Subacute sclerosing panencephalitis

Introduction to subacute sclerosing panencephalitis Subacutes sclerosing panencephalitis (SSPE), also known as Dawson encephalitis, is a rare progressive dementia disease in children and adolescents associated with measles virus or measles virus variants. Sexual onset, subacute or chronic progression and fatal outcome. In 1924, Schilder first described the characteristics of the disease. In 1933, Dawson discovered inclusion bodies in the brain tissue of two death cases, called subacute inclusion body encephalitis, which was confirmed to be related to viral pathogens. Paramyxovirus-like particles. High titer anti-measles virus antibodies were detected in the patient's cerebrospinal fluid and serum. In 1969, measles virus was isolated from the patient's brain cell culture. basic knowledge The proportion of illness: 0.005% Susceptible people: no special people Infection mode: virus infection. Complications: disturbance of consciousness, coma

The cause of subacute sclerosing panencephalitis

(1) Causes of the disease

It is believed that this disease is a chronic infection of measles virus, and whether the measles virus will become defective and continue to infect the body is related to the body's immune regulation function defects.

The study found that patients with serum and cerebrospinal fluid increased the titer of anti-mesher virus antibody, there is measles virus antigen in the cerebral cortex, brain biopsy can find intracellular inclusions, and there is measles-like dense particle accumulation, the brain tissue of patients Non-neural cells are co-cultured, about half of which can be obtained by virus, and the animal brain tissue is inoculated into the animal, which can successfully infect the animal. All of the above cases support the disease and measles virus infection.

(two) pathogenesis

1. Pathogenesis: The pathogenesis of SSPE has not been fully elucidated. It is speculated that the molecular pathogenesis of SSPE may be due to the mutation of the original measles virus or the infection of the measles virus, which cannot be eliminated.

Multiple groups of studies have found that the membrane proteins that cause SSPE measles virus, matrix protein (M protein), fusion protein (fusion protein, F protein) and hemagglutinate protein (H protein) have defects in expression, affecting The budding and extracellular release of the virus causes the virus to accumulate in the brain cells, forming a persistent infection of the central nervous system.

Another speculation is that the body's immune response to measles virus is defective, causing measles virus to infect the brain for a long time, and under certain conditions, this is the immune pathogenesis of SSPE, because SSPE occurs mostly in young age (especially Within 1 year of age, children infected with measles think that the virus acts on young hosts with immature immune function, resulting in the virus persisting in the central nervous system with incomplete or defective type. It is presumed that the virus M polypeptide is defective because The translation process of information RNA to M polypeptide fails, and it is believed that the complete measles virus producing free virus evolves into the M protein polypeptide-deficient virus that does not produce free virus in the central nervous system, causing persistent infection may be in the pathogenesis of SSPE. A key issue, the defective virus is transmitted to neighboring cells in the form of nucleocapsids in the brain, resulting in progressive damage of brain cells.

In summary, the pathogenesis of SSPE may be related to the characteristics of the virus and the immune status of the host.

2. Pathology: Its pathological damage spreads throughout the white matter and gray matter of the central nervous system.

The diffuse brain atrophy can be seen by the naked eye, and it can be felt too hard. The microscopic examination showed that the perivascular lymphocytes in the cortex and white matter, the macrophages and plasma cells were in a sleeve-like infiltration, and the gray matter of the brain showed different degrees of nerve cell loss. In the white matter and white matter, there are patchy demyelination and gliosis (sclerosing encephalitis), and eosinophilic inclusions can be seen in the nucleus and cytoplasm of nerve cells and glial cells. Electron microscopy shows that inclusion bodies are composed of The nucleocapsid of the mucinous virus is composed of hollow small tubes. The fluorescent antibody staining shows that the measles virus is positive, and the inclusions in the acute phase or the shorter course are more common. In the chronic cases, more white matter myelin is lost.

Subacute sclerosing panencephalitis prevention

Measles vaccination is the most effective way to prevent this disease. Since the application of live attenuated vaccine, the green color of SSPE has decreased significantly.

1. Newborns and children actively implement planned immunization as required.

2. Early comprehensive treatment, reduce complications and prolong survival.

Subacute sclerosing panencephalitis complications Complication, conscious disorder, coma

Can be secondary to secondary infection, circulatory failure, cachexia and so on.

1. Consciousness disorder, and finally gradual coma.

2. Go to the cortex or go to the brain to be stiff, and there may be a horn arch.

3. Often accompanied by autonomic dysfunction.

4. Combined infection or circulatory failure.

Subacute sclerosing symptoms of whole brain inflammation Common symptoms Amnesia muscle hernia reflex hyperinjury intelligent decline coma circulatory failure

Insidious onset, slow development, no fever, can be divided into four phases according to the evolution of the disease:

The first phase is the period of behavioral and mental disorders, with forgetfulness, decreased academic performance, emotional instability, personality changes and behavioral abnormalities. This period lasts for several weeks to several months.

The second phase is the dyskinesia period, which is mainly characterized by severe progressive mental decline with extensive myoclonus, ataxia, seizures, and visual impairment caused by progressive chorioretinitis, which lasts about 1 to 3 months.

The third phase is coma, the angulation of the horn, the limb muscle rigidity, the hyperreflexia, the Babinski sign positive, the cortex or the brain tonic, the angulation, and finally the coma, often accompanied by autonomic dysfunction It can last for several months.

The fourth phase is the end stage, the cerebral cortex function is completely lost, the eyeball is floating, the muscle tension is low, the myoclonus disappears, and the patient eventually dies from co-infection or circulatory failure.

The total course of disease is usually 1 to 3 years, and 10% of deaths and survival in 3 months each account for about 10%.

Examination of subacute sclerosing panencephalitis

1. Cerebrospinal fluid: normal pressure and routine examination, or a slight increase in the number of cells, protein content can also be increased, the gold curve is a typical paralysis type.

2. Determination of measles virus antibodies in serum and cerebrospinal fluid: There are persistent high-dose measles virus antibodies in the serum, and there are persistent measles virus antibodies in the cerebrospinal fluid. It is currently believed that measles virus is found in cerebrospinal fluid on the basis of sustained high serum antibody levels. Antibodies have significant diagnostic value.

3. CT examination: early brain disease CT can be found without positive, with the development of the disease, it can show cortical atrophy, ventricular enlargement and focal or multiple white matter low density lesions.

4. Brain MRI: In the early stage of the disease, sometimes the high-signal area of the focal T2-weighted image can be displayed, first involving the cortex, subcortical white matter, then affecting the white matter around the ventricle, and showing progressive extensive brain atrophy, severe white matter can be Complete loss, corpus callosum is also thin, basal ganglia lesions usually occur in the early and middle stages of the disease, with soy nucleus damage more common.

5. EEG examination: its typical change shows that several direct-like high-amplitude (200-600V) slow waves appear periodically in each lead in normal background activities, lasting about 0.5~3s, and every 4~20s bursts once. That is, "R complex wave", such abnormal changes have important value for the diagnosis of SSPE, often appearing synchronously with clinical myoclonus.

Diagnosis and diagnosis of subacute sclerosing panencephalitis

According to the typical clinical characteristics, combined with special EEG abnormal wave and high titer measles virus antibody of serum cerebrospinal fluid, the clinical diagnosis of SSPE can be made. If there is pathological histological material confirmed or detected measles-like virus, then The diagnosis is diagnosed, but it is generally considered after the second period. It is difficult to make a diagnosis in the first phase. It is noted that the use of sound, light and tactile stimulation in the early stage of the disease can induce the patient to appear early. Sexual "action sputum" and EEG changes (especially easier to induce during sleep), this induced test is important for early diagnosis.

It needs to be differentiated from childhood and adolescent dementia, such as congenital hypoplasia, inherited metabolic diseases, brain trauma, and other developmental disorders of the central nervous system (HIV and rubella).

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.