Rare condition that occurs in the third trimester of pregnancy in which there is a rapid accumulation of fat within the liver cells causing acute hepatitis

Pathophysiology

• Acute fatty liver of pregnancy results from impaired processing of fatty acids in the placenta
• This is the result of a genetic condition in the fetus that impairs fatty acid metabolism
  • The most common cause is long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency in the fetus, which is an autosomal recessive condition

Clinical features

The presentation is with vague symptoms associated with hepatitis:

• General malaise and fatigue
• Nausea and vomiting
• Jaundice
• Abdominal pain
• Anorexia (lack of appetite)
• Ascites

Investigations

• Bloods:
  • Liver function tests will show elevated liver enzymes (ALT and AST)
    • Acute fatty liver vs obstructive cholestasis: in AFL ALT/AST will be more elevated, in obstructive cholestasis ALP will be more elevated
  • Other bloods may be deranged, with:
    • Raised bilirubin
    • Raised WBC count
    • Deranged clotting (raised prothrombin time and INR)
    • Low platelets

Management

• Acute fatty liver of pregnancy is an obstetric emergency and requires prompt admission and delivery of the baby
• Most patients will recover after delivery
• Management also involves treatment of acute liver failure if it occurs, including consideration of liver transplant