Autoimmune encephalitis is rare in children and develops as a manifestation of a parainfectious or paraneoplastic syndrome. The disease is characterised by a sudden or subacute onset and a broad spectrum of neurological and/or psychiatric disorders. We present a case of a 17-year-old girl with anti-N-methyl-D-aspartate receptor encephalitis. The patient was admitted to hospital in a severe condition, unconscious, with injuries indicating a recent status epilepticus. Previous infection was found to be the most likely causative factor. Antiviral, antibacterial, immunosuppressive and anticonvulsant treatments were used with good outcomes. The aim of the paper is to point out the need to include autoimmune processes in the differential diagnosis of neuroinfections in children, which will allow for prompt implementation of appropriate treatment and improve prognosis.