Chapter 66: Acute Liver Failure

CLINICAL PRESENTATION

• Symptoms may include nausea, vomiting, itching, fever.

• Signs may include encephalopathy, ascites, scleral icterus/jaundice.

• Though there are no strict diagnostic criteria, consider acute liver failure if all of these are present:

  • Hepatic failure within 8 weeks of onset of hepatic disease

  • Elevated serum AST, ALT, and/or bilirubin

  • Coagulopathy (PT >15, INR >1.5) does not correct with vitamin K

  • No prior history of chronic liver disease

  • Encephalopathy (confirmatory, not required)

ETIOLOGY

• Likelihood of various etiologies depends on age and geography

• Causes can be classified into the following categories:

  • Infectious

  • Metabolic

  • Autoimmune

  • Toxin or drug mediated

  • Indeterminate

  • Other

DIAGNOSTIC EVALUATION

• Physical exam: look for jaundice, encephalopathy, Kayser-Fleischer rings.

• History: ask about timing of symptom onset, family history, medications or recreational drugs, and fever.

• Serum labs: coagulation factors, complete metabolic panel, amylase, lipase, complete blood count, acetaminophen level, ammonia, lactate

• Secondary testing once diagnosis of acute liver failure is confirmed:

  • If cytopenia is present in two cell lines perform hemophagocytic lymphohistiocytosis (HLH) testing with ferritin, triglyceride, and fibrinogen.

  • If older than 5 years perform Wilson's disease testing with serum ceruloplasmin.

  • Viral hepatitis serology, viral PCR (herpes simplex virus [HSV], Epstein-Barr virus [EBV], cytomegalovirus [CMV], adenovirus, parvovirus, enterovirus)

  • Perform tests for specific genetic etiologies based on age of patient and newborn screening results.

• Liver biopsy may be indicated if etiology remains unknown.

MANAGEMENT

• Acute liver failure may lead to rapid systemic decompensation, so PICU admission is often appropriate.

• Frequently monitor for hyponatremia, hypoglycemia, hypokalemia, and hypophosphatemia.

• Manage fluids to avoid fluid overload. Consider continuous renal replacement therapy early in the treatment course.

• Routine monitoring of coagulation factors:

  • Give vitamin K one time to assess response in coagulopathy.

  • Empiric correction of coagulopathy with plasma infusion is not indicated, unless done prior to an invasive procedure.

• Respiratory support: respiratory failure requiring mechanical ventilation is common due to fluid overload, pulmonary edema or hemorrhage, encephalopathy, or sepsis.

• Frequently reassess the clinical exam, including assessment of encephalopathy staging. See Table 66-1.

• Neurologic care in early stages of hepatic encephalopathy (grades 0–II):

  • Head of bed elevated 30 degrees

  • Oxygen saturation >96%

  • Temperature control to maintain normothermia

  • Maintain adequate blood pressures to ensure good cerebral perfusion pressure (CPP)

  • Target serum sodium 145 to 150 mEq/L and serum osmolarity 300 to 320 mOsm/L with hypertonic saline

  • Baseline EEG

  • Obtain baseline head imaging to evaluate for cerebral edema (MR ventricle with diffusion weighted imaging [DWI]).

• Neurologic care when worsening clinical exam and/or hepatic encephalopathy grades III and IV:

  • Invasive intracranial pressure (ICP) monitoring can be considered, but there is risk of bleeding and lack of evidence it improves survival.

    • Mannitol and/or hypertonic saline may be used for acutely elevated ICP

    • CPP goal range 40 to 60 mmHg depending on age

  • Target PaCO₂ 35 to 40 mmHg using mechanical ventilation.

  • Active cooling to keep temperature <37.5°

• Monitor ...