Acute Fatty Liver of Pregnancy
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Direct answer
Nausea, vomiting, abdominal pain and jaundice progressing to hypoglycaemia, coagulopathy, encephalopathy and renal failure in late pregnancy characterise acute fatty liver of pregnancy (AFLP) — a rare, potentially fatal microvesicular fatty infiltration of hepatocytes occurring in the third trimester or immediately postpartum. Diagnosis is clinical, supported by the Swansea criteria (six or more features), and management is intensive supportive care with delivery of the fetus without delay — usually by caesarean section — alongside correction of glucose, coagulation and fluid balance. It is associated with fetal long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency, which explains both recurrence risk and the neonatal screening implication.
What you must remember
- Typical patient — a primigravida (often with a male fetus or twins) in the third trimester, presenting with a few days of anorexia, nausea, vomiting, upper abdominal pain and malaise; jaundice and fever may follow.
- Swansea criteria — six or more of fifteen features: vomiting, abdominal pain, polydipsia or polyuria, encephalopathy, bilirubin above 14 micromol/L, hypoglycaemia below 4 mmol/L, high urate, urea and creatinine impairment, leucocytosis over 15, ascites or bright liver on ultrasound, elevated AST, raised ammonia, renal impairment, coagulopathy with INR over 1.4, and microvesicular steatosis on biopsy — a favourite structured answer.
- Biochemical signature — low glucose, low fibrinogen with high INR and APTT (a DIC-like picture, unlike the thrombocytopenia-dominant HELLP), raised ammonia, transaminases usually below 1000, and deranged renal function.
- Association with fetal LCHAD (long-chain 3-hydroxyacyl-CoA dehydrogenase) deficiency — maternal disease is triggered by fetal fatty acid metabolites; recurrence can occur and affected neonates need metabolic work-up.
- Distinguish from HELLP — AFLP has marked coagulopathy, hypoglycaemia, encephalopathy and ascites with modest transaminase rises and often absent hypertension; haemolysis is the HELLP hallmark.
- Management — stabilise, then deliver promptly (caesarean commonly chosen for speed, vaginal if labour advanced and the mother stable); anaesthetic care avoids hepatotoxins, and regional techniques are limited by coagulopathy.
- Supportive pillars — glucose infusions, fresh frozen plasma, cryoprecipitate and platelets, correction of acidosis, renal support, and intensive monitoring; plasma exchange and, rarely, liver transplantation are salvage options.
- Prognosis — maternal mortality has improved with early recognition but remains significant; survivors recover fully as liver function normalises over days to weeks.
From symptom to delivery in a real timeline
A 27-year-old primigravida at 36 weeks reports five days of vomiting and right-upper-quadrant pain; she looks ill, is mildly jaundiced, and her blood pressure is 138/88 with trace proteinuria. Initial bloods: glucose 2.8 mmol/L, bilirubin 60 micromol/L, AST 280 U/L, creatinine 1.6 mg/dL, platelets 130,000, INR 1.8, fibrinogen 1.2 g/L, ammonia raised. Counting Swansea features — vomiting, abdominal pain, jaundice, hypoglycaemia, high urate, renal impairment, coagulopathy, high transaminases — she crosses six easily.
Two actions run in parallel. First, stabilisation: 10 per cent dextrose for hypoglycaemia, vitamin K and blood products for the coagulopathy, and strict fluid balance with a urinary catheter. Second, the definitive therapy — delivery. With an unfavourable cervix and a sick mother, caesarean section under carefully chosen anaesthesia (general if coagulopathy precludes regional) proceeds once products are running, not after the laboratory "normalises", because the liver recovers only when the pregnancy ends.
Postpartum is the critical window: coagulopathy and encephalopathy may deepen for 48-72 hours, she stays in intensive care with glucose, product and renal support, and liver trends are followed daily. If she deteriorates despite delivery, plasma exchange and transplant referral follow. Once she recovers, two pieces of counselling close the episode — recurrence risk in future pregnancies, and testing the baby for fatty-acid oxidation defects, since an affected fetus is what triggered her disease.
How the exam frames it
Stems contrast AFLP with HELLP and viral hepatitis: the pregnant woman with low glucose, low fibrinogen and encephalopathy is AFLP; the hypertensive woman with haemolysis, high LDH and platelets under 100,000 is HELLP; transaminases in the thousands with positive serology suggest hepatitis. The number six — Swansea features needed — and the LCHAD fetal enzyme link are the two recalled facts, followed by the management answer: stabilise and deliver, do not wait. A viva favourite is why the biopsy is rarely done — the coagulopathy contraindicates it, and the diagnosis is clinical.
Frequently asked questions
How is acute fatty liver of pregnancy diagnosed?
Clinically, using the Swansea criteria — six or more features of liver failure with hypoglycaemia, coagulopathy and renal impairment in a woman in late pregnancy; biopsy is rarely required.
How does AFLP differ from HELLP syndrome?
AFLP shows marked hypoglycaemia, coagulopathy, encephalopathy and ascites with modest transaminase elevation and often no hypertension, whereas HELLP features haemolysis, thrombocytopenia and hypertension.
What is the definitive treatment of AFLP?
Prompt delivery of the fetus after initial stabilisation with glucose and blood products, combined with intensive supportive care — the liver recovers once the pregnancy ends.
Why is AFLP linked to a fetal enzyme defect?
Fetal long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency produces abnormal fatty acid metabolites that accumulate in and injure the maternal liver.