Revision

Question 1

Risk assessment in iron overdose

Answer 1

Elemental Iron

• Asymptomatic < 20 mg/kg
• Local (GI) symptoms 20-60 mg/kg
• Systemic toxicity 60-120 mg/kg
• potentially lethal > 120 mg/kg

Question 2

5 stages of iron toxicity

Answer 2

1. 0-6 hrs. GI symptoms, diarrhoea, bleeding. +/- hypovolaemia, shock, acidosis.
2. 2-24 hrs. quiescent.
3. 6-48 hrs. Systemic toxicity. shock and MOF. Hypovolaemia, vasodilation, low CO, acidosis, renal failure. Seizures.
4. 2-3 days. Hepatic phase. Acute liver failure. Jaundice, coma, coagulopathy, hypoglycaemia.
5. 2-6 weeks. Delayed GI sequale.

Question 3

Treatment of iron overdose

Answer 3

Gastric lavage if > 120 mg/kg < 1 hr
Whole bowel irrigation if > 60 mg/kg iron & tablets in GI tract on AXR.

Desferrioxamine if
- systemic toxicity (shock, acidosis, altered consciousness)
- serum iron > 60 micromol/L & symptoms
- serum iron > 90 micromol/L at 4-6 hrs
15 mg/kg/hr

Question 4

Antidote for cyanide poisoning

Answer 4

Hydroxocobalamin. 5g over 15 min IV.

Older treatments

• Sodium thiosulphate (conv to sodium thiocyanate)
• Sodium nitrite (conv to methaemoglobin)
• Dicobalt edetate (siginificant AE, especially if not cyanide poisoning)

Question 5

Antidote to hydrofluoric acid toxicity

Answer 5

Topical:

• Calcium gulconate gel
• Infiltration with calcium gluconate 0.5 mls/cm2
• regional calcium - arterial cannula, biers block

Occular: saline irrigation with 1-2g calcium gluconate, local anaesthetic

Ingestion: GI contamination with aspiration, calcium antacid. Systemic calcium and magnesium replacement. Avoid hyperkalaemia. Haemodialysis if severe /refractory hypocalcaemia.

Question 6

Treatment of anticholinesterase poisoning

Answer 6

Muscarinic (DUMBELLS): Atropine 1-3 mg IV, double doses 3-5 min. to HR > 80 and clear chest.
Nicotinic (resp weakness): ETT and ventilation. Consider pralidoxime.
CNS (ACS, seizures, resp failure): ETT and ventilation, benzodiazepines.

Question 7

Treatment of toxic alcohol poisoning

Answer 7

ABC - Intubation with sodium bicarb to prevent worsening acidosis and hyperventilate.

Ethanol - 8 mls/kg IV 10% ethanol then 1-2 mls/kg/hr,
ETOH level < 33 mmol/kg
Fomepizole 15 mg/kg IV, then BD dosing of 10 mg/kg

Haemodilaysis