Myelitis (Spinal Cord Inflammation)

What happens in myelitis

The spinal cord carries motor signals from the brain to the muscles, and sensory signals back. Inflammation damages the myelin insulation and nerve fibers at the affected level. Everything below that level can be affected: movement, sensation, and bladder, bowel and sexual function.

Types

• Transverse myelitis: inflammation across both sides of a section of the cord, usually in the thoracic (mid-back) region. See transverse myelitis.
• Partial myelitis: affects part of the cord's width; more typical of multiple sclerosis.
• Longitudinally extensive myelitis: spans three or more vertebral segments; typical of NMOSD.
• Acute flaccid myelitis (AFM): a rare, polio-like condition mostly in children, often after viral infections such as enterovirus D68, causing sudden floppy weakness in one or more limbs.

Symptoms

Symptoms develop over hours to days and may worsen for up to 3 weeks:

• weakness of the legs, sometimes arms, ranging from mild to complete paralysis
• sensory changes: numbness, tingling, burning, or a tight band around the trunk, with a "sensory level" below which feeling is altered
• pain in the back or in a band around the body
• bladder problems: urgency, incontinence or urinary retention
• bowel problems: constipation or incontinence
• sexual dysfunction
• later, muscle stiffness and spasms (spasticity)

Causes

• Multiple sclerosis: myelitis can be the first sign
• Neuromyelitis optica spectrum disorder (NMOSD): severe myelitis and optic neuritis, linked to aquaporin-4 antibodies
• MOG antibody-associated disease (MOGAD)
• Systemic autoimmune diseases: lupus, Sjögren's syndrome, sarcoidosis
• Infections: viruses (herpes, varicella zoster, enteroviruses, HIV, West Nile), bacteria (Lyme disease, syphilis, tuberculosis), parasites
• After infection or, very rarely, vaccination
• Paraneoplastic syndromes linked to cancer
• Idiopathic: no cause found in a proportion of people

Conditions that can mimic myelitis include spinal cord compression from a disc, tumor or abscess, spinal cord stroke, and vitamin B12 or copper deficiency.

Diagnosis

Myelitis is a neurological emergency. Tests include:

• Urgent MRI of the spine to exclude compression and show inflammation; brain MRI to look for MS or NMOSD
• Lumbar puncture: spinal fluid cell count, protein, oligoclonal bands and infection tests
• Blood tests: aquaporin-4 and MOG antibodies, autoimmune screens, vitamin B12, copper, infections
• Eye examination and optical coherence tomography for silent optic nerve involvement

Treatment

Acute treatment

• High-dose IV methylprednisolone for 3 to 5 days is standard first-line treatment.
• Plasma exchange for severe cases or those not improving with steroids.
• IV immunoglobulin in some situations, including AFM.
• Antimicrobials when an infection is identified.
• Supportive care: bladder catheterization, bowel management, blood clot prevention, pain control.

Preventing relapses

Depending on the cause:

• disease-modifying therapy for MS
• long-term immunotherapy for NMOSD (such as eculizumab, inebilizumab, satralizumab or rituximab) or recurrent MOGAD
• treatment of underlying lupus or sarcoidosis

Rehabilitation

Physical and occupational therapy, bladder and bowel programs, spasticity treatment, mobility aids and psychological support are central to recovery.

Outlook

Recovery usually begins within weeks and can continue for up to 2 years. About a third of people with transverse myelitis recover well, a third have moderate lasting problems, and a third have significant disability. Faster onset, complete paralysis and severe back pain at the start predict a poorer outcome. Recurrence depends on the underlying cause.

Frequently asked questions

What are the symptoms of myelitis?

Symptoms include weakness in the legs or arms, numbness or tingling below a certain level of the body, a tight band sensation around the trunk, back pain, and bladder or bowel problems. They develop over hours to days.

What causes inflammation of the spinal cord?

Common causes include multiple sclerosis, neuromyelitis optica spectrum disorder, MOG antibody disease, lupus and other autoimmune conditions, and viral or bacterial infections. In some people no cause is found.

Can you recover from transverse myelitis?

Many people recover partly or fully, with most improvement in the first 3 to 6 months and continuing up to 2 years. Some are left with weakness, stiffness, pain or bladder problems. Early treatment and rehabilitation improve outcomes.

Is myelitis the same as multiple sclerosis?

No. Myelitis is inflammation of the spinal cord, which can have many causes. Multiple sclerosis is one cause, and myelitis can be the first sign of MS. Brain MRI and spinal fluid tests help determine whether MS is present.