Acute liver failure
Aetiology
- Paracetamol toxicity 50%
- Other drugs (esp. NSAIDs, anticonvulsants)
- Acute viral hepatitis (incl. Hep A)
- Acute deterioration in liver function (often previously normal) leading to encephalopathy and encephalopathy
- 50 % die or need transplant (less if acute on chronic dysfunction)
- Most develop SIRS (early treatment significanlty improves prognosis)
- Very rapid progress (time jaundice to encephalopathy < 8 days) relatively better prognosis (if no cerebral oedema)
Initial assessment
King’s College criteria for Liver Transplant in ALF
Paracetamol toxicity
- Lactate > 3.5 4 hrs after resuscitation
or
- pH< 7.30 or lactate > 3.0 12 hrs after resusc.
or
- INR > 6.5 (PT > 100 sec)
- Creat > 3.4 mg/dl
- Stage 3 or 4 encephalopathy
Non-paracetamol causes
- Lactate > 3.5 4 hrs after resuscitation
or
- INR > 6.5 (PT > 100 sec)
or
- any 3 of the following:
- INR > 3.5 (PT > 50 sec)
- Age <10 or > 40 years
- Serum bilirubin > 17.5 mg/dl
- Duration of jaundice > 7 days
- Etiology: drug reaction
Differntial DDx hepatic dysfunction and atlered mentation
- acutely decompensated chronic liver disease
- sepsis
N-acetylcysteine?
- Immediately indicate if ANY chance paracetamol toxicity
- Helps with repletion of hepatic glutathione and O2 delivery to cells
- Probably Indicated in most cases, irrespective of aetiology
Transfer to liver unit?
- Discuss potential cases early
- Beware INR > 2 or encephalopathy
- Extremes of age
- Early transplant being considered
- Beware HYPOGLYCAEMIA (ccontinue 5% dextrose)
- Beware airway (consider RSI and ETT in all) if encephalopathy
Complications
- SIRS and multiorgan failure often triggered by sepsis
- Immunocompromise (side effect ALF)
- Invasive lines, chest (bacterial or fungal), UTI (catheter)
- Clinical signs sepsis may be lacking
- Prophyllactic antibiotics indicated in most ALF
- Beware subtle, progressive airway compromise
- ARDS occurs in 1/3
- 1/4 develop cerebral oedema (? ammonia trigger)
Cerebral oedema
- Oedema more common in hyperacute ALF
- Consider ICP monitoring
- Nures 300 head up
- Prophylactic lactulose & antibiotics to reduce ammonia
- Opiate sedation realtively safe
- Actively treat pyrexia
- Monitor for and avoid hyponatraemia
- Mannitol (1 g/kg body weight) if worse confusion, serum osmolality is <320 mOsm/l, or high osmolar gap
- Seizures (atypical) very common in encephalopathy, phenytoin unproven
Other complications
- Vasodilation and hypoperfusion treated a per sepsis (response to crystalloid challenge +/- early inotropes)
- Beware adrenal failure
- Despite coagulation factor deficit and thrombocytopenia, bleeding only really with invasive procedures
- Prophylactic PPI (ulcer). Variceal haemorrhage rare!
- Acute renal failure (acute tubular necrosis +/or hepatorenal synd.) common (50%), esp. in paracetamol poisoning
- Renal repalcement therapy indicated for azotemia, volume overload, acidosis and electrolyte problems
- All above aggressively treated to try to prevent cerebral oedema
