Meningoencephalitis

Meningoencephalitis (/mɪˌnɪŋɡoʊɛnˌsɛfəˈlaɪtɪs, -ˌnɪndʒoʊ-, -ən-, -ˌkɛ-/; from Ancient Greek μῆνιγξ (meninx) 'membrane' ἐγκέφαλος (enképhalos) 'brain' and -itis 'inflammation'), 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 of meningoencephalitis include unusual behavior, personality changes, nausea, and thinking problems.

Symptoms may include headache, fever, pain in neck movement, light sensitivity, and seizure.

The organisms which cause meningoencephalitis include bacterial pathogens, protozoans, and viruses.^{[citation needed]}

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-1β), 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 (causes Rocky Mountain spotted fever [RMSF]), Rickettsia conorii, Rickettsia prowazekii (causes epidemic louse-borne typhus), 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 (HME), caused by Ehrlichia chaffeensis (a species of rickettsiales bacteria).

Other bacteria that can cause meningoencephalitis are Mycoplasma pneumoniae, Tuberculosis, Borrelia (Lyme disease), and Leptospirosis.

The viral organisms that cause meningoencephalitis include: