Paracetamol Overdose

Question 1

Define:

Answer 1

Excessive ingestion of paracetamol causing toxicity

Question 2

Aetiology:

Answer 2

Max dose: 2x500mg 4 doses in 24hrs

12g in adults can lead to hepatic necrosis but prompt treatment can prevent liver damage

Question 3

Risk factors:

Answer 3

o Chronic alcohol abusers
o Patients on enzyme-inducing drugs (e.g. anticonvulsants)
o Malnourished
o Anorexia nervosa
o HIV
o Paracetamol overdose is commonly associated with ingestion of large amounts of alcohol

Question 4

Epidemiology:

Answer 4

• Most COMMON intentional drug overdose in the UK

* Causes 100 deaths/yr in the UK

Question 5

Symptoms at 0-24 hrs:

Answer 5

o ASYMPTOMATIC usually
o Mild nausea/vomiting
o Lethargy
o Malaise

Question 6

Symptoms at 24-72 hrs:

Answer 6

RUQ pain

Vomting

Question 7

Symptoms at 72+:

Answer 7

o Increased confusion (encephalopathy)
o Jaundice
o +/- acute kidney injury

Question 8

Signs at 0-24 hrs:

Answer 8

none

Question 9

Signs 24-72 hrs:

Answer 9

Liver enlargement and tenderness

Question 10

Signs 72+ hrs:

Answer 10

jaundice, coagulopathy, hypoglycaemia, renal angle tenderness

Question 11

Investigations:

Answer 11

• Measure paracetamol levels
o NOTE: peak paracetamol levels are 4 hrs after ingestion
• Others: FBC, U&Es, Glucose, LFTs, Clotting Screen, Lactate and ABG

Question 12

Treatment:

Answer 12

N-acetyl cysteine