SESSION TITLE: Neurological Crises in Critical CareSESSION TYPE: Rapid Fire Case ReportsPRESENTED ON: 10/18/2022 01:35 pm - 02:35 pmINTRODUCTION: Anti-N-methyl-d-aspartate receptor(NMDAR) encephalitis is an autoimmune disorder first described in 2007 in women with teratomas. Presenting psychiatric symptoms include psychosis, anxiety, insomnia, mania and catatonia. For patients with anti-NMDAR encephalitis, initial miss-classification as a psychiatric disease results in delayed diagnosis and worse outcome.CASE PRESENTATION: A 37-year-old woman presented to an urgent care center with hallucinations, dizziness and headaches, which was treated as acute otitis media. Her symptoms progressively worsened to agitation and she was admitted to a psychiatric unit for acute psychosis. Antipsychotics did not improve her condition, became catatonic and was transferred to the ICU for further management. Infectious work-up was negative and thyroid function tests were normal. EEG showed generalized rhythmic delta activity. CSF analysis was positive for oligoclonal bands and 98% lymphocytes. She was treated empirically with high-dose steroids(250mg Q6 hours) for 6 days and IV immune globulin 140g over 5 days for high suspicion of autoimmune encephalitis. Her NMDAR antibodies were reported positive in serum and CSF 10 and 31 days after collection with a CSF titer of 1:64. Abdominal US revealed a dermoid cyst which was surgically removed. Rituximab therapy was considered but not initiated due to concern for sepsis. Clinical course was complicated by status epilepticus requiring intubation, symptomatic bradycardia, cardiogenic shock, renal failure, atrial fibrillation and central hypoventilation. Repeat CT revealed anoxic brain injury. She passed a few days later.DISCUSSION: The most common presenting features of anti-NMDAR encephalitis are psychiatric symptoms, like mood alteration(anxiety or depression), aggression, mania, delusion, schizoaffective episodes, hallucinations; and seizures. Lymphocytic pleocytosis or oligoclonal bands in CSF, slow, epileptic activity or delta brush pattern on EEG, and mesiotemporal hyperintensities or atrophy pattern on MRI have been described with anti-NMDAR encephalitis. Patients presenting with high antibody titer groups(>1:32 in CSF), such as observed in our patient, more likely present teratoma and result in poor patient outcome. Although improved outcomes are associated with timely initiation of treatment, residual psychiatric symptoms have been noted in a significant portion of patients. First line immunotherapy includes corticosteroids, immunoglobulins or plasma exchange; and second line escalations like rituximab and cyclophosphamide may be added.CONCLUSIONS: Anti-NMDAR encephalitis may be misdiagnosed as a primary psychotic disorder. Confirmatory diagnostic testing are often delayed leading to worse outcomes. Hence, in a patient presenting with new onset psychosis, high index of suspicion for anti-NMDAR encephalitis and early initiation of therapy should be considered prior to confirmatory diagnostic testing.Reference #1: Ford B, McDonald A, Srinivasan S. Anti-NMDA receptor encephalitis: a case study and illness overview. Drugs Context. 2019;8:212589. Published 2019 Aug 30. doi:10.7573/dic.212589Reference #2: Wang W, Zhang L et al. Psychiatric symptoms of patients with anti-nmda receptor encephalitis. Front. Neurol., 24 January 2020. https://doi.org/10.3389/fneur.2019.01330Reference #3: Dalmau J, Armangué T, et al. An update on anti-NMDA receptor encephalitis for neurologists and psychiatrists: mechanisms and models. The Lancet Neurology, Volume 18, Issue 11, 2019, Pages 1045-1057.DISCLOSURES: No relevant relationships by Aditi DesaiNo relevant relationships by Daniel Fein SESSION TITLE: Neurological Crises in Critical Care SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/18/2022 01:35 pm - 02:35 pm INTRODUCTION: Anti-N-methyl-d-aspartate receptor(NMDAR) encephalitis is an autoimmune disorder first described in 2007 in women with teratomas. Presenting psychiatric symptoms include psychosis, anxiety, insomnia, mania and catatonia. For patients with anti-NMDAR encephalitis, initial miss-classification as a psychiatric disease results in delayed diagnosis and worse outcome. CASE PRESENTATION: A 37-year-old woman presented to an urgent care center with hallucinations, dizziness and headaches, which was treated as acute otitis media. Her symptoms progressively worsened to agitation and she was admitted to a psychiatric unit for acute psychosis. Antipsychotics did not improve her condition, became catatonic and was transferred to the ICU for further management. Infectious work-up was negative and thyroid function tests were normal. EEG showed generalized rhythmic delta activity. CSF analysis was positive for oligoclonal bands and 98% lymphocytes. She was treated empirically with high-dose steroids(250mg Q6 hours) for 6 days and IV immune globulin 140g over 5 days for high suspicion of autoimmune encephalitis. Her NMDAR antibodies were reported positive in serum and CSF 10 and 31 days after collection with a CSF titer of 1:64. Abdominal US revealed a dermoid cyst which was surgically removed. Rituximab therapy was considered but not initiated due to concern for sepsis. Clinical course was complicated by status epilepticus requiring intubation, symptomatic bradycardia, cardiogenic shock, renal failure, atrial fibrillation and central hypoventilation. Repeat CT revealed anoxic brain injury. She passed a few days later. DISCUSSION: The most common presenting features of anti-NMDAR encephalitis are psychiatric symptoms, like mood alteration(anxiety or depression), aggression, mania, delusion, schizoaffective episodes, hallucinations; and seizures. Lymphocytic pleocytosis or oligoclonal bands in CSF, slow, epileptic activity or delta brush pattern on EEG, and mesiotemporal hyperintensities or atrophy pattern on MRI have been described with anti-NMDAR encephalitis. Patients presenting with high antibody titer groups(>1:32 in CSF), such as observed in our patient, more likely present teratoma and result in poor patient outcome. Although improved outcomes are associated with timely initiation of treatment, residual psychiatric symptoms have been noted in a significant portion of patients. First line immunotherapy includes corticosteroids, immunoglobulins or plasma exchange; and second line escalations like rituximab and cyclophosphamide may be added. CONCLUSIONS: Anti-NMDAR encephalitis may be misdiagnosed as a primary psychotic disorder. Confirmatory diagnostic testing are often delayed leading to worse outcomes. Hence, in a patient presenting with new onset psychosis, high index of suspicion for anti-NMDAR encephalitis and early initiation of therapy should be considered prior to confirmatory diagnostic testing. Reference #1: Ford B, McDonald A, Srinivasan S. Anti-NMDA receptor encephalitis: a case study and illness overview. Drugs Context. 2019;8:212589. Published 2019 Aug 30. doi:10.7573/dic.212589 Reference #2: Wang W, Zhang L et al. Psychiatric symptoms of patients with anti-nmda receptor encephalitis. Front. Neurol., 24 January 2020. https://doi.org/10.3389/fneur.2019.01330 Reference #3: Dalmau J, Armangué T, et al. An update on anti-NMDA receptor encephalitis for neurologists and psychiatrists: mechanisms and models. The Lancet Neurology, Volume 18, Issue 11, 2019, Pages 1045-1057. DISCLOSURES: No relevant relationships by Aditi Desai No relevant relationships by Daniel Fein