A 45-year-old woman presents to the clinic with a 6-month history of fatigue, pruritus, and mild upper abdominal discomfort. She denies fevers, weight loss, or night sweats. Past medical history is unremarkable, and she does not take any medications. Vital signs are within normal limits. On physical examination, she is noted to have hepatomegaly and xanthelasma, but no jaundice. Laboratory tests reveal the following:
An abdominal ultrasound shows a normal common bile duct without evidence of extrahepatic biliary obstruction. Which of the following is the most appropriate next step in the management of this patient?
A) Check anti-mitochondrial antibodies
The patient presents with symptoms and laboratory findings suggestive of cholestasis, including fatigue, pruritus, and elevated alkaline phosphatase. The presence of xanthelasma, a sign of hyperlipidemia, further supports this. The ultrasound performed excludes extrahepatic biliary obstruction. The most appropriate next step is to check serum anti-mitochondrial antibodies to diagnose primary biliary cholangitis (PBC), a chronic liver disease characterized by autoimmune destruction of intrahepatic bile ducts.
Answer choice B: Check antinuclear antibodies, is incorrect. ANA testing is used to diagnose autoimmune conditions such as systemic lupus erythematosus and other connective tissue diseases. It is not specific for primary biliary cholangitis (PBC) and is not the most appropriate next step given this patient's presentation.
Answer choice C: Check anti-smooth muscle antibodies, is incorrect. Anti-smooth muscle antibodies are associated with autoimmune hepatitis, which typically presents with elevated transaminases (AST and ALT) rather than the cholestatic pattern seen in this patient (elevated alkaline phosphatase).
Answer choice D: Order a liver biopsy, is incorrect. While a liver biopsy can provide a definitive diagnosis, it is more invasive and not necessary as the first step. The presence of cholestasis and specific symptoms in a middle-aged woman suggests primary biliary cholangitis (PBC), which can be diagnosed with less invasive tests such as serum anti-mitochondrial antibodies.
Answer choice E: Prescribe oral ursodeoxycholic acid, is incorrect. Ursodeoxycholic acid is a treatment for PBC but should be prescribed after confirming the diagnosis. The first step is to obtain serum anti-mitochondrial antibodies to confirm the diagnosis of PBC.
Key Learning Point
In a patient with symptoms of cholestasis, elevated alkaline phosphatase, and no extrahepatic biliary obstruction on ultrasound, the next step is to check serum anti-mitochondrial antibodies to diagnose primary biliary cholangitis (PBC).
