S5567 An Atypical Case of Acute Fatty Liver of Pregnancy: A Case Report

Introduction: Acute fatty liver in pregnancy (AFLP) typically occurs in the third trimester and is caused by microvesicular fatty infiltration of hepatocytes. It can be diagnosed using the Swansea criteria which includes clinical presentation (e.g., vomiting and abdominal pain) and laboratory findings (e.g., hyperbilirubinemia and hypoglycemia). We present an atypical case of AFLP in a patient who did not meet the Swansea criteria but improved rapidly after giving birth. Case Description/Methods: A 27-year-old woman presents at 35 weeks’ gestation with abdominal pain, nausea, vomiting, and worsening liver enzymes. She denied pruritus. During her first trimester, she had normal liver enzymes; however, they started to rise around her third trimester with aspartate aminotransferase (AST) 190 U/L and alanine aminotransferase (ALT) 349 U/L. She denied recent travel, sick contacts, or use of antibiotics. Viral hepatitis and autoimmune serologies were negative. Her serum bile acids were elevated at 33.8 µmol/L. Her liver enzymes continued to rise peaking at AST 626 U/L, ALT 972 U/L, and alkaline phosphatase 203 IU/L. Her platelet count, creatinine, PT/international normalized ratio, glucose, ammonia, leukocyte count, and total bilirubin remained normal. Due to the continued rise of her liver enzymes, a prompt decision for induction of labor was made. Maternal liver enzymes after birth significantly improved. Her infant was found to have rising AST/ALT and hypoglycemia prompting transfer to a higher level of care. MRI/MRCP in the mother was normal. Genetic testing for deficiency in long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) was positive in the mother and infant. Discussion: AFLP is a rare but serious complication of pregnancy which can lead to both maternal and fetal mortality. It is traditionally diagnosed when meeting 6 or more of the Swansea criteria. Our case highlights a patient who only met 3 of the diagnostic criteria but who clinically worsened during her hospitalization. The differential for elevated liver enzymes in pregnancy includes AFLP, viral hepatitis, cholestasis of pregnancy, autoimmune hepatitis, and HELLP syndrome. Serologic workup was negative except for her serum bile acids. However, the absence of symptoms such as pruritus and the hepatocellular pattern of liver enzymes suggested an alternative process. The diagnosis of AFLP in this case is supported by the rapid improvement in liver enzymes after birth, infant hypoglycemia, and deficiency in LCHAD. Cognizance of atypical presentations of AFLP can expedite workup and prevent mortality of the mother and the fetus.