Myofibrillit

Myofibrillit is a descriptive term used to denote inflammation or inflammatory damage affecting myofibrils, the contractile protein units (actin and myosin) within skeletal muscle fibers. It is not a single well‑defined disease but a histopathological finding that can occur in several clinical contexts, including infectious myositis, autoimmune inflammatory myopathies, toxin‑induced injury, and as a secondary change in some muscular dystrophies.

Clinically, myofibrillit may present with muscle pain, weakness, swelling, reduced range of motion, and functional impairment. Laboratory findings can include elevated serum creatine kinase and inflammatory markers. Electromyography, muscle magnetic resonance imaging, and laboratory testing for infectious or autoimmune causes can guide evaluation. Definitive identification typically relies on muscle biopsy, which shows inflammatory cell infiltrates, myofibrillar disruption, and sometimes necrosis or regeneration of fibers.

Management focuses on treating the underlying cause: antimicrobial therapy for infections, immunosuppressive or immunomodulatory treatments for autoimmune conditions, removal of offending drugs or toxins, and supportive measures such as analgesia, physiotherapy, and nutritional support. Prognosis varies with etiology, disease severity, and response to therapy; some causes are reversible while others lead to chronic weakness.

The term should be distinguished from myofibrillar myopathy, a genetically mediated group of disorders characterized by progressive structural disorganization of myofibrils without primary inflammatory etiology. Accurate diagnosis requires integration of clinical, laboratory, imaging, and histopathological data.