Introduction: Anti-N-methyl-D-aspartate (NMDA) receptor antibody encephalitis was initially described as a paraneoplastic syndrome associated to ovarian teratomas. Yet, an increasing number of reports are being published involving cases of young women and children with signs and symptoms of an autoimmune encephalopathy, in 40-50% of the cases secondary to a viral infection. Clinically, it is characterised by a progressive picture of psychiatric manifestations, convulsive seizures, dyskinesias and dysautonomias. One neuroimaging finding that has received little attention is reversible cortical atrophy, the underlying mechanism of which is unknown.
Case report: We report the case of a 6-year-old girl who started with focal convulsive seizures, with an abnormal epileptogenic electroencephalogram and an initial tomography scan of the head that was normal. Anticonvulsive treatment was established. At three weeks new convulsive seizures, psychiatric manifestations and disorders in the sleep-arousal cycle appeared. Suspecting a case of anti-NMDA antibody receptor encephalitis, analyses were performed to test for the presence of these antibodies in serum and in cerebrospinal fluid, the results being positive. Magnetic resonance imaging conducted during hospitalisation revealed generalised cortical atrophy. The Paediatric Oncology department ruled out any association with tumours. Two years after onset of the clinical picture, with the patient free of convulsive seizures, a neuropsychological appraisal was carried out. Results showed involvement of the executive functions and a follow-up magnetic resonance scan revealed recovery from the cortical atrophy.
Conclusions: The mechanism underlying reversible cortical atrophy is unknown but in patients with anti-NMDA receptor antibody encephalitis it could be directly proportional to the amount of antibodies in circulation and the length of time the cerebral cortex was exposed to them. An early diagnosis and initiating immunomodulation are essential.
Title: Atrofia cortical reversible secundaria a encefalitis por anticuerpos antirreceptor de NMDA.
Introduccion. La encefalitis por anticuerpos antirreceptor de N-metil-D-aspartato (NMDA) inicialmente se describio como un sindrome paraneoplasico asociado a teratoma de ovario, pero cada vez con mas frecuencia se han ido publicando casos en mujeres jovenes y niños como un cuadro encefalopatico autoinmune secundario en el 40-50% de los casos a un proceso viral. Clinicamente, se caracteriza por un cuadro progresivo de manifestaciones psiquiatricas, crisis convulsivas, discinesias y disautonomias. Un hallazgo neurorradiologico poco comunicado es la atrofia cortical reversible, de la cual se desconoce su mecanismo. Caso clinico. Niña que a los 6 años comenzo con crisis convulsivas focales, con electroencefalograma epileptogeno y tomografia de craneo inicial normal. Se inicio tratamiento anticonvulsionante. A las tres semanas aparecieron nuevas crisis convulsivas, manifestaciones psiquiatricas y alteraciones en el ciclo de sueño-vigilia. Ante la sospecha de encefalitis por anticuerpos antirreceptor de NMDA, estos se determinaron en el suero y el liquido cefalorraquideo con resultado positivo. Resonancia magnetica durante el ingreso con atrofia cortical generalizada. Oncologia Pediatrica descarto asociacion a tumores. A los dos años del cuadro, con la paciente libre de crisis convulsivas, una valoracion neuropsicologica mostro la afectacion de funciones ejecutivas y una resonancia magnetica de control evidencio la recuperacion de la atrofia cortical. Conclusion. El mecanismo de la atrofia cortical reversible se desconoce, pero en pacientes con encefalitis por anticuerpos antirreceptor de NMDA podria ser directamente proporcional a la cantidad de anticuerpos circulantes y el tiempo de exposicion a estos en la corteza cerebral. Es muy importante el diagnostico temprano y el inicio de inmunomodulacion.