Paracetamol overdose

Question 1

A 23 year old woman presents to the ED 6 hours after taking several packets of Panadol. How would you assess and manage her?

Answer 1

Impression
PDx is of an intentional paracetamol overdose, acute concerns are about the risks of subsequent liver failure, but would like to address underlying mental health which may have precipitated this incident. However would not expect any acute liver failure within first 24 hours

Goals
- ensure HD stability and patient/staff safety
- conduct thorough Hx/Ex/Ix, including psych assessment
- NAC infusion as definitive treatment if paracetamol levels are above the nomogram.
- consider mental health unit as patient disposition

Toxic dose
- >10g in 24hr period
- >6g per 24 hr
If a toxic dose

NAC - works on NAPQI pathway and binds toxic metabolite of acetaminophen

Question 2

Paracetamol overdose - History

Answer 2

History
- PC: details of overdose, timing, how many tablets, what type (immediate (Panadol osteo) vs slow release), any other substances ingested, assess the intent
- Psych: screen mood, mania, psychotic features, as we;; as self/harm/suicide: concrete plans, past attempts, family history
- past psych history
- PMHx, medications, allergies
- ?pregnancy, any underlying liver disease or considerable EtOH abuse

Question 3

Paracetamol overdose - Examination

Answer 3

Examination
- General appearance + vitals
- MSE
- Abdo exam: signs of acute liver failure [low grade fever, jaundice, diffuse abdo tenderness]

Question 4

Paracetamol overdose - Investigations

Answer 4

Investigations
Key;
- serum Paracetamol concentration: should be measured 4hrs after ingestion, plot on nomogram

Bloods: LFT, BSL, UEC, FBC, ß-HCG

No imaging indicated

Question 5

Paracetamol overdose - Management

Answer 5

Management
Definitive treatment
- administer IV NAC infusion according to paracetamol nomogram; if >8hrs post ingestion and a toxic dose has been administered, then commence NAC regardless while waiting for the paracetamol level to come back, otherwise administer according to paracetamol level, cease if/when below treatment line.
o nomogram only useful if taken the overdose all at once, not over a longer period of time.
- Monitor serum level LFTs and INR

• if less than 2-4 hrs post-ingestion, can consider activated charcoal administration to reduce absorption
• consult toxicology if uncertain.
• empirical treatment if taken the Panadol over a longer period of time, can’t use the nomogram for this patient.

Other supportive
- mental health review, consider admission if safety concerns/issues