Emergencies and substance abuse

Question 1

mechanism of action of adrenaline

Answer 1

alpha-receptor agonist (reverses peripheral vasodilation and oedema)

also has beta-receptor activity (dilates bronchial airways, increases force of myocardial contraction and suppresses histamine and leukotriene release)

Question 2

dosage of adrenaline to use for anaphylaxis at different ages

Answer 2

• adult >12 = 500mcg
• child 6-12 = 300mcg
• child <6 years = 150mcg

Question 3

first choice vasopressor in septic shock

Answer 3

noradrenaline

dobutamine can be added if myocardial dysfunction

Question 4

leading cause of death in acute MI

Answer 4

cariogenic shock

Question 5

stages I-IV of haemorrhagic shock

Answer 5

I = <15% blood loss
II = 15-30%
III = 30-40%
IV = >40%

Question 6

examples of non-haemorrhagic hypovolaemic shock

Answer 6

• dehydration, D&V, burns, polyuria

- 3rd space loss - pancreatitis, ascites

Question 7

why not to push BP >100 if in haemorrhagic shock

Answer 7

might dislodge clot trying to form

Question 8

when to consider major haemorrhage protocol and what does it entail

Answer 8

• actively bleeding, HR >110, BP <90

- 4 units blood, 4 units FFP every 20 mins

Question 9

causes of T2RF

Answer 9

• COPD
• near fatal asthma
• drug overdose/poisoning
• myasthenia gravis
• polyneuropathy
• muscle disorders

Question 10

usual cause of cardiogenic pulmonary oedema

Answer 10

complication of MI/IHD

Question 11

usual cause of non-cardiogenic pulmonary oedema

Answer 11

IV fluid overload

could also be caused by decreased plasma oncotic pressure e.g. hypoalbuminaemia

Question 12

ABG result in pulmonary oedema

Answer 12

acidotic - not perfusing tissues

hypoxic and hypercapnia - impaired gas exchange

lactate likely elevated - tissues hypo perfused

Question 13

dose of furosemide to give in pulmonary oedema/acute heart failure

Answer 13

20-40mg if diuretic naive

otherwise 40mg

Question 14

antiemetic to give in pulmonary oedema

Answer 14

ondansetron 4-8mg

Question 15

signs of obstructive shock

Answer 15

fluid overload:

• pulmonary oedema
• cardiomegaly
• raised JVP

Question 16

causes of obstructive shock

Answer 16

• PE
• tension pneumothorax
• cardiac tamponade

basically blocking outflow of blood from heart

Question 17

brain complication of paracetamol overdose

Answer 17

hepatic encephalopathy

Question 18

LFT results in paracetamol overdose indicating hepatotoxicity

Answer 18

ALT >1000

Question 19

blood glucose level in paracetamol overdose

Answer 19

hypoglycaemic

Question 20

amount of paracetamol ingested suggesting severe liver damage

Answer 20

> 150mg/kg

more than 24 tablets (12g) is potentially fatal

Question 21

what drugs increase paracetamol toxicity

Answer 21

p450 INDUCERS: P CARBS

P - phenytoin
C - carbamazepine
A - alcohol (chronic) 
R - rifampicin
B - barbiturates 
S- sulfonylureas

Question 22

when can pabrinex (NAC) be stopped after paracetamol overdose

Answer 22

once INR <1.3 and ALT <2x upper limit of normal/hasn’t doubled

Question 23

when to consider liver transplant for paracetamol overdose

Answer 23

if pH <7.3 24 hours after ingestion OR

• PTT >100 seconds AND
• creatinine >300 ANDF
• grade III or IV encephalopathy

Question 24

how much naloxone to give in opiate overdose

Answer 24

0.4-2mg

may require infusion/multiple doses (IV/IM)

Question 25

ECG findings in TCA overdose

Answer 25

- sinus tachycardia - widening PR or QRS complexes - QRS >100ms associated with increased risk of seizures - QTc heart block - ventricular dysrhythmias

Question 26

drugs to give in TCA overdose

Answer 26

- IV bicarbonate | - IV lipid emulsion (binds free drug and reduces toxicity)

Question 27

doses of salicylates likely to cause toxicity (e.g. aspirin)

Answer 27

>250mg/kg - moderate >500mg/kg - severe/fatal

Question 28

how to take plasma salicylate concentration

Answer 28

- taken 2 hours (symptomatic) or 4 hours (asymptomatic) after ingestion - repeat after a further 2 hours - intoxication usually associated with concentrations >350mg/L - check potassium every 3 hours

Question 29

when is hospital admission not required for aspirin overdose

Answer 29

ingested <125mg/kg and no symptoms

Question 30

when to consider activated charcoal/gastric lavage for aspirin overdose

Answer 30

- charcoal if >125mg/kg less than 1 hour ago | - gastric lavage if >500mg/kg less than 1 hour ago

Question 31

when to do haemodialysis in aspirin overdose

Answer 31

- serum concentration >700mg/L - metabolic acidosis resistant to treatment - acute renal failure - pulmonary oedema - seizures - coma

Question 32

antidote to iron overdose

Answer 32

desferrioxamine mesylate IV

Question 33

mechanism of action of ketamine

Answer 33

NMDA antagonist

Question 34

mechanism of action of cocaine

Answer 34

monoamine reuptake inhibitor potentiates dopaminergic, serotinergic and noradrenalinergic transmission

Question 35

what can be used for heroin detox

Answer 35

- symptom relief = lofexidine (alpha agonist) - loperamide - metoclopramide - ibuprofen - methadone or buprenorphine or dihydrocodeine

Question 36

mechanism of action of benzodiazepines and GHB

Answer 36

GABA agonist

Question 37

how long to give chlordiazepoxide for alcohol withdrawal

Answer 37

over 5-7 days with reducing dose

Question 38

management of delirium tremens

Answer 38

parenteral thiamine (Pabrinex): - no WK syndrome = 250mg/day for 3-5 days - WK syndorme = 500mg/day for 3-5 days prophylactic carbamazepine (if previous hx of seizures) chlordiazepoxide

Question 39

what counts as binge drinking

Answer 39

twice the recommended daily unit limit in one session - 6 units