Encephalitis

introduction

Encephalitis is the inflammation of the brain tissue. The isolated infection of the brain, without involvement of the meninges, is most often caused by viruses. The course is usually mild. The disease can also have serious to fatal consequences.
The inflammation of the meninges, which is called meningitis referred to as. With such infections, the brain tissue can also be affected if treatment is neglected or insufficient - meningoencephalitis develops. If the disease is viral, the spinal cord may be involved in what is known as encephalomyelitis.

causes

Viruses are the main cause of encephalitis without involvement of the meninges. Often, however, the inflammation is also due to a previous bacterial attack on the meninges (meningitis), which affects the brain cells (Neurons) spreads. This is called meningoencephalitis.
If fungi or other parasites are the cause of encephalitis, this is rare in people with a healthy immune system, but in immunocompromised patients it is often the result of a long-term illness, such as an HIV infection.

Viral pathogens: Viruses reach the brain via the bloodstream or retrograde (walking backwards) via nerve tracts that flow into brain tissue either directly or indirectly via the spinal cord. They can be transmitted through direct body contact, but also through airborne infections or sexual intercourse.
Most encephalitides are caused by herpes simplex viruses I, which were previously in the body and eventually break out. Over 90% of the population carry the virus, sometimes without knowing about it.
Usually the first infection with the so-called herpes labiales (Cold sore), which has no significant consequences and does not require any special treatment. The pathogen then settles in what is known as the nerve node (Spinal ganglia) of the host and remains there until the end of his life.
If the immune system is weakened, this can lead to a renewed outbreak of the virus and so-called herpes simplex encephalitis.
Other relevant virus strains:

• Varicella zoster virus (chickenpox, shingles)
• Cytomegalovirus
• Measles virus (measles)
• Rubella virus (rubella)
• Influenza virus (flu)
• HIV
• Rabies virus (rabies)

The meninges are involved in the Epstein-Barr virus, in the causative agent of early summer meningo-encephalitis (flavovirus) and in HIV infection.

Bacterial pathogens: Encephalitis caused by bacteria is usually the result of previous meningitis, an inflammation of the meninges that was not adequately treated or for which therapy did not work.
Spirochetes, a type of bacteria that appear as spiral-shaped pathogens under the microscope, play a special role in the bacterial genesis (cause) of encephalitis. Treponema pallidum causes neurosyphilis and Borellia burgdorferii causes neuroborreliosis. Furthermore, infection with Rickettsia prowazekii can cause typhus encephalitis.

Other pathogens: Less common than viruses or bacteria, other pathogens cause encephalitis. The immune status, i.e. the patient's health, is very important here. Because the worse this is, the more likely an infection with various rare pathogens, such as protozoa (Unicellular organisms, most common Toxoplasma gondii), helminths (worms, most commonly schistosomes) and fungi (most commonly Aspergillus fumigatus and Cryptococcus neoformans).

Viral encephalitis

Viral encephalitis is a viral infection of the brain that can be acute or chronic. Children, the elderly and people with a weakened immune system are especially at increased risk of developing viral encephalitis. The disease is caused by enteroviruses, herpes viruses and adenoviruses or TBE (early summer meningo encephalitis) and usually occurs in the warm seasons.
The viruses infect the central nervous system (CNS) cross the blood-brain barrier and lead to inflammation in the brain. To control the infection, the body reacts with an immune response that leads to collateral damage to lesions in the CNS.

The symptoms of viral encephalitis are very diverse and depend on which region of the brain is affected by the inflammation. Initially the symptoms are similar to those of the flu and include headache, fever, fatigue, nausea with vomiting and sensitivity to light. Seizures and impaired consciousness occur later (Vigilance disorders) on. In addition, patients with inflammation of the meninges suffer from neck stiffness (Meningism). Paralysis and psychotic changes are also possible with encephalitis.

The diagnosis is made by a lumbar puncture with evidence of pathogens in the spinal fluid and by imaging methods such as CT or MRI. The condition is only treated symptomatically and antiviral drugs are only used for herpesvirus and HIV infection. With immediate treatment, the chances of recovery are good.

Read more about this under: Viral encephalitis

Herpes encephalitis

Herpes encephalitis is inflammation of the brain caused by the herpes simplex virus (HSV). Mostly it is an infection with the herpes simplex virus type 1. Worldwide there is a high infection rate with HSV, whereby the infections often remain asymptomatic or manifest as herpes labialis. The viruses can spread to the brain via the olfactory nerve and lead to encephalitis there. Stress and a weakened immune system favor the infection.
The encephalitis leads to fever and meningism, seizures, psychotic symptoms and increasing disturbances of consciousness up to coma.

If herpes encephalitis is suspected, the intravenous administration of antivirals (drugs that stop the virus from multiplying) must be given immediately, as otherwise the disease has a high mortality rate of 70%. The risk of consequential damage such as paralysis and mental impairment is high.

Read more about this under: Herpes simplex encephalitis

Tick ​​encephalitis

Tick ​​encephalitis is also called early summer meningoencephalitis (TBE). This viral disease is transmitted to humans by ticks and causes a combined inflammation of the brain and meninges. Southern Germany, Austria and the Czech Republic in particular are endemic areas in which the majority of ticks carry the TBE virus in their blood and the risk of infection is particularly high.

A tick bite can get the viruses into people and especially people who are often in the forest, such as forest workers, hunters or farmers, have a high risk of developing TBE. After an incubation period of 7 to 14 days, the first symptoms of tick encephalitis become noticeable and lead to fever, headache and body aches. After a few days, the symptoms subside and a symptom-free phase follows. As the virus progresses, it affects the central nervous system and leads to neurological complaints: headache, nausea, inheritance, stiff neck, impaired consciousness and possibly paralysis or cramps.

Encephalitis caused by ticks has a favorable prognosis and most often the disease heals completely. In some cases, however, there are long-term effects. After surviving the disease, those affected have lifelong immunity to tick encephalitis. People who stay longer in risk areas should consider a TBE vaccination.
Read about this: Vaccination against TBE

Influenza encephalitis

Influenza viruses (Flu viruses) can lead to influenza encephalitis or influenza encephalitis. This is a rare but serious complication of the flu in which the viruses get into the brain and cause inflammation.
Symptoms of influenza encephalitis include a high fever, headache, and stiff neck. It can also cause severe neurological symptoms such as decreased consciousness and seizures. In particular, children are affected by influenza encephalitis, as their nervous system is particularly sensitive to harmful influences.

In the first few days of influenza A or B flu, the viruses can spread to the brain and lead to encephalitis. Outbreaks of disease in the later stages of the flu have also been observed. A flu shot can prevent severe influenza infections, including influenza encephalitis. Therefore, children and young adults in particular should receive a flu shot. Read about this: The flu vaccination

Influenza encephalitis is a serious illness with a complicated course, especially for children. If influenza encephalitis is suspected, a lumbar puncture and an MRI scan are performed and, if the diagnosis is confirmed, therapy is started immediately. Patients are given antiviral drugs and, in many cases, must be monitored in the intensive care unit.

Read more about this under: Treating flu

Japanese encephalitis

Japanese encephalitis is a tropical disease that causes brain inflammation in various Southeast Asian countries. The inflammation is triggered by the Japanese encephalitis virus (JEV), which affects pigs and wild birds. Mosquitoes ingest the pathogen through a meal of blood on infected animals and transmit the virus to humans through a bite. In humid areas where mosquitoes are high and during the monsoon season there is a high risk of infection and epidemic outbreaks of the disease occur every few years in Asia. There is now an effective vaccine and vaccination is recommended for longer stays in risk areas.
Read more about this under: Vaccination against Japanese encephalitis

Symptoms of Japanese encephalitis appear 5 to 15 days after being infected by the mosquito bite and are similar to the general characteristics of encephalitis. These include headaches, high fever, stiff neck and neurological deficits. Prompt treatment in the hospital is important to minimize the risk of long-term effects and disabilities. If left untreated, Japanese encephalitis is often fatal.

Read more about this under: Japanese encephalitis

Diagnosis

The main concern of diagnostics should always be the Determination of the pathogen type because the various therapies differ fundamentally in some cases.
Since a Viruses If the encephalitis caused is often milder, the diagnosis can be made more difficult. If symptoms occur, both a Throat swab, as well as a Stool and blood sample be examined by laboratory diagnostics. In addition, a Lumbar puncture Cerebral fluid, known as liquor in technical terms, can be used for diagnosis (CSF diagnostics).

At bacteria, Mushrooms or the like can be done with the help of a Microscope or by means of a Cultivation In many cases a suitable diagnosis can be made on growth plates, on which the treatment is ultimately based. Since viruses cannot be seen under the light microscope, others have to Verification procedure applied like the PCR (Polymerase chain reaction), of the ELISA test or a Immunofluorescence test.

Because one Laboratory diagnostics take a certain amount of time and if there is inflammation in the brain, one should not wait physical examination, such as imaging procedures carried out. The latter include, for example Computed Tomography (CT) or MRI (Magnetic resonance imaging).
During the physical exam, special attention is paid neurological symptoms placed. Which includes Failures in motor functions, Sensory disturbances, Disorders of consciousness or also a unusual feeling of pain.
With the help of the physical examination one is able, among other things, to locate the inflammation in the brain close. Besides, that will EEG (electroencephalogram) used as a diagnostic aid. The excitation in the brain is measured and the function of this can be assessed.

MRI of the brain

In addition to the lumbar puncture, encephalitis is detected by magnetic resonance imaging (MRI) of the brain. The high resolution of an MRI can detect pathological changes and inflammation that causes encephalitis. Contrast media are often used to better differentiate the various tissues. The entire exam usually takes 15 to 20 minutes.

Read more about this under: MRI of the brain

Frequency distribution

The rate of New illnesses of encephalitis, as well Meningitis (Inflammation of the brain and the Meninges) is around 15 diseases per 100,000 inhabitants per year.
The disease rate is in patients with an immunodeficiency, for example at AIDSPatients, significantly higher. Since 90 percent of the population den Herpes simplex virus I carry with you, there is an increased risk of illness.

Symptoms

The symptoms of encephalitis can be milder or more severe, depending on the pathogen, and thus strongly influence therapy and course.
In principle, in contrast to meningitis, encephalitis can be assumed to have a milder course if the symptoms are recognized and treated quickly. Initially, the inflammation may produce signs of a cold, and the patient may experience a fever and chills.
As a result, patients often complain of increasing headaches, impaired consciousness, and neurological and psychotic symptoms. The disturbances in consciousness can range from poor concentration to extreme tiredness to fainting.

The way in which the neurological-psychotic symptoms manifest themselves is strongly influenced by which areas of the brain are affected by the inflammation. For example, if the frontal lobe is affected (the front of the brain) possible that there will be personality changes. Up to this point of the disease, with effective treatment, the previous state can almost always be reached and the disease completely cured.
If the physical condition worsens or therapy is neglected, brain swelling (cerebral edema) or cerebral haemorrhage (cerebral hemorrhage) occur and cause permanent brain damage.

Some pathogens cause special symptoms that create a specific clinical picture:

• Herpes simplex virus I: Several foci of inflammation form in the brain (Herd encephalitis). As a result, speech disorders, disorders of the sense of smell, epileptic seizures and disorders of consciousness develop that can extend to a coma.
• HIV: Immune cells infected by the virus infect brain cells and thus cause the brain to be destroyed. Memory disorders, listlessness and disorders of fine motor skills are neurological symptoms of AIDS. Movement and sensation can also be restricted. Cranial nerve failures are observed regularly. About one fifth of patients develop AIDS dementia, which is associated with the HI virus. In addition, opportunistic infections (infections that only arise due to the poor immune system) with a wide variety of pathogens can occur more frequently in AIDS patients.
• Rabies virus (Rhabdovirus): After the bite of a rabies-infected animal, sensory disturbances develop in the area of ​​the bite site. A special feature of a rabies infection is the very aggressive behavior, which gave the disease its name.
• Spirochetes: Also the symptoms of neurosyphilis (Treponema pallidum) and neuroborreliosis (Borellia burgdorferii) are very prominent.

also read

• Meningitis
• Meningoencephalitis

What are the long-term effects of encephalitis?

Most patients who develop encephalitis get well again with appropriate therapy and do not suffer any serious damage. Nevertheless, long-term effects from encephalitis are possible, especially if the disease was not treated in time. The most common long-term effects include headaches, difficulty concentrating and persistent exhaustion. Further long-term effects can include serious neurological deficits, cognitive impairments and epileptic seizures. In addition, behavior problems and changes in personality can occur.
The long-term effects are not always that drastic; some long-term damage to the brain can also be relatively mild and often go unnoticed. In general, it is important that encephalitis is diagnosed quickly and treated immediately, because the longer the disease is left untreated, the greater the risk that the patient will suffer long-term brain damage.

How long do the symptoms last?

The duration of encephalitis can vary widely and depends on the individual course of the disease and the type of pathogen. Another important factor that significantly influences the duration of an encephalitis is the time until the start of treatment.
Some inflammations are very mild and only last a few days, in other cases it takes months for the disease to completely heal. Affected people can retain permanent damage to the nervous system. In severe cases or if encephalitis is not diagnosed and treated in time, the disease is fatal.

therapy

The medical therapy depends strongly on the type of pathogen.
In bacterial (Meningo-) Encephalitis must first be laboratory diagnosed genus be determined, whereupon the appropriate antibiotic can be chosen. A combination various active ingredients increases the effectiveness of the treatment, taking on eventual Allergies (for example Penicillin allergy) must be observed.
At resistance of the pathogen, as it is more and more often found in hospital germs today, is a must Antibiogram be created. A wide variety of antibiotics are determined that are effective against the bacterium are effective.

In comparison, treatment for viral causes is usually less complicated.
bed rest and symptom-related medication can usually weaken the course of the disease and wait for the viral encephalitis to heal.
For herpes simplex encephalitis, as well as HIV-induced infections of the CNS (Central nervesystem) a more intensive therapy must be selected. Antiviral drugs, how Acyclovir, are toxic to the body, but are the only way to stop the virus from multiplying. For HIV, which belongs to the group of so-called retroviruses, special antiretroviral drugs must be selected in order to achieve the best possible treatment.
Come against mushrooms Antifungal drugs (e.g. fluconazole, amphoterizine B), against worms Anthelmintics (e.g. Praziquantel) and against protozoa such as Toxoplasma sp. Antiparasitic drugs (e.g. pyrimethamine) are used.

Chances of recovery from encephalitis

Encephalitis is always treated in the hospital, as patients must be constantly monitored and serious complications can be treated there immediately. Complications can include the development of brain edema or the spread of the inflammation.

Depending on the type of illness and its course, encephalitis can have different degrees of severity. In many cases the patient is completely cured, but encephalitis can often be life-threatening and fatal. Some patients retain long-term effects after the inflammation subsides, e.g. Difficulty concentrating, having a headache, or having trouble falling asleep. Due to the sometimes severe course of the disease, it is important that encephalitis is detected in good time and treated immediately. There are also protective vaccinations against many viruses that can cause encephalitis (influenza, TBE, measles, mumps, rubella).

prophylaxis

Basically, as with all pathogens, Hygiene precautions as the most effective prophylaxis against infections. Here can Wash your hands and disinfection after using public toilets or the like most of the recorded bacteria and Viruses kill.
Various sexually transmitted diseases, such as infections with HIV or Treponema pallidum, by prevention With Condoms be prevented. Other contraceptives do not protect against sexually transmitted diseases.
An infestation with Herpes simplex I virus is nearly inevitable, as the infection rate in the population is extremely high. However, a outbreak the diseases caused by the virus Keeping the body healthy be prevented.

The vaccination against encephalitis cause is only conditionally possible. For example, a standard "triple" vaccination of all children against rubella, measles and mumps carried out. Partly the vaccination against Poliovirus made in this context. Three of these four viruses can have serious CNS infections permanent consequential damage cause, which is why all children should be vaccinated.
Against the Rabies virus vaccination can be carried out. This is especially recommended for people who work a lot work with wildlife, such as forester.
An infection with chickenpox should be overcome in childhood. This, through the Varicella zoster virus disease caused, can severe permanent damage in adults cause.

Special forms of encephalitis

Meningoencephalitis

In meningoencephalitis, in addition to the brain (Encephalitis) also the meninges (Meninges) affected by the inflammation. The meninges are structures made of connective tissue that attach to the brain and serve to protect the brain.
Meningoencephalitis is mainly caused by viruses and less often by bacteria, whereby one of the most common forms in our part of the world is early summer meningoencephalitis (TBE). Meningoencephalitis is typically followed by another disease, e.g. an infection with measles, rubella, or mumps. Children, the elderly and immunodeficient people in particular have an increased risk of developing meningoencephalitis.
The symptoms of meningoencephalitis include severe headaches, nausea, stiff neck, clouded consciousness and various neurological deficits such as paralysis or speech disorders.

The prognosis of a combined inflammation of the brain and spinal cord depends essentially on the pathogen, whereby in all cases a quick diagnosis and an immediate start of therapy have a great influence on the course of the disease. The sooner a treatment is started, the lower the risk that the patient will suffer consequential damage.

Read more about this under: Meningoencephalitis

Brainstem encephalitis

Brain stem encephalitis, or Bickerstaff encephalitis, is a rare disease of the central nervous system in which antibodies against the brain stem are formed.The brain stem is a part of the brain that lies below the diencephalon and regulates important functions such as breathing and heart rate.
The cause of brainstem encephalitis is not yet known, but it is suspected that the disease is caused by an infection with bacteria or viruses. Typical symptoms are dizziness, speech disorders and coordination problems. With the right treatment, brainstem encephalitis can be treated well and heals completely.

Lymphatic encephalitis

If the central nervous system is infected with viruses or bacteria, the body tries to eliminate the pathogens through an acute inflammatory reaction. Lymphatic encephalitis is characterized by a lymphocyte-dominated inflammatory reaction. Lymphocytes are part of the immune system and comprise certain types of cells that lead to a specific defense reaction.

Lymphatic encephalitis

Certain pathogens cause necrotizing encephalitis, in which the tissue in the brain dies as a result of a specific form of cell death - necrosis. Herpes simplex viruses, for example, lead to hemorrhagic necrosis of certain areas in the brain: that is, nerve cells die due to necrosis and at the same time there is heavy bleeding into the affected area ("hemorrhagic"). The severe course means that the encephalitis is often fatal or that the survivors suffer permanent neurological damage.

Lethargic encephalitis

Lethargic encephalitis is also known as European sleeping sickness and is an inflammation of the brain that leads to sudden sleep attacks. The disease was first described at the beginning of the 20th century and was common in Europe at that time. Nowadays the disease is rare and individual diseases only occur sporadically. The exact pathogen causing European sleeping sickness is not yet known, but it is probably a virus.

The main characteristic of lethargic encephalitis is uncontrolled sleep attacks, from which it is difficult or impossible to wake the affected person. The patients also have neurological disorders that are similar to Parkinson's disease. After the sleep attacks, the patients suffer from severe headaches, nausea and high fever. Even years after the disease has healed, neurological disorders can still occur.

Encephalitis disseminata

Disseminated encephalitis is better known as multiple sclerosis (MS). This is a chronic autoimmune disease that is relapsing or progressive (advancing) runs. The cause of the disease is not yet known, but it is believed that a genetic predisposition and various environmental components contribute to the outbreak.
In multiple sclerosis, the body incorrectly produces antibodies against the covering layer of the nerve fibers. This destroys these structures and causes inflammation in the brain and spinal cord.

Multiple sclerosis is diagnosed using magnetic resonance imaging (MRI) and lumbar puncture, during which spinal fluid is removed and examined for destroyed nerve components. The MRI shows lesions and scars in the brain caused by the inflammation. The symptoms are very diverse, which is why the disease is also referred to as the "disease with a thousand faces". The complaints range from impaired vision, paralysis and sensory disturbances to impaired coordination. So far, disseminated encephalitis is not curable, but there are very good treatment options that enable those affected to lead an almost symptom-free life.

Read more on this topic at: Diagnosis of multiple sclerosis

Vascular encephalitis

Vascular means "concerning the blood vessels". In vascular encephalitis, the inflammation damages blood vessels in the brain. This leads to circulatory disorders and an undersupply of nerve cells with oxygen. The result is severe neurological symptoms such as speech disorders, dizziness, nausea or blindness.