Content

Introduction

Introduction

Encephalitis is an inflammation of the brain tissue and can affect anyone even if the people most at risk are the elderly, immunosuppressed individuals and children. The disease is very rare, but very serious, it can require urgent care that needs to be done in the hospital and, in some cases, it can be fatal.

Symptoms

Symptoms

Symptoms of encephalitis, especially in the early stages, are not specific; flu-like symptoms (symptoms) such as high fever, headache (headache) or nausea and vomiting, which, over hours, days or weeks, can become worse with the appearance of more specific symptoms, such as:

  • mental confusion or disorientation
  • convulsions
  • personality change or behavior
  • difficulty speaking
  • reduced or absent ability to move some parts of the body (paresis, paralysis)
  • hallucinations visual and / or auditory
  • loss of sensation in some parts of the body
  • involuntary eye movements
  • vision problems and sensitivity to light (photophobia)
  • loss of consciousness

Disturbances characteristic of meningitis such as:

  • intense headache
  • sensitivity to light (photophobia)
  • stiffness in the neck and nape
  • appearance of redness and reliefs on the skin (skin rashes) that do not subside under pressure. (the red area, pressed with a finger to check the reaction, does not change the color)

In the presence of even some of the specific disorders (symptoms) described, it is essential to contact the emergency services immediately (to be accompanied to the emergency room). A suspected encephalitis, in fact, must be considered a "medical emergency that requires" immediate attention by qualified personnel.

Causes

Causes

In over 50% of cases of encephalitis, the causes remain unknown, but known causes of encephalitis can include:

Infectious agents

  • common viral infections: encephalitis can be a rare complication of more frequent viral infections, herpes simplex virus infections, chicken pox, measles, mumps (mumps), flu and rubella are some examples
  • viral infections contracted from animals or vector arthropods: for example, tick-borne encephalitis, rabies (transmitted by canids and other mammals), West Nile virus encephalitis (west nile, transmitted by mosquitoes), Japanese encephalitis (transmitted by mosquitoes), encephalitis summer from "Toscana virus" (transmitted by sand flies) and, probably, rare cases originating from the zika virus (transmitted by mosquitoes). Some of the viruses that can cause encephalitis are present in Italy, such as the West Nile virus, the tick-borne encephalitis virus, the "Toscana virus", while others are present in certain geographic areas, so you must inform yourself about the risks if you intend to travel to countries where the disease is present (Travelers' diseases)
  • bacterial infections: some bacterial infections can reach the central nervous system and cause meningitis and meningo-encephalitis, among the bacterial infections, those from pneumococcus (streptococcus pneumoniae), haemophilus (haemophilus influenzae) and listeria (listeria monocytogenes) are the most frequent
  • in rare cases they can be caused by fungi (fungi) or parasites

Encephalitis caused by infectious agents, by themselves, are not transmissible from individual to individual.

The encephalitis listed above are also defined primary as the virus or other infectious agent directly affects the brain.

Encephalitis due to impaired immune response

Encephalitis due to impaired immune response, also called secondary they are caused by an abnormal reaction of the body's defense system (immune system) following an infection that has occurred in other parts of the body. The immune system, instead of attacking only the agents responsible for the infection, mistakenly attacks healthy cells as well of the brain. Often, secondary encephalitis occurs two to three weeks after the initial infection.

Diagnosis

Diagnosis

The disorders (symptoms) caused by encephalitis can have different causes, therefore, to arrive at the definitive assessment (diagnosis) of the disease, several investigations are necessary, which include:

  • radiographic investigations, useful for differentiating encephalitis from other diseases that can cause similar disorders (symptoms) such as, for example, stroke or brain haemorrhages, tumors or brain aneurysms:
    • CT scan (computerized axial tomography) of the skull: uses X-rays, projected from different angles and, subsequently, processed by a computer to create a "detailed image of the brain
    • MRI (nuclear magnetic resonance imaging) of the skull: uses magnetic fields and radiofrequencies to produce a "high-resolution image of the brain
  • lumbar puncture, procedure that allows you to take a small amount of cerebrospinal fluid from the spine to analyze it and verify the presence, or not, of some alterations, such as viruses, bacteria, specific antibodies, fungi, parasites or other that allow to ascertain (diagnose ) "encephalitis
  • other investigations
    • electroencephalogram (EEG), allows, through the application of some electrodes on the scalp, to record the electrical activity of the brain. Some anomalies of this activity suggest the presence of encephalitis
    • blood and urine tests, allow you to detect any signs of infection
    • brain biopsy, taking a very small fragment of brain tissue for further analysis. It is a rarely performed procedure
Therapy

Therapy

Treatment (therapy) of mild cases of encephalitis may consist of bed rest, hydration and the use of anti-inflammatory drugs to combat fever and headache (headache).

In the case of viral encephalitis, antiviral drugs such as, for example, aciclovir, ganciclovir and foscarnet can be used. These drugs, however, are not effective against all types of viruses responsible for the disease. For diseases caused by bacteria or fungi, treatment with antibiotic or antifungal drugs is carried out.

Supportive therapy includes, if necessary, respiratory assistance, intravenous hydration and the use of anti-inflammatory drugs.

In the period following the acute phase, depending on the type of complications that may have appeared, physiotherapy, occupational therapy (or occupational therapy), speech therapy, cognitive-behavioral therapy or psychotherapy may be useful.

Prevention

Prevention

Prevention is especially effective for encephalitis caused by infectious agents. The best way to prevent viral or bacterial encephalitis is to take all necessary precautions to avoid contact with the viruses and bacteria responsible for the disease.

Certain hygiene rules must be observed such as, for example, washing your hands frequently and thoroughly with soap and water, especially after going to the bathroom and before and after meals (Video); do not use other people's cutlery if not well washed; avoid the exchange of cutlery at school and at home and teach children to practice hygiene rules.

In particular for the prevention of infection with listeria monocytogenes (listeriosis), attention must be paid to the conservation status and preparation of certain foods, such as cheeses and dairy products, ready-to-eat foods, cured meats and packaged fish products.

Furthermore, it is strongly advised to follow the vaccination protocols and, before going abroad, to inquire about the vaccinations recommended for the state you intend to visit, as effective vaccines are available for some viruses and bacteria responsible for encephalitis.

Finally, in areas where mosquito-borne or tick-borne viruses are present, all measures must be taken to avoid being bitten:

  • use repellents
  • dress appropriately
  • use protective nets at night
Bibliography

Bibliography

Mayo Clinic. Encephalitis (English)

NHS Choices. Encephalitis (English)

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