Keywords

FormalPara Pearls and Pitfalls

  • Acute liver failure is a common pathway for many conditions and insults, leading to massive hepatic necrosis and/or loss of normal hepatic function.

  • Transaminases can be elevated secondary to many intra- and extrahepatic causes.

  • The level of transaminitis should not be the sole determinant in management and disposition.

  • Patients with acute liver failure should be considered for early transfer to a liver transplant center, ideally prior to elevation in intracranial pressure or the development of severe coagulopathy.

When Does Transaminitis Become Acute Hepatic Failure?

Transaminases (aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) are frequently obtained in the acute care setting [1,2,3]. Non-toxicological causes of elevated transaminases include infection, ischemia, metabolic derangement, malignancy, autoimmune disease, and primary graft failure after transplant [1].

Acute Hepatic Failure

Non-toxicological causes of acute liver failure are listed in Table 69.1 [1]. Toxicological causes of acute liver failure are listed in Table 69.2 [1]. Viral hepatitis is the most common cause of acute liver failure worldwide, while acetaminophen is the most common cause of acute liver failure in the United States [3]. Acute liver failure is a common pathway for many conditions and insults, leading to massive hepatic necrosis and/or loss of normal hepatic function.

Table 69.1 Non-toxicological causes of acute liver failurea
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Table 69.2 Toxicological causes of acute liver failurea
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Acute liver failure can be classified into subgroups by acuity of encephalopathy. Hyperacute liver failure is encephalopathy within 1 week of jaundice onset. Acute liver failure is encephalopathy within 8–28 days of jaundice onset. Subacute liver failure is encephalopathy within 5–12 weeks of jaundice onset [4, 5].

Complications

Each subgroup has its own set of complications. Hyperacute and acute liver failure have an increased incidence of cerebral edema, but hyperacute liver failure patients are more likely to survive with supportive care, and acute liver failure patients are more likely to die without liver transplant. Subacute liver failure patients have increased mortality, less cerebral edema, and increased likelihood of portal hypertension, leading to ascites and renal failure [5].

Other complications from acute liver failure include [5]:

  • Bleeding (including exsanguination)

  • Cardiovascular derangements

  • Pulmonary and ventilatory derangements

  • Central nervous system dysfunction (temperature dysregulation causing hypothermia, disruption of the blood-brain barrier, and increased intracranial pressure leading to encephalopathy)

  • Metabolic derangements

  • Infection

The higher the number of complications, the more likely the patient will not survive [1].

Overall, outcomes have improved due to earlier identification of causes, earlier initiation of treatment, improved intensive care, and improved transplant science. Formerly, mortality was 55–95%, and now mortality is 30–40% [4, 6].

Laboratory Abnormalities

Liver failure generally results in laboratory abnormalities beyond transaminitis. Blood work in acute liver failure may show [1, 7]:

  • Synthetic dysfunction, which is usually the first sign of impending liver failure – decreased albumin and clotting factor levels, increased coagulation profiles

  • Defects in gluconeogenesis – decreased serum glucose

  • Worsening toxicant metabolism – increased ammonia

  • Decreased hepatic excretory function – increased bilirubin

  • Decreased renal function – elevated creatinine from prerenal azotemia, acute tubular necrosis, and/or hepatorenal syndrome

Table 69.3 reviews the utility of labs , imaging, and other ancillary tests in the evaluation of potential acute hepatic failure [1, 3, 8].

Table 69.3 Initial diagnostic testing in fulminant hepatic failure
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Non-hepatic Transaminitis

In the appropriate clinical setting , elevations in AST and ALT should prompt the clinician to consider rhabdomyolysis and order a creatinine kinase level. Rhabdomyolysis-induced transaminitis occurs secondary to AST (and some ALT) release from muscle breakdown. In the past, ALT was considered liver-specific, but ALT elevations may occur in patients with myopathy but no liver disease [9]. Hypoperfusion from other medical issues can lead to transaminitis as well.

Prognostication

The King’s College Criteria is used to determine potential for liver transplant in both acetaminophen toxicity and other causes of acute liver failure.

The King’s College Criteria for acetaminophen toxicity suggests transplant if [4, 10]:

  • pH <7.3 (irrespective of other factors)

  • Grade III–IV encephalopathy (Table 69.4) and protime >100 s and serum creatinine >3.4 mg/dL

Table 69.4 Stages of clinical hepatic encephalopathy
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The King’s College Criteria for non-acetaminophen toxicity suggests transplant if [4, 10]:

  • PT >35 s

  • INR >7.7

  • Any three of the following:

    • Age <10 or >40 years old

    • Unfavorable etiology (non-A and non-B hepatitis, idiosyncratic drug reaction, halothane hepatitis, Wilson’s disease)

    • Serum bilirubin >17 mg/dL

    • Time from jaundice to encephalopathy >7 days

    • INR >4

The Acute Physiology and Chronic Health Evaluation III Score (APACHE III Score) may also identify those in need of liver transplant [11].

What Is the Management of Transaminitis and Acute Hepatic Failure?

Transaminitis

Initial management of acute transaminitis includes fluid resuscitation, pain management, and nausea management. Generally, the cause of transaminitis will determine treatment and disposition. Transaminase values alone do not determine disposition. Admission is recommended for higher-risk (elderly and pregnant) patients or when there is no response or poor response to supportive care. It is also recommended for bilirubin ≥20 mg/dL, PT >50% above normal, hypoglycemia, spontaneous bacterial peritonitis, new or worsening hepatic encephalopathy, hepatorenal syndrome, or coagulopathy with bleeding. Additionally, the patient should be admitted if the he or she cannot ambulate safely or if there is an unsafe home condition. Any patient with acetaminophen toxicity (using the Rumack-Matthew nomogram) should be admitted, even if the transaminases and coagulation factors are normal [8].

Acute Hepatic Failure

Patients with acute liver failure should be considered for early transfer to a liver transplant center, ideally prior to intracranial pressure elevation or development of severe coagulopathy [1]. Prophylactic treatment of coagulopathy is unnecessary. Fresh frozen plasma or factor VII should be given if there is active bleeding or before invasive procedures [12]. Patients with grade IV encephalopathy generally require intubation. Providers should elevate the head of bed to 10–20 ° and consider avoiding positive end-expiratory pressure if possible (grade III recommendation) [13]. With cerebral edema, intracranial pressure monitoring and decompression may be necessary.

Antidotes and Specific Treatments

Specific antidotes exist for acetaminophen toxicity (n-acetylcysteine) and for Amanita mushroom poisoning (silibinin and intravenous penicillin G). Shock liver will improve with the restoration of perfusion. Herpes causing transaminitis can be treated with acyclovir. Acute Budd-Chiari syndrome (thrombosis of the hepatic veins) can be treated with transjugular intrahepatic portosystemic shunt (TIPS), surgical decompression, or thrombolysis. Autoimmune hepatitis can be treated with steroids. Idiosyncratic drug-induced transaminitis can be treated with withdrawal of the drug. Rechallenge of the drug should not be performed unless there is no alternate therapy [1].

Suggested Resources

  • Interpretation of liver function tests. (2013). http://www.oscestop.com/LFT_interpretation.pdf.

  • Bernal W, Wendon J. Acute liver failure. N Engl J Med. 2013;369:2525–34.

  • Farkas S, Hackl C, Schlitt HJ. Overview of the indications and contraindications for liver transplantation. Cold Spring Harb Perspect Med. 2014;4