Encephalitis is one of the most relevant neuropathologies that causes high morbidity and mortality worldwide. It is an inflammation of the brain parenchyma that leads to neurological changes. Currently, the incidence of encephalitis ranges between 7 and 15 cases per 100,000 inhabitants, depending on the country. Encephalitis can affect individuals of all ages, but is often seen in the pediatric and elderly population. Some of the possible causes of encephalitis are: arboviruses, enteroviruses, herpes simplex virus, varicella-zoster virus, mumps virus, adenoviruses and cytomegalovirus. In addition to viruses, the causative agents can also be other microorganisms. Encephalitis can be both infectious, caused as a result of a direct invasion of the brain by pathogens, most commonly gray matter, and immune-mediated, caused by immune-mediated damage (usually white matter). Within the infectious group, both neurotropic and non-neurotropic (accidental) pathogens can cause encephalitis. The key to early recognition and treatment is knowledge of the encephalitis syndrome, which includes altered mental status (usually more then 24 hours) accompanied by evidence of brain parenchymal inflammation. The severity of the manifestations varies greatly from a mild febrile illness associated with headache to a severe disorder with convulsions, coma, neurological disturbances and death. Among the diagnostic procedures, it is important to emphasize the lumbar puncture. There is no specific treatment for most encephalitis, except for herpesvirus. When viral encephalitis is suspected, initial measures include supportive care and correction of any electrolyte disturbances, autonomic dysregulation, and renal and hepatic dysfunction. It is also important to treat seizures and non-convulsive status epilepticus. Viral infection of the brain can cause permanent neurological damage, which is more common after viral encephalitis. Regardless of etiology, most survivors suffer long-term consequences of some form. The key to a positive outcome is a timely recognition of encephalitis symptoms, which is one of the main tasks of a highly educated nurse. The paper describes in detail the case of a young girl, which was compared with three other different clinical pictures of encephalitis.