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 form simultaneously into meningeoencephalitis.[6] The bacterium commonly targets the sensitive structures of the brain stem. L. monocytogenes meningoencephalitis has been documented to significantly increase the number of cytokines, such as IL-1β, IL-12, IL-15, leading to toxic effects on the brain.[7]
Adenovirus, although meningoencephalitis is almost solely seen in heavily immunocompromised patients.[11]
Mumps, a relatively common cause of meningoencephalitis. However, most cases are mild, and mumps meningoencephalitis generally does not result in death or neurologic sequelae.[12]
HIV, a very small number of individuals exhibit meningoencephalitis at the primary stage of infection.[13][14]
Anti-N-methyl-D-aspartate (anti-NMDA) receptor antibodies, which are also associated with seizures and a movement disorder, and related to anti-NMDA receptor encephalitis.
NAIM or "Nonvasculitic autoimmune inflammatory meningoencephalitis" (NAIM).[16] They can be divided into GFAP- and GFAP+ cases. The second is related to the autoimmune GFAP astrocytopathy.
Clinical diagnosis includes evaluation for the presence of recurrent or recent herpes infection, fever, headache, altered mental status, convulsions, disturbance of consciousness, and focal signs. Testing of cerebrospinal fluid is usually performed.[citation needed]
Antiviral therapy, such as acyclovir and ganciclovir, work best when applied as early as possible. May also be treated with interferon as an immune therapy. Symptomatic therapy can be applied as needed. High fever can be treated by physical regulation of body temperature. Seizure can be treated with antiepileptic drugs. High intracranial pressure can be treated with drugs such as mannitol. If caused by an infection then the infection can be treated with antibiotic drugs.[citation needed]
^ ab"Herpes Meningoencephalitis". Johns Hopkins Medicine. The Johns Hopkins University, The Johns Hopkins Hospital, and The Johns Hopkins Health System Corporation. Retrieved 26 January 2019.
^ ab"Herpes Meningoencephalitis". Columbia University Department of Neurology. Columbia University. Retrieved 26 January 2019.
^Shelat, Amit; Ziegler, Olivia. "Herpes Meningoencephalitis". University of Rochester Medical Center - Health Encyclopedia. University of Rochester Medical Center Rochester, NY. Retrieved 26 January 2019.
^Keith A Josephs, Frank A Rubino, Dennis W Dickson, Nonvasculitic autoimmune inflammatory meningoencephalitis, Neuropathology 24(2):149-52 · July 2004, DOI: 10.1111/j.1440-1789.2004.00542.x