Introduction Alcohol-related neurocognitive disorders result from chronic and excessive alcohol consumption in combination with liver dysfunction and/or dietary deffiencies. Long-term alcohol abuse can affect higher and lower-order functions of neurocognition including but not limited to global deficits in visuospatial abilities, impulsivity, executive functions, working and episodic memory. According to the DSM-5, these disorders are divided in mild and major, forms with further division of the latter into amnestic-confabulatory and non-amnestic form. We present here a patient with new-onset psychosis that after careful evaluation of etiological causes was attributed to alcohol consumption with subsequent fullfilment for diagnostic criteria of Wernicke-Korsakoff. These disorders may be increasing worldwide, particularly in the elderly population. Interventions such as treatment of amnestic features as well as comorbidites, medication and engagement with psychosocial support systems has been associated with better outcomes. Methods We describe the case of a Latinx 74-year-old male with no past psychiatric history and a past medical history of hypertension and DM2 admitted to geriatric unit after exhibiting agitated behavior and paranoia. Collateral information obtained from family revealed that patient had recent on-set of insomnia, paranoia, visual hallucinations, confabulation and impulsivity that started 2 to 3 months before admission to our unit. It was also disclosed that patient had a history of nicotine and a chronic alcohol use which led to peptic ulcer disease and subsequent alcohol abstinence. A thorough medical work up revealed microcytic anemia and hyperglycemia with otherwise unremarkable hepatic function, TSH, Vitamin B12, folic acid and STD panel. MRI was remarkable for scattered hyperdensities suggestive of chronic small vascular ischemia. Results During first encounter, patient had bizarre behavior (holding a napkin between his lips to avoid air contamination), was seen talking to himself and exhibited paranoid ideation towards team. He was started on oral thiamine 100mg, medications for comorbidities and risperidone 0.5mg twice daily which he refused on multiple occasions requiring Olanzapine 2.5mg intramuscullarly. On day three, patient reported paranoid ideation towards family; he felt threatened, therefore he admitted he hid a machete under his bed at home before admission. On multiple ocassions patient was seen writing incomprehensible notes with nonsensical themes. The patient refused formal cognitive screening (MOCA) initially, yet he was oriented to sourroundings. On further evaluation, patient continued paranoid, isolated and refusing medication as he believed team was trying to poison him. Further collateral information from family revealed that patient exhibited neurocognitive symptoms at least 1 year before presentantion as well as increased alcohol consumption one month before admission into our unit. On day nine, thiamine was switched to intramuscular formulation as a 100mg twice a day dosing. By day twelve, patient was more cooperative and calm, exhibiting less psychosis and disorganization. He was able to perform a MOCA, with deficits in encoding and information retrieval and MMSE of 19/30. By day 15, patient was less delusional, socializing and with improved insight into his condition. We postulate that resolution of psychosis was achieved after intramuscular thiamine was initiated. Conclusions This presentation highlight a case of new-onset psychosis in an elderly patient with multiple comorbidities and imaging suggestive of vascular dementia. Management included a multifaceted approach with antipsychotic and thiamine treatment that after careful evaluation was attributed to alcohol induced amnestic disorder. Psychiatrists should understand the symptoms that could be associated to chronic ethanol use in the elderly population as well as treatment strategies to target symptoms. This research was funded by None

Introduction New immunotherapies are increasingly being used as treatment for different types of malignancies. Immunotherapeutic agents such as immune checkpoint inhibitors (ex. pembrolizumab) have been associated with various side effects, including encephalitis. Pembrolizumab, a monoclonal antibody which mechanism of action consists of activity against programmed cell death antigen (PD-1) has been associated with encephalitis. Methods We present the case of a 76-year-old man with past medical history of angiosarcoma of the nose that was treated with radiation, chemotherapy with Taxol. Due to the patient's high tumor mutation burden, he began treatment with pembrolizumab. After six months of treatment with pembrolizumab, he presented to the emergency department with acute changes in mentation. The patient was confused and wanted to go to vote in the middle of the night. He was waking up every 30 minutes and exhibited disorganized thought process and visual hallucinations. Full delirium work-up was done without any major findings. The following tests were in the normal range or negative: thyroid function tests, prolactin, LH, cosytropin stimulation test, ACTH, UA, CBC and CMP. Brain MRI excluded evidence of acute intracranial findings, acute ischemia or brain metastases. Psychiatry was consulted. Pembrolizumab was stopped. Recommendation was made to start aripiprazole 5mg daily. Patient improved after implementing these measures. Results We postulate that the patient developed encephalitis triggered by pembrolizumab in the context of angiosarcoma of the nose. Autoimmune encephalitis is a rare adverse effect of immune checkpoint inhibitors but it may be severe and potentially lethal. The etiology is not known and diagnosis can be challenging. We postulate that the patient developed encephalitis triggered by pembrolizumab in the context of angiosarcoma of the nose. Conclusions This case highlights the need of psychiatrists to understand the behavioral symptoms that could be attributed to immunotherapy agents in patient undergoing cancer treatment. Early identification and treatment of the behavioral symptoms are important in order to evaluate and manage appropriately, especially in the elderly population. It is important to consider autoimmune encephalitis secondary to immunotherapy as a differential for psychiatric disorders. Funding No funding

El linfoma orbitario es un tipo de tumor muy infrecuente que afecta a la órbita y a sus anexos. En raras ocasiones es bilateral. Es de vital importancia hacer un diagnóstico temprano para darle un tratamiento oportuno y así prevenir complicaciones. Nosotros reportamos un caso de un paciente del sexo femenino de 66 años que se presenta al servicio de urgencias de oftalmología por una celulitis periorbitaria. Al no remitir el cuadro, se le hospitalizó para realizar estudios complementarios que concluyeron que se trataba de un linfoma no Hodgkin de tipo B de la zona marginal (MALT). Los aspectos referentes a este tipo de linfoma como su epidemiología, etiología, etapas, diagnóstico y tratamiento se discuten en este reporte de caso.