Statin Associated Autoimmune Myonecrosis: Case Report With Delayed Onset and Treatment Challenges

Area of Science:

• Immunology
• Neurology
• Pharmacology

Background:

• Statin-associated autoimmune myopathy (SAAM) is a rare condition.
• Delayed onset SAAM can occur even after prolonged statin use.

Observation:

• A 54-year-old male developed proximal weakness and dysphagia upon restarting atorvastatin.
• Initial symptoms and elevated creatine kinase (CK) levels suggested myopathy.
• Positive anti-HMGCR antibodies confirmed the diagnosis of SAAM.

Findings:

• The patient experienced recurrent relapses despite initial treatment with corticosteroids and IVIG.
• Triple combination therapy, including rituximab, was necessary to achieve sustained remission.
• Complete remission was maintained for over six months with a combination of corticosteroids, rituximab, and IVIG.

Implications:

• This case highlights the importance of considering delayed SAAM in patients with unexplained myopathy, especially after statin re-initiation.
• Early identification and aggressive, multi-agent immunosuppressive therapy are crucial for managing recurrent SAAM.
• Rituximab may be a valuable addition to standard therapy for refractory or relapsing cases of SAAM.