Acute fatty liver of pregnancy (AFLP) is a relatively rare but very serious complication of pregnancy that typically occurs in the latter half of the third trimester or occasionally after delivery.
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Histologically, AFLP is due to fatty degeneration of the liver cells by microvesicles of fat, in the absence of hepatocellular inflammation or necrosis. Occurring in only 1 in 10-15 000 pregnant women, it used to claim a high maternal and fetal mortality of 75% and 90%, respectively.
However, current treatment protocols have successfully brought this rate down to 7% and 15% respectively, primarily due to the adoption of prompt delivery of the mother with better management of preterm neonates.
The pathogenesis is still unknown, but the incidence is highest between 35-36 weeks, though a few cases have occurred with AFLP being diagnosed as early as 22 weeks. Risk factors for AFLP include primiparity, a multiple gestation, and a male fetus.
Clinically, AFLP is characterized by jaundice, nausea and vomiting, epigastric pain due to stretching and irritation of the liver capsule, fever, malaise, and headache. The upper abdomen is usually tender to the touch, either in the central area or the right side.
Serious complications occur in about a third of these cases, and may be predicted by a rise in total and direct bilirubin and prothrombin time (PT). With progressive or severe disease, the patient develops multiorgan breakdown, including hepatorenal failure, encephalopathy, bleeding into the gut, pancreatitis and pancreatic pseudocyst formation with secondary infection, retroperitoneal bleeding from the pancreas, and coagulopathy.
Preeclampsia and hypertension are also relatively common. Metabolic acidosis, hypoglycemia, and intrauterine fetal distress are all too often observed to occur in this condition.
Diagnosis and management
The Swansea criteria are currently used to diagnose this condition and distinguish it from other lookalike conditions, including the HELLP syndrome, severe preeclampsia, viral hepatitis, and intrahepatic cholestasis of pregnancy. Liver biopsy provides the definitive diagnosis but is rarely employed since it requires normal coagulation function.
The principles of management of AFLP are timely delivery of the pregnant woman, with comprehensive medical support in an intensive care setting, with a good recovery typically occurring once the fetus is delivered. The major causes of a fatal outcome for the mother include sepsis, hemorrhage, acute renal failure, pancreatitis, and aspiration. Almost 70% of babies born to mothers with AFLP are preterm, due to the decision to deliver the baby once there is a high degree of suspicion of this diagnosis.
Delivery is usually vaginal, unless the condition of the fetus and mother are rapidly deteriorating. In such a situation, the mother is stabilized first, and emergency operative delivery is performed. Intensive care unit admission is mandatory to prevent maternal death, if the patient shows any signs of developing multiorgan involvement.
Supportive medical management includes keeping the airway open, normalizing the blood pressure, intravascular volume and metabolic parameters, including the blood glucose and electrolytes. Blood transfusions should be given if required. Frequent and careful monitoring is necessary since progression of the condition is often wayward and rapid.
Liver transplantation is performed in the rarest of cases, but may bring about immediate resolution. Only a few indications exist, such as failure to recover from fulminant hepatic failure following delivery of the fetus with intensive medical support, or if the patient shows hepatic encephalopathy, metabolic acidosis or progressive coagulation failure. Liver rupture with necrosis of liver cells is another indication if observed on CT scanning.