Internal medicine multiple choice question with explanation (FCPS, MRCP, USMLE, PLAB)

A 53-year-old woman presents complaining of fatigue over the past 6 months. During this time, she has also developed pruritus and lost 4 pounds. She is not sexually active, and her past medical history is significant only for Sjögren syndrome.
On physical examination, she is afebrile and has mildly icteric sclera. There are excoriations noted on all four extremities and trunk and back. The liver edge is smooth and non-tender and measures 9 cm at the midclavicular line. There is no ascites, splenomegaly, or peripheral edema.
Laboratory results reveal a normal complete blood count, normal electrolytes, and liver function tests with an alkaline phosphatase of 260 U/L (normal, <110 U/L), total bilirubin of 3.1 mg/dL, and normal transaminase levels. Which of the following is the most likely diagnosis?
a) Acute cholecystitis
b)Acute hepatitis A infection
c)Bacterial cholangitis
d)Primary biliary cirrhosis
e)Primary sclerosing cholangitis 


Explanation:
The correct answer is D.
This woman has a classic presentation of primary biliary cirrhosis. It typically affects middle-aged women and will progress gradually to the point of end-stage liver disease over a number of years. The disease is due to an autoimmune destruction of intrahepatic bile ductules, and the diagnosis is made by liver biopsy. The serology that should be checked is the antimitochondrial antibody. Primary biliary cirrhosis is often seen in individuals with other autoimmune diseases, such as Sjögren syndrome, pernicious anemia, and Hashimoto thyroiditis.
Acute cholecystitis (choice A) presents acutely with right upper quadrant pain and fever and not with chronic fatigue and pruritus.
Acute hepatitis A (choice B) may cause jaundice and fatigue, but it is a self-limiting infection and does not last 6 months.
Cholangitis (choice C) is due to acute obstruction of the common bile duct and presents urgently with fever, right upper quadrant pain, and jaundice (Charcot's triad).
Primary sclerosing cholangitis (choice E) is a sclerosing process of the extra- and intrahepatic ducts, which usually presents in young males with underlying inflammatory bowel disease.