Myelitis: Causes, Types, Symptoms, Complications, Diagnosis, Treatment and Prognosis

This dangerous neurological condition can affect the white matter or gray matter of the spinal cord, with the unfortunate end effect of altering the functions of the spinal cord.

Myelitis is an inflammation of the spinal cord .

The causes of myelitis are numerous. These include viral infections (including known polio), bacterial infections (eg, Lyme disease), fungal infections, parasitic infections, autoimmune diseases, and some vaccination practices.

The symptoms of myelitis vary from patient to patient, depending on the cause and involvement of the white matter and gray matter.

To plan an appropriate treatment against the consequences of myelitis, an accurate diagnosis of the causative factor is essential; This explains why the diagnostic procedure always involves different investigations (neurological examination, radiological examinations, lumbar puncture, etc.).

Brief review

The spinal cord is, along with the brain, one of the two fundamental components of the central nervous system.

Structurally very complex, this vital nervous organ presents several groups of neurons (arranged in white matter and gray matter) and 31 pairs of nerves (the so-called spinal nerves), and covers the important task of classifying the incoming and outgoing signals between the different areas of the brain (cerebral lobes, cerebellum, etc.) and the rest of the body.

The spinal cord takes place, to receive protection, within the so-called spinal canal, which is the tube resulting from the superposition of the vertebrae of the spine and their characteristic holes.

What is myelitis?

Myelitis is a disease of the central nervous system, characterized by inflammation of neurons in the white matter or gray matter of the spinal cord.

What does myelitis involve?

The proper functioning of the spinal cord depends on the good health of each of its constituent parts.

The inflammation produced by myelitis is potentially capable of damaging the neurons of the gray matter or the white matter and this, as a consequence, the failure by the spinal cord of the vital process of classifying the nerve signals between the various brain areas and the rest of the organism.

Implications of transverse myelitis

The bundles of nerves that occupy the cervical area control the diaphragm (breathing muscles), hands, arms, and also the neck.

Those of the chest, on the other hand, control certain parts of the upper limbs and torso. And finally the sacral nerve bundles (the lower segment of the spinal cord) have control of some parts of the lower extremities and the groin.

Well, when a segment of the spinal cord is injured, the problems that will be generated will be borne by the areas that are innervated by the same section of the spinal cord, in addition to those innervated by the underlying spinal segments.

The patient with transverse myelitis shows demyelination of the thoracic tract. This causes problems in the movements of the lower limbs, the bladder and bowel control.

Name’s origin

The term “myelitis” is the result of the union of the words “myelo”, which refers to the spinal cord, and “itis”, which in medicine is the suffix that indicates inflammatory processes.

The viral origin theory

Transverse myelitis can grow from viral infections caused by the ‘Varicella Zoster’ virus, or by ” Herpes Simplex ‘, including cytomegalovirus or Epstein-Barr virus, influenza, HIV (Human Immunodeficiency Virus, AIDS), or even hepatitis A or rubella.

But some bacteria could also be at the origin of myelitis, a bacterial pneumonia, a middle ear infection (the famous otitis media) as well as a simple skin infection.

Regarding the cases of transverse myelitis derived from an infection, it seems that the human immune system attacks its own tissue by mistake, which would generate the inflammatory process with the subsequent lesions that affect the myelin within the spinal cord.

Acute transverse myelitis often stems from multiple sclerosis, but it can also occur with vasculitis, mycoplasma infection, syphilis, Lyme syndrome, viral meningoencephalitis, and tuberculosis.

Cases of establishment of myelitis due to the ingestion of amphetamines and / or heroin or antiparasitic drugs are not uncommon. This pathology is sometimes associated with optic neuritis, also called “Devic’s disease.”

This association leads researchers to consider the hypothesis that it is a type of autoimmune disease. Inflammation attacks the spinal cord, but not necessarily on a single level. If it ever happened in an “isolated” way, we would speak of an idiopathic cause.


Myelitis is due to several causes, some of which have a direct action against the spinal cord (that is, their target is only the spinal cord), while others have an indirect action (that is, their specific target is another, but they are still capable of inflaming the spinal cord).

The causative factors of myelitis include pathogens, such as bacteria, viruses, fungi, and parasites, autoimmune diseases, and some vaccines.

Myelitis and bacteria

The best known bacteria that can cause myelitis are:

  • La bacteria de la tuberculosis (Mycobacterium tuberculosis).
  • The bacteria responsible for Lyme disease (Borrelia burgdorferi).
  • Syphilis bacteria (Treponema pallidum).
  • The bacteria that cause meningitis (meningococcal, pneumococcal, and Haemophilus influenzae type B).

In general, it is very rare that a form of myelitis can be the result of a bacterial infection.

Mielitis y virus

Viruses associated with the development of myelitis include:

  • The poliovirus is the polio virus. It has a direct action on the spinal cord because, by causing myelitis, it specifically affects the neurons of the medullary gray matter.
  • Herpes zoster virus, chickenpox virus, HIV (or AIDS virus), some enteroviruses and flaviviruses (for example, West Nile and Japanese encephalitis virus). These viruses can directly cause myelitis, as they can penetrate and infect neurons in the spinal cord.
  • Some viruses of the respiratory tract and gastrointestinal tract. Any myelitis resulting from these viruses usually appears late in the infection.

Myelitis and fungi

Fungi due to myelitis are those that can infect the bones of the spine (vertebrae) and form in these abscesses or granulomas; in fact, these formations produce a compression of the spinal cord, contained in the spinal canal, with inflammatory results.

Specifically, in the list of pathogenic fungi related to myelitis, participates:

  • Cryptococcus neoformans.
  • Coccidioides immitis.
  • Blastomyces dermatitidis.
  • Histoplasma capsulatum.
  • Some species of Candida.
  • Some species of Aspergillus.
  • Zygomycetes.

Myelitis and parasites

The parasites responsible for myelitis are those that, particularly the larval forms, can enter the cells of the central nervous system, including the neurons of the spinal cord.

In detail, among the parasites capable of producing myelitis, they include:

  • Some species of Schistosoma.
  • Toxocara canis.
  • Some species of Echinococcus.
  • Tape in state.
  • Trichinella spiralis.
  • Some species of Plasmodium.

Myelitis and autoimmune diseases

Autoimmune diseases are disorders in which the immune system of an organism, instead of protecting the latter, attacks it with inappropriate and exaggerated responses.

In myelitis incurred by an autoimmune disease, inflammation of the spinal cord is the result of inappropriate aggression that the immune system exerts damage to neurons of the white or gray matter.

Among the autoimmune diseases capable of producing myelitis, the following deserve mention: systemic lupus erythematosus (SLE), multiple sclerosis, Sjogren’s syndrome and neuromyelitis optica (or Devic’s disease).

Myelitis and vaccines

Vaccines that, in some rare circumstances, can cause myelitis include:

  • The vaccine for hepatitis B.
  • The measles, mumps, and rubella vaccine.
  • The Tetanus and Diphtheria Vaccine.

Types of myelitis

Experts recognize, based on the causes and location of the inflammation in the spinal cord, the existence of at least 4 types of myelitis.

These 4 types of myelitis are:


This type includes all forms of myelitis that affect neurons in the gray matter of the spinal cord.

Usually it is connected to the aforementioned poliovirus (which gives rise to its name); however, it can also arise as a result of infections with other viruses, such as some echoviruses, coxsackieviruses, and enteroviruses.

Polio is also known as gray matter myelitis.


This type includes all forms of myelitis characterized by a lesion of the neurons of the white matter of the spinal cord.

Transverse myelitis

This type includes all forms of myelitis transmitted by the white matter in which the inflammation extends over the entire width of a more or less relevant section of the spinal cord.

La myelitis meningitis (o meningomyelitis)

To this type belong all forms of myelitis in which there is also inflammation of the meninges of the spinal cord.

Pathophysiology overview, what harm does myelitis cause?

In myelitis, damage to the spinal cord affects the axon devoid of myelin, in the case of gray matter neurons, and myelin in the case of white matter neurons (myelin is the lipid layer of the axons in the white matter).


Symptoms of myelitis vary depending on the cause and location of the inflammation in the spinal cord; in other words, they change depending on the type of pathology present (eg, gray matter-borne myelitis produces different symptoms from white matter-borne myelitis).

Having clarified this important aspect, in a general list of all the possible symptoms of myelitis, fall correctly:

  • Pain and stiffness in the neck, back and / or extremities.
  • Sharp pains in arms, legs, chest and abdomen.
  • Loss of bladder control (urinary incontinence) and / or bowel function (fecal incontinence).
  • Difficulty urinating and / or constipation.
  • Fever.
  • Headache.
  • Nausea and vomiting
  • General tiredness
  • Muscle spasms.
  • Loss of appetite
  • Paralysis of the upper and lower limbs.
  • Sense of weakness in the arms and legs.
  • Loss of sensation in the skin, pain, tingling and / or burning sensation in the hands and / or feet (paraesthesia).
  • Postural instability and difficulty walking.
  • Muscle atrophy.
  • Cardiovascular problems.

Symptoms of Polio and Transverse Myelitis

This section is dedicated to the symptoms of the two most important forms of myelitis: polio and transverse myelitis.

In polio, the typical picture of symptoms include: fever, headache, nausea, generalized fatigue, pain and a sense of stiffness in the neck, back and extremities, muscle spasms, flaccid paralysis, vomiting, feeling of tingling in different parts of the body, atrophy muscular and cardiovascular problems (in severe cases).

In transverse myelitis, however, the characteristic symptoms include: pain, numbness in the hands and feet, paralysis of the extremities, weakness in the arms and legs, urinary and fecal incontinence, difficulty urinating, constipation, loss of appetite, spasms, muscle pain and sharp in arms, legs, chest and abdomen.

Symptoms of myelitis, how long does it take?

Typical myelitis symptoms appear within hours to a few days and gradually worsen over a week or two.

For example, in the case of transverse myelitis, the characteristic symptomatic picture sets in within a few hours and reaches its peak of severity within 10 days of the onset of the condition.

Some data

  • Pain induced by a neurological disease such as myelitis is an example of neuropathic pain.
  • In medicine, the term “neuropathic pain” indicates the painful sensation that appears as a result of the deterioration or malfunction of neurons in the central and / or peripheral nervous system.


In the absence of proper care and in the most severe cases, myelitis can irreversibly damage the spinal cord and lead to complications such as:

  • Chronic pain: neck pain, back pain and limb pain become severe. Chronic pain is very debilitating for the patient, since it makes it difficult to carry out many daily activities, even the simplest ones.
  • Increasingly frequent muscle spasms: Regarding the chronicity of pain, even the increased frequency of muscle spasms is an obstacle to daily activities.
  • Total paralysis of arms and / or legs: drastically limits the daily needs of patients.
  • Sexual dysfunction For men, they essentially consist of erectile dysfunction; for women, however, in anorgasmia (absence of orgasm).
  • Depression: it is the result of previous complications; Furthermore, the patient does not enjoy moments of pain relief, it is impossible for him to do even very simple activities, and he can no longer fully experience his sexuality.
  • Serious cardiovascular problems – are possible in the presence of severe forms of myelitis; they can cause the death of the patient.


In general, what leads to the diagnosis of myelitis and its causes, are vital information from: the history of the patient’s symptoms, medical history, physical examination and a thorough neurological examination that tests the radiological spine and spinal cord (eg MRI), lumbar puncture, and blood tests.

Symptom history, objective examination, and medical history

The history of symptoms is very important for diagnostic purposes, as it allows the doctor to know in detail the precise suffering of the patient.

Objective examination and history serve to further clarify the symptom picture and identify possible causative factors for the current condition.

neurological visit

An accurate neurological visit serves to establish the patient’s health from a neurological point of view.

It is a survey that provides various tests for the evaluation of nerve function.

Radiological exams

Magnetic resonance imaging and computerized axial tomography of the spine provide highly detailed images of the spine and the spinal cord, which can identify any abnormality or alteration (eg, granulomas or fungus-induced abscesses).

Radiological examinations are also useful for the so-called differential diagnosis (that is, the diagnostic approach that makes it possible to identify a pathology procedure by exclusion).

Lumbar puncture

The lumbar puncture consists of the collection, from the spinal canal of the vertebral column, of some cerebrospinal fluid that has a later laboratory analysis.

It is a fundamental test to detect the presence of infectious agents in the spinal cord (and in the nervous system in general) and to understand if local inflammation is taking place.

In a suspected case of myelitis, rachicentesi allows the diagnosing physician to establish whether there really is inflammation at the site and whether this inflammation is due to a certain pathogen.

Blood test

In the context of myelitis, blood tests can help determine whether the condition is dependent on pathogens or abnormal behavior of the immune system (eg, in those with neuromyelitis, it can help identify the typical antibodies responsible for the condition) .

Why is it important to identify the causes of myelitis?

The knowledge of the causes of myelitis is very important, since it depends on the causal factors that depend on the planning of the most appropriate therapy.


The treatment of myelitis varies depending on the triggering cause, which means that certain causes require some treatment, and depending on the severity of the symptoms, it means that, in the presence of severe symptoms, more drastic treatments are needed, compared to the circumstances milder.

Unfortunately, myelitis can cause irreversible neurological damage, which even careful and adequate therapy can negate.

Possible Myelitis Treatments

Among the treatments that can be performed in case of myelitis, are:

  • The administration of intravenous corticosteroids: cortisones are anti-inflammatory drugs; therefore, in the presence of myelitis, they serve to reduce inflammation of the spinal cord.
  • Plasma exchange (or plasmapheresis): is a therapeutic procedure that allows the liquid component of the blood (plasma) to be temporarily separated from the cellular component (always blood), in order to subject it to purification work.
  • The treatment alternative to intravenous administration of cortisone is used in the presence of myelitis of an autoimmune nature.
  • Administration of immunosuppressants: it is suitable for the treatment of autoimmune myelitis.
  • Antiviral Medication Administration – Used when there is a viral infection at the source of the myelitis.
  • Administration of classic analgesics (eg, ibuprofen, naproxen sodium, paracetamol, etc.).
  • The administration of medications for neuropathic pain (for example, antidepressants, such as sertraline and anticonvulsants, such as gabapentin or pregabalin).
  • The administration of drugs against muscle spasms (antispasmodics), urinary incontinence and / or fecal incontinence.
  • Psychotherapy: useful for patients who have developed a form of depression due to debilitating myelitis.
  • Physiotherapy: serves to counteract the physical-motor problems caused by some forms of myelitis.
  • Occupational therapy: pursues the objective of teaching the patient with severe myelitis how to take care of himself, without always having to depend on others.


The prognosis for myelitis depends on the severity of the triggering cause: Serious causative factors (eg, poliovirus) can cause forms of myelitis that are very debilitating, even fatal to the patient.