Definition
Meningoencephalitis is a combined inflammation of the brain (encephalitis) and its meninges (meningitis). Meningoencephalitis partly combines the symptoms of the two inflammatory diseases and is caused by various pathogens. Most often, viruses are responsible for the disease. Especially people with a weakened immune system can fall ill with severe meningoencephalitis. In some cases, severe secondary damage can remain.
Causes and pathogens of meningoencephalitis
The cause of meningoencephalitis is usually an infestation of the central brain or its meninges by a pathogen. Viral infections account for the largest proportion of these. Examples of viral pathogens are enteroviruses, the measles virus, the herpes simplex virus I (cause of lip herpes), the Eppstein-Barr virus (cause of whistling glandular fever) and the flavivirus, which causes TBE, the early summer meningoencephalitis.
The latter is transmitted by tick bites. Bacteria normally cause isolated inflammation of the meninges. However, some strains can also attack the brain as part of this infection.
The pathogens that are responsible for bacterial meningoencephalitis in most cases are called Listeria monocytogenes. Other representatives are Staphylococcus aureus, Treponema pallidum (pathogen of syphilis) and Mycoplasma pneumoniae. In rare cases and primarily in immunocompromised patients, meningoencephalitis can also be caused by fungi or other parasites. Cryptococcus neoformans is a yeast fungus that initially attacks the lungs and may spread to the brain. Parasitic pathogens are Toxoplasma gondii (transmitted by cats), Plasmodium falciparum (trigger of a malaria form) and Trypanosoma.
Symptoms of Meningoencephalitis
Meningoencephalitis is a combination of the symptoms of meningitis and encephalitis. Meningitis is characterized by severe headache and neck pain, high fever, nausea and vomiting, and in the advanced stages of the disease, clouding of consciousness (somnolence, drowsiness). If consciousness is very severely impaired (vigilance reduction), the examining physician should interpret this as an indication of meningoencephalitis, since meningitis alone is very rarely as severe.
Epileptic seizures can also occur in the context of meningitis. A symptom that can be easily controlled diagnostically is neck stiffness. If the examiner tries to lift the patient’s head while lying flat, the patient suffers severe pain and a defensive movement (the patient resists the movement).
The symptoms of encephalitis are much more unspecific than those of meningitis. The inflammatory processes in the brain cause so-called focal symptoms. Depending on which part of the brain is inflamed, the corresponding functions fail.
Typical for encephalitis and also a possible symptom of meningoencephalitis can therefore be the change in nature caused by an infestation of the front lobe. For example, increased aggression of the affected person. Neurological changes such as speech and vision disorders can also occur, depending on the location of the inflammation. General symptoms can be clouding of consciousness or headaches, but these originate from the meninges, as the brain itself cannot feel pain. A dangerous symptom of meningoencephalitis is the increase in intracranial pressure, which can lead to life-threatening constrictions.
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