r e v c o l o m b p s i q u i a t . 2 0 1 9; 4 8(2) :127–130 www.elsevier.es/rcp Case Report Red flags for suspecting anti-NMDAr encephalitis in a first psychotic episode: Report of two cases  Miguel Restrepo Martínez a,* , G. Paola Bautista b , Mariana Espínola-Nadurille c , Leo Bayliss d a Universidad CES, Medellín, Colombia b Instituto Nacional de Neurología y Neurocirugía, Ciudad de México, Mexico c Unidad de Neuropsiquiatría, Instituto Nacional de Neurología y Neurocirugía, Ciudad de México, Mexico d Unidad de Neurología, Instituto Nacional de Neurología y Neurocirugía, Ciudad de México, Mexico a r t i c l e i n f o Article history: Received 19 May 2017 Accepted 22 October 2017 Available online 10 April 2019 Keywords: Anti-N-Methyl-d-Aspartate receptor encephalitis Encephalitis Psychosis Catatonia Differential diagnosis Mental disorders a b s t r a c t Anti-N-methyl-d-Aspartate receptor (NMDAr) encephalitis is a recently described clinical entity with an increasing number of reported cases. Psychiatric symptoms in the early stages of the disease constitute a diagnostic challenge for the treating physician. We present two clinical cases: clinical case 1, a 26-year-old man, and clinical case 2, an 18-year-old man; both presented with a first episode of psychosis and were hospitalized as psychiatric disorders. Subsequently, both cases were diagnosed as anti-NMDAr encephalitis. The high prevalence of psychiatric symptoms in anti-NMDAr encephalitis forces psychiatrists and neurologists to have a high degree of suspicion in the presence of atypical symptoms in patients evaluated for the first episode of psychosis. © 2017 Asociaci ´ on Colombiana de Psiquiatr´ ıa. Published by Elsevier Espa ˜ na, S.L.U. All rights reserved. Banderas rojas para sospechar encefalitis anti-NMDAr en un primer episodio psicótico: reporte de dos casos Palabras clave: Encefalitis antirreceptor N-Metil-D-Aspartato Encefalitis r e s u m e n La encefalitis asociada a anticuerpos contra el receptor de N-metil-D-Aspartato (NMDAr) es una entidad clínica recientemente descrita con un número creciente de casos reporta- dos. Los síntomas psiquiátricos en etapas tempranas de la enfermedad conforman un reto diagnóstico para el médico tratante. Presentamos dos casos clínicos: el caso clínico 1, un DOI of original article: https://doi.org/10.1016/j.rcp.2017.10.002.  Please cite this article as: Restrepo Martínez M, Bautista GP, Espínola-Nadurille M, Bayliss L. Banderas rojas para sospechar encefalitis anti-NMDAr en un primer episodio psicótico: reporte de dos casos. Rev Colomb Psiquiat. 2019;48:127–130. * Corresponding author. E-mail address: mrm87356@hotmail.com (M. Restrepo Martínez). https://doi.org/10.1016/j.rcpeng.2017.10.003 2530-3120/© 2017 Asociaci ´ on Colombiana de Psiquiatr´ ıa. Published by Elsevier Espa ˜ na, S.L.U. All rights reserved.