[Toxic hydroxychloroquine-induced cardiomyopathy complicating systemic lupus treatment]

Area of Science:

• Cardiology
• Toxicology
• Rheumatology

Background:

• Hydroxychloroquine (HCQ) is a widely used medication for systemic lupus erythematosus (SLE).
• While generally considered safe, HCQ can have rare but severe adverse effects.
• Cardiac toxicity is an underrecognized complication of long-term HCQ therapy.

Observation:

• A 72-year-old woman with SLE on long-term HCQ treatment developed cardiomyopathy and conductive disorders post-kidney transplant.
• Endomyocardial biopsy revealed myocardial fibrosis and vacuolated myocytes.
• Electron microscopy identified curvilinear bodies and pseudomyelin figures, characteristic of HCQ toxicity.

Findings:

• The patient's cardiac condition was consistent with HCQ-induced cardiomyopathy.
• Immunohistochemistry showed impaired autophagy (accumulation of LC3b, p62, beclin-1) in cardiac myocytes.
• This suggests a cellular mechanism contributing to HCQ cardiotoxicity.

Implications:

• Clinicians should consider HCQ-induced cardiomyopathy in patients with SLE experiencing unexplained cardiac disease during long-term HCQ therapy.
• Diagnostic endomyocardial biopsy is crucial for identifying this potentially fatal adverse effect.
• This case underscores the importance of monitoring cardiac health in patients on long-term HCQ treatment.