Imagine waking up one morning with a strange numbness or tingling in your feet that, over the course of just a few hours or days, rapidly ascends up your legs, leaving you weak and unable to walk. This frightening experience is a reality for individuals who develop myelitis, a serious neurological condition defined by spinal cord inflammation. Myelitis disrupts the vital communication highway between the brain and the body, leading to a sudden onset of muscle weakness or paralysis, sensory loss, and other neurological problems. It is a medical emergency that requires urgent evaluation and treatment to stop the inflammation and maximize the chances of recovery. Understanding this rare but serious condition is crucial for recognizing its warning signs and seeking immediate medical care.

Myelitis is a general term referring to inflammation of the spinal cord. The spinal cord is the central bundle of nerves that extends from the base of the brain down the back. It acts as the body’s primary data superhighway, carrying a constant stream of messages between the brain and the rest of the body. Motor commands travel down from the brain to control muscle movement, while sensory information travels up from the body to the brain, allowing us to feel touch, pain, and temperature. Most of the nerve fibers in the spinal cord are coated with a protective, fatty layer called the myelin sheath, which acts like insulation on an electrical wire, allowing nerve signals to travel at high speed.

In myelitis, the immune system attacks the spinal cord, causing inflammation. This inflammation can damage or destroy the myelin sheath (a process called demyelination) and can also damage the nerve fibers themselves.

This damage is like a sudden, intense wildfire breaking out on a section of the data superhighway. The fire (inflammation) damages the road surface and burns insulation (myelin). This interrupts traffic flow, blocking messages from getting through. Commands from the brain can no longer reach the muscles, leading to weakness or paralysis. Sensory information from the body cannot reach the brain, leading to numbness or strange sensations.

The most well-known form of myelitis is Transverse Myelitis (TM). The term “transverse” implies that the inflammation extends horizontally across a specific level or segment of the spinal cord. This causes a disruption of function at and below the level of the inflammation. Myelitis can be a one-time (monophasic) event, or it can be a sign of a recurring or chronic demyelinating disease like multiple sclerosis.

In my experience, the most concerning cases of myelitis are those that begin with vague symptoms, like tingling or stiffness, but progress rapidly to weakness or bladder problems. Acting quickly is critical in these cases.

Myelitis is caused by inflammation within the spinal cord. The more complex question is what triggers this inflammation. In many cases, the cause is an abnormal and misdirected immune system response.

Post-Infectious Autoimmune Response

This is believed to be the most common cause of isolated, monophasic myelitis. In this scenario, the myelitis is not caused by a direct infection of the spinal cord itself, but is a complication of the immune system’s reaction to a recent infection elsewhere in the body.

• The theory is that the immune system, revved up to fight off a common virus or bacterium, becomes confused. Through a process known as “molecular mimicry,” the antibodies and immune cells produced to fight the germ mistakenly recognize proteins on the surface of the spinal cord’s myelin as being similar to the germ. They then launch a cross-reactive attack on the healthy myelin, triggering inflammation and damage.
• This post-infectious reaction typically occurs several days to a few weeks after a respiratory or gastrointestinal illness.

Direct Infection

In some, less common cases, a virus or bacterium can directly infect and inflame the spinal cord. Viruses that have been linked to myelitis include herpes viruses (like varicella-zoster, the virus that causes chickenpox and shingles), enteroviruses (including poliovirus), West Nile virus, and Zika virus.

Systemic Autoimmune Diseases

Myelitis can be one of the first and most severe manifestations of a broader, systemic autoimmune disease in which the body’s immune system is chronically dysregulated. These include:

• Multiple Sclerosis (MS): A chronic disease where the immune system attacks the myelin in the brain, optic nerves, and spinal cord. An episode of myelitis can be the first sign of MS.
• Neuromyelitis Optica Spectrum Disorder (NMOSD): A rare autoimmune disease that specifically targets the optic nerves and the spinal cord. It is associated with a specific autoantibody against a protein called aquaporin-4.
• Other Autoimmune Disorders: Myelitis can also occur in the context of systemic lupus erythematosus (lupus) or Sjögren’s syndrome.

In a significant number of cases, despite a thorough investigation, a specific cause or trigger for the myelitis cannot be identified. This is called idiopathic myelitis.

I’ve seen many cases triggered by common viral infections that seemed to have passed, patients often don’t realize the immune system was still active afterward, quietly causing damage to their spinal cord.

Myelitis is not something you can catch from another person, it is not contagious. it does not typically run in families in a predictable pattern, although a genetic predisposition to autoimmunity may play a role.

The primary “risk factor” or preceding event for developing acute transverse myelitis is having had a recent viral or bacterial infection. Most people report a respiratory illness (like a cold or flu) or a gastrointestinal illness in the weeks leading up to the onset of their neurological symptoms.

Other risk factors include:

• Having a known systemic autoimmune disease like MS or lupus.
• Rarely, myelitis has been reported to occur following certain vaccinations, though this link is extremely rare and a causal relationship is difficult to prove. The risk of developing myelitis from a natural infection is far greater than from a vaccine (NINDS, 2023).

In clinical practice, it’s common to diagnose myelitis only after ruling out stroke, disc herniation, or other spine related problems. What makes it tricky is that it doesn’t always present with full paralysis, it can start with subtle numbness or bladder changes.

The symptoms of myelitis vary based on the segment of the spinal cord affected and how rapidly the inflammation sets in. Inflammation is most common in the thoracic (mid-back) region.

Myelitis produces a characteristic set of four main categories of symptoms:

• Motor Weakness: This often starts as a feeling of heaviness or weakness in the legs and can rapidly progress. It can range from difficulty walking to complete paralysis of the legs (paraplegia). If the inflammation is higher in the neck, it can also affect the arms.
• Sensory Changes: Numbness, tingling, burning, or coldness are common. Many people experience hypersensitivity to touch, where even light pressure from clothing can be painful. A very characteristic sign is the development of a sensory level , a distinct line or band-like sensation across the torso, below which sensation is altered or absent.
• Pain: About half of all myelitis patients experience pain. The pain may be localized to the back at the site of inflammation, or it can be a sharp, shooting, neuropathic pain that radiates down the legs, arms, or around the torso.
• Bladder and Bowel Dysfunction: This is a very common feature. Symptoms can include an urgent need to urinate, urinary incontinence, difficulty urinating or urinary retention, constipation, and loss of bowel control.

Patients often describe a “strange heaviness” or loss of control in their legs as one of the first warning signs. I’ve learned to pay close attention when someone says it feels like their limbs don’t respond the way they used to, especially if combined with back pain or numbness.

Diagnosing myelitis requires a combination of neurological evaluation and imaging. The diagnostic process for myelitis is comprehensive:

• Neurological Examination: A neurologist will perform a detailed exam to assess muscle strength, sensation, and reflexes that help to localize the level of the spinal cord that is affected.
• Magnetic Resonance Imaging (MRI): This is the most important diagnostic test for myelitis. An MRI of the spine with a contrast dye can directly visualize the inflammation and swelling within the spinal cord. An MRI of the brain is also always performed at the same time to look for any lesions.
• Lumbar Puncture (Spinal Tap): This procedure involves taking a sample of cerebrospinal fluid (CSF) from the lower back. The CSF is then analyzed in a laboratory. In myelitis, the CSF will typically show signs of inflammation.
• Blood Tests: Blood is drawn to test for infections and to look for specific autoantibodies (such as the aquaporin-4 antibody for NMOSD) that are associated with certain causes of myelitis.

When I see spinal cord inflammation without a clear mechanical cause on MRI, I immediately think of myelitis. The key is always correlating the imaging with the physical exam and patient’s history, each clue matters.

Treatment of myelitis depends on the underlying cause and severity of symptoms. The goals are to reduce inflammation, support recovery, and manage complications.

1. Acute Phase Treatment (To Reduce Inflammation)

• High-Dose Intravenous Steroids: This is the first-line treatment, given to aggressively suppress the immune attack and reduce swelling in the spinal cord.
• Plasma Exchange (PLEX) or Intravenous Immunoglobulin (IVIG): If the patient doesn’t respond well to steroids, these other immunomodulatory therapies may be used to “clean” the blood of harmful antibodies or modulate the immune response.

2. Rehabilitation (The Cornerstone of Recovery)

Once the acute inflammation is under control, the long and often arduous process of recovery begins. The nervous system has a remarkable capacity for healing (a concept known as neuroplasticity), but this takes time and intensive therapy. Rehabilitation is the best part of long-term care.

• Physical Therapy: Focuses on rebuilding muscle strength, improving coordination and balance, and relearning how to stand, walk, and transfer.
• Occupational Therapy: Helps patients relearn the skills of daily living, such as dressing, bathing, and cooking, and provides strategies and adaptive equipment to manage any long-term disabilities.
• Symptom Management: Other therapies are focused on managing the consequences of the spinal cord damage, such as medications for nerve pain, and developing a program for bladder and bowel management.

3. Recovery and Prognosis

Recovery from myelitis is highly variable and can be difficult to predict. The “rule of thirds” is often used to describe the general outcomes (as described by organizations like the Siegel Rare Neuroimmune Association):

• About one-third of individuals make a good or full recovery with minimal or no lasting symptoms.
• About one-third are left with moderate long-term deficits, such as some limb weakness or bladder issues.
• About one-third have severe disabilities, such as significant paralysis, and may remain dependent on a wheelchair.

Recovery is typically fastest in the first three to six months after the event, but improvement can continue for two years or even longer.

In my practice, the sooner treatment starts, the better the outcome. Time truly matters, early steroid use can mean the difference between walking again or permanent weakness.

Myelitis is a serious and frightening neurological disorder that represents a sudden and aggressive autoimmune attack on the spinal cord. Its rapid onset of paralysis, numbness, and pain is a clear medical emergency that demands immediate hospitalization and treatment. The diagnostic journey involves advanced imaging and specialized tests to pinpoint the inflammation and rule out other conditions. While the road to recovery can be long and challenging, and not everyone returns to their previous baseline, there is significant hope.

1. National Institute of Neurological Disorders and Stroke (NINDS). (2023). Transverse Myelitis. Retrieved from https://www.ninds.nih.gov/health-information/disorders/transverse-myelitis
2. Mayo Clinic. (2023). Transverse myelitis. Retrieved from https://www.mayoclinic.org/diseases-conditions/transverse-myelitis/symptoms-causes/syc-20354726
3. Siegel Rare Neuroimmune Association (SRNA). (n.d.). What is Transverse Myelitis? Retrieved from https://wearesrna.org/living-with-srrna/transverse-myelitis/