Statin-associated myopathy with normal creatine kinase levels

Area of Science:

• Neurology
• Biochemistry
• Pathology

Background:

• Statin therapy is widely used for cardiovascular disease prevention.
• Muscle symptoms are a known side effect of statins, but the underlying mechanisms are not fully understood, especially when creatine kinase levels are normal.

Observation:

• This study reports on four patients experiencing muscle symptoms during statin treatment.
• These symptoms, including weakness, improved upon cessation of statin therapy and recurrence upon re-challenge.
• Patients could distinguish between blinded statin and placebo treatments.

Findings:

• Muscle biopsies revealed significant myopathy with signs of mitochondrial dysfunction, such as increased lipid stores and abnormal staining.
• These histopathological changes reversed in patients after discontinuing statins.
• Crucially, all patients exhibited normal creatine kinase levels despite demonstrable muscle damage.

Implications:

• The findings suggest that statin-induced myopathy can occur with normal creatine kinase levels.
• This highlights the importance of considering muscle biopsy for diagnosis in patients with unexplained muscle symptoms during statin therapy.
• Further research into mitochondrial dysfunction as a mechanism for statin-induced myopathy is warranted.