Acute fatty liver of pregnancy

Acute fatty liver of pregnancy is a rare life-threatening complication of pregnancy that occurs in the third trimester or the immediate period after delivery. It is thought to be caused by a disordered metabolism of fatty acids by mitochondria in the fetus, caused by long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency. This leads to decreased metabolism of long chain fatty acids by the feto-placental unit, causing subsequent rise in hepatotoxic fatty acids in maternal plasma. The condition was previously thought to be universally fatal, but aggressive treatment by stabilizing the mother with intravenous fluids and blood products in anticipation of early delivery has improved prognosis. Acute fatty liver of pregnancy (or hepatic lipidosis of pregnancy) usually manifests in the third trimester of pregnancy, but may occur any time in the second half of pregnancy, or in the puerperium, the period immediately after delivery. On average, the disease presents during the 35th or 36th week of pregnancy. The usual symptoms in the mother are non-specific including nausea, vomiting, anorexia (or lack of desire to eat) and abdominal pain; excessive thirst may be the earliest symptom without overlap with otherwise considered normal pregnancy symptoms; however, jaundice and fever may occur in as many as 70% of patients. In patients with more severe disease, pre-eclampsia may occur, which involves elevation of blood pressure and accumulation of fluid (termed oedema). This may progress to involvement of additional systems, including acute kidney failure, hepatic encephalopathy, and pancreatitis. There have also been reports of diabetes insipidus complicating this condition. Many laboratory abnormalities are seen in acute fatty liver of pregnancy. Liver enzymes are elevated, with the AST and ALT enzymes ranging from minimal elevation to 1000 IU/L, but usually staying in the 300-500 range. Bilirubin is almost universally elevated. Alkaline phosphatase is often elevated in pregnancy due to production from the placenta, but may be additionally elevated.