What is Encephalitis, types and prevention

Simon Doyle
What is Encephalitis, types and prevention

Encephalitis is a disease in which inflammation of the central nervous system (CNS) manifests, affecting the brain mainly. Its etiology can be multifactorial, however the most common is due to viral or bacterial infections.


  • How encephalitis is generated
  • Signs and symptoms of encephalitis
  • Some types of encephalitis
  • Viral etiology of some types of encephalitis
  • Treatment for encephalitis
  • Encephalitis: fun facts
  • Encephalitis: 10 preventive measures
    • Links
    • Bibliographic reference

How encephalitis is generated

When infections pass into the bloodstream and cerebrospinal fluid (CSF), it can reach nerves and certain membranes causing inflammation, which is harmful and damages or destroys neurons.

Among the infections of the Central Nervous System (CNS), encephalitis is considered one of the most important along with meningitis, which is an infection of the membranes that surround the brain and spinal cord (meninges). When the brain and spinal cord become inflamed, it gives rise to a different condition called encephalomyelitis, and when there is damage to other structures near the brain such as the meninges, meningoencephalitis occurs..

Anyone can suffer from encephalitis, however subjects who have a depressed immune system, people with HIV / AIDS, those who take immunosuppressants, young children and the elderly must take better care of themselves, as they are risk groups in which encephalitis could have severe complications from not being treated promptly and properly.

The National Institute of Neurological Disorders and Stroke (NINDS) states that: “some types of encephalitis can be spread by contact with saliva, nasal discharge, feces or respiratory and throat secretions, they are a often spread through kissing, coughing, or sharing glasses, food utensils, or personal items such as toothbrushes, lipsticks, or cigarettes ".

When traveling or living in regions where there are certain mosquitoes and ticks, the pertinent preventive measures should be taken, such as maintaining the hygiene of your body and your home, using repellent and clothing that covers the body to minimize the risk of contagion, above all at some times of the year and hours of the day, when there is more proliferation of these animals.

Signs and symptoms of encephalitis

The prodromal picture is usually flu-like, includes headache, muscle or joint pain, as well as fever and fatigue. It may be asymptomatic at first or present a picture similar to that of a mild influenza. Sometimes the syndrome becomes acute and fulminant, some of its most severe symptoms are: sensory or motor problems, such as loss of sensitivity or paralysis in certain areas of the face or body, agitation, seizures, loss of consciousness, confusional states, problems of hearing and speech, likewise, hallucinations may occur.

It is important to be very attentive in the care of the health of children and babies, in the latter, the characteristic symptoms of encephalitis include protrusion in fontanelles, which are the "soft spots" between the bones of the baby's skull..

In addition to the symptoms of a nonspecific reaction, focal or generalized neurological symptoms appear. Timely and appropriate diagnosis and treatment can mark the course of the condition and its consequences..

Some types of encephalitis

Vallejo divides them into: allergic, demilelinating of undefined etiology and viral or infectious, there are many types of viruses capable of developing encephalitis in humans, as well as bacteria, fungi and parasites, among many other agents. Two main types of encephalitis are identified:

  1. Primary encephalitis: occurs when a virus or other agent infects the brain, it can be a reactivation of a virus that had been inactive after an illness and be localized in a single region or be widespread.
  2. Secondary encephalitis: caused by a faulty reaction of the immune system in response to an infection in other parts of the body or to a systemic inflammatory response, in this type of encephalitis instead of fighting the cells that cause the infection, the immune system also attacks cells healthy brain. Like progressive multifocal leukoencephalopathy, which is demyelinating, its course is fatal after three or four years, it is usually associated with leukemia and lymphomas.

There are many types of encephalitis, due to their varied etiology; we can find the following categories with some representative examples:

  1. Fungal: cryptococcus, coccidioides, aspergillus.
  2. Bacterial: pneumococcus, meningococcus, staphylococcus aureus.
  3. Parasitic: cysticercosis, schistosomiasis, echinococcosis.
  4. Viral: influenza, rotavirus, adenovirus.

Viral etiology of some types of encephalitis

Herpes simplex encephalitis (HSE): in most cases it is caused by the reactivation of an infection, the virus manages to survive by remaining in a latent state within the body.

  1. Herpes simplex virus type 1 (HSV1): it is transmitted by contact with an affected person, brain damage can become serious when it is not treated in time, especially in adults and children after the neonatal period, it mainly affects the temporal and frontal lobe as well as the limbic system.
  2. Herpes simplex virus type 2 (HSV2): transmitted through sexual contact, it is not so frequent; although it happens in few cases, the mother with HSV2 can transmit it to her child at birth through contact with genital secretions.

Others are the varicella-zoster virus (VZV) and the Epstein-Barr virus, which often causes infectious mononucleosis. Measles, mumps and rubella, were the cause of common encephalitis, this problem has greatly diminished thanks to vaccination.

Some of the viruses transmitted by mosquitoes are arboviruses, they are transmitted by hematophagous arthropods ... Flies, mosquitoes, arachnids and certain ticks, such as: LaCrosse, San Luis and West Nile, the latter is transmitted by the bite of An infected mosquito, likewise, can manifest itself after transplantation of a rejected organ and by transfusions of infected blood or blood products. Older adults and people with immune deficiencies are at higher risk for complications.

Powassan encephalitis is caused by viruses transmitted by ticks, the arbovirus is carried by them, the symptoms appear after 7 to 10 days, the most severe ones come to manifest partial paralysis and coma, it is estimated that in half of the cases it produces permanent neurological damage and mortality is low. Lyme disease can also cause encephalitis.

Treatment for encephalitis

It must be indicated by a doctor, self-medication for the treatment of symptoms can put the patient's health at risk and lead to unnecessary complications. For example, in certain cases, the use of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) is contraindicated due to their antiplatelet activity, despite being widely used drugs. Only a trained doctor can guide you in this regard.

Encephalitis: fun facts

  • An encephalitis epidemic ravaged Europe in the 1920s; Using a biological model, cases of encephalitis were studied whose subcortical sequelae were superimposable to the authentic obsessive manifestations (Vallejo, 1989).
  • Certain pictures of encephalitis, traumatic injuries and tumors can cause dysphasia, this differs from that of development by the presence of focal signs or associated seizures.
  • Postviral encephalitis can lead to tics and damage Von Economo neurons, they are those nerve cells that compare signals received from the sensory organs with those from the brain.
  • Post-encephalitic residual pictures can cause alterations in memory, language, intellectual, affective and behavioral, as well as psychotic pictures very similar to endogenous ones.

Encephalitis: 10 preventive measures

  1. Maintain good personal hygiene.
  2. Get vaccinated and vaccinate your children, this is how you protect them.
  3. Identify and perform vector control in your home, your yard and areas that you frequent.
  4. Keep your house and surroundings clean, avoiding leaving stagnant water.
  5. Use mosquito repellent that does not harm the environment, if your environment warrants it.
  6. In case of travel to an endemic place due to a primary cause of encephalitis, take measures and prevent risks.
  7. Strengthen and take care of your immune system.
  8. Protect the central nervous system
  9. Don't share eating or drinking utensils, or cosmetics like lipsticks.
  10. Assist with your doctor to perform health checks or "check up's", especially if you manifest any symptoms and have ignored them.


  • https://espanol.ninds.nih.gov/disorders/meningitis_y_encephalitis.htm
  • https://www.msdmanuals.com/fr/accueil/troubles-du-cerveau,-de-la-moelle-%C3%A9pini%C3%A8re-et-des-nerfs/infections-c%C3%A9r% C3% A9brales / enc% C3% A9phalite

Bibliographic reference

Moore, David P. and Jefferson, James W. (2005). Manual of medical psychiatry. 2nd. Edition. Spain: Mosby / Elsevier.

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