Toxicology

Question 1

Causes of NAGMA

Answer 1

Renal tubular acidosis
Acetazolamide
Diarrhoea
High stoma output
Hyperchloraemic acidosis (saline)
Addison’s disease 

Chloride gain or bicarb loss

• chronic laxative abuse
• severe diarrhoea or losses via NG
• urinary diversions
• fistulas

Loss of base via kidney
- RTA 1,2 and 4

Gain of acid
- HCl infusion

Question 2

Beta blocker toxicity

Answer 2

Bradycardia and hypotension

• propranolol Na channel blocker -> QRS the widening, seizures, arrhythmia
• sotalol K channel blocker -> QT prolongation and risk of torsades
• atropine 0.01-0.03mg/kg
• isoprenaline 4mcg/min
• IV fluids
• HIET 1u/kg bolts and

Question 3

Na channel blockers

Answer 3

LAs - lignocaine
TCAs - amitryptiline
Antiarrhythmics - quinine, flecainide, procainamide, propranolol
Cocaine
Chloroquine/hydroxychloroquine

Question 4

Management of Na channel blocker toxicity

Answer 4

Early intubation
Hyperventilation
Bolus NaHCO3 - 1-2mmol/kg until correction if QRS

Question 5

Methods of enhanced elimination

Answer 5

MDAC

• These People Drink Charcoal
• theophylline, phenobarbital, dapsone, carbamazepine

Haemodialysis

• toxic alcohols
• lithium
• carbamazepine, valproate
• salicylate
• metformin

Urinary alkalinisation

• salicylate
• phenobarbital

Question 6

Most common cause of toxicological seizures

Answer 6

Venlafaxine
Tramadal (sodium channel blocker)
Amphetamines
Bupropion 
ETOH and Benzo withdrawal

Question 7

Management of toxicological seizures

Answer 7

IV benzo first line
- Midazolam 5mg IV
- Diazepam
- Clonazepam
Barbiturates second line for refractory seizures in acute poisoning
Pyridoxine for isoniazid toxicity

Phenytoin contraindicated as may exacerbate sodium channel blockade.

Question 8

Toxic alcohol treatment

Answer 8

Ethanol 10% 6ml/kg bolus
1ml-2ml/kg/hr infusion IV or NG

Elimination
Methanol: calcium folinate 50mg IV q6hr for 2 days OR folic acid 50mg IV q6hr for 2 days
Ethylene glycol: pyridoxine 50mg IV every 6hrs for 2 days OR thiamine 100mg IV q6hrs for 2 days

Question 9

Neuroleptic malignant syndrome

Answer 9

Criteria:
Exposure to dopaminergic agent or withdrawal in last 72hrs
Hyperthermia > 38
Sympathetic n system: Hypertensive with systolic > 25% baseline, diaphoresis, urinary incontinence, PR > 25% baseline, RR > 50% baseline
Raised CK > 4 x normal
Lead pipe rigidity