Encephalitis: causes and classification

Encephalitis is an inflammation of the brain substance. Currently, encephalitis is not only called infectious, but also infectious-allergic, allergic and toxic damage to the brain.

The classification of encephalitis reflects the etiological factors associated with them clinical manifestations and features of the course.

By the time of occurrence

• Primary - independent diseases caused mainly by neurotropic viruses:
  • viral:
    • viral (polysone): herpetic, enterovirus, influenza, cytomegalovirus, rabies, etc .;
    • arbovirus (transmissible): tick-borne, mosquito (Japanese), Australian Murray Valley, American St. Louis;
    • caused by an unknown virus: epidemic (Economone);
• microbial and rickettsial:
  • with syphilis;
  • borreliose;
  • typhus and others.
• Secondary - diseases that occur against the background of the underlying disease:
  • postexemembrane:
    • measles;
    • rubella;
    • wind turbines;
  • post-vaccination:
    • after DTP;
    • after measles, rubella, mumps vaccination;
  • bacterial and parasitic:
    • staphylococcal;
    • streptococcal;
    • tubercular;
    • toxoplasmic;
    • chlamydial;
    • malarial and others;
  • demyelinating:
    • acute encephalomyelitis;
    • multiple sclerosis.

By the rate of development and flow:

• super-fast;
• sharp;
• subacute;
• chronic;
• recurrent.

By localization:

• cortical;
• subcortical;
• stem;
• defeat of the cerebellum.

By prevalence:

• leukoencephalitis (white matter damage);
• polyoencephalitis (damage to gray matter);
• panencephalitis.

By morphology:

• necrotic;
• hemorrhagic.

By gravity:

• of moderate severity;
• heavy;
• extremely heavy.

Complications:

• edema-swelling of the brain;
• dislocation;
• cerebral coma;
• epileptic syndrome;
• cystosis.

Outcomes:

• recovery;
• vegetative state;
• gross focal symptoms.

Encephalitis caused by neurotropic viruses is characterized by epidemics, contagiousness, seasonality and climatic and geographic features of distribution. Depending on the primary localization of encephalitis are divided into stem, cerebellar, mesencephalic, diencephalic. Often, along with the substance of the brain, some parts of the spinal cord also suffer; in such cases they speak of encephalomyelitis. Encephalitis can be diffuse and focal, the nature of the exudate - purulent and serous.

Primary polyseason encephalitis

This group includes encephalitis of various etiologies, including those caused by enteroviruses Coxsackie (A9, B3, B6), ECHO (2, 11, 24) and many unknown viruses.

Clinical picture

In the clinical picture of enteroviral encephalitis several syndromes are distinguished: stem, cerebellar, hemispheric. Focal neurological symptoms develop against a background of moderately expressed common infectious and cerebral symptoms on the 2-5th day of the disease. The etiologic factor is identified in virological and serological studies. In the cerebrospinal fluid, lymphocytosis is usually detected.

The course is favorable, with complete regression of neurologic symptoms. Rarely are slight lesions of III, VI, VII pairs of cranial nerves, hemi and monoparesis, aphasic disorders. The most favorable cerebellar form, the recovery with it is always complete.

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