Acute Transverse Myelitis

What happens in transverse myelitis

The spinal cord carries signals between the brain and the body. "Transverse" means the inflammation extends across the width of the cord at one level. The immune system attacks the cord, stripping the insulating myelin from nerve fibers and sometimes damaging the fibers themselves. Everything below the affected level can be weakened or numbed. The thoracic (chest) section of the cord is most often affected, so the legs, bladder and bowel are usually involved while the arms are spared.

Symptoms

Symptoms typically develop over 4 hours to 21 days and peak within that time:

• Weakness: in the legs, sometimes progressing to paralysis; arms are affected if the neck is involved.
• Sensory changes: numbness, tingling, burning or a tight band around the trunk, with a "sensory level" below which feeling is reduced.
• Pain: in the back or radiating around the trunk or down the legs.
• Bladder and bowel problems: urgency, incontinence, inability to pass urine, constipation.
• Sexual dysfunction.
• Muscle spasms and stiffness later in the course.

Causes

• Multiple sclerosis: partial myelitis affecting one side or a short segment is often the first sign of multiple sclerosis.
• Neuromyelitis optica spectrum disorder (NMOSD): long lesions over three or more spinal segments, often with optic neuritis; linked to aquaporin-4 antibodies.
• MOG antibody-associated disease (MOGAD).
• Infections: viruses (herpes viruses, enteroviruses, West Nile, HIV, COVID-19), bacteria (Lyme disease, syphilis, tuberculosis, mycoplasma) and parasites. Myelitis can occur during infection or weeks after (post-infectious).
• Systemic autoimmune diseases: lupus, Sjögren's syndrome, sarcoidosis, antiphospholipid syndrome.
• Acute disseminated encephalomyelitis (ADEM), mostly in children after an infection.
• Very rarely after vaccination.
• Idiopathic: no cause is found in a substantial proportion.

Diagnosis

Transverse myelitis must be distinguished quickly from conditions needing surgery, such as spinal cord compression from a disc, tumor, abscess or bleed.

1. Urgent MRI of the whole spine to show inflammation and rule out compression. MRI of the brain looks for MS-type lesions.
2. Lumbar puncture: spinal fluid shows inflammation (raised white cells or IgG), oligoclonal bands (MS), and tests for infection.
3. Blood tests: aquaporin-4 and MOG antibodies, autoimmune markers (ANA, anti-Ro/La, antiphospholipid), B12, copper, syphilis, HIV and other infections.
4. Eye tests: visual evoked potentials or optic nerve MRI if NMOSD or MS is suspected.

Myelitis is distinguished from Guillain-Barré syndrome, which affects peripheral nerves, causes loss of reflexes and usually spares the bladder and has no sensory level.

Treatment

Acute treatment

• High-dose IV methylprednisolone for 3 to 5 days, started as soon as compression and infection are excluded.
• Plasma exchange (PLEX): for severe cases or those not improving with steroids; particularly important in NMOSD.
• IV immunoglobulin or other immunotherapy in selected cases.
• Antimicrobials if an infection is identified.

Supportive care

• bladder catheterization for retention
• bowel management
• prevention of blood clots and pressure sores while immobile
• treatment of pain and muscle spasms (gabapentin, baclofen)

Long-term treatment

People with MS, NMOSD or MOGAD need long-term immune therapy to prevent relapses. Idiopathic myelitis is usually a one-time event.

Rehabilitation

Physical and occupational therapy start early and continue for months: strengthening, walking training, equipment, bladder training and help with daily activities.

Outlook

Recovery usually begins within weeks and can continue for 1 to 2 years. Roughly a third of people recover with little or no disability, a third have moderate lasting problems (such as stiffness, bladder urgency or walking difficulty), and a third have significant disability. Rapid onset, complete paralysis and severe back pain at the start predict a poorer recovery. Most people with idiopathic myelitis have only one episode, while those with an underlying condition may relapse.

Frequently asked questions

What is acute transverse myelitis?

It is sudden inflammation across a section of the spinal cord that disrupts signals to and from the body below that level. It causes weakness, numbness, back pain and bladder and bowel problems that develop over hours to days.

What causes transverse myelitis?

Causes include viral and bacterial infections, autoimmune conditions such as multiple sclerosis, neuromyelitis optica, MOG antibody disease, lupus and sarcoidosis, and post-infectious immune reactions. In many people no specific cause is found, which is called idiopathic transverse myelitis.

Can you recover from transverse myelitis?

Many people do. About a third recover fully or nearly fully, a third have moderate lasting symptoms, and a third have significant disability. Most improvement happens in the first 3 to 6 months, but gains can continue for up to 2 years with rehabilitation.

How is transverse myelitis treated?

Treatment starts with high-dose intravenous steroids. Plasma exchange is used for severe cases or when steroids do not help. Supportive care manages the bladder, bowel, pain and spasms, and rehabilitation helps restore function. Underlying conditions such as MS or NMOSD need long-term treatment.

Can transverse myelitis come back?

Idiopathic transverse myelitis usually happens once. Recurrence is more likely when there is an underlying condition such as multiple sclerosis, neuromyelitis optica, MOG antibody disease or lupus. Identifying these conditions allows preventive treatment to reduce relapses.