The term encephalitis refers to the inflammation of the parenchyma of the central nervous system, located in the cranial cavity. We report the case of a 17-year-old female patient with a history of tuberculous gonarthritis, who was admitted for convulsive seizures complicated by status epilepticus. Medical imaging did not reveal any brain lesions and biology revealed an elevated PCT. Through this case, we underline the risk of diagnostic errancy and thus of delay in the treatment of autoimmune encephalitis which, in 70% of cases, is effective. It also seemed important to us to insist on the fact that the absence of autoantibodies does not invalidate the diagnosis of autoimmune encephalitis, especially in developing countries where the technical platform to search for them is lacking both in terms of equipment and human resources. Finally, it should be noted that new autoantibodies are found almost every year by teams in developed countries. Thus, in front of any acute or sub-acute neurological picture not explained, it is necessary to think about autoimmune encephalitis and to start an immunomodulatory treatment, which guarantees the cure or the substantial improvement in most cases.