Meningoencephalitis
Meningoencephalitis, also known as herpes meningoencephalitis, is a medical condition that simultaneously resembles both meningitis, which is an infection or inflammation of the meninges, and encephalitis, which is an infection or inflammation of the brain tissue.
Signs and symptoms
Signs of meningoencephalitis include unusual behavior, personality changes, nausea, and thinking problems.Symptoms may include headache, fever, pain in neck movement, light sensitivity, and seizure.
Causes
The organisms which cause meningoencephalitis include bacterial pathogens, protozoans, and viruses.Bacterial
Veterinarians have observed meningoencephalitis in animals infected with listeriosis, caused by the pathogenic bacteria L. monocytogenes. Meningitis and encephalitis already present in the brain or spinal cord of an animal may simultaneously form into meningeoencephalitis. The bacteria commonly targets the sensitive structures of the brain stem. L. monocytogenes meningoencephalitis has been documented to significantly increase the number of cytokines, such as interleukin-1beta, IL-12, and IL-15, leading to toxic effects on the brain.Meningoencephalitis may be one of the severe complications of diseases originating from several Rickettsia species, such as Rickettsia rickettsii, Rickettsia conorii, Rickettsia prowazekii, and Rickettsia africae. It can impair the cranial nerves, cause paralysis to the eyes, and sudden hearing loss. Meningoencephalitis is a rare, late-stage manifestation of tick-borne ricksettial diseases, such as RMSF and human monocytotropic ehrlichiosis, caused by Ehrlichia chaffeensis.
Other bacteria that can cause meningoencephalitis are Mycoplasma pneumoniae, Tuberculosis, Borrelia, and Leptospirosis.
Viral
The viral organisms that cause meningoencephalitis include:- Tick-borne encephalitis
- West Nile virus
- Measles
- Epstein–Barr virus
- Varicella-zoster virus
- Enterovirus
- Herpes simplex virus type 1
- Herpes simplex virus type 2
- Rabies virus
- Adenovirus
- * Meningoencephalitis is almost solely seen in heavily immunocompromised patients.
- Mumps
- * A relatively common cause of meningoencephalitis. However, most cases are mild, and mumps meningoencephalitis generally does not result in death or neurologic sequelae.
- HIV
- * A very small number of individuals exhibit meningoencephalitis at the Acute [HIV infection|primary stage] of infection.
Autoimmune
- Antibodies targeting amyloid beta peptide proteins have been used during research on Alzheimer's disease.
- Anti-N-methyl-D-aspartate receptor antibodies, which are also associated with seizures and a movement disorder, are related to anti-NMDA receptor encephalitis.
- Nonvasculitic autoimmune inflammatory meningoencephalitis can be divided into glial fibrillary acidic protein negative and GFAP positive cases. The second is related to the autoimmune GFAP astrocytopathy.