Review Note

• A rare but potentially fatal complication of late pregnancy, with an estimated maternal mortality of 10-20% and perinatal mortality of 20-30%.

Pathophysiology:

• Caused by abnormal oxidation of mitochondrial fatty acids and LCHAD deficiency, leading to a buildup of long fatty acids incorporated into triglycerides within hepatocytes.
• This results in microvesicular deposition and infiltration in the liver.
• Mitochondrial dysfunction causes hepatocyte failure.

Clinical Features:

• Presentation after 30 weeks gestation.
• Early prodromal illness lasting 1-2 weeks with RUQ discomfort and general malaise, followed by worsening abdominal pain, anorexia, nausea, and vomiting.
• Liver function abnormalities: 3-10x increase in transaminases and raised ALP.
• Jaundice and 50% of patients show features of preeclampsia (PET), though proteinuria and hypertension are usually mild.

Investigations & Diagnosis:

• Can be confused with HELLP syndrome but AFLP tends to cause a greater rise in bilirubin, leading to jaundice not typically seen in other pregnancy-related liver diseases.
• Liver biopsy is the gold standard but risky due to coagulopathy. It is only used when the diagnosis is unclear, and delivery will not be delayed. The biopsy findings include:
  • Microvesicular fatty infiltration
  • Fibrin deposition
  • Hemorrhage
• Swansea criteria for diagnosis, requiring ≥6 criteria in the absence of another cause:
  • Vomiting
  • Polydipsia/polyuria
  • Abdominal pain
  • Encephalopathy
  • Elevated bilirubin (>14umol/L)
  • Elevated urea (>340umol/L)
  • Hypoglycemia (<4mmol/L)
  • Leucocytosis (>11x10^9/L)
  • Ascites or bright liver on ultrasound
  • Elevated ammonia (>47umol/L)
  • Elevated transaminases (AAT or ALT >42 IU/L)
  • Renal impairment (Cr >150umol/L)
  • Coagulopathy (PT >14 or APTT >34s)
  • Microvesicular steatosis on liver biopsy.

Management:

• Supportive care is essential.
• Expeditious delivery of the baby improves outcomes, with rapid reversal of clinical and lab abnormalities.
• Correction of coagulopathy and treatment of hypoglycemia.
• Careful fluid balance.
• In severe cases, the patient may require ICU admission for ventilation and dialysis.
• Liver transplantation may be considered for patients with fulminant hepatic failure and encephalopathy.

Anaesthesia and AFLP:

• Balancing risks between general anesthesia (GA) and regional anesthesia (RA):
  • GA may worsen or confuse encephalopathy.
  • RA may not be appropriate in those with worsening coagulation.
• Postoperative analgesia is challenging:
  • Paracetamol (normal doses) is typically safe in liver disease.
  • NSAIDs are contraindicated due to antiplatelet function and potential renal dysfunction.
  • Opioid clearance may be impaired.