myelitis

Myelitis is inflammation of the spinal cord, which can disrupt motor, sensory, and autonomic pathways. It can be focal or extend over multiple spinal segments. Transverse myelitis refers to inflammation across a spinal level with symptoms on both sides of the body, while longitudinally extensive myelitis involves longer segments of the cord. Myelitis can be caused by infections, autoimmune or inflammatory processes, or be post-infectious or parainfectious.

Causes and pathophysiology vary. Infections may be viral, bacterial, or less commonly fungal or parasitic. Autoimmune and inflammatory processes include conditions such as multiple sclerosis–associated myelitis, neuromyelitis optica spectrum disorder, sarcoidosis, and post-infectious or parainfectious inflammatory responses. In some cases no clear cause is identified. Inflammation damages spinal cord tissue, potentially affecting myelin, axons, and gray matter, and can lead to edema and functional impairment of neural pathways.

Clinical features typically include sudden or subacute limb weakness, sensory changes (including a defined sensory level), back pain, and autonomic symptoms such as bladder or bowel dysfunction. Diagnosis combines clinical assessment with magnetic resonance imaging of the spinal cord, which may show focal or longitudinal lesions. Cerebrospinal fluid often shows elevated white cells and protein; autoantibody testing (for example against AQP4 or MOG) and infectious studies help identify underlying causes. Additional testing may include blood work and neurophysiology to exclude compressive lesions or alternative diagnoses.

Treatment targets the underlying cause and may include high-dose corticosteroids, plasmapheresis or intravenous immunoglobulin for inflammatory forms, and antimicrobials if infection is suspected. Supportive care and rehabilitation are important. Prognosis varies; some patients recover substantial function, while others have persistent deficits. Prevention focuses on controlling infectious triggers when possible and vaccines where available. In acute presentations, timely evaluation is essential to guide therapy.