The encephalitis Is a pathology that falls within the inflammatory pathologies of the nervous system. Different medical conditions with inflammation can produce a wide variety of symptoms: fever, headache, convulsions, behavioral changes, confusion, brain damage or even death (National Institute of Neurological Disorders and Stroke, 2016)
Specifically, when inflammation refers to the brain and spinal cord , The pathology is called encephalitis. Unlike meningitis, which Produces an inflammation of the membranes that protect the brain and spinal cord, meninges (National Institute of Neurological Disorders and Stroke, 2016).
In this way, encephalitis is defined as an inflammatory process of the central nervous system that is associated with a neurological dysfunction clinically Evident (Navarro Gómez, 2016).
Although encephalitis may be the result of multiple etiological agents, many of them common to meningitis, in general the most common cause Recurrent are viruses (Navarro Gómez, 2016). Specifically, in the United States, most cases of encephalitis are caused by Enterovirus : Herpes Simplex 1 and 2, rabies virus, arbovirus, etc. (National Institute of Neurological Disorders and Stroke, 2016).
The signs and symptoms of encephalitis will depend to a great extent on the etiological causes and the severity of the pathology although we can distinguish Some very common in the majority of cases: symptoms related to the own of the flu processes, alterations in the hearing, the speech, Double vision, loss of consciousness, numbness in some body areas, muscle weakness, partial paralysis in the upper extremities and Inferiors, significant memory problems, seizures, among many others (National Institute of Neurological Disorders and Stroke, 2016).
Despite being a treatable medical condition, it puts the survival of the individual at grave risk. When many of the signs described above Appear suddenly, emergency medical treatment will be essential. When many of the signs described above appear Emergency medical treatment (National Institute of Neurological Disorders and Stroke, 2016).
What is encephalitis?
Encephalitis is an inflammation of the brain And spinal cord, which occurs as a result of the presence of an infectious process. The most Common of encephalitis are viruses (Mayo Clinic, 2014).
As in other inflammatory conditions, the meningitis Can produce an elevated body temperature, recurrent headache, confusion, Seizures, problems in the processing of stimulation or control and coordination of movements (Mayo Clinic, 2014).
Many of the diagnosed cases of encephalitis may present mild or even absent symptoms. However, in the most severe cases, Symptoms may put the person's survival at risk (Mayo Clinic, 2014).
Due mainly to the differential involvement of inflammation in brain structures, the course of encephalitis can be very heterogeneous and Unpredictable in an individual case (Mayo Clinic, 2014).
Especially because of the contiguity of the areas and structures that make up our central nervous system, it is possible that mixed pigs (Navarro Gómez, 2016):
- Meningoencephalitis : When the inflammation affects both the brain and the meninges.
- Encephalitis: Inflammation affects the brain exclusively.
- Myelitis : When the inflammation exclusively affects the spinal cord.
- Encephalomyelitis: When inflammation affects the brain and spinal cord jointly.
About us
Inflammation of the brain or encephalitis is a frequent medical disorder, especially in certain regions of the world (Encephalitis, 2015).
Regarding statistical data, the incidence of encephalitis in the general population is estimated at 0.3-0.5 / 100,000 (Navarro Gómez, 2016):
In the case of the child population, cases of encephalitis are more frequent. Its incidence is estimated in 5-10 cases per 100,000 children, reaching The number of 17 cases per 100,000 children during the first year of life (Navarro Gómez, 2016).
Every year thousands of cases of encephalitis occur worldwide, but not all are diagnosed. In many cases, encephalitis produces symptoms Or even nonexistent, so there could actually be a higher number of cases (National Institute of Neurological Disorders and Stroke, 2016).
Signs and symptoms
As we noted earlier, large numbers of cases of encephalitis occur as a result of the action of a virus. People who suffer This type of condition may present an asymptomatic state or begin to develop some mild symptoms related to the flu.
Typically the symptoms begin to appear between 2 and 3 weeks after you have contracted the virus that will trigger it (National Institute of Neurological Disorders and Stroke, 2016).
Minor Symptoms (Enefalitis, 2015)
- Headache .
- High body temperature.
- Pain and discomfort at the muscle and joint level.
- Tiredness, weakness, fatigue.
- Significant sleepiness.
Severe symptoms (Enefalitis, 2015)
- Recurrent and severe headache.
- High body temperature.
- Alterations of the level of consciousness.
- Agitation and / or confusion.
- Behavioral changes.
- Paralysis and loss of sensation in body regions.
- Muscular weakness.
- Alterations in the control and coordination of the movement.
- Double vision.
- Hallucinations.
- Changes in hearing and speech.
- Convulsions.
Symptoms in newborns and young children (Enefalitis, 2015)
- Nausea and vomiting.
- Constant and recurrent crying.
- Lack of appetite.
- Appearance of bulges in the soft areas of the baby's skull.
Many of these symptoms will require emergency medical intervention, especially those that refer to the occurrence of episodes Seizures, loss of consciousness, muscular paralysis, among others (Cleveland Clinic, 2016).
Types
In general, encephalitis is usually classified into two types (National Institute of Neurological Disorders and Stroke, 2016):
- Primary encephalitis : This type of encephalitis is also called Acute viral encephalitis And is caused By a direct infection of the spinal cord and the brain by a virus.
- Secondary encephalitis : In this type we can distinguish Post-infectious That develop as a complication Of the current presence of other viruses and the Disseminated encephalitis Acute infections that occur as a result of an immunization or Infection.
Causes
Encephalitis is caused by an infectious process. It can be caused by the action of different bacteria, or more frequently by infections Viral.
In the case of the USA, most of the encephalitis chaos are due to the herpes simplex virus, the bite of an animal that transmits the virus Rabies or arbovirs that can be transmitted by different insects (ticks, mosquitoes, etc.) (National Institute of Neurological Disorders and Stroke, 2016).
The Mayo Clinic (2014) points out some of the most common viruses that can infect the nervous system:
- Herpes Simplex Virus : Type 1 and type 2.
- Other S: Epstein-Barr, Varicella-Zoster.
- Enterovirus : Polio, Coxsackie Virus.
- Viruses transmitted by mosquitoes : Can cause West Nile encephalitis, La Crosse, Saint Louis, equine encephalitis, among others.
- Tick-borne viruses and other animals : Powassan virus, rabies virus.
- Childhood Infections : Rubella, mumps, measles.
Below we will describe some of the most common etiological causes in the US (National Institute of Neurological Disorders and Stroke, 2016):
- Herpes simplex encephalitis : Approximately 10% of cases of encephalitis are due to the action of this type of virus. This type Of encephalitis can develop due to the action of herpes simplex virus type 1 (it produces sores and blisters in the mouth and around the eyes) and The herpes simplex virus type 2 (genital herpes). It usually produces rapid evolution and is life threatening if left untreated. These viruses Transmitted by contact with an infected person.
- Powassan encephalitis : This type of encephalitis is produced by the action of a virus that is transported by ticks. Behind the Stinging, about 10 days later or before, symptoms such as nausea, partial paralysis or coma appear. In over 50% neurological damage occurs serious.
- Equine encephalitis : Is a type of viral encephalitis transmitted by mosquito bites and affects both horses and humans. In the case of humans, the symptoms begin to develop between 4-10 days after the bite. More than half of infected patients die.
- Lactose Encephalitis : Is also a type of encephalitis that is transmitted by the bite of a mosquito. The majority of cases Occur in the infantile population and usually appear approximately 5 days after the bite. Symptoms include fever, lethargy, and vomiting.
- Encephalitis of St. Louis: Is common in children and the elderly. Symptoms appear within 7 days of the bite and may appear Some complications such as tremors, disorientation, convulsions and even alterations of the level of consciousness.
- West Nile Encephalitis: This type of encephalitis may occur due to a mosquito bite, Transfusion. Symptoms related to rash, fever, headache and joint are usually present. In most common Among children and adult motor with a weakened immune system.
Risk factor's
Anyone who is exposed to any of the conditions described in the previous section may develop encephalitis. However, Identified a number of factors that may increase risk (Mayo Clinic, 2014);
- Age: Both children and older adults may be at a higher risk for some types of viral encephalitis Due to the greater susceptibility of their immune systems.
- Impaired or impaired immune system : Those who are under treatment with immunosuppressive or have pathologies Related to the immune system may be at a higher risk of contracting viral encephalitis.
- Visiting or living in specific geographic regions : There are some types of meningitis that are transmitted by the sting of Mosquitoes or ticks that are more common in some specific areas.
- Moment or season of the year : Viruses that are transmitted by insects are more frequent in spring, summer and autumn, the Months of the year.
Diagnosis
In the diagnosis of encephalitis, it is essential to collect all relevant information related to symptoms, risk factors and Medical history (Encephalitis, 2015).
In addition, it is also necessary to use some diagnostic tests (Encephalitis, 2015):
- Brain imaging : If there are symptoms compatible with the presence of an inflammatory disorder such as encephalitis, The use of brain imaging techniques such as magnetic resonance wave tomography , Can help us to identify those areas that present inflammation.
- Lumbar puncture: Is used to extract a small amount of cerebrospinal fluid And to identify the presence of cells Blood and proteins that indicate the presence of infection or inflammation.
- Blood tests, urine or other biological excretions: Are used to identify the presence of infection indicators.
Treatment
Usually antiviral drugs are used to treat encephalitis that have a viral origin. In addition, in the case of encephalitis Antibiotics are used.
Parallel to these therapeutic measures, other types of measures are often used to reduce or control some symptoms:
- Anticonvulsants : They are used to reduce the occurrence of convulsive events and the probability of developing secondary brain damage.
- Cortico steroids : Are usually used to reduce inflammation of brain structures.
- Analgesics and antipyretics : Are used to reduce headache and body temperature.
People suffering from pathologies related to inflammation of areas of the nervous system should receive urgent medical attention, Are generally hospitalized both for tests that confirm the diagnosis and for an early therapeutic intervention.
References
- Cleveland Clinic. (2016). What are Meningitis and Encephalitis? Obtained from Cleveland Clinic .
- Encefalitis.org. (2015). Encephalitis . Retrieved from Encefalitis.org: http://encefalitis.org/.
- Navarro Gómez, M., González, F., Santos Sabastián, M., Saavedra Lozano, J., & Hernández Sampelayo Matos, T. (2016). Encephalitis . Obtained from Spanish Association of Pediatrics.
- NIH. (2014). Encephalitis . Obtained from MedlinePlus.
- NIH. (2016). Meningitis and Encephalitis . Retrieved from the National Institute of Neurological Disorders and Stroke.
- NIH. (2016). Meningitis and Encephalitis Fact Sheet . Retrieved from the National Institute of Neurological Disorders and Stroke.
- Uninet. (2016). Emergency Principles, Emergencies and Critical Care . Obtained from Acute Infections of the Central Nervous System.