Toxins

Question 1

benzodiazepines

Answer 1

flumazenil 200 mcg over 15s, then 100 mcg at 1 min intervals as needed.
usual total dose 300-600 mcg
total dose 1 mcg, 2 mcg under ITU care
s/e seizure provoking

Question 2

beta-blockers

Answer 2

atropine 3 mg IV
then...
glucagon 2-10 mg IV + 5% dextrose (call MedReg/Cardio)
then...
glucagon infusion
then...
pacing (transvenous temporary)

Question 3

methaemoglobinaemia, (methaemoglobin >30%)

Answer 3

methylthioninium chloride

Question 4

what are the poisons requiring haemodialysis?

Answer 4

ethylene glycol, lithium, methanol, salicylates, valproate, phenobarbital

Question 5

when is alkalinisation of urine useful?

Answer 5

salicylate poisoning

Question 6

what drug(s) poisoning presents with tachycardia/tachyarrythmia?

Answer 6

salbutamol
antimuscarinics
tricyclics
quinine

Question 7

what drug(s) poisoning presents with respiratory depression?

Answer 7

opiates

benzodiazepines

Question 8

what drug(s) poisoning presents with hyperthermia?

Answer 8

cocaine, amphetamines, MDMA
MAO-I’s
SSRIs, antipsychotics (NMS, SS)

Question 9

what drug(s) poisoning presents with coma?

Answer 9

BZD/barbituates
alcohol
opiates
tricyclics

Question 10

what drug(s) poisoning presents with seizures?

Answer 10

recreational drugs
hypoglycaemia
tricyclics
theophylline(s)

Question 11

what drug(s) poisoning presents with pin-point pupils?

Answer 11

opiates

organophosphates

Question 12

what drug(s) poisoning presents with dilated pupils?

Answer 12

amphetamines, cocaine, MDMA
quinine
tricyclics

Question 13

what drug(s) poisoning presents with hyperglycaemia?

Answer 13

organophosphate
theophylline
MAO-I’s

Question 14

what drug(s) poisoning presents with hypoglycaemia?

Answer 14

insulin, sulphonylurea
alcohol
salicylates

Question 15

what drug(s) poisoning presents with acute renal dysfunction?

Answer 15

salicylates
ehtylene glycol
paracetamol

Question 16

what drug(s) poisoning presents with metabolic acidosis?

Answer 16

ethylene glycol/methanol
paracetamol/salicylates
alcohol
carbon monoxide

Question 17

what blood tests should always be added (besides routine sets) in the setting of acute poisoning?

Answer 17

paracetamol and salicylates

blood glucose

Question 18

use of activated charcoal in acute poisoning

Answer 18

activated charcoal given for two reasons: 1) GI decontamination; 2) increase the rate of elimination of a toxin from the blood
initially given as a 50g dose with water, then repeated 50 g/4 hrs for elimination.
use smaller doses in children.
consult with product literature or BNF with regards to the poisons that are CI’s to charcoal, such as metal salts or alcohols.
s/e: foul taste, GI disturbance, black stools

Question 19

cyanide

Answer 19

100% oxygen and GI decontamination
sodium nitrate/sodium thiosluphate
dicobalt edetate
follow with 50 mL 50% glucose

Question 20

in cyanide poisoning, what are the indications for hyperbaric oxygen?

Answer 20

COHb >20%
pregnant
neuro/psych disturbance
cardiovascular impairment

not responding to 100% oxygen

Question 21

digoxin

Answer 21

anti-digoxin antibodies: DigiFab (R) 800 mg
monitor U&E for disturbance contributing to arrythmia, correct them
12-lead ECG/cardiac monitoring

Question 22

iron

what are the rules for GI detox?

Answer 22

desferrioxamine 15 mg/kg/hr IVI
if iron ingested in the last hour, gastric lavage
if longer, consider whole bowel irrigation under expert guidance

Question 23

opiates

Answer 23

naloxone 0.5-2 mg IV
short half-life so maybe needed repeatedly.
max dose 10 mg

give until breathing is adequate

Question 24

what are the considerations with giving naloxone for opiate poisoning?

Answer 24

naloxone = opiate withdrawal

GI symptoms will respond to co-phenotrope/Lomotil (diphenoxylate and atropine)

Question 25

anti-cholinesterase clinical features

Answer 25

SLUD
hypersalivation
lacrimation
urination
diarrhoea

Question 26

what is an added blood test useful in organophosphate poisoning?

Answer 26

serum cholinesterase function

Question 27

what is the treatment of organophosphate poisoning

Answer 27

atropine 0.5-2 mg IV, repeat until skin dry, pupil dilated, HR >70
pradiloxime
diazepam (regardless of seizure status)

treatment maybe needed over a few days

Question 28

what are the signs and symptoms of paracetamol poisoning?

Answer 28

none initially… maybe nausea and RUQ pain

then jaundice, hepatic encephalopathy, asterixis, transaminitis, AKI

Question 29

what are the lethal doses of paracetamol?

Answer 29

about 12 g - so 24 tablets
roughly 150 mg/kg
for patients over 110 kg, calculate exposure as 110 kg so you don’t underestimate toxicity
malnourishment - 75 mg/kg can be lethal

Question 30

GI decontamination for paracetamol poisoning?

Answer 30

yes, if presenting under 4 hours following ingestion

Question 31

what are the guiding principles of managing paracetamol poisoning?

Answer 31

get the graph of time since ingestion versus blood paracetamol level (mg/L)
treat if levels are above the line.
treatment is n-acetylcyctine infusion
stop infusion when levels are below the line or ALT/INR have normalised

Question 32

what are the threshold levels for aspirin toxicity?

Answer 32

150 mg/kg - mild toxicity
500 mg/kg - severe toxicity
700 mg/L - potentially fatal

Question 33

what is the pattern of metabolic disturbance in aspirin poisoning?

Answer 33

initial respiratory alkalosis
then metabolic acidosis …

…. as OxPhos becomes uncoupled, anaerobic takes over leading to lactic acidosis

Question 34

managing salicylate poisoning

Answer 34

blood - glucose, acid-base, hypokalaemia (b/c therapeutic alkalinosis)
urine - catheterise and monitor pH for duration of treatment
alkalinisation - if serum levels >500 mg/L or severe acidosis
use 1.5 L 1.24% sodium bicarb IV over 3 hours. aim for urine pH 7.5-8
if resistant or serum level >700 mg/L, dialysis