Introduction: Fulminant hepatic failure (FHF) is a true medical emergency. It's defined as a potentially reversible condition as a consequence of severe liver injury in which encephalopathy develops within four to eight weeks of the onset of first symptoms in the absence of preexisting liver disease. A major insult usually viral or toxic in origin, prompts the massive destruction of hepatocytes. Clinically this manifests as coagulopathy and encephalopathy with disturbances of metabolic and excretory functions of the liver like hypoglycemia, metabolic acidosis, and jaundice. It may lead to multi-organ failure.

Management: The management of acute liver failure includes:

• Assessment of prognosis for liver transplantation.
• Prevention of complications while awaiting hepatic regeneration on a donor liver
• Hepatic support

Investigations carried out are liver function tests, renal function tests, base line hematological tests, septic screen and radiological tests. Besides these diagnostic investigations are carried depending on the age of the child and the suspected etiology of the child. These viral serology, PCR's of viruses such as CMV, EBV, HSV etc, autoantibodies, Wilson 's screening, urine aminoacidogram, succinylacetone etc.
Priorities of intensive care management should include airway breathing and circulation. In patients with worsening encephalopathy (Grade III, IV) and cerebral edema, increasing oxygen requirement, early acute respiratory distress syndrome (ARDS), or shock with or without multi-organ failure, endotracheal intubation and mechanical ventilation should be considered.
A central venous catheter will be required for assessment of central venous pressure and volume status. An indwelling arterial line for measurement of blood pressure for biochemical and acid-base monitoring is essential. A nasogastric tube is put in with regular gentle saline lavage to detect upper gastrointestinal bleed. The urinary bladder is catheterized and strict output record maintained.
The complications of acute liver failure are numerous and include: sepsis, gastrointestinal bleeding, cerebral edema, renal and cardiac failure. Gastro-intestinal bleeding is frequent and may be prevented by using H2 antagonists, proton pump inhibitors, and sucralfate. The role of broad spectrum antibiotics in the prevention of infection is controversial but there is growing evidence that the use of prophylactic antibiotics leads to a decrease in bacterial infections, fever deaths and shortened hospital stay. The use of N-acetylcysteine, which is particularly useful in paracetamol poisoning, has anecdotal success in the management of acute liver failure.

Hepatic Encephalopathy and Cerebral Edema Hypoxemia, hypoglycemia, sepsis, hypokalemia, and gastrointestinal bleeding exacerbate hepatic encephalopathy and should be identified and treated. Lactulose is given to maintain loose stools. Neomycin may also be helpful. More than 75-80 percent of patients, especially in stage 4 hepatic encephalopathy develop cerebral edema. Fluid restriction (50% maintenance) and the use of intravenous mannitol (0.5 g/kg over 4-6 hours) may be helpful in the short term. Serum osmolarity should not exceed 320 mOsm/l during mannitol therapy.
    Convulsions should be promptly treated with phenytoin or phenobarbitone or thiopentone infusion.

Coagulopathy and FHF
It is not necessary to maintain coagulation parameters (PT) in the normal range. In general mild to moderate coagulopathy (PT<30s) requires no therapy except support for procedures.

Respiratory complication of FHF
There are many respiratory problems which can complicate FHF. These include respiratory depression, hypoventilation, aspiration, pneumonia, ARDS, intrapulmonary hemorrhage, and intrapulmonary shunts.

Renal failure and FHF
Renal failure develops in more than 50% of patients with acute liver failure. Typically the renal failure is secondary to hepatorenal syndrome. Renal failure is sometimes due to acute tubular necrosis or drug toxicity. Hemodialysis or continuous arteriovenous hemofiltration may be indicated. Thus the development of renal failure in FHF should not preclude transplantation.

Metabolic abnormalities and FHF
Hypoglycemia is commonly seen in FHF. Other electrolyte abnormalities include hyponatremia, hypokalemia, hypomagnesemia and hypophosphatemia. FHF patients are extremely catabolic, hence the need for early nutritional supplementations.

Specific Therapies in FHF
Therapy is mainly supportive. Specific therapies are available for a limited number of causes of FHF which are enumerated in table below:

N-acetylcysteine	-	Acetaminophen toxicity
Acyclovir	-	Herpes zoster
Ganciclovir	-	CMV
P.V.Decompression	-	Budd Chiari Syndrome
Steroids	-	Autoimmune hepatitis
Silibinin	-	Amanita Phalloides toxicity
Antioxidant cocktail	-	Neonatal Hemochromatosis
N.T.B.C.	-	Tyrosinemia

Hepatic support in FHF
Recent research in hepatic failure has focused on the concept of hepatic support. Initial trial with techniques such as human cross-circulation, plasma exchange plasmapheresis, and charcoal hemoperfusion have shown no significant survival benefit.
     The most recent development of the Extracorporeal Liver Assist Device (ELAD) (33, 34) or Bioartificial Liver (BAL) is similar in technique to hemodialysis and uses liver cell lines placed in hollow perfusable cartridges. Recent advances include the application of MARS (Molecular Adsorbent Recirculating System) in patients of hepatic failure especially as a bridge to liver transplantation. MARS system is an extracorporeal non-biological liver support method based on the principle of dialysis, filtration and adsorption that is it's a combination both kidney and liver dialysis. MARS uses human albumin to cleanse the blood because it can attract toxin bound to albumin in the blood that the aqueous solution in kidney dialyses cannot remove.

Orthotopic liver transplantation in FHF
The only proven therapy for FHF in liver transplantation (OLT). The most frequently used criteria for selection of patients for OLT are King's College criteria.

(A) For other causes
     PT> 100 sec.
     Or any 3 of the following
     PT> 50 sec.
     Bil> 17.5 mg%
     Age <10 years

• Cryptogenic or drug induced
  
• Jaundice for more than 7 days before onset of encephalopathy

(B) For acetaminophen poisoning
     Arterial pH <7.3
     Or the following 3 factors
     PT PT> 100 sec.
     Bil Creatinine> 3.5 mg%
     Grade III or IV encephalopathy

• Cryptogenic or drug induced
  
• Jaundice for more than 7 days before onset of encephalopathy

Liver transplantation could be:

• Cadaveric
  
? Whole graft-when the whole liver is used
? Split graft-when the donor liver is used for recipients.
? Reduced related when the donor liver is reduced to suit the size for recipient
• Living related when a live donor gives part of his/her liver to the recipient.
  Survival post liver transplantation for acute liver failure has improved and most recipients can expect a 70 percent, 5-year survival.

Pedgastro 2005 - Conference Abstracts.Pediatric Oncall [serial online] 2006 [cited 15 March 2006(Supplement 3)];3. Available from:
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Management_of_fulminant_heaptic_failure.asp