdose)
- Naloxone (Narcotic overdose)
- Atropine (Organophosphate Poisoning)
- Digoxin specific antibodies
[expand title=”RISK ASSESSMENT”]
The distinct cognitive step that allows you to predict the likely clinical course and possible complications for the individual patient in this presentation. Allows you to make plans for any anticipated deterioration and to determine disposition.
Always consider the worst case scenario when conducting the risk assessment.
- Ask the patient, ask ambulance officers, ask family and friends
- Checking prescriptions and what they may have had access to at home
- Correlate with clinical features below
- Consider immediate release and extended release preparations
- What is the worst case scenario dose?
- Count missing tablets
Time Since Ingestion
- If estimating use the latest possible time of ingestion – things are likely to get worse.
- Paracetamol is the exception – estimate the earliest time of ingestion to allow for accumulation effect.
- The patient’s vital signs
- Correlate with likely toxins
- Does the patient’s clinical presentation match the stated ingestants? If not you must consider other likely agents.
- Hepatic and Renal Function
[expand title=”SUPPORTIVE CARE”]
Supportive care is based on the likely clinical course as predicted by the risk assessment. The aim is to optimise organ function and minimise secondary complications from the poisoning, the coma or the hospital admission.
- Observations and monitoring
- Sedation / Seizure control or prophylaxis
- Oxygen therapy / ventilation
- Fluids and hydration / nutrition
- Temperature Control
- Management plans for agitation or delirium
- Planning for absconders
- Bladder care
- Thromboembolism prophylaxis
- Mental health input
Investigations are either for screening or specific purposes. They are:
- Paracetamol Level
- Blood sugar
- Other tests depending on patient’s comorbidities, drug ingestants and possible drug levels
[expand title=”DECONTAMINATION, ENHANCED ELIMINATION, ANTIDOTES, DISPOSITION”]
This is a collection of specific interventions as indicated by the risk assessment.
- Removal of a drug from the body BEFORE it has been absorbed
- Gastrointestinal and cutaneous are the two main types
- Activated Charcoal – indicated when it is likely that toxin remains in GI tract (with exceptions below). The benefit of giving charcoal must outweigh the risk of complications from administration. If supportive care alone will result in an acceptable outcome then charcoal may be unnecessary.
- Administration is of benefit in certain situations in the 1st hour, or where a large pill bolus may remain in the GI tract following massive overdose. Consider delayed charcol in massive ingestions of slow release paracetamol (panadol osteo).
- No benefit in
- Hydrocarbons and alcohols
- No benefit in
- A strategy to increase and enhance the physioloigcal processes by which the body normally eliminates absorbed drugs
- Multiple-dose activated charcoal – colchicine, carbamazepine, dapsone, phenobarbitone, quinine, theophylline (in enterohepatic circulation)
- Urinary Alkalinisation – phenobarbitone, salycilates
- Haemodialysis – lithium, metformin, potassium, toxic alcohols, valproic acid, theophylline, salycilates
- Depending on toxin – see Toxinz
Depending on the risk assessment patients may either:
- Require admission to Intensive Care Unit
- Require period of observation in Emergency Obs Ward (EMW)
- Require Psychiatric Review / Admission.
- Be safely discharged home.
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