Conclusion
A patient presenting with ongoing symmetrical muscle weakness after statin discontinuation with elevated CK levels should have anti-HMG-CoA reductase antibodies checked. Together with positive anti-HMGCR and supporting evidence of MRI or muscle biopsy consistent with necrotizing myopathy, the diagnosis of statin-induced IMNM is highly suspicious. This should lead to the initiation of immunosuppressive therapy and long-term follow-up.