Immune-mediated necrotizing myopathy: an emerging disorder

Area of Science:

• Neurology
• Immunology
• Rheumatology

Background:

• Immune-mediated necrotizing myopathy (IMNM) is a rare autoimmune disorder.
• Statins are frequently associated with IMNM development.
• Accurate diagnosis and timely management are essential for patient outcomes.

Purpose of the Study:

• To characterize the clinical features of IMNM patients.
• To describe the diagnostic and management strategies employed.
• To evaluate trends in IMNM diagnosis.

Main Methods:

• Observational, monocentric, retrospective study.
• Analysis of 16 IMNM patients diagnosed between 2013-2021.
• Review of clinical data, autoantibody profiles, and treatment responses.

Main Results:

• Median age of diagnosis was 71.5 years, with a female predominance (56.3%).
• 81.3% of patients had prior statin exposure.
• Anti-3-hydroxy-3-methyl-coenzyme A reductase (HMGCR) antibodies were detected in 13 patients (81.3%).
• Proximal muscle weakness and myalgia were the most common symptoms.
• Corticosteroids were the primary treatment, with 50% requiring additional immunosuppressants.

Conclusions:

• IMNM diagnoses have increased in recent years.
• Anti-HMGCR antibodies are key diagnostic markers for IMNM.
• Early diagnosis and prompt treatment, often involving combination immunosuppression, are vital for effective management.