Acute Fatty Liver Of Pregnancy

Acute fatty liver of pregnancy (AFLP) is a rare, life threatening third trimester disorder with microvesicular fatty infiltration of the liver and acute liver failure.

• Incidence 1 in 7,000 to 20,000 pregnancies. Risk factors are first pregnancy, multiple gestation, male fetus, low BMI, pre eclampsia.
• Fetal long chain 3 hydroxyacyl CoA dehydrogenase (LCHAD) deficiency (G1528C mutation) in the fetus overloads maternal mitochondrial beta oxidation with toxic fatty acid metabolites.
• Onset at 30 to 38 weeks, rarely postpartum.
• Maternal mortality now 2 to 10%, fetal 10 to 20%.
• Complications: hypoglycaemia, coagulopathy, DIC, renal failure, pancreatitis, encephalopathy.

• Nausea, vomiting, anorexia, epigastric or right upper quadrant pain, malaise.
• Jaundice develops after a few days, with polyuria and polydipsia (transient diabetes insipidus).
• Hypoglycaemia, hypertension (50%), ascites, encephalopathy, bleeding.
• Overlap with HELLP syndrome and pre eclampsia.

Swansea criteria (6 or more in the absence of another cause): vomiting, abdominal pain, polydipsia or polyuria, encephalopathy, raised bilirubin (above 14 µmol/L), hypoglycaemia (under 4 mmol/L), raised urate (above 340 µmol/L), leucocytosis (above 11 x 10^9/L), ascites or bright liver on ultrasound, raised transaminases (above 42 U/L), raised ammonia (above 47 µmol/L), renal impairment (creatinine above 150 µmol/L), coagulopathy (PT above 14 s or aPTT above 34 s), microvesicular steatosis on biopsy.

• Features: low antithrombin, prolonged PT, elevated INR, low fibrinogen, low platelets.
• Imaging has low sensitivity. Biopsy is rarely needed (coagulopathy).
• Exclude viral hepatitis, HELLP, intrahepatic cholestasis, Budd Chiari, drug injury, acute liver failure causes.
• Screen the newborn and mother for LCHAD deficiency.

• Prompt delivery after maternal stabilisation, regardless of gestation (vaginal delivery if feasible; caesarean for obstetric reasons).
• Intensive care: IV glucose (10% dextrose infusion to keep glucose above 4 mmol/L), correct coagulopathy with fresh frozen plasma, cryoprecipitate, platelets and vitamin K 10 mg IV.
• N acetylcysteine infusion (150 mg/kg over 1 hour, then 12.5 mg/kg/h for 4 hours, then 6.25 mg/kg/h) is used for liver failure.
• Treat hypertension, renal failure (dialysis if needed), seizures (magnesium sulphate), infection.
• Plasma exchange for refractory cases. Liver transplant for progressive failure after delivery.
• Recovery occurs within days to weeks after delivery. Neonatal screening and care for LCHAD deficiency (frequent feeds, medium chain triglyceride diet).
• Recurrence is uncommon (10 to 20%), and higher with LCHAD carrier status. Counsel and monitor future pregnancies.