Toxicology

Question 1

Types of exposure

Answer 1

Accidental/unintentional
-exploratory in children (U4)

Occupational accidents

Intentional - deliberate

• peaks in teens, females
• developing - pesticides, chemical, herbicides
• developed - BZ, paracetamol, NSAIDs, antidepressants, antipsychotics, aspirin

Question 2

History

-key questions

Answer 2

Drug, dose, time
-any thing else taken at the same time

If drowsy, confused, withdrawn => Collateral

• DHx
• Empty bottles in bed, bag
• SHx

Question 3

Examinations

-investigations you’d like to do

Answer 3

Specific toxidromes

Neuro, mental state, GCS, pupil responses
CV - HR, BP
Temp
Resp - aspiration risk

12ECG - tachycardia, QRS prolongation, QTc prolongation => torsade de pointes, heart block
VBG
FBC, U&E, LFT, INR, CRP, glucose

Question 4

Paracetamol poisoning

• toxic dose
• presentation
• investigations
• management
• complications and criteria

Answer 4

Toxic dose - 75mg/kg => 4hr paracetamol level, INR, VBG, LFT, U&E, FBC
Urgent action needed - 150mg/kg => NAC immediately

Can be asymptomatic
-N+V, sweaty, abdo pain => jaundice

Common to be asymptomatic early on

Paracetamol level

• 4hrs after single OD
• immediately if staggered

NAC most effective within 8hrs
NAC given if
-staggered
-doubt over time
-paracetamol level at 4hrs on/above line
Anaphylactoid reaction => antihistamines

Liver transplant recommended if

• metabolic acidosis U7.3
• PT 100s+
• III/IV encephalopathy
• creatinine 300+ in 24hrs

Question 5

Management

Answer 5

Resus, supportive within ED or ED obs ward - 5 half lives needed to eliminate drug
-cardiac monitoring

NOT COMMONLY USED - only for immediate presentation
Measures to decrease absorption - gastric lavage, activated charcoal, irrigation
Measures to increase elimination - repeat charcoal, urinary manipulation, dialysis

Psychosocial assessment
Psych assessment in self harm

Question 6

Activated charcoal

• when to use
• what can you not use it for

Answer 6

U1hr of ingestion to reduce absorption
ONLY IF patient can swallow

Not for

• acids, alkalis
• alcohol
• metal
• organic solvents

Question 7

TCAs

• presentation
• invetigations
• management

Answer 7

Rapid onset - 10mg/kg
Anticholinergic features - mad as a hatter, red as a beet, dry as a bone, hot as a hare
-high HR, low RR
-increased tone and reflexes

VBG - metabolic acidosis
Serial ECG - QRS, QTc prolongation

Charcoal if U1hr
Supportive
-sodium bicarbonate - arrythmias, seizures, acidosis, long QRS => TDP

Question 8

Benzodiazepine

• presentatioon
• management

Answer 8

CNS depressant => reduced GCS

Supportive

• airway
• flumazenil - NOT ROUTINELY GIVEN, risk of arrythmias, seizures (check medications for arrythmias, AEDs)

Question 9

Opioid

• presentation
• management

Answer 9

Reduced GCS
Pinpoint pupils
Resp depression

Resus, supportive care

• O2, resp support
• Paracetamol level - esp with cocodamol
• Naloxone -lowest dose to improve alertness