encephalitis

Encephalitis: description

encephalitis is the medical term for encephalitis. This is usually caused by viruses. However, encephalitis can also be caused by other pathogens such as bacteria, unicellular organisms or worms, or by a defective immune response.

Since untreated encephalitis is associated with high mortality, it is important to begin treatment as early as possible in the hospital. Since at the beginning of the disease often can not be determined which pathogen is the cause, various drugs are given simultaneously. Once the pathogen has been detected by laboratory tests, only those drugs will be administered that are directed against this particular pathogen. In addition, the symptoms themselves are treated, such as pain or seizures with appropriate preparations. With timely treatment in many cases a cure of encephalitis is possible.

Encephalitis: symptoms

Depending on the pathogens, the symptoms of encephalitis very different. This is because different pathogens preferentially infect certain brain regions. In viral encephalitis, there are initially general flu-like symptoms such as fever, headache, fatigue, muscle aches and nausea. Only then do the specific symptoms of encephalitis develop. Symptoms are:

• Awareness disorders (eg unconsciousness or confusion)
• sudden impairment of concentration and memory
• Behavioral changes (eg conspicuous mood swings, hallucinations, paranoia or disorientation [organic psychosyndrome])
• Vomit
• neurological deficits (eg disorders of speech and speech, paralysis of individual extremities or eye muscles)
• seizures
• simultaneous irritation of the meninges (meningoencephalitis): neck and / or back stiffness (meningism)

Complications that occur at a encephalitis may be a persistent seizure (status epilepticus) or a swelling of the brain (cerebral edema).

Encephalitis: causes and risk factors

The encephalitis is usually the result of a viral infection. One differentiates between the primary and secondary form. In the primary form, the viruses cause inflammation directly in the brain. In the secondary form, the body’s own immune system derailed in response to a viral infection in the body and subsequently attacked the brain (autoimmune reaction). In the process, structures (autoantibodies) that are directed against specific components in the brain are formed by the body.

Encephalitis is often triggered in Germany by the following viruses:

• Herpes simplex virus
• Varicella-zoster virus
• Epstein-Barr virus
• measles virus
• mumps virus
• rubella virus
• enteroviruses
• TBE (Fruhsommer-Meningo-enzephalitis) viruses

There are other viruses worldwide that are considered to be the cause of encephalitis:

• Lyssaviruses (rabies)
• West Nile Virus
• Arboviruses (Japanese Encephalitis)

The TBE viruses (causative agent of early summer meningoencephalitis) are transmitted to humans through tick bites. Animal bites (eg of bats) can infect you with rabies.

In addition to the viruses, there are other triggers of encephalitis. These include various bacteria (eg the causative agents of syphilis, tuberculosis or Lyme disease), unicellular organisms (eg the pathogens of toxoplasmosis), parasites (eg worms), fungi or autoimmune diseases (eg. Multiple sclerosis).

Encephalitis, the cause of which is still unclear, is the so-called European sleeping sickness (encephalitis lethargica). It occurred mainly between the years 1917 to 1928 worldwide and may later lead to Parkinson’s disease.

Particularly at risk of developing encephalitis are children and young adults. In addition, individuals with weakened immune systems – such as those infected with HIV – have a greater risk of developing encephalitis. Since some of the viruses mentioned do not occur in our latitudes, long-haul travelers are also at greater risk.

Encephalitis: examinations and diagnosis

To diagnose encephalitis, the doctor asks about the symptoms and the medical history. Information on general diseases, viral infections or even tick bites help with the diagnosis. In addition to questioning the patient, the doctor attempts to obtain a second description by family members. This is necessary because people with encephalitis are often limited in their perception, thinking and communication skills. Other useful information relates to recent vacation travel, contact with livestock or other people with encephalitis.

The next step is an accurate physical and neurological examination in which the physician tests posture, motor skills, and various nerve-directed responses, among other things. In addition to the described symptoms, skin symptoms or disturbances of the water balance in the body sometimes occur.

If the doctor suspects encephalitis, he also examines the patient’s blood and cerebrospinal fluid (cerebrospinal fluid) for signs of inflammation (changes in CSF, pathogen or antibody detection). In order to detect the type of pathogen, the so-called polymerase chain reaction (PCR) is suitable; she identifies even the smallest amounts of virus. The doctor gains a sample of the liquor by means of a lumbar puncture. However, many pathogens of encephalitis can not be detected or only with great effort and often only after days or weeks. For example, in the acute phase of the disease, no pathogens are usually detectable in the CSF. Therefore, at first often only the symptoms can show the way to diagnose encephalitis and its trigger.

As a rule, if there is suspicion of encephalitis, the doctor will immediately perform a computed tomography (CT) to rule out other brain diseases (eg cerebral hemorrhage or brain abscess). Magnetic resonance imaging (MRI) is also possible.

The brain abscess differs from the encephalitis in that it is mostly caused by (other) bacteria. It is spatially limited and consists of a collection of pus, which is surrounded by a connective tissue capsule.

In addition – especially if the encephalitis caused by herpesviruses – an electroencephalography (EEG) performed. Although this can give an indication of the pathogen only in exceptional cases, but make it visible at an early stage, whether and how the inflammation affects the brain function.

Encephalitis: treatment

Encephalitis is always treated and monitored in the hospital in order to be able to quickly recognize and influence possible, possibly life-threatening complications. The procedure is based on the trigger of the brain inflammation.

If there is a suspicion of encephalitis caused by herpes viruses (eg herpes simplex viruses or varicella-zoster viruses), intravenous administration of acyclovir, a drug against viruses (antivirals), is started immediately. If bacterial inflammation can not be ruled out at this early stage, various antibiotics (anti-bacterial drugs) are also given.

Only when the causative agent of encephalitis has been clearly established, the doctor discontinues the potentially ineffective remedies and uses, if possible, specially directed against the pathogen drugs.

In addition to the treatment against the encephalitis pathogen itself, the symptoms of the patients are also treated. If necessary, antipyretic drugs or pain medications can be given. In addition, possibly occurring seizures and the swelling of the brain (brain edema) are treated with appropriate drugs. Furthermore, the temperature, the respiration and the water balance are checked regularly.

Due to the early use of the active substance acyclovir in a herpes virusencephalitis, Before the patient loses consciousness, both the probability of survival and the chances of recovery can be significantly improved.

Encephalitis: disease course and prognosis

The chances of cure for encephalitis depend on the severity of the disease, the nature of the pathogen, and the time to treatment. If the brain inflammation detected in time and treated immediately, the prognosis is usually good.

It is important to take warning signs such as sudden high fever with nausea, headaches and disturbances of consciousness seriously and promptly in the hospital – preferably in a neurological department – to clarify.

Thus, for example, encephalitis, which is triggered by the aggressive herpes simplex virus, untreated leads to death in up to 70 out of 100 cases. With the help of modern medicines and rapid therapy, however, up to 80 out of every 100 patients recover. However, encephalitis has the potential for permanent damage to the nervous system.

Encephalitis can be complicated if, for example, a seizure persists (status epilepticus) or a swelling of the brain develops (cerebral edema). These complications are potentially life threatening.

To prevent encephalitis there are vaccinations against many of the pathogens. Nationwide vaccinations against measles, mumps, rubella and polio (poliomyelitis) are offered. In addition, there are vaccinations for people who are at increased risk of developing encephalitis. This includes TBE vaccination for residents in areas where TBE viruses are more commonly transmitted by ticks. It is also advisable for travelers to Southeast Asia to oppose the Japanese encephalitis if they intend to stay longer or to travel to rural areas.