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Difficulty: MediumGastroenterology and Hepatology

A 51-year-old woman visits her primary care provider due to severe, unrelenting itchiness and worsening fatigue that has developed over the past eight months. She notes that her pruritus is particularly bothersome at night. The patient has no history of alcohol consumption, illicit drug use, or recent travel. Her body mass index is 24 kg/m224 \text{ kg/m}^2. Vital signs are within normal limits. On physical examination, there is mild hepatomegaly, widespread skin excoriations, and hyperpigmentation. There is no ascites, splenomegaly, or palpable abdominal mass.

Laboratory testing shows:
- Total bilirubin: 2.5 mg/dL2.5 \text{ mg/dL}
- Direct bilirubin: 2.1 mg/dL2.1 \text{ mg/dL}
- Alkaline phosphatase: 610 U/L610 \text{ U/L}
- Aspartate aminotransferase (AST): 48 U/L48 \text{ U/L}
- Alanine aminotransferase (ALT): 52 U/L52 \text{ U/L}
- Antimitochondrial antibody (AMA): Positive (1:320)

An abdominal ultrasound demonstrates a normal-sized gallbladder and no intrahepatic or extrahepatic biliary ductal dilation.

Which of the following is the most appropriate initial medical therapy to slow the progression of this patient's underlying condition?

  1. Ursodeoxycholic acidAnswer
  2. B
    Oral glucocorticoids
  3. C
    Cholestyramine
  4. D
    D-penicillamine
  5. E
    Intravenous piperacillin-tazobactam

Answer

Ursodeoxycholic acid
The correct answer is ursodeoxycholic acid. This patient's presentation of fatigue, severe pruritus, hepatomegaly, and a cholestatic laboratory pattern (markedly elevated alkaline phosphatase with relatively normal aminotransferases), along with a positive antimitochondrial antibody (AMA), is highly characteristic of primary biliary cholangitis (PBC). PBC involves the autoimmune destruction of the small intrahepatic bile ducts. Ursodeoxycholic acid is a hydrophilic bile acid that is the first-line disease-modifying therapy for PBC. It works by replacing more toxic endogenous bile acids, thereby protecting cholangiocytes from ongoing autoimmune injury, delaying disease progression, and improving transplant-free survival.

Step-by-Step Solution

1
Analyze the patient's symptoms and physical examination findings.
The patient has chronic fatigue, severe pruritus, and hepatomegaly without signs of acute infection or decompensated cirrhosis.
These findings suggest a chronic liver or biliary disorder rather than an acute inflammatory process.
2
Interpret the laboratory and imaging results.
Labs show a cholestatic pattern (markedly elevated alkaline phosphatase with normal transaminases), a positive AMA, and an ultrasound showing no biliary dilation.
The absence of biliary dilation rules out extrahepatic obstruction. Intrahepatic cholestasis with a positive AMA is highly specific for primary biliary cholangitis (PBC).
3
Determine the appropriate disease-modifying treatment for the diagnosed condition.
Ursodeoxycholic acid is the treatment of choice to slow disease progression in PBC.
It alters the bile acid pool to become less toxic, thereby reducing ongoing damage to the intrahepatic bile ducts.

Key Concept

Primary biliary cholangitis is an autoimmune disease causing intrahepatic cholestasis (elevated alkaline phosphatase, positive AMA) and is treated with ursodeoxycholic acid to slow disease progression.
Estimated Time:1m 15s
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Topics

Gastroenterology and Hepatology

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