What is the exact gist and management of Acute Fatty Liver of Pregnancy (AFLP)?

Acute Fatty Liver of Pregnancy (AFLP): Causes and Management

Acute Fatty Liver of Pregnancy (AFLP) is a rare but potentially fatal condition characterized by hepatic failure typically in the third trimester that requires prompt recognition, immediate delivery, and comprehensive supportive care to reduce maternal and fetal mortality.

Pathophysiology and Epidemiology

• AFLP is a rare disorder occurring in the third trimester with an estimated incidence of 1/6,692-1/13,328 pregnancies 1
• The condition is characterized by microvesicular fatty infiltration of hepatocytes leading to hepatic failure 2
• There is a strong association between AFLP and fetal long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, suggesting a metabolic component 3
• Primigravidas and multiple gestations appear to have increased risk 4

Clinical Presentation

• Initial symptoms vary considerably, with nausea and vomiting (23%) being the most common presenting symptoms 5
• Other common presentations include:
  • Epigastric distress followed by jaundice 4
  • Features of pre-eclampsia such as hypertension and proteinuria 6
  • Coagulopathy and low platelets 6
  • Hypoglycemia (occurs in approximately 53% of cases and is characteristic) 3, 4

Diagnosis

• Diagnosis is based on the Swansea criteria, with ≥6 criteria highly correlating with clinical diagnosis 3
• Laboratory abnormalities include:
  • Elevated transaminases (ALT, AST) 5
  • Elevated direct bilirubin 5
  • Coagulation disorders (abnormal fibrinogen, D-dimer, and fibrin degradation products) 5
  • Lactic acidosis 6
• Imaging studies showing hepatic steatosis support the diagnosis 6
• Liver biopsy with Oil-red O staining can demonstrate hepatic steatosis but is rarely needed 6

Management Algorithm

Step 1: Maternal Stabilization

• Patients with AFLP who develop encephalopathy, elevated serum lactate (>2.8 mg/dl), MELD score >30, or Swansea criteria >7 should be admitted to intensive care 6, 3
• Correct coagulopathy and metabolic derangements before delivery 6, 3
• Monitor and treat hypoglycemia, which is common in AFLP 3

Step 2: Expedited Delivery

• Early recognition of AFLP and prompt delivery are critical in achieving good outcomes and constitute the definitive treatment 6
• Decisions about mode of delivery should be made jointly by obstetricians, hepatologists, and the multidisciplinary team 6
• Emergency cesarean section may be necessary in many cases 4

Step 3: Post-Delivery Management

• Recovery is typically rapid after delivery, with supportive care being the primary treatment 6
• Plasma exchange post-delivery may be considered to improve maternal disease severity and decrease recovery time in severe cases 6
• N-acetylcysteine may be considered in women requiring intensive care admission, although evidence is limited 6
• Monitor for complications including:
  • Hepatic encephalopathy 4
  • Renal failure 4
  • Postpartum hemorrhage 4
  • Disseminated intravascular coagulation 1

Step 4: Liver Transplantation Consideration

• In women with AFLP who have severe hepatic impairment, early referral to a transplant center should be made 6
• Postpartum transplantation has occasionally been necessary in severe cases 6

Prognosis and Follow-up

• With early diagnosis and prompt management, maternal mortality has decreased from as high as 80% to approximately 10% 2
• Ensure normalization of liver function tests within 3 months post-delivery 3, 7
• If liver function tests remain abnormal, investigate for underlying liver disease 7
• Newborns of mothers with AFLP should be screened for LCHAD deficiency 3

Differential Diagnosis

• HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) 6
• Preeclampsia 6
• Viral hepatitis 6
• Other causes of acute liver failure in pregnancy 6

Common Pitfalls and Caveats

• Delay in diagnosis may lead to rapid progression to hepatic failure, DIC, hemorrhage, encephalopathy, multiple organ failure, and death 1
• Prothrombin time (PT) and international normalized ratio (INR) are risk factors for fatal complications in patients with AFLP 5
• Perinatal mortality is linked to gestational age at delivery and levels of fibrin degradation products 5
• AFLP can be confused with HELLP syndrome; laboratory derangements provide distinct features to differentiate between these conditions 2