Poisoning

Question 1

Which are the 2 most groups most likely to present with poisoning?

• accidental/ deliberate
• more common in males/ females

Answer 1

Young children (1-5yo)
More common in Males.
Accidental.

Adolescents
Equal rates in Males and Females.
Deliberate self-harm

Question 2

4 top poisons causing death in UK

Answer 2

1. Paracetamol
2. TCAs
3. Opiates (heroin, methadone)
4. Carbon monoxide (smoke from housefires)

Question 3

State whether the following are depressants or stimulants:

1. BZDs
2. opioids
3. cocaine
4. MDMA
5. theophylline

Answer 3

1. BZDs: depressant
2. opioids: depressant
3. cocaine: stimulant
4. MDMA: stimulant
5. theophylline: stimulant

Question 4

Which poison should be tested for in everyone who presents with overdose?
Why?

Answer 4

Paracetamol

Cos most common overdose method + won’t show early signs

Question 5

Features of BZD overdose

Answer 5

1. CNS depression (ataxia, nystagmus, dysarthria)
2. Respi depression
3. Hypothermia
4. Rhabdomyolysis

Question 6

ECG features in BZD overdose

Answer 6

1. Heart block (1st/2nd degree)

2. QT prolongation

Question 7

Treatment for BZD overdose

Answer 7

1. Flumazenil

2. Activated charcoal, MDAC

Question 8

Late clinical features of paracetamol overdose (including metabolic disturbances)

Answer 8

1. RUQ liver pain
2. Jaundice, encephalopathy
3. Coagulopathy
4. Raised creatinine

Metabolic disturbances

1. Hyperglycaemia
2. Metabolic acidosis

Question 9

Which investigations are best for predicting prognosis after a paracetamol overdose.

What levels of this indicate poor prognosis

Answer 9

PT and INR

POOR PROGNOSIS

• PT or INR rising after day 3
• PT >180s at any time

Question 10

What investigative features (including ABG) indicate that someone requires a liver transplant after paracetamol overdose

Answer 10

1. Metabolic acidosis
2. Raised lactate
3. Encephalopathy (3 or 4 ie worsened confusion, coma)
4. Creatinine >300umol/L

Question 11

Treatment for paracetamol overdose

Answer 11

1. Activated charcoal
2. N-acetylcysteine
3. Haemodialysis (if v high paracetamol concentration >700mg/L)

Question 12

How long/ what method should N-acetylcysteine be given for?

Answer 12

IV for 21h

Question 13

How does N-acetylcysteine work

Answer 13

Can be converted by body into glutathione so that it can then detoxify NAPQI (toxic metabolite of paracetamol)

Question 14

Common complication of N-acetylcysteine.

How is this managed?

Answer 14

Anaphylactoid reaction
-urticaria, wheeze, hypotension

Give antihistamine + reduce dose of N-acetylcysteine

Question 15

What level of paracetamol ingestion requires treatment with N-acetylcysteine

Answer 15

> 150mg/kg

Question 16

How long after paracetamol overdose can blood tests be done to determine whether or not to treat

Answer 16

4h after overdose

Question 17

Overdose with what drug should be considered in a pt with metabolic acidosis + respiratory alkalosis

Answer 17

Aspirin

Question 18

Symptoms of mild/ moderate aspirin overdose

Answer 18

1. Tinnitus
2. Sweating, vomiting, dizziness
3. Hyperventilation

Question 19

Symptoms of severe aspirin overdose

Answer 19

1. Agitation, delirium, coma, fits
2. Arrhythmias
3. Pulmonary/ cerebral oedema
4. Heart/ renal failure

Question 20

Metabolic complications of severe aspirin overdose

Answer 20

1. Metabolic acidosis
2. Respiratory alkalosis
3. Hypoglycaemia
4. Hypokalemia

Question 21

Treatment for aspirin overdose

Answer 21

1. Charcoal, MDAC

2. Sodium bicarbonate (prevents CNS penetration, enhances elimination by alkalinising urine)

Question 22

Symptoms of opioid overdose

Answer 22

1. Pin point pupils
2. CNS, respiratory depression
3. Hypotension, tachycardia
4. Hallucinations
5. Rhabdomyolysis
6. Non-cardiac pulmonary oedema

Question 23

Metabolic complications of opioid overdose

Answer 23

1. Respiratory acidosis

2. Metabolic acidosis

Question 24

Treatment for opioid overdose

Answer 24

Nalozone (opioid receptor antagonist)

Question 25

Half life of naloxone

Answer 25

40-60min

Question 26

Complications of naloxone

Answer 26

ACUTE WITHDRAWAL SYNDROME - arthralgia - tremor, irritability, palpitations - DnV, cramps - rhinorrhoea

Question 27

Symptoms of TCA overdose due to anticholinergic effects

Answer 27

1. Pupil dilation 2. Dry eyes 3. Urinary retention 4. Tachycardia 5. Agitation, delirium 6. Fits, coma 7. Hypertonia, hyper-reflexia

Question 28

Symptoms of TCA overdose due to sodium channel blocking effects

Answer 28

1. Heart block 2. Heart arrhythmias 3. Prolonged QT/ wide QRS

Question 29

What signs on ECG indicate poor prognosis in TCA overdose

Answer 29

QRS >120ms (3 small sq) = urgent action required QRS >160ms (4 small sq) = high risk of arrhythmia

Question 30

Treatment for TCA overdose

Answer 30

1. Charcoal, MDAC 2. Sodium bicarbonate (treat arrythmia, correct acidosis) 3. BZD for fits

Question 31

Early features of iron overdose

Answer 31

1. NnV, abdo pain 2. Bloody diarrhoea 3. Massive GI fluid loss

Question 32

Late features of iron overdose

Answer 32

1. Black offensive stools 2. Reduced GCS, coma, fits 3. Shock 4. Liver/ renal failure 5. Gastric strictures

Question 33

Features of severe iron poisoining (list by ABCDE)

Answer 33

C: shock, hypotension D: reduced GCS/ fits; hypergycaemia E: metabolic acidosis/ rectal bleed/ vomiting blood

Question 34

Treatment for iron overdose

Answer 34

1. Desferrioxamine (binds to iron) | 2. Gastric lavage if large OD (charcoal won't work)

Question 35

When is Desferrioxamine used

Answer 35

For severe iron OD - iron conc >3mg/L + - features of severe poisoning

Question 36

2 antidotes for alcohol poisoning

Answer 36

1. Methanol | 2. Ethylene glycol