TOXICOLOGY
Approach to Poisoned Patient.
A framework below. I strongly recommend purchasing the Toxicology Handbook by Lindsay Murrey. It's the only textbook I routinely use in my everyday practice! Details on the general approach and specific toxins are found there.
A Mnemonic to help remember the approach Resus - RSI DEAD
RESUS - Specific toxicological considerations
Consider prolonged CPR in case of arrest --> good outcomes with even prolonged downtime
Consider resuscitative antidotes where appropriate (eg NaHCO3 in TCA, Naloxne in opioid OD)
Treat Seizures with benzodiazapines NOT phenytoin!
Seek and treat hyperthermia
Seek and treat hypoglycemia
RISK ASSESSMENT
How much, of what, when. What clinical effects are expected. Refine your risk assessment with clinical findings (ie drowsiness and tachycardia in TCA overdose precede severe toxicity) Risk asessment may further be refined with investigations (eg: Levels)
SUPPORTIVE CARE AND MONITORING
Guided by risk asessment, specific to toxin ingested. eg: Telemetry for cardiotoxic ingestions, IDC for anticolinergic urinary retention)
INVESTIGATIONS
Routine screening in deliberate self harm - paracetamol level and ECG (look for wide QRS indicating Na+ channel blockade and long QT) (long QT becoming less important with withdrawl of more cadiotoxic antipsychotics)
Other specific investigations should be guided by risk assessment
DECONTAMINATION
Activated charcoal not routinely used but has an important role in ingestions with poor prognosis despite good supportive care usually within 1 hour of presentation (but there are exceptions). Beware ALOC, vomiting and aspiration.
Activated Charcoal Vs Whole bowel Irrigation
Simple measures are important (eg, remove contaminated clothing in organophosphate poisoning)but this should not take priority of resuscitative care
Know which drugs don't bind activated charcoal. (metals, caustics, hydrocarbons)
ENHANCED ELIMINATION
Urinary alkylisation (salycilate toxicity)
MDAC (Rarely used)
Haemodialysis - Specific indications for sepecific drus (eg: Toxic alcohol, salycilate, Theophyline, chronic lithium toxicity)
ANTIDOTES
Know the antidotes for some common and serious ingestions, for example below
NAC, NaHCO3, Calcium, atropine, High dose insulin euglycemic therapy
DISPOSITION
This is usually the critical decison we need to make in ED. How long do we need to monitor in an acute area? When to transfer to SSU? When is the patient medically clear? Don't forget pshychological risk asessment and risk of further self harm + mental health follow up.
Common and Serious Toxins
Read about the following toxins and have an understanding of the risk assessment and management
Na Channel Blockers (TCAs, propranolol, local anaesthetics)
Calcium Channel Blockers
Digoxin
Lithium
Iron
Toxic Alcohols - (Methanol, ethylene glycol)
Carbon Monoxide
Colchicine
Cyanide (Think house fire and severe lactic acidosis)
Hydrofluoric Acid
Organophosphates
Paracetamol
Salycilates (aspirin)
Sulphonureas
Snake Bite + envenomation
Toxidromes
Toxidromes are useful to guide risk assessment particularly when history is limited - they may indicate a certain likely ingestion. Be familiar with the following:
Serotonin Syndrome
Neuroleptic Malignant Syndrome
Anticholinergic Syndrome
Sympathomimetic
Opioid
Cholinergic Syndrome
A framework below. I strongly recommend purchasing the Toxicology Handbook by Lindsay Murrey. It's the only textbook I routinely use in my everyday practice! Details on the general approach and specific toxins are found there.
A Mnemonic to help remember the approach Resus - RSI DEAD
RESUS - Specific toxicological considerations
Consider prolonged CPR in case of arrest --> good outcomes with even prolonged downtime
Consider resuscitative antidotes where appropriate (eg NaHCO3 in TCA, Naloxne in opioid OD)
Treat Seizures with benzodiazapines NOT phenytoin!
Seek and treat hyperthermia
Seek and treat hypoglycemia
RISK ASSESSMENT
How much, of what, when. What clinical effects are expected. Refine your risk assessment with clinical findings (ie drowsiness and tachycardia in TCA overdose precede severe toxicity) Risk asessment may further be refined with investigations (eg: Levels)
SUPPORTIVE CARE AND MONITORING
Guided by risk asessment, specific to toxin ingested. eg: Telemetry for cardiotoxic ingestions, IDC for anticolinergic urinary retention)
INVESTIGATIONS
Routine screening in deliberate self harm - paracetamol level and ECG (look for wide QRS indicating Na+ channel blockade and long QT) (long QT becoming less important with withdrawl of more cadiotoxic antipsychotics)
Other specific investigations should be guided by risk assessment
DECONTAMINATION
Activated charcoal not routinely used but has an important role in ingestions with poor prognosis despite good supportive care usually within 1 hour of presentation (but there are exceptions). Beware ALOC, vomiting and aspiration.
Activated Charcoal Vs Whole bowel Irrigation
Simple measures are important (eg, remove contaminated clothing in organophosphate poisoning)but this should not take priority of resuscitative care
Know which drugs don't bind activated charcoal. (metals, caustics, hydrocarbons)
ENHANCED ELIMINATION
Urinary alkylisation (salycilate toxicity)
MDAC (Rarely used)
Haemodialysis - Specific indications for sepecific drus (eg: Toxic alcohol, salycilate, Theophyline, chronic lithium toxicity)
ANTIDOTES
Know the antidotes for some common and serious ingestions, for example below
NAC, NaHCO3, Calcium, atropine, High dose insulin euglycemic therapy
DISPOSITION
This is usually the critical decison we need to make in ED. How long do we need to monitor in an acute area? When to transfer to SSU? When is the patient medically clear? Don't forget pshychological risk asessment and risk of further self harm + mental health follow up.
Common and Serious Toxins
Read about the following toxins and have an understanding of the risk assessment and management
Na Channel Blockers (TCAs, propranolol, local anaesthetics)
Calcium Channel Blockers
Digoxin
Lithium
Iron
Toxic Alcohols - (Methanol, ethylene glycol)
Carbon Monoxide
Colchicine
Cyanide (Think house fire and severe lactic acidosis)
Hydrofluoric Acid
Organophosphates
Paracetamol
Salycilates (aspirin)
Sulphonureas
Snake Bite + envenomation
Toxidromes
Toxidromes are useful to guide risk assessment particularly when history is limited - they may indicate a certain likely ingestion. Be familiar with the following:
Serotonin Syndrome
Neuroleptic Malignant Syndrome
Anticholinergic Syndrome
Sympathomimetic
Opioid
Cholinergic Syndrome