Demyelination

Introduction to demyelination Demyelination refers to the damage of myelin sheath after myelination. The demyelinating disease is a group of diseases characterized by loss of neuromyelin, and relatively minor involvement of neuronal inclusions and axons, including hereditary And access to two major categories. Hereditary demyelinating diseases mainly refer to white matter malnutrition, which is more common in children. Acquired demyelinating diseases are divided into two categories: central and peripheral. The most representative of the peripheral demyelinating diseases are acute and chronic inflammatory demyelinating polyneuropathy. Central demyelinating diseases include multiple sclerosis and acute disseminated encephalomyelitis. basic knowledge The proportion of illness: 0.025% Susceptible people: no specific population Mode of infection: non-infectious Complications: hemiplegia

Demyelinating cause

1. Immune-mediated, such as multiple sclerosis, acute infectious polyneuritis.

2, viral infections, such as progressive multifocal leukoencephalitis, subacute sclerosing whole encephalitis.

3, nutritional disorders, such as pons central myelin disintegration.

4. Hypoxia, such as demyelin encephalopathy after delayed hypoxia, progressive cortical ischemic encephalopathy. Generally, the clinical diagnosis of demyelinating diseases refers to immune-mediated demyelinating diseases, including multiple sclerosis and acute infectious polyneuritis.

Demyelinating prevention

1, it is recommended to avoid infection, especially respiratory and digestive system infections.

2. The recurrence of some young female patients is accompanied by pregnancy, suggesting an increased risk during pregnancy, and attention should be paid to changes in neurological symptoms during pregnancy.

Demyelinating complications Complications

Demyelinating diseases develop with the disease and often cause hemiplegia.

Demyelinating Symptoms Common Symptoms Lack of eye muscle paralysis limb weakness, sensory disturbance, cerebellar ataxia, hyperthermia visual impairment, muscle tone reduction, hemianopia, lateral limb hemiplegia

1, multiple sclerosis

The onset age is mostly between 20 and 40 years old, mostly in a subacute manner. Most patients show multiple lesions, and the course of disease is characterized by remission-recurrence.

(1) The most common weakness of the limbs, about 50% of patients with first symptoms of one or more limb weakness.

(2) Paresthesia is manifested by the numbness of the body, trunk or face, chills of the limbs, sensation of the ants.

(3) Eye symptoms, acute monocular vision loss, eye muscle paralysis.

(4) Some patients with ataxia can be seen with nystagmus, intentional tremor, and poetry-like language.

(5) Sudden onset of paroxysmal symptoms, sensation or motor abnormality that can be induced by special factors.

(6) Psychiatric symptoms are mostly depression, irritability and temper.

(7) Other symptoms include bladder dysfunction, and male patients may also have sexual dysfunction.

2, acute disseminated encephalomyelitis

Occurs in children and young adults, sporadic cases are more common. Most of them start acutely from 1 to 2 weeks after infection or vaccination. Encephalomyelitis often occurs 2 to 4 days after the rash, often manifested as the rash is subsiding, the symptoms are improving, suddenly there is high fever again, accompanied by headache, fatigue, body aches, convulsions and disturbance of consciousness in severe cases. Hemiplegia, hemianopia, visual impairment and ataxia are also common.

3. Acute inflammatory demyelinating polyneuropathy

It can occur at any age, and the incidence rate is similar for men and women. Most patients have symptoms of respiratory or gastrointestinal infections. The first symptom is the distal symmetry weakness of the extremities, which quickly increases and progresses to the proximal end. Severe can cause respiratory paralysis. Flaccid phlegm. Sensory dysfunction manifests as paresthesia of the distal extremities and a decrease in gloves and socks. Muscles can have tenderness. Bilateral paralysis is most common.

4. Chronic inflammatory demyelinating polyneuropathy

It occurs at any age and is more common in middle-aged men. There is often no history of pre-infection, mainly manifested as peripheral neuropathy involving both sensory and motor. Physical examination showed that the muscles of the extremities were reduced, the muscle tension was reduced, the anti-reflection disappeared, and the extremities of the extremities felt diminished.

Demyelinating examination

1, multiple sclerosis

(1) Examination of cerebrospinal fluid The number of mononuclear cells can be normal or slightly elevated. Intrathecal IgG synthesis or oligoclonal IgG bands are important indicators for the diagnosis of multiple sclerosis. In the acute phase of cytology, small lymphocytes are dominant; the remission phase is mainly activated monocytes and macrophages.

(2) Electrophysiological examinations include visual, brainstem auditory and somatosensory evoked potentials, without diagnostic specificity, and assist in early diagnosis.

(3) Imaging examination routine CT scan is more normal. MRI is the most effective adjunct to the diagnosis of multiple sclerosis. The characteristic manifestation is that there are multiple long T1 and T2 signals in the white matter, which are scattered around the ventricles, the corpus callosum, the brainstem and the cerebellum.

2, acute disseminated encephalomyelitis

(1) The white blood cell count of the surrounding blood is increased, and the erythrocyte sedimentation rate is increased.

(2) The number of cerebrospinal fluid cells is normal or slightly increased, mainly monocytes. The protein is mildly or severely elevated.

(3) EEG is extensive and moderately abnormal.

(4) The diffuse multifocal low-density area in the white matter of CT is obviously enhanced in the acute phase.

(5) Most MRIs are long T1 and long T2 abnormal signals.

3. Acute inflammatory demyelinating polyneuropathy

(1) The peripheral blood cell count is slightly elevated.

(2) Protein-cell separation after 2 to 3 weeks of onset, that is, cerebrospinal fluid protein is increased and the number of cells is normal, which is characteristic.

(3) Electromyography shows that the F wave or H reflection is delayed or disappeared, and the nerve conduction velocity is slowed down.

4. Chronic inflammatory demyelinating polyneuropathy

(1) The number of cells in the cerebrospinal fluid is normal, and the protein content is significantly increased.

(2) Electrophysiological examination showed that the movement speed was significantly slowed down and the F wave latency was prolonged.

(3) Neurobiopsy showed neurofibrillary myelin segmental loss with axonal degeneration.

Demyelination diagnosis

diagnosis

First, medical history and symptoms:

Many young and middle-aged patients have symptoms of respiratory infection or vaccination within two weeks before the disease. There are causes of cold, overwork, trauma and other causes. The first symptom was numbness and weakness in the lower limbs, back pain and banding in the corresponding parts of the lesion, urinary retention and fecal incontinence.

Second, physical examination found:

There is a manifestation of traverse damage of the spinal cord:

1. In the early stage, the "Spiral Shock Stage" manifested as a flaccid paralysis. After the shock period (3-4 weeks), the limbs under the lesion showed upper motor neuron.

2. The depth of the lesion below the plane disappears, and some may have a lesion-like sensory allergy zone.

3, autonomic disorders: manifested as urinary retention, a large number of residual urine and filling urinary incontinence, fecal incontinence. After the shock period, there is a reflex bladder and constipation, and the penis is abnormally erect.

Third, auxiliary inspection:

1. The white blood cell count in the peripheral phase of the acute phase is normal or slightly higher.

2, cerebrospinal fluid pressure is normal, some patients with mild increase in white blood cells and protein, sugar, chloride content is normal.

3. Spinal MRI showed thickening of the spinal cord and abnormal signal.

Identification

Need to be differentiated from acute epidural abscess, spinal tuberculosis, spinal metastatic tumor, optic neuromyelitis, spinal cord hemorrhage.

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