What is the best course of action for a patient with dermatomyositis, elevated liver enzymes, and a positive HBV (Hepatitis B Virus) core antibody, who is currently on prednisone and Vrlmidy (Tenofovir), despite normal liver biopsy and MRCP (Magnetic Resonance Cholangiopancreatography) results?

Management of Elevated Liver Enzymes in Dermatomyositis with HBV Core Antibody Positivity

Continue prednisone and IVIG for dermatomyositis while maintaining tenofovir (Vrlmidy) for HBV prophylaxis, and attribute the elevated liver enzymes to dermatomyositis-associated liver involvement rather than drug toxicity, given the normal liver biopsy and negative autoimmune hepatitis workup. 1

Primary Cause: Dermatomyositis-Associated Liver Disease

• Liver enzyme elevation in dermatomyositis represents "liver disease associated with rheumatoid diseases" rather than drug-induced hepatotoxicity or autoimmune hepatitis, particularly when liver biopsy shows no significant pathology and autoimmune liver markers are negative. 1

• The predominant liver-type alkaline phosphatase isoenzyme confirms hepatic origin but does not indicate specific liver pathology requiring treatment modification. 1

• Dermatomyositis-associated liver involvement typically responds to corticosteroid therapy for the underlying inflammatory myopathy, with normalization of liver enzymes paralleling improvement in muscle disease. 1, 2

HBV Management Strategy

Prophylactic antiviral therapy with tenofovir must be continued indefinitely while on immunosuppression because:

• Patients receiving rituximab or high-dose corticosteroids who are HBV core antibody positive require prophylactic antiviral therapy regardless of HBsAg status, with treatment continuing for at least 12-18 months after stopping immunosuppression. 3, 4

• The American College of Rheumatology strongly recommends prophylactic antiviral therapy over monitoring alone for all patients on rituximab or high-dose immunosuppression who are anti-HBc positive, due to high reactivation risk. 3

• Tenofovir (or entecavir) should be started before initiating immunosuppression and continued throughout therapy to prevent potentially fatal HBV reactivation. 4, 5

Critical Management Algorithm

Step 1: Confirm the liver enzyme elevation is stable or improving with current therapy

• Monitor ALT, AST, alkaline phosphatase, and bilirubin every 4-8 weeks while on immunosuppression. 3
• Expect gradual normalization of liver enzymes as dermatomyositis responds to prednisone and IVIG. 1, 2

Step 2: Continue current immunosuppressive regimen without modification

• Maintain prednisone taper as planned for dermatomyositis control. 3, 1
• Continue IVIG therapy given documented clinical improvement. 1
• Do not discontinue or reduce immunosuppression based solely on elevated liver enzymes when liver biopsy is normal. 1

Step 3: Maintain HBV prophylaxis throughout immunosuppression

• Continue tenofovir without interruption during entire course of prednisone and IVIG therapy. 3, 4
• Monitor HBV DNA and HBsAg every 1-3 months during immunosuppression to detect any breakthrough reactivation. 6, 4
• Plan to continue tenofovir for at least 12-18 months after completing all immunosuppressive therapy. 4

Step 4: Monitor for drug-induced hepatotoxicity from prednisone (unlikely given normal biopsy)

• Persistent elevation ≥3-fold upper limit of normal for >12 months would warrant gastroenterology consultation. 3
• Declining serum albumin below normal range in well-nourished patient would require further evaluation. 3
• Neither scenario applies here given normal liver biopsy and improving clinical status. 1

Key Pitfalls to Avoid

Do not stop or reduce immunosuppression prematurely:

• Glucocorticoid withdrawal in HBV-positive patients with dermatomyositis can precipitate both disease flare and HBV reactivation. 5, 2
• The normal liver biopsy excludes significant hepatotoxicity requiring treatment modification. 1

Do not discontinue HBV prophylaxis:

• Stopping tenofovir while on high-dose corticosteroids risks fulminant hepatitis B reactivation, which can be fatal. 4, 5
• HBV core antibody positivity alone (even with negative HBsAg) requires prophylaxis during rituximab or high-dose steroid therapy. 3

Do not misattribute liver enzyme elevation to drug toxicity:

• Dermatomyositis itself commonly causes transaminase elevation through muscle and liver inflammation. 1, 2
• Normal liver histology excludes significant drug-induced liver injury or autoimmune hepatitis. 1

Monitoring Strategy Going Forward

• Check ALT, AST, alkaline phosphatase, bilirubin, and albumin every 4-8 weeks during active immunosuppression. 3

• Monitor HBV DNA and HBsAg every 1-3 months to detect reactivation early. 6, 4

• Expect liver enzymes to normalize as dermatomyositis responds to therapy, typically within 3-6 months of adequate immunosuppression. 1, 2

• Gastroenterology consultation is indicated only if liver enzymes remain >3-fold elevated for >12 months or albumin declines despite adequate nutrition. 3