What Is Viral Encephalitis?

The brain inflammation caused by the virus directly invading the brain parenchyma is called viral encephalitis. Symptoms such as hemiplegia, tetraplegia, and vision loss can occur.

The brain inflammation caused by the virus directly invading the brain parenchyma is called viral encephalitis. Symptoms such as hemiplegia, tetraplegia, and vision loss can occur.

English name

viral encephalitis

Visiting department

Neurology

Whether it is contagious

infection

Disease site

brain

Can it be cured

Can be cured

way for spreading

Respiratory secretions

Causes and common diseases of viral encephalitis

Most of the diseases are enterovirus infections, including polioviruses, coxsackieviruses A and B, and ecovirus. They are epidemic or scattered, and they are transmitted mainly through the fecal-oral route, and a few are transmitted through respiratory secretions. Followed by mumps virus, herpes virus and adenovirus infection. Mumps virus occurs frequently in winter and spring and is often self-limiting. Herpesviruses include herpes simplex virus, Epstein-Barr virus, cytomegalovirus, and varicella-zoster virus. Arboviruses are viruses that are conserved in nature through transmission between vertebrate and haemophilous arthropod hosts. They are distributed in multiple virus families, and at least 80 species can infect humans.

Differential diagnosis of viral encephalitis

(1) Mumps virus encephalitis:

The virus directly invades the brain, most of which are symptoms of meningitis, hemiplegia, tetraplegia, vision loss, deafness, and aphasia. Mumps often occur at the same time or successively with encephalitis. The general diagnosis is not difficult. Those without mumps can be diagnosed by serum immunology. The prognosis is good after symptomatic treatment.

(Two) herpes zoster encephalitis:

Rarely, individual cases develop meningitis and encephalitis after herpes on the trunk or head and face. Treatment is the same as herpes simplex encephalitis.

(3) CMV Encephalitis:

Most are fetal and neonatal infections, occasionally seen in children and adults. Most of the disease manifests as brain dysplasia, microcephaly, calcification around the ventricles and in the brain, and hydrocephalus. Adults can show acute polyneuritis. Any infant with small head deformities, especially with choroiditis, omental calcification, cataracts, and optic nerve atrophy, should be suspected of this disease.

(4) Progressive rubella encephalitis:

It means that the mother suffered from rubella during pregnancy, and the encephalitis that occurred within 14 years of age of the child was a lentivirus infection. Symptoms are progressive and may include epilepsy, deafness, and dementia. Or show various brain developmental abnormalities. Acquired rubella encephalitis is usually mild, and the prognosis is good without special treatment. Virus isolation and serum immunoassay during infection can confirm the diagnosis.

(5) Infectious mononucleosis (EB virus) encephalitis:

It occurs in the case of systemic diseases, and occasionally occurs before blood and visceral symptoms. May have paralysis, aphasia, hyperactivity, neurological damage to the cerebellum, ataxia, and paraplegia. Typical hematology and Heterophil confirm the diagnosis. The prognosis is good, and more complete recovery.

Viral encephalitis test

(1) CT examination:

1. Part:

It is mainly located in the anterior medial temporal lobe and insula, and the density to the outside of the lenticular nucleus is suddenly normal, which is a characteristic CT manifestation of the disease. Lesions can affect the frontal lobe forward, the frontal parietal lobe upward, the occipital lobe backward, and the inner capsule inward.

2. Ordinary scanning:

The diseased area appears as a low-density area with unclear boundaries. This sign is most obvious in the first week after the disease, which can last for more than 4 weeks, and the density becomes lower and lower with the course of the disease, and the boundary of the low-density area becomes increasingly clear. High-density lesions can be seen in many cases, which is a sign of encephalitis bleeding. Due to severe cerebral edema in the necrotic area, a space-occupying effect may occur, causing compression and deformation of the adjacent ventricle, and the midline structure may shift to the healthy side.

3. Enhanced scanning:

About 2 to 4 weeks after the onset, about half of the cases showed line-like enhancement around the low-density area, with the lateral fissure and the most prominent around the islets.

(B) MRI examination:

Viral encephalitis has more manifestations on MRI, but they are not characteristic, mainly single or multiple lesions in the brain with blurred borders; T1WI is equal and low signal, T2WI is high signal, of which herpes simplex virus The MRI manifestations of encephalitis are: the basal, medial, and insular areas of the temporal lobe are limited by long T1 and long T2 signals, which are usually localized on one or the other side and are lighter. They can spread to the frontal lobe and sometimes spotted and patchy Hemorrhage, diffuse or cerebral gyrus enhancement after Gd-DTPA injection.

Viral encephalitis treatment principles

(A) general care:

Maintain a quiet environment in the ward, keep the air in the ward free, and control the room temperature at 20 22 ; ensure a high-calorie, high-protein, high-vitamin diet, light and easy to digest, maintain sufficient energy supply, and avoid spicy and irritating food.

(2) antiviral treatment;

(Three) symptomatic treatment:

Cool down, stop panic and reduce intracranial pressure.