Enterovirus-Associated Meningoencephalitis and Enteroviruses in Patients with Acute Encephalitis

Abstract

Enteroviruses are from the family of Picornaviridae, consisting of hundreds of serotypes, all having single positive-stranded RNA genome. The Enterovirus group comprises of 12 species, including 4 human species: A to D. Encephalitis and meningoencephalitis are infrequent presentations of enteroviral infection, but various enterovirus serotypes, coxsackievirus serotypes, and echovirus serotypes are reported in epidemics in the Southeast Asia region and some European countries. Enteroviruses mostly enter via faeco-oral routes and present with asymptomatic or mild diseases. However, they are also known to present as biphasic prodromal disease, with neurological involvement often beginning as invasion in the anterior horn cells, or even as progression to the brainstem, cerebellum, midbrain, or motor cortex, causing paralysis from neuronal death. More so, enterovirus encephalitis can present as fever with headache, altered sensorium, acute onset muscle flaccidity, hyporeflexia, meningeal signs, and myoclonic jerks. The diagnosis of enteroviral neurological illness is ‘definitive’ when it is detected by cerebrospinal fluid polymerase chain reaction or culture, along with detection by polymerase chain reaction from throat, rectal swabs, and serum. Diagnosis is ‘probable’, if enterovirus is detected in polymerase chain reaction analysis of throat and rectal swabs. If it is detected in either throat or in rectal swab polymerase chain reaction tests, it is denoted as ‘possible’ enterovirus infection. There is no definitive treatment for enteroviruses, although, intravenous immunoglobulins and ribavirin have shown some promising outcomes in patients diagnosed with enteroviral encephalitis.