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Acute Liver failure

Section: Hepatobiliary Sub-section: Liver Curriculum: Curriculum, page 72, Curriculum, page 87

Definition

Acute liver failure refers to the development of severe acute liver injury with impaired synthetic function (INR of ≥1.5) and altered mental status in a patient without cirrhosis or preexisting liver disease

Causes

  • Acetaminophen (paracetamol)
  • Idiosyncratic drug reactions
  • Viral hepatitis
    • Hepatitis A, B, C, D, and E.
    • Herpes simplex virus (HSV), varicella zoster virus, Epstein-Barr virus, adenovirus, and cytomegalovirus
  • Autoimmune hepatitis
  • Wilson disease
  • Ischemic hepatopathy
  • Budd-Chiari syndrome
  • Veno-occlusive disease
  • Acute fatty liver of pregnancy/HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome
  • Malignant infiltration (most often breast cancer, small cell lung cancer, lymphoma, melanoma, or myeloma)
  • Hepatectomy
  • Toxin exposure, including mushroom poisoning
  • Sepsis
  • Heat stroke
  • Hemophagocytic lymphohistiocytosis (primarily a disorder of children

Post-operatively

  • Hepatic insufficiency following liver resection
    • Liver has capacity to rapidly regenerate. Preexisting overcapacity of several functions.
    • Critical minimum residual liver volume ~25%
    • Difficult to determine true liver function and who is at risk of failure.
    • Poor correlation between volume and function.
    • Risk factors: chemotherapy, hepatic steatosis
    • Short term ischaemia/reperfusion
      • Unclear but may enhance resistance to subsequent injury or negatively effect a liver with where defence mechanism against oxidative stress are deficient
      • Unclear if 15/5 min Pringle manoeuvre is beneficial.
  • Monitoring
    • Postop transplanted liver
    • Trends in clinical status and bloods more important than absolute values.

Clinical

  • Confusion (encephalopathy), loss of consciousness
  • Jaundice (over a few days)
  • Hypoglycaemia
  • Coagulopathy (bruising/bleeding)

Scoring system

Schindl score

  • Postop hepatic dysfunction
Total bilirubin
< 200
21-601
>602
Prothrombin time (sec above normal)
<40
4-61
>62
Serum lactate
<1.50
1.6-3.51
>3.52
Encephalopathy (West Haven criteria)
None0
1 & 21
3 & 42
Severity: None = 0; mild 1-2; mod 3-4; severe > 4

King’s College Criteria

  • Purpose: To identify patients with ALF who are unlikely to survive without liver transplant
  • Separate criteria for:
    • Paracetamol-induced ALF
      • Arterial pH < 7.3 (regardless of other values)
      • OR all of:
        • INR > 6.5
        • Creatinine > 300 µmol/L
        • Grade III or IV encephalopathy
    • Non-paracetamol-induced ALF
      • INR > 6.5 regardless of other factors
      • OR three of the following:
        • Age <10 or >40
        • Aetiology: non-A, non-B hepatitis, halothane, idiosyncratic drug reaction
        • Duration of jaundice before encephalopathy >7 days
        • INR > 3.5
        • Bilirubin > 300 µmol/L

Investigations

Blood tests

  • Prothrombin time/INR.
  • Serum chemistries (sodium, potassium, chloride, bicarbonate, blood urea nitrogen, creatinine, glucose, calcium, magnesium, phosphate, lactate dehydrogenase).
  • Liver blood tests (AST, ALT, alkaline phosphatase, GGT, total and direct bilirubin, albumin).
  • Complete blood count with differential.
  • Acetaminophen level.
  • Blood and urine toxicology screen including phosphatidylethanol testing.
  • Viral hepatitis serologies (anti-hepatitis A IgM, hepatitis B surface antigen, anti-hepatitis B core IgM, anti-hepatitis C virus antibodies, hepatitis C RNA, HSV type 1 and type 2 DNA polymerase chain reaction [PCR], varicella zoster virus DNA PCR, Epstein-Barr virus [EBV] DNA PCR, anti-viral capsid antigen IgM, antiviral capsid antigen IgG, anti-EBV nuclear antigen, cytomegalovirus [CMV] DNA PCR, anti-CMV virus antibodies; anti-hepatitis E IgM in patients who are pregnant).
  • Serum pregnancy test in females of childbearing potential who are not already known to be pregnant.
  • Autoimmune markers (antinuclear antibody, antismooth muscle antibody, anti-liver/kidney microsomal antibody type 1, anti-liver soluble antigen, immunoglobulin levels).
  • Arterial blood gas.
  • Arterial ammonia
  • Serologic testing for HIV.
  • Amylase and lipase

Imaging:  - To look for Budd-Chiari syndrome or malignancy

Biospy

  • If testing fails to identify cause

Test of liver function

  • Biochemical
    • INR
    • Alb
    • LFTs
    • Bili
    • Ammonia
  • Functional
    • Indigo cyanine green
    • Lidocaine clearance test
  • Radiological
    • Ascite
    • Spleen
    • Varicies
    • Liver
  • Clinical
    • Enchalopathy
    • Ascites
    • Varcies
    • Hepatic flap

Management

  • Supportive care
  • Vitamin K
  • Albumin
  • Hepatic encephalopathy
    • Lactulose
      • Decrease ammonia in 3 ways
          1. Increases colonic transit and decreases uptake
          1. Increases ammonia uptake by colonic bacteria due to the reduced pH
          1. Reduces intestinal production of ammonia as it is preferably metabolised by bacteria compared to glutamine and therefore less amonia production
  • Liver transplant

Graph View

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