Generality
Myelitis is inflammation of the spinal cord.
This dangerous neurological condition can affect the white substance or the gray substance of the spinal cord, with the unpleasant final effect of altering its functions.
The causes of myelitis are numerous; these include: viral infections (including the known poliomyelitis), bacterial infections (eg, Lyme disease), fungal infections, parasitic infections, autoimmune diseases and some vaccination practices.
Myelitis symptoms vary from patient to patient, depending on the cause and the involvement of the white substance or gray substance.
In order to plan an appropriate treatment against the consequences of myelitis, a precise diagnosis of the causal factor is essential; this explains why the diagnostic procedure always involves several investigations (neurological examination, radiological examinations, lumbar puncture, etc.).
Brief Review of the Spinal Cord
The spinal cord is, together with the brain, one of the two fundamental components of the central nervous system .
Structurally very complex, this vital nervous organ has several groups of neurons (arranged in white and gray matter ) and 31 pairs of nerves (the so-called spinal nerves ), and covers the important task of sorting incoming and outgoing signals between the different brain areas ( lobes of the brain, cerebellum, etc.) and the rest of the organism.
The spinal cord takes place, in order to receive protection, inside the so-called spinal canal, ie the conduit resulting from the overlapping of vertebral vertebral column and their characteristic holes.
What is Myelitis?
Myelitis is a disease of the central nervous system, characterized by the inflammation of the neurons of the white matter or of the gray substance of the spinal cord.
What does myelitis involve? The main consequences
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 able to damage the neurons of the gray substance or white substance and this has, as a consequence, the non-fulfillment, by the spinal cord, of the vital process of sorting the nerve signals between the various areas brain and the rest of the body.
Myelitis: origin of the name
The term "myelitis" is the result of the union of the words "mielo", which refers to the spinal cord, and "ite", which in medicine is the suffix indicating the inflammatory processes.
Causes
Myelitis is due to several causes, some of which have a direct action against the spinal cord (ie their target is the spinal cord), while others have an indirect action (ie their specific target is another, but they are nevertheless able to ignite 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 most well-known bacteria capable of causing myelitis are:
- The tuberculosis bacterium ( Mycobacterium tuberculosis );
- The bacterium responsible for Lyme disease ( Borrelia burgdorferi );
- The bacterium of syphilis ( Treponema pallidum );
- Bacteria that cause meningitis (Meningococcus, Pneumococcus and Haemophilus influenzae type B).
In general, it is very rare that a form of myelitis can result from a bacterial infection.
Myelitis and Virus
Among the viruses related to myelitis onset are:
- The poliovirus . It's the polio virus. It has a direct action on the spinal cord, since, in causing myelitis, it specifically affects the neurons of the medullary gray matter;
- The herpes zoster virus, the varicella virus, the HIV virus (or AIDS virus ), some enteroviruses and the Flaviviruses (eg, West Nile virus and Japanese encephalitis virus ). These viruses can cause myelitis directly, as they are able to penetrate and infect spinal cord neurons;
- Some viruses in the respiratory tract and gastrointestinal tract . Any myelitis resulting from these viruses generally appears at the end of the infection.
Myelitis and Fungi
The fungi causing myelitis are those that can infect the bones of the spine (vertebrae) and form on these abscesses or granulomas ; these formations, in fact, produce a compression of the spinal cord, contained in the spinal canal, with inflammatory results.
Specifically, the following are included in the list of myelitis-related fungal pathogens:
- Cryptococcus neoformans ;
- Coccidioides immitis ;
- Blastomyces dermatitidis ;
- Histoplasma capsulatum ;
- Some species of Candida ;
- Some species of Aspergillus ;
- Some zygomycetes.
Myelitis and Parasites
The parasites responsible for myelitis are those that, in particular larval forms, are able to penetrate into the cells of the central nervous system, including the neurons of the spinal cord.
In detail, among the parasites capable of producing myelitis, there are:
- Some Schistosoma species;
- Toxocara canis ;
- Some species of Echinococcus ;
- Taenia solium ;
- Trichinella spiralis ;
- Some species of Plasmodium.
Myelitis and Autoimmune Diseases
Autoimmune diseases are pathologies in which the immune system of an organism, instead of protecting it, attacks it through improper and exaggerated responses.
In myelitis sustained by an autoimmune disease, spinal cord inflammation is the result of improper aggression that the immune system exerts against neurons of the white or gray substance.
Among the autoimmune diseases capable of producing myelitis, the following are worth mentioning: systemic lupus erythematosus ( SLE ), multiple sclerosis, Sjogren's syndrome and optic neuromyelitis (or Devic's disease ).
Myelitis and Vaccines
Among the vaccines that, in some rare circumstances can cause myelitis, include:
- The hepatitis B vaccine;
- The measles, mumps and rubella vaccine;
- Tetanus and diphtheria vaccine.
Types of Myelitis
Experts recognize the existence of at least 4 types of myelitis based on the causes and location of inflammation in the spinal cord.
These 4 types of myelitis are:
- Polio. This type includes all forms of myelitis that affect the neurons of the gray matter of the spinal cord.
Usually, it is connected to the aforementioned poliovirus (which explains its name); however, it can also arise as a result of infections caused by other viruses, such as for example some echoviruses, coxsackieviruses and enteroviruses .
Polio is also known as gray matter myelitis .
- Leukomyelitis . This type includes all forms of myelitis characterized by a lesion of neurons of the spinal cord white matter.
- Transverse myelitis . This typology includes all forms of myelitis of the white substance in which the inflammation extends over the entire width of a more or less relevant spinal cord.
- Meningococcal myelitis (or meningomyelitis ). To this type belong all forms of myelitis in which there is also an inflammation of the meninges of the spinal cord.
Outline of Physiopathology: what does myelitis cause harm?
In myelitis, damage to the spinal cord regards the myelin-free axons, in the case of neurons of the gray substance, and myelin, in the case of white matter neurons (NB: myelin is the lipid coating of the white matter axons).
Symptoms and Complications
Myelitis symptoms vary depending on the cause and the area in which the spinal cord is located; in other words, they change according to the pathological type present (eg: a myelitis affecting the gray substance produces symptoms other than a myelitis affecting the white substance).
Once this important aspect has been clarified, all the possible symptoms of myelitis are covered by law in a general list:
- Pain and stiffness in the neck, back and / or extremities (limbs);
- 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;
- Temperature;
- Headache;
- Nausea and vomit;
- Widespread fatigue;
- Muscle spasms;
- Loss of appetite;
- Upper and lower limb paralysis;
- Sense of weakness in the arms and legs;
- Loss of skin sensitivity, soreness, tingling and / or burning sensation in the hands and / or feet ( paresthesia );
- Posture instability and difficulty walking;
- Muscular atrophy;
- Cardiovascular problems.
Did you know that ...
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 following the deterioration or malfunction of the neurons of the central and / or peripheral nervous system.
Symptoms of Poliomyelitis and Transverse Myelitis
This section is dedicated to the symptoms of the two most important forms of myelitis: poliomyelitis and transverse myelitis.
In polio, the typical symptomatic picture includes: fever, headache, nausea, widespread fatigue, pain and stiffness in the neck, back and extremities, muscle spasms, flaccid paralysis, vomiting, tingling in various parts of the body, atrophy muscle and cardiovascular problems (in the most severe cases).
In transverse myelitis, however, the characteristic symptomatology includes: pain in the back, paresthesia in the hands and feet, paralysis of the limbs, sense of weakness in the arms and legs, urinary incontinence, fecal incontinence, difficulty in urinating, constipation, loss of appetite, spasms muscle and acute pain in arms, legs, chest and abdomen.
Myelitis symptoms: how long do they appear?
The typical symptoms of a myelitis appear within hours or a few days and gradually worsen as one or two weeks pass.
For example, in the case of transverse myelitis, the characteristic symptom picture is established within a few hours and reaches its peak of severity within 10 days of the onset of the condition.
Complications
In the absence of adequate care and in the most severe cases, myelitis can irreversibly damage the spinal cord and give rise to complications such as:
- Chronic type pain . Neck pain, back pain and pain in the limbs become chronic.
The chronicity of pain is highly debilitating for the patient, because it makes it difficult to carry out numerous daily activities, even the simplest.
- Increasingly frequent muscle spasms . As with chronic pain, even the increased frequency of muscle spasms is an obstacle to daily activities.
- Total paralysis of arms and / or legs . It drastically limits the daily needs of patients.
- Sexual dysfunctions . For men, they consist essentially of erectile dysfunction; for women, however, in anorgasmia (absence of orgasm).
- Depression . It is the result of previous complications; after all, the patient does not enjoy moments of respite from pain, he finds it impossible to carry out even very simple activities and he is no longer able to fully live his sexuality.
- Serious cardio-circulatory problems . They are possible in the presence of severe forms of myelitis; can cause patient death.
Diagnosis
In general, to reach the diagnosis of myelitis and its causes, the information coming from: the patient's account of the symptoms, the anamnesis, the physical examination, an accurate neurological examination, radiological examinations of the spine are indispensable and spinal cord (ex: CT and MRI), lumbar puncture ( rachicentesi ) and blood tests .
Tale of symptoms, physical examination and medical history
- The telling of symptoms is very important for diagnostic purposes, because it allows the doctor to know in detail the precise suffering of the patient.
- The physical examination and the anamnesis serve to further clarify the symptomatological picture and to identify the possible causal factors of the condition in progress.
Neurological examination
An accurate neurological examination serves to establish the patient's health from a neurological point of view.
It is a survey that includes several tests to assess nerve function.
Radiological examinations
Magnetic resonance imaging and CT scan of the spine provide very detailed images of the latter and the spinal cord, so they are able to identify any anomalies or alterations (eg: granulomas or abscesses induced by some fungus).
Radiological examinations are also useful for the purposes of the so-called differential diagnosis (ie the diagnostic approach that allows the identification of a pathology proceeding by exclusion).
Lumbar puncture
The lumbar puncture consists in the collection, from the spinal canal of the vertebral column, of some cerebrospinal fluid and in its subsequent 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 a local inflammation is in progress.
In a suspected case of myelitis, rachicentesis allows the diagnostic physician to determine if there is actually inflammation in progress and whether this inflammation is due to a certain pathogen.
Blood analysis
In a context of myelitis, blood tests can help establish whether the condition depends on pathogens or an abnormal behavior of the immune system (eg: in those suffering from optic neuromyelitis, they allow to 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, because it is from the causal factors that the most adequate therapy planning depends.
Therapy
The treatment of myelitis varies in relation to the triggering cause - which means that certain causes require a certain treatment, while other causes another - and in relation to the severity of the symptoms - this means instead that, in the presence of severe symptoms, treatments are needed more drastic, compared to milder circumstances.
Unfortunately, myelitis is able to produce irreversible neurological lesions, which even a proper and scrupulous therapy is able to cancel.
Possible treatments against myelitis
The possible treatments for myelitis include:
- Intravenous administration of corticosteroids . Cortisonics are anti-inflammatory drugs; therefore, in the presence of myelitis they serve to reduce inflammation of the spinal cord;
- Plasma exchange (or plasmapheresis ). It is a therapeutic procedure that allows to temporarily separate the liquid component of the blood (the plasma) from the cellular component (always of the blood), in order to subject it to a work of purification.
Alternative treatment to intravenous administration of cortisone, it is used in the presence of autoimmune myelitis.
- Administration of immunosuppressants . It is suitable for the treatment of forms of autoimmune myelitis.
- The administration of antiviral drugs . It is used when there is a viral infection at the origin of myelitis.
- The administration of classic painkillers (eg: ibuprofen, naproxen sodium, acetaminophen etc.).
- The administration of drugs against neuropathic pain (eg, antidepressants, such as sertraline, and anticonvulsants, such as gabapentin or pregabalin).
- Drug administration against muscle spasms ( antispasmodics ), urinary incontinence and / or fecal incontinence.
- Psychotherapy . It is useful for patients who have developed a form of depression due to debilitating myelitis.
- Physiotherapy . It is used to counteract the physical-motor problems induced by some forms of myelitis.
- Occupational therapy . It pursues the aim of teaching the patient with severe myelitis how to take care of themselves, without always having to rely on others.
Prognosis
The prognosis in case of myelitis depends on the severity of the triggering cause: serious causal factors (eg: poliovirus) can cause strongly debilitating forms of myelitis, if not fatal for the patient.
