What is encephalitisEncephalitis is a diffuse inflammation of the brain, i.e., of the brain. Its main cause is viral infections. It's a disease whose frequency is difficult to determine; This is because most of the time the encephalitis cause symptoms mild and very diffuse, similar to the flu or a cold. Why is suspected that some flu-like pictures are actually mild encephalitis that heal alone. However, in a small percentage of cases, encephalitis can cause severe symptoms, which are the manifestation of a brain injury. Although the mortality of encephalitis is not very high, it is frequent neurological sequelae after illness from appearing.
Incidence of encephalitisThe frequency of encephalitis in the general population is not very high. Only appear three or five cases for every million inhabitants. The population groups that suffer most from the disease are children, in those who are five or 10 cases per 100,000 inhabitants, and especially the children of less than one year of age. The aftermath of encephalitis is much more dramatic in this age group, since they have a whole life ahead which may be conditioned by a disability.
Encephalitis can be cured, only treatment of symptoms is required and to let time do its work. Fortunately, every time there are more specific drugs to kill the viruses responsible for. But if there is something that has changed the impact of this disease in the society they are vaccines. Many viral infections that cause encephalitis (measles, enterovirus, poliomyelitis, etc.) are preventable today with vaccines safe, and mandatory in most countries of the world.
Causes of encephalitisThe cause of encephalitis are infections by virus neurotropos, i.e. viruses that have a special affinity for the central nervous system. These viruses can be transmitted in different ways; some of them by airway (such as measles virus), some faecal (such as polio virus) and even STDs (such as herpes simplex type 2 virus). The main virus that can cause encephalitis are:
- Herpes simplex virus type 1 or 2 (VHS): are the viruses that cause innocent cold sores or genital herpes. The virus remains in nervous ganglia life, and occasionally migrates to the skin causing itching and blistering. In a few cases the virus can go wrong and migrate towards the central nervous system causing an encephalitis.
- Other herpes-type viruses: within the Group of herpes viruses, there are others that can cause encephalitis, as well as other diseases. Some of them are the Epstein-Barr virus (responsible for infectious mononucleosis), the Cytomegalovirus (CMV), or the varicella virus (which also causes herpes zoster).
- Mosquito-borne viruses: are called Arboviruses. They appear especially in specific regions of the world, such as West Nile Virus and Japanese encephalitis virus (which is also found in Southeast Asia). Other viruses that cause encephalitis are transmitted through animal bites, such as rabies virus.
- Pediatric virus: measles, mumps, and rubella can cause acute encephalitis. The vaccination of all children has made that cases decrease in the population.
- HIV: HIV can produce an encephalitis from the first contact (rare) or in any of the Reactivations of the virus by abandonment of antiretroviral therapy.
Symptoms of encephalitisThe symptoms of encephalitis most seem minor flu symptoms. Headache may persist for a few days, appear fever, pains in joints and muscles, and very tired. The picture can last three to ten days, just like the flu, and when it happens so rarely diagnosed encephalitis.
Sometimes the symptoms are most striking and give the alarm that there is concrete damage in the brain. The most frequent are:
- Alteration of consciousness: be drowsy or have very slow thinking are signs indicating brain damage. There have been cases of cerebral coma and death, although it is not as often.
- Ataxia: named to the alteration of the March; people suffering from ataxia cannot walk without much separate toes and cling to any point of support.
- Very severe headache: much more than what can be expected in a flu.
- Seizures: appear suddenly and in people who have not previously had epileptic patterns.
- Loss of muscle strength or sensation: they simulate a stroke, but his appearance at the time added symptoms and body distribution, help differentiate it.
- Visual or olfactory hallucinations: smell odors, see double or fuzzy shapes with colors, are fairly common symptoms.
- Personality changes: although it seems rather anecdotal, is a very common and characteristic symptom. It can happen suddenly and is the fact that most alert to family members.
- Nausea and vomiting: especially in young children.
- Irritability and continuous crying: can be the only symptom in children under one year.
Diagnosis of encephalitisThe early encephalitis diagnosis is essential to provide a specific treatment, if any, and control the symptoms to prevent a severe brain damage. The most important aspect to the diagnosis of this pathology are clinical symptoms, which can help the physician to suspect the disease. To do this, the doctor will perform a clinical interview the patient, and in most cases also family members.
Within complementary to diagnose tests to be done to diagnose encephalitis is the most important is the lumbar puncture. Thanks to it you get cerebrospinal fluid (which is the fluid that lubricates the brain), and can be analyzed in the laboratory in search of abnormalities characteristic of viral infection. The analysis of laboratory that is essential is PCR (polymerase chain reaction), that detects the presence or absence of viruses that cause encephalitis frequently in cerebrospinal fluid.
Other important tests to detect an encephalitis are the Imaging of the central nervous system such as computed tomography (CT) and magnetic resonance imaging (MRI). The TC must always be before making a lumbar puncture to check that there are no major internal changes and that the puncture can be done well. MRI is not a test that is carried out urgently, but it is useful to make it the days or hours of the onset of symptoms, because sometimes the encephalitis cause brightness of the brain in these images. Also useful evidence is the electroencephalogram (EEG) because it allows to know if there is damage to the brain electrical activity and estimates the odds that it is an epilepsy as a sequel.
Treatment of encephalitisThe ideal encephalitis treatment must meet three key points: controlling symptoms, remove the virus from the nervous system, and prevent the onset of permanent neurological sequelae.
- Control of symptoms: General measures as to remain lying down with the head of the bed elevated, and drink lots of fluids, help a lot to improve the malaise, and headaches and joint disorders. They used most often analgesics and NSAIDs (such as paracetamol or ibuprofen) to lower the fever and pain. Corticosteroids are also used in all cases, since they help to decrease cerebral inflammation in a direct way and that decreases the probability of appearance of sequelae.
- The virus removal: not all viruses have a specific treatment that remove them from the nervous system. Only the family of herpes viruses can be attacked using antiviral drugs. The first to be discovered was the acyclovir, which is also used in chicken pox in adults, or to prevent genital herpes. Another well-known drug ganciclovir, which has special utility in (Cytomegalovirus infections is CMV). In recent years have been studied most powerful new drugs, such as foscarnet, and thanks to large investments in HIV research will soon be available new antiviral medications.
- Prevention of permanent sequelae: the emergence of sequels is prevented with early treatment from all fronts. Once finalized the symptoms of encephalitis testing may be making sure really what residual damage is in the brain, and once identified, various therapies can advertise:
- Speech therapy: resumes speech, understanding, or the writing of a particular language.
- Physical therapy: consists of physical exercises to improve muscle strength, mobility, gait and coordination.
- Occupational therapy: is to improve different neurological capacities through the implementation of activities of daily living (make the bed, cooking, crafts, etc).
Prevention of encephalitisPrevention of viral encephalitis consists of the basic measures that prevent any other viral illness, from a cold to gastroenteritis. In cases of more specific virus (rabies, Japanese encephalitis, HIV...) extra efforts. In general, these tips for preventing this infection:
- Comply with the measures of hygiene: wash your hands before eating or going to the bathroom, sneezing in handkerchiefs and not sharing cutlery, are some of them.
- Washing fruits and vegetables before eating them, with two drops of bleach and water.
- Sexual intercourse with a condom.
- Get vaccinated and vaccinate children of viruses that most commonly cause this disease.
- Protect yourself from mosquito bites in places of risk, using repellent, long sleeves of insects, mosquito nets, etc.