Paracetamol Overdose Flashcards
What mass of paracetamol per kg in healthy adults may be fatal?
If a pt is malnourished what mass of paracetamol per kg may be fatal?
- Health adult= 150mg/kg
- Malnourished adult =75mg/kg
Paracetamol overdose can be acute or staggered and it is important to determine which it is; explain the difference between the two and state which has worse prognosis
- Acute= all tablets <1hr
- Staggered= tablets taken over >1hr
If it has been >4hrs since paracetamol overdose hepatotoxicity unlikely if….? (4)
- No symptoms of liver damage
- Serum paracetamol <10mg/L
- ALT normal
- INR = 1.3
Describe the signs & symptoms someone with paracetamol overdose may present with
Initially may have:
- Asymptomatic
- Vomitting
- RUQ pain
Later on may have:
- Jaundcie
- Encephalopathy
- Asterixis
- Hepatomegaly
- Loin pain (due to significant AKI)
What blood investigations would you order for someone with suspected paracetamol overdose?(7) For each investigation state why you want it
- Paracetamol level: to help guide treatment
- LFTs: to check for liver enzymes
- INR: to check liver function
- FBCs:
- U&Es: to check for AKI
- VBG: to check for acidosis
- Glucose: check hypoglycaemia
Discuss the management of an acute paracetamol overdose, in which pt took all tablets within 1 hour, and presents ___ hours after event:
- = 8hrs
- 8-24hrs
- >/= 24hrs
= 8hrs
- Consider activated charcoal if presented within 1hr of overdose in SELECTED pts
-
Wait 4 hrs, check plasma paracetamol concentration then see if above treatment line for N-acetylcysteine IV
- NOTE: if pt ingested >150mg/kg and there will be delay of >8hrs for blood resuls start NAC
8-24hrs
- >150mg/kg start NAC
- <150mg/kg await bloods and treat if above line
>/= 24hrs
- If clincial suspicion of hepatoxicity start NAC
- Otherwise await bloods and treat if paracetamol detectable, ALT raised or INR >1.3
Discuss the management of a staggered paracetamol overdose
- Start NAC (DO NOT WAIT FOR BLOODS)
- Check bloods (when it has been at least 4hrs since last paracetamol)
- Discontinue NAC if hepatoxicity unlikely
Explain how N-acetylcysteine is administered
3 bags, of varying concentration, given IV over a 21hr period:
- 1st bag (150mg/kg in 200mL) over 1hr
- 2nd bag (50mg/kg in 500mL) over 4hrs
- 3rd bag (100mg/kg in 1L) over 16hrs
Combine with 5% glucose or 0.9% saline- but check trust guidelines & toxbase. Check toxbase for details.
Discuss the management of a paracetamol overdose following initial 21hr NAC regime
- Recheck INR, LFTs, U&Es
- If INR = 1.3 & ALT normal consider stopping NAc
- If INR >1.3 or rising or ALT rising continue NAC & re-check bloods in 8-16hrs
What advice do you need to give to a pt who had a paracetamol overdose on discharge?
- Avoid paracetamol for 2 weeks
- Return to hospital if: jaundice, abod pain or vomitting
If a pt has consumed alcohol aswell as their paracetamol overdose, does this give a better or worse prognosis?
Better prognosis as alcohol and paracetamol use same liver enzymes hence compete for enzymes and less of toxic NAPQI builds up in system.
What would the LFTs show in parcetamol overdose:
- ALT
- ALP
- Gamma GT
- Bilrubin
- ALT= markedly raised
- ALP= normal or raised
- Gamma GT= normal orraised
- Bilirubin= nomral or raised
Summary from uni day
