Statin-Induced Necrotizing Autoimmune Myopathy (SINAM): A Case Report

Purpose

Statins are widely recognized for their efficacy in reducing cardiovascular risk through cholesterol reduction. Their use, however, is occasionally associated with adverse muscular effects, ranging from mild myalgias to statin-induced necrotizing autoimmune myopathies (SINAM). SINAM presents a significant clinical challenge due to persistent muscle weakness and elevated creatine kinase (CK) levels, even after statin withdrawal.

Methods

We explored the diagnostic journey of a 69-year-old African-American male with a history of extensive statin use, who presented with progressive muscular weakness and exceptionally high CK levels. A multidisciplinary diagnostic approach was employed, involving comprehensive laboratory testing, electromyography, muscle biopsy, and advanced imaging techniques. The diagnosis of SINAM was confirmed by identifying anti-HMGCR antibodies.

Results

Despite cessation of statin therapy, the patient's muscular symptoms persisted, with laboratory tests revealing remarkably elevated CK levels. The initiation of immunosuppressive therapy, including corticosteroids and intravenous immunoglobulin, led to a gradual improvement in muscle strength and a decrease in CK levels. However, the recovery journey highlighted the chronic nature of SINAM, necessitating ongoing management and careful consideration of long-term immunosuppressive treatment strategies.

Conclusion

This case report emphasizes the critical need for heightened vigilance and a high index of suspicion among healthcare providers when patients present with unexplained muscle weakness and elevated CK levels following statin use. Early and accurate diagnosis of SINAM, followed by the prompt initiation of immunosuppressive therapy, is paramount in preventing irreversible muscle damage and optimizing patient outcomes. Future research should focus on elucidating the precise mechanisms underlying SINAM, identifying at-risk populations, and developing targeted treatment protocols.