Diagnostics
The main objective of diagnostics should always be to determine the type of pathogen, since the various therapies sometimes differ fundamentally. Since encephalitis caused by viruses is often milder, the diagnosis can be made more difficult. If symptoms are present, a throat swab as well as a stool and blood sample should be taken for laboratory diagnosis.
In addition, cerebrospinal fluid, known as cerebrospinal fluid (CSF), can be used to diagnose a lumbar puncture (CSF diagnostics). In the case of bacteria, fungi or similar, a suitable diagnosis can be made in many cases with the aid of a microscope or by means of cultivation on growth plates, which is then used as the basis for treatment. Since viruses cannot be detected under a light microscope, other detection methods must be used, such as PCR (polymerase chain reaction), ELISA test or an immunofluorescence test.
Because laboratory diagnostics take a certain amount of time and should not be waited for in the case of inflammation in the brain, a physical examination and imaging procedures are also performed. The latter include computer tomography (CT) or MRT (magnetic resonance imaging). During the physical examination, special attention is paid to neurological symptoms.
These include loss of motor functions, sensory disturbances, disturbances of consciousness or unusual pain sensation. With the help of the physical examination one is also able to deduce the localization of the inflammation in the brain. Furthermore, the EEG (electroencephalogram) is used as a diagnostic aid.
The excitation in the brain is measured and the function of the brain can be assessed. In addition to lumbar puncture, encephalitis is detected by magnetic resonance imaging (MRI) of the brain. Due to the high resolution of an MRI, pathological changes and inflammations that cause encephalitis can be detected. Contrast media are often used to better differentiate the different tissues. The entire examination usually takes 15 to 20 minutes.
Frequency distribution
The rate of new cases of encephalitis and meningitis (inflammation of the brain and meninges) is about 15 cases per 100,000 inhabitants per year. The disease rate is significantly higher in patients with an immunodeficiency, for example AIDS patients. Since 90 percent of the population carries the herpes simplex virus I, there is an increased risk of illness.
