Miscellaneous

Question 1

Dose of ibuprofen indicating admission

Answer 1

> 200mg/kg

a. <200 mg/kg = asymptomatic
b. 200-400 mg/kg = mild GI and CNS effects
c. >400 mg/kg = risk of multi-organ dysfunction

Question 2

Activated charcoal uses

Answer 2

1-2g/kg, ideally within 1hr of ingestion
Salicyclates
Amphetamines, cocaine, ectstasy
Barbiturates
Theophyllines

Question 3

Dose of salicylate indicating admission

Answer 3

> 150mg/kg - consider use of charcoal

<150mg/kg Minimal symptoms
150-300mg/kg Mild-moderate symptoms: Tinnitus, vomiting, hyperventilation
>300mg/kg Severe symptoms: Acidosis, seizures, hyperthermia

Question 4

Contraindications to activated charcoal/when is it unhelpful

Answer 4

Iron
Hydrocarbons (e.g. petrol)
Caustic/corrosive substances
Alcohol
Ibuprofen
Paracetamol
Benzodiazepines
Essential oils (risk of aspiration)

Question 5

Is salicylate blood level accurate/helpful?

Answer 5

Yes to a degree, peaks around 2-4hrs post ingestion, however can be misleading as there is a poor correlation between salicylate concentration and toxicity and deterioration may still occur with falling serum concentrations due to rising CNS concentration

Question 6

Endoscopic grading in caustic/corrosive substances

Answer 6

1. Grade 0 — normal
2. Grade I — mucosal edema and hyperemia
3. Grade IIA — superficial ulcers, bleeding and exudates
4. Grade IIB — deep focal or circumferential ulcers
5. Grade IIIA — focal necrosis
6. Grade IIIB — extensive necrosis

Question 7

What volume of essential oil can cause toxicity?

Answer 7

5-15ml in adults, 2-3ml in children
Mimic fat soluble drugs, absorbed through mucous membranes/skin
Admit any dose >5ml

Question 8

How many times greater is the affinity of CO to haemoglobin c/w O2

Answer 8

240x
Binds to iron moiety of haem, causing allosteric changes in the haem protein = reduced ability of the other 3 O2 binding sites to offload haem into the peripheral tissues i.e. causes a LEFT SHIFT of O2 dissociation curve
Also binds to myoglobin, cytochromes and NAPH –> impaired oxidative phosphorylation in mitochondria

Question 9

Indications for hyperbaric O2

Answer 9

patients with COHb >25%, end-organ ischaemia, LOC, pregnancy
Children have a higher risk of hypothermia, and do a CXR first to exclude congenital anomalies

Question 10

Mechanism of cyanide poisoning

Answer 10

Normal aerobic metabolism = ATP generated from ETC following TCA cycle
Cyanide binds to Ferric ion (Fe3+) of cytochrome oxidase a3 –> inhibits final enzymes in ETC –> can’t make ATP so cell does anaerobic metabolism –> lactic acidosis, increased anion gap, metabolic acidosis

Question 11

What is the antidote for cyanide and is it really needed?

Answer 11

YES. Hydroxycobalamin (B12)