Introduction:

Anti-receptor N methyl-D aspartate (anti-NMDA) autoimmune encephalitis is the leading cause of acute autoimmune encephalitis in children and adolescents, with the male group accounting for the highest proportion of cases in children under 12 years of age.

Case presentation:

We present the case of a female patient of six years of age, who presented signs and symptoms suggestive of encephalitis, the most outstanding were aphasia of expression, hypotonia, seizures and disautonomy. After ruling out a viral etiology, in cerebrospinal fluid sample was performed for the detection of anti-NMDA autoantibodies, which was positive. After the start of steroid and immunoglobulin treatment, the patient gradually improved.

Conclusions:

Autoimmune N-methyl-D aspartate encephalitis should be suspected as part of the differential diagnosis of acute encephalitis. Early treatment is associated with a better prognosis.