poisoning

Question 1

man admitted to A&E with hypotonia, hyporeflexia, hypotension (80/40mmHg).
found with empty box of diazepam 5mg tabs.
what other info is needed?

Answer 1

any other agent/s involved including co-agents e.g. alcohol, paracetamol
route of exposure
date + time of ingestion
quantity ingested
if exposure is single OD/ staggered/ chronic

Question 2

The px swallowed single OD of mother’s diazepam. took 14 5mg tabs, approx 2 hrs ago.
Hes not taking any other meds and doesnt usually take benzodiazepines. no PMH.
What med to administer as antidote for benzos?

Answer 2

Flumazenil

Question 3

Benzodiazepine antidote/ antagonist?

Answer 3

Flumazenil

Question 4

when is flumenazil most likely advised?

Answer 4

in a px with a benzodiazepine OD and history of COPD as potential alternative to ventilation

Question 5

toxidromes (symptoms) of amitryptiline poisoning

Answer 5

coma
hypertonia
dilated pupils
urinary reternsion
sinus tachycardia
hyperreflexia

tricyclic antidepressants have significant anticholinergic activity –> tachycardia….
cardiotoxic in OD

Question 6

toxidromes (symptoms) of heroin poisoning

Answer 6

coma
reduced resp rate
constricted pupils

classical opioid triad.
not all features need to be rpesent in cases of poisoning

Question 7

toxidromes (symptoms) of ecstasy poisoning

Answer 7

delirium
tachycardia
agitation
dilated pupils
hyperthemia
amfetamine derivatived cause sympathetic overdrive

Question 8

toxidromes (symptoms) of phenobarbital poisoning

Answer 8

coma
hypotonia
hyporeflexia
hypotension
barbiturates have sig depressive activity- some used an anaesthetic agents

Question 9

samples should be sent to measure concs for suggestive poisoning with which agents?

Answer 9

ethylene glycol
iron salts
lithium salts
methanol
paracetamol
salicylates (e.g. aspirin)
theophylline

Question 10

risk factors for OD?

Answer 10

alcohol intake
age
marital status
psychiatric disease

Question 11

px admitted to A&E. taken 32 Tylex capsules8 hrs previously. drowsy but otherwise unwell.
check BNF first…
what test best predicts severity of paracetamol poisoning?

Answer 11

plasma paracetamol conc

Question 12

where to seek further advice for management plan. poisoned px

Answer 12

TOXBASE
or NPIS

Question 13

tests used in investigation of iron poisoning?

Answer 13

ABGs
LFTs
serum iron conc
abdominal x ray
FBC
INR (prothrombin time)

Question 14

…

Question 15

16yo girl 50kg presents to A&E following OD of 20 ferrous sulphate tabs (elemental iron content 65mg/ tab).
she has nausea, vomiting, diarrhoea
what level of toxicity would be expected?

Answer 15

total amount ingetsed: 20 tabs x 65mg tab = 1300mg
amount elem iron ingested on mg/kg basis: 26mg/kg.
moderate iron tox

Question 16

… 4 hour serum iron conc: 4.8mg/L
mild nausea but px improves. can px be dischharged?

Answer 16

no… see notes

Question 17

2 things initially presc for opioid poisoning?

Answer 17

naloxone
IV fluids

Question 18

what effect may Flumazenil have in px with benzodiazepine dependance?

Answer 18

may precipitate withdrawal symptoms

Question 19

effective management of poisoning should aim to… (3)

Answer 19

1. reduce absorption
2. give antidote
3. increase elimination

Question 20

what does activated charcoal do?
+ timeframe

Answer 20

bind to many poisons in GIT to reduce absorption…
if given with/ soon (1 hour) after ingestion

Question 21

activated charcoal is NOT effective at adsorbing which drigs? and give examples

Answer 21

strongly ionised drugs or alcohols…
- inorganic acids
- strong alkalis
- iron salts
- li salts
- methanol/ ethanol
- ethylene glycol

Question 22

acetylcysteine is an antidote for…

Answer 22

paracetamol poisoning

Question 23

atropine is an antidote for…

Answer 23

= anticholinergic for cholinergic excess.
also to inhibit action of parasympathetic action of vagus nerve in poisonings that cause bradycardia (beta blockers, digoxin, CCBs)

Question 24

desferrioxamine is an antidote for…

Answer 24

iron poisoning

Question 25

digoxin is an antidote for…

Answer 25

= specific antibody (Fab) fragments for digoxin tox. antibodies bind to dig, stop it acting at Na/K ATPase pump… dig-antibody complex then renally excreted

Question 26

Flumazenil is an antidote for…

Answer 26

benzodiazepines.

Question 27

flumazenil should not be given as diagnostic trial… why?

Answer 27

can precipitate seizures

Question 28

fomepizole is an antidote for…

Answer 28

methanol and ethylene glycol poisoning.
blocks enz: alcohol dehydrogenase .. limiting toxic metabolite prodn

Question 29

glucagon is an antidote for…

Answer 29

beta blocker tox

Question 30

naloxone is an antidote for…

Answer 30

opioid poisoning

Question 31

phytomenadione (vit K) is an antidote for…

Answer 31

warfarin poisoning.
ensure px have adequate thromboprophylaxis for underlying condition: complete referral of effects of warafrin can put px at risk

Question 32

what does multiple dose activated charcoal do?

Answer 32

can increase elim rate of drugs that undergo enterohepatic recirculation
- carbamazepine
- dapsone
- phenobarbital
- quinine
- theophylline

Question 33

what does urine alkalinisation do?

Answer 33

with sodium bicarb, inc renal clearance of salicylate (aspirin)

Question 34

dialysis and haemoperfusion may be useful for poisons with….

Answer 34

low Vd, drug e.g.
ethanol
ethylene glycol
Li slats
methanol
salicylates

Question 35

leading cause for acute liver failure in UK?

Answer 35

paracetamol

Question 36

what test best predicts severity of paracetamol poisoning?

Answer 36

plasma paracetamol conc
reasonably accurate predictor of liver damage taken 4-15 hrs after ingestion.
sample taken earlier than 4hrs may be misleading and 15hrs later may be uncertain

Question 37

mechanism of paracetamol tox?

Answer 37

paracetamol metab in liver by conjugation to form paracetamol glucoronide and sulfate
bit of drug oxidised –> NAPQI. reacts straight away with thiols first then glutathione, cyteine, mercapturate.
lots of NAPQI… liver damage as attacks -SH attached to liver cell proteins and depletes normal defences against oxi damage

Question 38

when does max. liver damage occur with paracetamol tox?

Answer 38

72-96hrs after ingestion