Demyelinating disease is a pathological process of destruction of the myelin sheath that affects neurons in the brain and spinal cord. At the same time, the conductivity of impulses in the nervous system deteriorates. The disease is characterized by the destruction of brain myelin. This dangerous condition affects the functioning of the entire body. The disease occurs with equal frequency in both adults and children. Modern medicine does not have the means to completely cure this disease. It can only be weakened and the flow slowed down.
Demyelination
Demyelinating brain disease according to ICD-10 has codes G35, G36 and G77. The process caused by damage to the nervous tissue negatively affects the functioning of the entire organism as a whole. Certain nerve endings are covered with a myelin sheath, which performs important functions in the body. For example, myelin ensures the rapid transmission of electrical impulses and, accordingly, if this process is disrupted, the entire system suffers. Myelin consists of lipids and protein compounds in a 70/30 ratio.
Demyelinating disease is not only multiple sclerosis, it is also neuromyelitis optica and acute disseminated encephalomyelitis. These diseases have no cure, but their progression can be slowed down. In general, doctors give a favorable prognosis when treating these pathologies. The diagnosis of “multiple sclerosis” is now made more often, but the disease itself is milder than 30-40 years ago.
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Demyelinating diseases
Several conditions lead to demyelination, and one of the best known neurodegenerative disorders is multiple sclerosis . Here, the immune system targets the myelin sheath or the cells that form and support it. This disease occurs twice as often among women than among men. Residents of central Russia and Siberia suffer the most from the disease.
The course of the disease in multiple sclerosis is usually relapsing, but it can also progress from the onset of the disease or become progressive after periods of remission. The latent phase between the initial onset of a symptom and the first relapse is variable.
- Transverse myelitis, in which there is inflammation of the spinal cord.
- Optic neuritis, which refers to inflammation of the optic nerve.
- Acute disseminated encephalomyelitis, in which there is inflammation of the spinal cord and brain
- Adrenomyeloneuropathy, or adrenoleukodystrophy, which are rare types of metabolic disorders.
Development mechanisms
The nervous system consists of central and peripheral sections. The regulation mechanism between them works as follows: impulses from the receptors of the peripheral system are transmitted to the nerve centers of the spinal cord, and from there to the brain. The disruption of this complex mechanism causes demyelination.
Nerve fibers are covered with a myelin sheath. As a result of the pathological process under consideration, this membrane is destroyed and fibrous tissue is formed in its place. She, in turn, cannot conduct nerve impulses. In the absence of nerve impulses, the functioning of all organs is disrupted, since the brain cannot issue commands.
Causes
Demyelinating diseases of the brain are characterized by damage to the peripheral and central nervous systems. They most often occur against the background of a genetic predisposition. It also happens that a combination of certain genes provokes disturbances in the functioning of the immune system. There are other causes of demyelinating diseases:
- state of chronic or acute intoxication;
- solar radiation;
- ionizing radiation;
- autoimmune processes in the body and genetic pathologies;
- complication of bacterial and viral infection;
- poor nutrition.
The Caucasian race is considered to be the most susceptible to this pathology, especially those representatives who live in northern latitudes. This type of disease can be provoked by a head or spinal injury, depression, or bad habits. Some types of vaccines can also trigger the development of such pathologies. This applies to vaccinations against measles, smallpox, diphtheria, influenza, whooping cough, and hepatitis B.
Classification
Demyelinating disease of the nervous system is classified into different types, which are based on the destruction of the myelin sheath. In this regard, the pathology under consideration is divided accordingly into multiple sclerosis, Marburg disease, Devic disease, progressive multifocal leukoencephalopathy and Guillain-Barré syndrome.
Multiple sclerosis
Multiple sclerosis is characterized as a severe chronic and immunodegenerative disease of the central nervous system, prone to progression. In most cases, the disease occurs at a young age and almost always leads to disability. This demyelinating disease of the central nervous system is assigned code G35 according to ICD-10.
Currently, the causes of the development of multiple sclerosis are not fully understood. Most scientists are inclined to the multifactorial theory of the development of this disease, when genetic predisposition and external factors are combined. The latter include:
- infectious diseases;
- state of chronic intoxication;
- taking certain medications;
- change of place of residence with a sharp change in climate;
- lack of fiber and high-calorie diet.
The progression of multiple sclerosis is characterized by the development of the following symptoms:
- sensory disturbances (goosebumps, numbness, tingling, burning, itching);
- visual impairment (impaired color rendering, decreased visual acuity, blurred picture);
- trembling of the limbs or torso;
- headache;
- speech disorders and difficulty swallowing;
- muscle spasms;
- gait changes;
- cognitive impairment;
- heat intolerance;
- dizziness;
- chronic fatigue;
- libido disturbance;
- anxiety and depression;
- stool instability;
- insomnia;
- autonomic disorders.
Treatment of multiple sclerosis is carried out using methods such as:
- plasmapheresis;
- taking cytostatics;
- prescription of immunosuppressants;
- use of immunomodulators;
- taking beta interferons;
- hormonal therapy.
- symptomatic therapy with the prescription of antioxidants, nootropic drugs and vitamins.
During the period of remission, patients are prescribed sanatorium treatment, massage, and physical therapy. In this case, all thermal procedures should be excluded. To alleviate the symptoms of the disease, medications are prescribed: those that reduce muscle tone, eliminate tremors, normalize urination, stabilize the emotional background, and anticonvulsants.
Marburg disease
Hemorrhagic fever or Marburg disease is an acute infectious pathology caused by the Marburg virus. It enters the body through damaged skin and mucous membranes of the eyes and mouth.
The symptoms of the disease depend on the stage of the pathological process. The incubation period lasts from 2 to 16 days. The disease has an acute onset and is characterized by an increase in body temperature to high levels. Along with fever, chills may appear. Signs of intoxication increase, such as weakness, headache, pain in muscles and joints, intoxication and dehydration. 2-3 days after this, gastrointestinal dysfunction and hemorrhagic syndrome appear.
All symptoms intensify by the end of the first week. Bleeding from the nose, gastrointestinal tract, and genital tract may also be observed. By the beginning of week 2, all signs of intoxication reach their maximum. In this case, convulsions and loss of consciousness are possible. According to the blood test, specific changes occur: thrombocytopenia, poikilocytosis, anisocytosis, granularity of erythrocytes.
If a person is suspected of having Marburg disease, he is urgently hospitalized in the infectious diseases department and must be kept in an isolated box. The recovery period may take up to 21-28 days.
Devic's disease
Neuromyelitis optica or Devic's disease has a chronic pattern similar to multiple sclerosis. This is an autoimmune disease, the causes of which are still unclear. One of the reasons for its development is an increase in the permeability of the barrier between the meninges and the vessel.
Some autoimmune diseases can trigger the progression of Devic's disease:
- rheumatoid arthritis;
- systemic lupus erythematosus;
- Sjögren's syndrome;
- dermatomyositis;
- thrombocytopenic purpura.
The disease has specific symptoms. Clinical manifestations are caused by disruption of conductive impulses. In addition, the optic nerve and spinal cord tissue are affected. In most cases, the disease manifests itself as visual impairment:
- a veil before the eyes;
- pain in the eye sockets;
- blurred vision.
As the disease progresses and there is no adequate treatment, the patient runs the risk of completely losing his vision. In some cases, regression of symptoms with partial restoration of eye function is possible. Sometimes it happens that myelitis precedes neuritis.
Neuromyelitis optica has two course options: a progressive increase in symptoms with simultaneous damage to the central nervous system. In rare cases, a monophasic course of the disease occurs. It is characterized by steady progress and worsening symptoms. In this case, the risk of death is increased. With the right treatment, the pathological process slows down, but complete recovery is not guaranteed.
The second option, the most common, is characterized by an alternating change of remission and exacerbation and is designated by the concept of “recurrent course.” It is also accompanied by visual disturbances and spinal cord dysfunction. During the period of remission, a person feels healthy.
To identify Devic's disease, a set of measures is carried out. In addition to standard diagnostic procedures, lumbar puncture with cerebrospinal fluid analysis, ophthalmoscopy and MRI of the spine and brain are performed.
Progressive multifocal leukoencephalopathy
People with immune deficiency may experience progressive multifocal multifocal leukoencephalopathy. This is an infectious disease caused by the penetration of the JC virus, which belongs to the Polyomavirus family, into the body. A feature of the pathology is that asymmetric and multifocal brain damage occurs. The virus affects the membranes of nerve endings, which are made of myelin. Therefore, this disease belongs to the group of demyelinating pathologies.
Almost 85% of patients with this diagnosis are AIDS or HIV infected. The risk group includes patients with malignant tumors.
Main symptoms of the disease:
- mood swings;
- visual disturbances;
- paresthesia and paralysis;
- memory impairment.
Guillain-Barre syndrome
An acute inflammatory disease characterized by “demyelinating polyradiculoneuropathy.” It is based on autoimmune processes. The disease manifests itself as sensory disturbances, muscle weakness and pain. It is characterized by hypotension and disorder of tendon reflexes. Respiratory failure may also occur.
All patients with this diagnosis should be admitted to the intensive care unit. Since there is a risk of developing respiratory failure and a ventilator may be required, the department must have intensive care.
Multiple sclerosis
Herpes
5960 12 July
IMPORTANT!
The information in this section cannot be used for self-diagnosis and self-treatment.
In case of pain or other exacerbation of the disease, diagnostic tests should be prescribed only by the attending physician. To make a diagnosis and properly prescribe treatment, you should contact your doctor. Multiple sclerosis: causes, symptoms, diagnosis and treatment methods.
Definition
Multiple sclerosis (multiple sclerosis) is a chronic, progressive neurodegenerative autoimmune disease of the central nervous system that affects the brain, spinal cord and optic nerves.
Causes of multiple sclerosis
Most nerve fibers are covered with a myelin sheath. The brain sends electrical impulses along nerves to different parts of the body. These impulses control all our voluntary and involuntary movements. Healthy nerves are isolated with the help of a myelin sheath, which is a protective layer that provides nutrition to the axon, maintains its structure, protects it from damage, and accelerates the transmission of nerve impulses.
In multiple sclerosis, a person's own immune system mistakenly attacks and destroys the myelin sheath of nerve fibers.
In the area of myelin loss, scar connective tissue forms, which can distort or completely block transmitted impulses. For some time, the nervous system compensates for the disruptions, but as the disease progresses, the severity of symptoms steadily increases from mild numbness of the limbs to paralysis and/or blindness.
The term “multiple sclerosis” means the presence of multiple scar lesions (or demyelinating plaques) scattered in different parts of the brain and spinal cord.
The reason why immune cells begin to attack the nerve fibers of their own body is still unknown. There is an opinion that the development of the disease can be influenced by many factors: genetic predisposition, active and passive smoking, vitamin D deficiency, exposure to retroviruses, human herpes virus, in particular Epstein-Barr, bacterial infections (staphylococci, streptococci), high salt content in foods nutrition, poor environment, brain injuries (concussions, bruises), damage to the spinal column, excess weight (especially in adolescents and children), stress, some autoimmune diseases. Residents of northern regions and representatives of the Caucasian race are at increased risk of developing multiple sclerosis.
The disease is most often diagnosed at the age of 20–45 years, but can also occur in children. Men get sick 2 times less often than women, but it is in them that the pathology is more severe and less responsive to treatment.
Classification of the disease
There are some typical flow options
multiple sclerosis:
- Remitting course is the most common variant in the onset of the disease. It is characterized by periods of exacerbations, alternating with periods of remission (with complete or incomplete restoration of functions in the periods between exacerbations), and the absence of an increase in symptoms during periods of remission. In many patients, the remitting course subsequently turns into secondary progression (with or without exacerbations);
- Progressive course:
- primary progressive – from the very beginning of the disease, for at least one year, there is an increase in the severity of the symptoms of the disease without periods of improvement;
- secondary progressive - the severity of the symptoms of the disease increases for at least 6 months without stabilization or improvement after the relapsing phase of the disease, progression with or without exacerbations is possible.
Multiple sclerosis is also classified by disease activity
- exacerbation or detection of new lesions in the brain and/or spinal cord during an MRI examination. The following forms can be distinguished:
- active multiple sclerosis (in the presence of exacerbations or signs of disease activity according to MRI);
- inactive multiple sclerosis (without exacerbations and without signs of activity according to MRI);
- multiple sclerosis with progression (new lesions are identified);
- multiple sclerosis without progression (new lesions of the nervous system have not been identified).
There are also several special forms of the disease that require aggressive treatment methods
:
- the malignant form (Marburg disease) is characterized by very rapid progression without periods of remission, in the most severe cases it can lead to the death of the patient;
- an aggressive or rapidly progressive form, in which two or more episodes of exacerbation are observed during the year, leading to an increase in the level of disability;
- the highly active form is characterized by two or more exacerbations per year and a significant increase in lesions of the nervous system according to MRI.
Symptoms of multiple sclerosis
The very first symptoms appear when about 50% of the nerve fibers are already affected - that is, at first the disease does not manifest itself in any way. This is explained by the fact that healthy brain cells take over the function of the affected areas.
Signs of multiple sclerosis depend on the location of the main part of the pathological foci.
As new areas are affected, the symptoms increase and become more diverse. Damage to the cerebellum and its pathways:
severe tension in the legs or arms (due to increased muscle tone), possible paralysis, poor coordination of movements, staggering when walking, involuntary movements, tremor of the arms and legs, impaired speech function, dizziness.
Optic nerve damage:
decreased vision in one eye up to complete blindness; black dot in the center of the field of view; a feeling of cloudy glass, a veil in front of the eye - these are manifestations of retrobulbar neuritis (pathology of the optic nerve in the area behind the eyeball as a result of damage to its myelin sheath). There is a disturbance in the movement of the eyeball, and double vision (diplopia) develops.
Spinal cord damage:
constant tiredness and fatigue, loss of bowel and bladder control, constipation and urinary retention, changes in sexual function, radiculopathy, Lhermitte's sign (when you bend your head forward, there is a sensation of electric current passing through the spine, sometimes radiating to the limbs), burning sensation or pain in response to touch, tingling or numbness in the limbs, development of spastic paraparesis.
Brain stem damage:
weakness or spasm of the facial muscles, intermittent numbness of one half of the face, central or peripheral paresis of the facial nerve, hearing loss, decreased taste sensitivity.
Damage to the cerebral hemispheres:
decreased memory and attention, speed of neuropsychological tests, behavioral disorders, excessive anxiety, bad mood, depression or euphoria.
After taking a hot bath and under the influence of a hot climate, the patient's condition temporarily worsens.
This must be taken into account and try to avoid overheating, which can provoke an attack. Nerve fibers deprived of their myelin sheath are extremely sensitive to increased temperature.
Diagnosis of multiple sclerosis
In general, the clinical manifestations of the disease are very diverse, which makes diagnosis difficult. Two main clinical signs confirming the presence of multiple sclerosis:
- symptoms appear in various parts of the central nervous system;
- the presence of at least two attacks of the disease, the occurrence of which is separated in time by a period of at least one month.
The diagnosis of “multiple sclerosis” is made last, that is, after excluding other causes of such multifocal brain damage.
Diagnostic methods:
Assessment of complaints, symptoms, clinical disorders.
During a neurological exam, the doctor checks nervous system function such as reflexes, balance, coordination and vision, and looks for areas of numbness. Ophthalmological examination with mandatory assessment of visual acuity, visual fields, condition of the fundus.
For a patient suspected of having multiple sclerosis, the following laboratory tests are recommended to assess the general condition of the body and determine the possibility of prescribing subsequent therapy:
- detailed clinical blood test;
Demyelinating disease of the central nervous system
Demyelinating diseases of the brain and spinal cord are pathological processes that lead to the destruction of the myelin sheath of neurons and disruption of the transmission of impulses between nerve cells of the brain. It is believed that the etiology of diseases is based on the interaction of the body's hereditary predisposition and certain environmental factors. Impaired impulse transmission leads to a pathological state of the central nervous system.
What diseases are these?
There are the following types of demyelinating diseases:
- Multiple sclerosis is a demyelinating disease of the central nervous system. The demyelinating disease multiple sclerosis is the most common pathology. Multiple sclerosis is characterized by a variety of symptoms. The first symptoms appear at the age of 20-30 years, women are more often affected. Multiple sclerosis is diagnosed by the first signs, which were first described by psychiatrist Charcot - involuntary oscillatory eye movements, trembling, scanned speech. Patients also experience urinary retention or very frequent urination, absence of abdominal reflexes, pallor of the temporal halves of the optic discs;
- ADEM, or acute disseminated encephalomyelitis. It begins acutely and is accompanied by severe cerebral disorders and manifestations of infection. The disease often occurs after exposure to a bacterial or viral infection and may develop spontaneously;
- diffuse disseminated sclerosis. It is characterized by damage to the spinal cord and brain and manifests itself in the form of convulsive syndrome, apraxia, and mental disorders. Death occurs within a period of 3 to 6-7 years from the moment the disease is diagnosed;
- Devic's disease, or acute neuromyelitis optica. The disease begins as an acute process, is severe, and progresses, affecting the optic nerves, which causes complete or partial loss of vision. In most cases, death occurs;
- Balo's disease, or concentric sclerosis, periaxial concentric encephalitis. The onset of the disease is acute, accompanied by fever. The pathological process occurs with paralysis, visual disturbances, and epileptic seizures. The course of the disease is rapid - death occurs within a few months;
- leukodystrophies - this group contains diseases that are characterized by damage to the white matter of the brain. Leukodystrophies are hereditary diseases; as a result of a gene defect, the formation of the myelin sheath of the nerves is disrupted;
- Progressive multifocal leukoencephalopathy is characterized by decreased intelligence, epileptic seizures, the development of dementia and other disorders. The patient's life expectancy is no more than 1 year. The disease develops as a result of decreased immunity, activation of the JC virus (human polyomavirus 2), often found in patients with HIV infection, after bone marrow transplantation, in patients with malignant blood diseases (chronic lymphocytic leukemia, Hodgkin's disease);
- diffuse periaxial leukoencephalitis. A hereditary disease that most often affects boys. Causes visual, hearing, speech, and other disorders. Progresses quickly - life expectancy is just over a year;
- Osmotic demyelination syndrome is very rare and develops as a result of electrolyte imbalance and a number of other reasons. A rapid increase in sodium levels leads to the loss of water and various substances from brain cells, causing the destruction of the myelin sheaths of nerve cells in the brain. One of the posterior parts of the brain is affected - the Varoliev bridge, which is most sensitive to myelinolysis;
- myelopathy is a general term for lesions of the spinal cord, the causes of which are varied. This group includes: tabes dorsalis, Canavan disease, and other diseases. Canavan disease is a genetic, neurodegenerative autosomal recessive disease that affects children and causes damage to nerve cells in the brain. The disease is most often diagnosed in Ashkenazi Jews living in Eastern Europe. Tabes dorsalis (locomotor ataxia) is a late form of neurosyphilis. The disease is characterized by damage to the posterior columns of the spinal cord and spinal nerve roots. The disease has three stages of development with a gradual increase in symptoms of damage to nerve cells. Coordination when walking is impaired, the patient easily loses balance, bladder function is often disrupted, pain appears in the lower limb or lower abdomen, and visual acuity decreases. The most severe third stage is characterized by loss of sensitivity of muscles and joints, areflexia of the tendons of the legs, development of astereognosis, the patient cannot move;
- Guillain-Barré syndrome - occurs at any age, refers to a rare pathological condition that is characterized by damage to the peripheral nerves of the body by its own immune system. In severe cases, complete paralysis occurs. In most cases, patients recover completely with adequate treatment;
- neural amyotrophy of Charcot-Marie-Tooth. A chronic hereditary disease, which is characterized by progression, affects the peripheral nervous system. In most cases, the myelin sheath of nerve fibers is destroyed; there are forms of the disease in which pathology of the axial cylinders in the center of the nerve fiber is detected. As a result of damage to the peripheral nerves, tendon reflexes fade and atrophy of the muscles of the lower and then upper extremities occurs. The disease belongs to progressive chronic hereditary polyneuropathies. This group includes: Refsum's disease, Roussy-Lévy syndrome, Dejerine-Sotta hypertrophic neuropathy and other rare diseases.
Genetic diseases
When damage to nerve tissue occurs, the body responds by destroying myelin. Diseases that are accompanied by the destruction of myelin are divided into two groups - myelinoclastics and myelinopathy. Myelinoclasty is the destruction of the membrane under the influence of external factors.
Myelinopathy is a genetically determined destruction of myelin associated with a biochemical defect in the structure of the neuron membrane. At the same time, this distribution into groups is considered conditional - the first manifestations of myelinoclasty may indicate a person’s predisposition to the disease, and the first manifestations of myelinopathy may be associated with damage caused by external factors.
Multiple sclerosis is considered a disease of people with a genetic predisposition to the destruction of the membrane of neurons, metabolic disorders, a deficient immune system and the presence of a slow infection. Genetic demyelinating diseases include: neural amyotrophy of Charcot-Marie-Tooth, hypertrophic neuropathy of Dejerine-Sottas, diffuse periaxial leukoencephalitis, Canavan disease and many other diseases. Genetic demyelinating diseases are less common than autoimmune demyelinating diseases.
Magnetic resonance imaging (MRI) in St. Petersburg
MRI of the brain. T2-weighted axial MRI. Multiple sclerosis. Color processing of the image.
Demyelination is the destruction of the sheath of the axon, the process of the nerve cell. The myelin sheath plays the role of “electrical wire insulation.” If it is violated, the conductivity of the electrical impulse is disrupted. Demyelinating diseases are of viral origin and proceed according to the autoimmune type. That is, the virus only triggers a breakdown of the immune system. There are 3 main demyelinating diseases: multiple sclerosis, acute disseminated encephalomyelitis and progressive multifocal leukoencephalopathy. MRI St. Petersburg has many centers where multiple sclerosis is detected. MRI in St. Petersburg demyelination occupies a large place in our clinics; we identify these processes both at the A.L. Polenov Research Institute of Neurosurgery and on open MRI. Multiple sclerosis (multiple sclerosis, MS) is an autoimmune demyelinating disease of the central nervous system. The process consists of local myelin destruction, axonal damage, gliosis and plaque formation. The frequency is about 2 per 1000 population. The M:F ratio is 1:2. The age of patients ranged from 2 to 74 years. However, in children and people over 50 years of age, the disease is rare, with a peak incidence at 35 years of age. Typically, the first attack of multiple sclerosis occurs around age 20. Clinic: several variants of the course of MS are known. Usually undulating, with progressive neurological deficit from relapse to relapse. Clinical signs – sensory and motor disorders, visual disturbances, pelvic disorders (80%). Various authors have proposed criteria for diagnosis. All of them are based on the results of MRI of the brain. The main thing for making a diagnosis is the presence of several (from 2 to 9) lesions typically located on MRI. The localization of the lesions can be any, but the typical one is the lower third of the corpus callosum, periventricular (around the ventricles of the brain), trunk, spinal cord. The shape of the lesions is round and ovoid, directed radially from the ventricles on sagittal (lateral) MRI (finger or Dawson sign), reflecting a perivenular (around the veins) process. There are many proposals for assessing process activity. Unfortunately, all methods of assessing activity are very unreliable. Typically, the edges of active lesions are unclear and there is weak contrast. The sensitivity and specificity of MRI in the earliest stages is 70-80%. However, after a very short period of the disease, the accuracy of MRI is already approaching 100%.
MRI of the brain. Multiple sclerosis. Axial T2-weighted MRI. Periventricular lesions.
Rare aggressive forms of multiple sclerosis include the tumor-like Marburg type and the concentric Balo type. Plaques reach large sizes with swelling and “layering” due to frequent exacerbations. Aggressive variants are bright on DWI-type MRI and contrast well.
MRI of the brain. T2-weighted axial MRI. Multiple sclerosis, Balo concentric type.
MRI of the brain, Same patient. Diffusion-weighted MRI.
Acute disseminated encephalomyelitis (post-infectious encephalitis) is an autoimmune disease that occurs after a viral infection or vaccination (3-6% of cases). The pathophysiology of ADEM closely resembles the early stages of multiple sclerosis. The frequency is about 1 per 100 thousand population. The age of the sick can be any, but 80% of the sick are children under 10 years old. The latent period (the period from infection to the first manifestations of the disease) ranges from 2 to 20 days. The onset of the disease is acute in the form of fever, impaired consciousness, lethargy, convulsions (25%), there may be optic neuritis, hemiparesis, ataxia (unsteadiness). Laboratory tests are nonspecific. Mortality even in the normal course is 10-30%. A variant of the disease is hyperacute hemorrhagic ADEM, which has a particularly high mortality rate. With a mild course of the disease, complete recovery is observed. The sensitivity of MRI for ADEM is 80-90%, and in some patients, changes are detected only a month after the onset of symptoms. MRI signs show demyelination - multiple asymmetrical, often confluent lesions. There are hemorrhages into the lesions. Localization, unlike RS, is any. In the first 1.5-2 months, the number of lesions increases. A characteristic sign of ADEM is the disappearance of lesions during recovery, which takes several months.
MRI of the brain. ODEM. Axial T2-weighted MRI. Dynamics of the process.
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of viral etiology that develops against the background of immunodeficiency. PML is a characteristic complication of AIDS, accounting for 1-4% of AIDS-related deaths. The etiology of PML, unlike MS, is well known - the disease is caused by the JC virus from the group of papovaviruses; it is the reactivation of a latent (“dormant”) infection against the background of immunodeficiency. The virus infects oligodendrocytes (cells that produce the myelin sheath of the nerve), destroying them, which leads to demyelination. Clinical manifestations increase gradually, from minor neurological disorders to impaired consciousness and death within 9-12 months. MRI reveals asymmetrical areas of demyelination, mainly in the parietal and occipital lobes. They are often confluent and extend to the subcortical zones.
MRI of the brain. PML. Early manifestations. Axial T2-weighted MRI.
You can also read about demyelination in the article “Radiation diagnosis of infectious diseases of the brain” on our website. With MRI in St. Petersburg in our clinics, when identifying a focal lesion, we see the main task in differential diagnosis, since similar lesions are found in many diseases.
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Symptoms
Demyelination always manifests itself as a neurological deficit. This sign indicates the beginning of the process of myelin destruction. The immune system is also involved. Brain tissue - spinal and brain - atrophies, and expansion of the ventricles is observed.
Manifestations of demyelination depend on the type of disease, causative factors and location of the lesion. Symptoms may be absent when the damage to the brain substance is minor, up to 20%. This is due to a compensatory function: healthy brain tissue performs the tasks of the affected areas. Neurological symptoms rarely appear - only when more than 50% of the nervous tissue is damaged.
The following are common signs of demyelinating brain diseases:
- paralysis;
- limited muscle mobility;
- tonic spasms of the limbs;
- dysfunction of the intestines and bladder;
- pseudobulbar syndrome (impaired pronunciation of sounds, difficulty swallowing, change in voice);
- impaired fine motor skills of the hands;
- skin numbness and tingling;
- visual dysfunction (decreased visual acuity, blurred images, fluctuations in the eyeballs, color distortions).
Neuropsychological disorders characteristic of the pathology in question are caused by memory deterioration and a decrease in mental activity, as well as changes in behavior and personal qualities. This is manifested by the development of neuroses, depression, dementia of organic origin, emotional swings, severe weakness and decreased performance.
Symptoms of demyelinating diseases
Demyelinating disease usually results in muscle weakness and stiffness, loss of vision, sensation and coordination, pain and bowel and bladder dysfunction. A more complete list of symptoms and signs consistent with demyelinating diseases:
- Motor symptoms: gait disturbance, limb weakness, spasticity, imbalance, hyperreflexia.
- Visual: diplopia (double vision), blurred vision, loss of vision and fluctuations in objects in the field of view.
- Sensory: parasthesia (tingling sensation), dysesthesia (abnormal sense of touch), numbness, pain in the trunk, trigeminal neuralgia (severe facial pain), hyperpathia (increased sensitivity and pain threshold), allodynia (pain from non-painful stimuli) and abnormal movement due to abnormal perception.
- Genitourinary: constipation, impotence, urinary incontinence, frequent urination, anorgasmia and dyspareunia (pain during sex).
- Nervous: anxiety, depression, irritability, impaired attention, concentration and memory impairment.
Diagnostics
An early stage of the pathology with the absence of characteristic symptoms is accidentally discovered during a diagnostic examination for another reason.
To confirm the diagnosis, neuroimaging is performed, and the neurologist determines the degree of impairment of the conductive function of the brain. The main diagnostic method is magnetic resonance imaging. In the photographs you can clearly see areas of the affected tissue. If you do angiography, you can determine the extent of vascular damage.
