INTRODUCTION: Acute disseminated encephalomyelitis (ADEM) is a rare immune-mediated condition affecting the central nervous system, characterized by acute encephalopathy and multifocal neurological deficits. This disorder predominantly impacts children but here, we document a rare adult case, emphasizing the necessity for considering organic causes in psychiatric symptomatology [1 ; 2]. AIMS / OBJECTIVES: A detailed review of literature was conducted through PubMed focusing on the atypical presentations of ADEM and the incidence of organic diseases manifesting psychiatric complaints. This approach informed our diagnostic strategy and management of an unusual adult case of ADEM, underscoring the importance of maintaining a wide differential diagnosis in emergency medicine [3 ; 4] CASE DESCRIPTION: A 22-year-old female presented with generalized weakness, confusion, apathy, and reduced appetite, following an upper respiratory tract infection and a distressing dental visit. Her neurological examination revealed dysarthria, dysmetria, and ataxia, with a significant reduction in motor strength and generalized hyperreflexia. Laboratory tests were largely unremarkable except for elevated ESR and CRP. MRI findings were consistent with a demyelinating process, See Figure 1A and 1B, fulfilling the criteria for ADEM diagnosis [5 ; 6]. RESULTS: Results: Initiation of a steroid regimen led to significant clinical improvement, and by day 11 of hospitalization, there was a marked improvement in the patient's condition, enabling discharge with outpatient neurology and ophthalmology follow-ups. A six-week steroid taper was prescribed. Follow-up MRI confirmed resolution of the demyelinating lesions, confirming the effectiveness of the treatment protocol [7 ; 8]. DISCUSSION: This case underscores the complexity of diagnosing ADEM in adults, particularly when presenting with psychiatric symptoms. It highlights the critical importance of comprehensive evaluation in emergency settings to identify rare organic causes of psychiatric presentations. This report reinforces the need for awareness among clinicians to consider ADEM in differential diagnoses, ensuring timely and appropriate management for affected patients [9; 10; 11]. REFERENCES: 1. [Pohl D, Alper G, Van Haren K, Kornberg AJ, Lucchinetti CF, Tenembaum S, Belman AL. Acute disseminated encephalomyelitis: Updates on an inflammatory CNS syndrome. Neurology. 2016 Aug 30;87(9 Suppl 2):S38-45. doi 10.1212/WNL.0000000000002825. PMID: 27572859.] 2. [De Fino C, Nociti V, Modoni A, Bizzarro A, Mirabella M. An atypical case of acute disseminated encephalomyelitis associated with cytomegalovirus infection. Mult Scler Relat Disord. 2016 Jan;5:70-2. doi: 10.1016/j.msard.2015.11.003. Epub 2015 Nov 10. PMID: 26856946.] 3. [Kamel MG, Nam NT, Han NHB, El-Shabouny AE, Makram AM, Abd-Elhay FA, Dang TN, Hieu NLT, Huong VTQ, Tung TH, Hirayama K, Huy NT. Post-dengue acute disseminated encephalomyelitis: A case report and meta-analysis. PLoS Negl Trop Dis. 2017 Jun 30;11(6):e0005715. doi: 10.1371/journal.pntd.0005715. PMID: 28665957; PMCID: PMC5509372.] 4. [Obermeier PE, Karsch K, Hoppe C, Seeber L, Schneider J, Mühlhans S, Chen X, Tief F, Kaindl AM, Weschke B, Böttcher S, Diedrich S, Rath B. Acute Disseminated Encephalomyelitis After Human Parechovirus Infection. Pediatr Infect Dis J. 2016 Jan;35(1):35-8. doi: 10.1097/INF.0000000000000928. PMID: 26741581.] 5. [Neeki MM, Au C, Richard A, Peace C, Jaques S, Johansson J. Acute Disseminated Encephalomyelitis in an Incarcerated Adolescent Presents as Acute Psychosis: Case Report and Literature Review. Pediatr Emerg Care. 2019 Feb;35(2):e22-e25. doi: 10.1097/PEC.0000000000000919. PMID: 27749808.] 6. [Chaudhry LA, Babur W, Chaudhry GA, Al-Atawi FE, Robert AA. Acute disseminated encephalomyelitis: a call to the clinicians for keeping this rare condition on clinical radar. Pan Afr Med J. 2018 M

Keywords: Adult Onset Acute Disseminated Encephalomyelitis (ADEM), Case Repot, weakness, confusion, neurological emergency, altered mental status, emergency Medicine