Fulminant Hepatic Failure

Fulminant Hepatic Failure

27/10/10

FANZCA Part II Notes

SP Liver Transplantation Notes

PY Mindmaps

Irwine and Rippe

= rapid onset of encephalopathy in conjunction with hepatic synthetic failure.

CAUSES (DAVES)

Drugs – paracetamol, idiosyncratic, illicit, herbal/alternative (amanita mushroom), halothane

Alcohol –

Viruses –HAV, HBV, HCV, CMV, EBV, HSV,

Extras –acute fatty liver of pregnancy, HELLP, toxins, ischaemic necrosis, vascular, metabolic, autoimmune, Wilson’s disease, Budd-Chiari, post hepatic surgery, idiopathic

Sepsis

HEPATIC ENCEPHALOPATHY

- sleep disturbance

- asterixis

- hyper-reflexic

- can be hemiplegic

- precipitating factor: GIH, infection, hypokalaemia, sedatives, increased protein intake, progressive hepatic dysfunction, renal failure

- types: A = acute liver failure, B = presence of portocaval shunting, C = in context of cirrhosis

- grade I -> IV: mildly drowsible but rousable and coherent -> responding to pain/unconscious

INVESTIGATIONS

- elevated ammonia (not required to make diagnosis of encephalopathy)

- urine and serum toxicology screen

- hepatitis serologies

- ceruloplasmin

- antinuclear antibodies

- smooth-muscle antibiodies

- serum protein electrophoresis

- CMV and EBV serology

- serum phosphate: decrease suggestive of hepatocyte recovery and regeneration -> good prognostic marker

MANAGEMENT

Resuscitation

A – intubated if unresponsive from encephalopathy (RSI to prevent aspiration)

B – often have respiratory failure from pleural effusions and may have aspirated requiring mechanical ventilation

C –fluid maintenance, often have a hyperdynamic circulation, vasoactive medication

D – monitoring for intra-cranial hypertension: ICP bolt, mannitol, propofol, thiopentone, moderate hypothermia (32-33 C), hypertonic saline

Once stabilized early consultation with Liver Transplant Centre

Vigilant monitoring for infection (bacterial, fungal)

Treatment

Specific

- paracetamol OD: N-acetylcysteine 150mg/kg LD, 50mg/kg over 4 hours, 100mg/kg over 16 hours

- Amanita poisoning: penicillin

- acute fatty liver of pregnancy: delivery of infant and placenta

- Wilson’s disease: zinc and trientine therapy, apheresis

- Acute Budd-Chiari: TIPS, surgical decompression, thrombolysis -> transplantation

- HSV: acyclovir

- ischaemic: restore circulation to liver

- encephalopathy: lactulose -> increases ammonia elimination, metronidazole -> alter gut flora to decrease ammonia production, flumazenil (controversial)

- coagulopathy: only treat with FFP if bleeding or prior to procedures, FVIIa safe and effective

- NAC: continue until encephalopathy resolves

- TIPS procedure (decrease portal hypertension and ascites)

- short-term extracorporeal hepatic support (MARS):

- ‘liver dialysis’

- Molecular Absorbent Recirculating System: detoxification method based on albumin dialysis

- can be used as a bridge to transplantation (experimental)

- requires two separate dialysis circuits

- limited case series shows some benefit in paracetamol OD

- contraindicated in active bleeding and coagulopathy

- expensive

- not available outside specialist centres.

CRITERIA FOR TRANSPLANTATION (King’s College Criteria)

Paracetamol induced fulminant hepatic failure

- pH < 7.3 or INR > 6.5 (PT > 100s)

+

- Cr > 300micromol/L

+

- grade III or IV encephalopathy

Non-paracetamol induced fulminant hepatic failure

- INR > 6.5 (PT > 100s) or any 3 of the following variables:

(1) age < 10 or > 40 yrs

(2) aetiology – non A, non B hepatitis, halothane hepatitis, idiosyncratic drug reactions

(3) duration of jaundice before encephalopathy > 7 days

(4) INR > 3.5 (PT > 50s)

(5) bilirubin > 300micromol/L

General

- electrolyte balance (hypokalaemia, hyponatraemia, hypophosphataemia)

- Na+ restriction + diuretics -> decreases ascites

- frequent glucose monitoring (hypoglycaemia)

- nutrition (amino acids, lipids, glucose, essential elements)

- renal failure is common (especially in paracetamol OD -> direct renal toxic effects)

- feed

Disposition

- management in ICU

- early discussion with liver transplant unit (prior to reversal of coagulopathy)

- discussion with family (high mortality)

COMPLICATIONS

- cerebral oedema and herniation

- coagulopathy

- GI bleed

- sepsis

- renal failure

- hypoglycaemia

- electrolyte abnormalities

- respiratory failure: impaired ventilation c/o coma, pleural effusions, ARDS, intra-pulmonary shunts, aspiration, sepsis

CONTROVERSIAL ISSUES

- targeted CPP management with insertion of an ICP monitor

- MARS therapy

- use of FVIIa

Jeremy Fernando (2011)