Toxicology - general

Question 1

In the unconscious patient, which specific agents should be investigated with drug levels?

Answer 1

Carbamazepine
Ethanol
Salicylate
Sodium Valproate

Question 2

Describe the enhanced elimination strategy for carbamazepine

Answer 2

Multidose activated charcoal

Haemodialysis

Question 3

Describe the enhanced elimination strategy for phenobarbitone

Answer 3

Multidose activated charcoal

Haemodialysis

Question 4

Describe the enhanced elimination strategy for Salicylate poisoning

Answer 4

Urinary alkalinisation

Haemodialysis

Question 5

Describe the enhanced elimination and antidote strategy for toxic alcohols

Answer 5

Ethanol

Haemodialysis

Question 6

Describe the enhanced elimination strategy for Sodium valproate

Answer 6

Haemodialysis

Question 7

Antidote for isoniazid

Answer 7

Pyridoxine 1g per g of isoniazid up to 5g (70 mg/kg in children), as slow IV infusion 0.5g / min until seizures stop, then remainder (if any) over 4 hrs

Question 8

Antidote for organophosphate poisoning

Answer 8

Atropine 1.2mg (50mcg/kg) IV Q5min double dose until dry

Pralidoxime 2g IV and then infusion 0.5g/hr (controversial)

Question 9

Management of VT due to sodium channel blockade?

What medication to avoid?

Answer 9

Intubation, hyperventilation
Bolus IV NaHCO3 1-2 mmol/kg IV Q1-2 min
NO AMIODARONE
When pH >7.5, IV lignocaine 1.5 mg/kg then infusion 2mg/min

Question 10

Management of tachycardia or acute coronary syndrome in setting of sympathomimmetic use

Answer 10

IV diazepam 5-10mg Q2-5min until

Question 11

4 categories of agents causing corrosive injury to the oropharynx which can result in airway compromise

Answer 11

Alkalis
Acids
Glyphosate
Paraquat

Question 12

Antidote in carbamate poisoning

Answer 12

Atropine 20-50 mcg/kg (1.2mg) IV Q5min doubling dose until dry

Question 13

Toxicological cause of hypocalcaemia

Answer 13

Hydrofluoric acid ingestion

Extensive cutaneous burns

Question 14

Management of VF due to hypocalcaemia

Answer 14

IV calcium gluconate 10% 60 to 90 mls IV bolus, repeated Q2min until defibrillation successful

Question 15

How do you undertake high dose insulin therapy?

Answer 15

High dose insulin therapy

• glucose 50% 50 mls IV bolus
• short acting Insulin 1 unit/kg IV bolus

Then

• glucose 25g/hr IV infusion via CVC titrate to euglycaemia
• Short acting insulin 0.5 units/kg/hr IV, increased to 1-2 units/kg/hr

Question 16

Management of SVT due to theophylline toxicity

Answer 16

IV beta-blocker titrate to effect

Urgent haemodialysis

Question 17

Management of calcium channel blocker toxicity

Answer 17

IV calcium gluconate 10% 60-90 mls

High dose insulin therapy

Question 18

Agents causing fast sodium channel blockade

Answer 18

TCA
1A antiarrhythmics
1C antiarrhythmic 
II antiarrhythmic: diltiazem 
IV: propranolol 
Local anaesthetic 
Hydroxychloroquine, chloroquine 
Quinine 
Dextropropoxyphene 
Amantadine
Carbamazepine

Question 19

Agents causing prolonged QT

Answer 19

Antipsychotics 
1A antiarrhythmic 
1C antiarrhythmic 
III: sotolol
TCAs
Antidepressants: escitalopram/citalopram, MAOI 
Antihistamines 
Chloroquine, hydroxychloroquine
Quinine
Fluroquinolones: moxifloxacin
Macrolides: azithromycin, erythromycin 
Methadone

Question 20

Causes of high osmolar gap

Answer 20

Acetone 
Ethanol 
Ethylene glycol 
Methanol 
Isopropyl alcohol 
Propylene glycol 
Mannitol 
Non-toxicological: DKA, CRF, hyperlipid/protein, lactic acidosis, trauma/burns, shock

Question 21

Causes HAGMA

Answer 21

HAGMA
Carbon monoxide, cyanide 
Alcohol, alcoholic ketosis 
Toulene
Metformin
Uraemia
DKA 
Paracetamol, paraldehyde, prolylene glycol 
Isoniazid, iron
Lactic acidosis 
Ethylene glycol
Salicylate, starvation ketosis

Question 22

Causes of NAGMA

Answer 22

RACE
Renal: RTA, addisons 
Acetazolamide 
Chloride excess
Extra loss: diarrhoea, fistula (pancreatic, small bowel, ureterostomy etc)

Question 23

Causes metabolic alkalosis

Answer 23

CLEVER PD
Contraction of volume (dehydration) 
Liquorice
Endocrine - conn's, cushings 
Vomiting, GI loss
Excess alkali - bicarb, antiacid, calcium
Renal - barters, gitleman
Post hypercapnoea 
Diuretic

Question 24

Agents requiring lower treatment threshold in pregnancy patients due to increased risk to foetus

Answer 24

Carbon monoxide
Methaemoglobinaemia induicing agents
Lead
Salicylate

Question 25

Tablets and poisons lethal to 10kg child in 1-2 tablets

Answer 25

``` A Baby Could Collapse Very Dead Over Picking Some Theophylline Tablets, Now Other Poisons Can Have Same Catastrophe. Amphetamine Baclofen Calcium channel blocker, carbamazepine, chloroquine Clozapine Venlafaxine Dextropropoxyphene Opioid Propranolol Sulphonylureas Theophylline TCA - dothiepine Napthalene (mothball) Organophosphate Paraquat Camphor Hydrocarbon Strychnine Corrosive + toxic alcohols / essential oils ```

Question 26

N-acetylcystine reigmen

Answer 26

200mg/kg over 4 hrs, then 100mg/kg over 16 hrs.

Question 27

Iron overdose antidote

Answer 27

Desferrioxamine 15 mg/kg

Question 28

Ethanol dosing as antidote

Answer 28

Loading dose 600 mg/kg and infusion of 80-150 mg/kg/hr

Question 29

Naloxone dose

Answer 29

5-10 mcg/kg (max 400 mcg) | Infusion 10 mcg/kg/hr

Question 30

Anticholinergic effects

Answer 30

``` Hyperthermia Myosin Dry flushed skin Delirium Urinary retention Tachycardia ```

Question 31

4 phases of iron overdose

Answer 31

6 hrs - GI irritation, hypotension 6-12 hrs - improving 12-24 hrs - metabolic acidosis, altered mental status, pulmonary oedema, coagulopathy/death 4-6 weeks - GI strictures

Question 32

Intervention level for toxicity in iron overdose

Answer 32

> 60mg/kg significant symptoms - AXR & lab investigations > 100 mg/kg potentially lethal

Question 33

Management of oral hypoglycaemic overdose

Answer 33

5 mls/kg glucose 10% | Octreotide - inhibit insulin secretion from pancreas, 1 mcg/kg IV bolus and infusion