A 59-year-old woman comes to the physician for a routine health maintenance examination. She feels well. She has systemic lupus erythematosus and hypertension. She does not drink alcohol. Her current medications include lisinopril and hydroxychloroquine. She appears malnourished. Her vital signs are within normal limits. Examination shows a soft, nontender abdomen. There is no ascites or hepatosplenomegaly. Serum studies show: Total bilirubin 1.2 mg/dL Alkaline phosphatase 60 U/L Alanine aminotransferase 456 U/L Aspartate aminotransferase 145 U/L Hepatitis A IgM antibody negative Hepatitis A IgG antibody positive Hepatitis B surface antigen positive Hepatitis B surface antibody negative Hepatitis B envelope antigen positive Hepatitis B envelope antibody negative Hepatitis B core antigen IgM antibody negative Hepatitis B core antigen IgG antibody positive Hepatitis C antibody negative Which of the following is the most appropriate treatment for this patient?

Pegylated interferon alpha therapy

Referral to a liver transplantation center

A 62-year-old woman with a history of hypertension, hyperlipidemia, and rheumatoid arthritis presents for evaluation of elevated serum liver chemistries. She has had three months of intense, unremitting itching. Current medications include chlorthalidone, atorvastatin, and ibuprofen. Physical exam is unremarkable. Laboratory studies show aspartate aminotransferase (AST) 42 units/L, alanine aminotransferase (ALT) 39 units/L, alkaline phosphatase 790 units/L, total bilirubin 0.8 mg/dL, and antimitochondrial antibody titer 1:80. What do you expect to see on liver biopsy?

Intrahepatic bile duct destruction

Bile plugging of hepatocytes and bile ducts

Intrahepatic and extra hepatic bile duct destruction

Lymphoplasmacytic and eosinophilic infiltration of portal tracts

A 42-year-old woman presents complaining of pain in her hands. She reports that the pain is in both hands, and that it is usually worse in the morning. She reports that her hands are also stiff in the morning, but that this gradually improves throughout the morning. She notes, however, that her symptoms seem to be getting worse over the last three months. What is the most likely pathogenesis of her disease process?

Production of antibodies against antibodies

Production of antibodies against smooth muscle

Anti-neutrophil cytoplasmic antibody production

Type 1 hypersensitivity reaction

A 44-year-old woman presents to the emergency department with jaundice and diffuse abdominal pain. She denies any previous medical problems and says she does not take any medications, drugs, or supplements. Her temperature is 97.6°F (36.4°C), blood pressure is 133/87 mmHg, pulse is 86/min, respirations are 22/min, and oxygen saturation is 100% on room air. Physical exam is notable for sclera which are icteric and there is tenderness to palpation over the right upper quadrant. Laboratory studies are ordered as seen below. Hepatitis B surface antigen: Positive Hepatitis B surface antibody: Negative Hepatitis B core antibody IgM: Negative Hepatitis B core antibody IgG: Positive Hepatitis B E antigen: Positive Hepatitis B E antibody (anti-HBe): Negative Which of the following is the most likely diagnosis?

No hepatitis B vaccination or infection

A 32-year-old woman comes to the physician with increasing jaundice and fatigue for the past week. She has no history of a serious illness. She takes no medications and denies use of recreational drugs. She does not drink alcohol. Her vital signs are within normal limits. Her body mass index is 21 kg/m2. On physical examination, she has icteric sclera. Otherwise, her heart and lung sounds are within normal limits. Hemoglobin 15 g/dL Leukocyte count 6,000/mm3 with a normal differential Serum bilirubin Total 6.5 mg/dL Direct 0.9 mg/dL Alkaline phosphatase 70 U/L Aspartate aminotransferase (AST, GOT) 430 U/L Alanine aminotransferase (ALT, GPT) 560 U/L γ-Glutamyltransferase (GGT) 43 U/L (N=5-50 U/L) Hepatitis A antibody Negative Hepatitis B surface antigen Negative Hepatitis C antibody Negative Rheumatoid factor 80 IU/mL (N=0-20 IU/mL) Antinuclear antibody (ANA) titer is 1:1280. Polyclonal immunoglobulin gamma is 5 g/dL. Which of the following antibodies is most likely to be positive in this patient?

Anti-cyclic citrullinated peptide

Anti-liver kidney microsomal type 2

A 47-year-old Caucasian woman presents with a 2-month history of general fatigue, slight jaundice, and mild itching. She has also noticed that her urine has been darker and stools have been lighter in color recently. She denies any fevers, chills, or alcohol use. She has no significant past medical or surgical history and is not taking any medications. She recalls that her mother saw a doctor for eye and mouth dryness but cannot remember the name of her diagnosis. She denies any illicit drug use, recent change in diet, or recent travel. On physical exam, her abdomen is soft and non-distended. There is right upper quadrant tenderness to deep palpation but a negative Murphy’s sign. Her laboratory findings were significant for increased liver enzymes, direct bilirubin, and alkaline phosphatase with normal levels of iron and ceruloplasmin. Ultrasound revealed no stones in the gallbladder or common bile duct and endoscopic retrograde cholangiopancreatography (ERCP) revealed normal extrahepatic biliary ducts. Which of the following findings is most likely to also be found in this patient?

Anti-neutrophilic cytoplasmic antibodies (ANCA)

Autoimmune hepatitis for USMLE Step 1: High-Yield Internal Medicine Lessons

Overview & Pathophysiology - The Liver's Civil War

Chronic, unresolving liver inflammation from immune-mediated hepatocyte destruction.
Pathogenesis: Loss of self-tolerance, leading to a T-cell-mediated attack on liver autoantigens.
- Genetic predisposition is key (HLA-DR3, HLA-DR4).
- Environmental triggers (e.g., viruses, drugs) may initiate the process.
Histological hallmark: Interface hepatitis (piecemeal necrosis) with a dense lymphoplasmacytic infiltrate.

Histopathology of Autoimmune Hepatitis

⭐ Autoimmune hepatitis frequently coexists with other autoimmune disorders (e.g., autoimmune thyroiditis, rheumatoid arthritis, ulcerative colitis).

Clinical Features - Jaundice & Friends

Presentation: Highly variable; from asymptomatic ↑ aminotransferases to acute hepatitis or even fulminant hepatic failure.
Common Symptoms: Insidious onset of fatigue (most frequent complaint), malaise, anorexia, RUQ pain.
Physical Exam: Jaundice, hepatosplenomegaly, spider angiomata, and abdominal striae.
Extrahepatic Features: Common, reflecting systemic autoimmunity.
- Migratory, non-deforming arthralgia.
- Co-existing autoimmune disorders: Thyroiditis, IBD, celiac disease.

⭐ Suspect in young to middle-aged women presenting with liver disease alongside other autoimmune conditions (e.g., thyroiditis, rheumatoid arthritis).

Diagnosis & Workup - The Antibody Hunt

Initial Labs: Predominantly hepatocellular pattern (↑↑ ALT/AST), with possible ↑ total bilirubin & ALP.
Hallmark Finding: ↑ total IgG level (hypergammaglobulinemia).
Autoantibody Panel is Key:
- Type 1 (Adults): ANA and/or ASMA (Anti-Smooth Muscle Antibody).
- Type 2 (Children): Anti-LKM-1 (Liver/Kidney Microsomal) and/or Anti-LC1 (Liver Cytosol).

Histology of Autoimmune Hepatitis with Interface Hepatitis

⭐ Exam Favourite: Liver biopsy is definitive, revealing a classic triad:

Interface hepatitis (piecemeal necrosis)

Lobular hepatitis

Prominent lymphoplasmacytic infiltrate (plasma cells are characteristic).

Treatment - Calming the Storm

Primary Goal: Induce biochemical and histological remission to prevent progression to cirrhosis.
Induction Therapy: Prednisone (or budesonide for non-cirrhotic, milder disease) ± Azathioprine (AZA).
- AZA is a steroid-sparing agent, crucial for long-term management.
Maintenance: Continue therapy for at least 24 months after remission, often lifelong.
Refractory/Intolerant cases: Switch to second-line agents like Mycophenolate Mofetil (MMF) or Tacrolimus.

⭐ Always test for Thiopurine S-methyltransferase (TPMT) enzyme activity before initiating Azathioprine. Deficiency can lead to severe, life-threatening myelosuppression.

High‑Yield Points - ⚡ Biggest Takeaways

Primarily affects young to middle-aged women and is often associated with other autoimmune conditions.

Presents with acute hepatitis-like symptoms; suspect in patients with unexplained ↑↑ aminotransferases.

Key serological markers include hypergammaglobulinemia (↑ IgG), (+) ANA, and (+) anti-smooth muscle antibodies (ASMA) for Type 1.

Liver biopsy is essential for diagnosis, revealing characteristic interface hepatitis and plasma cell infiltration.

Initial treatment is with corticosteroids (prednisone) with or without azathioprine.

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