ABSTRACT
TOPIC: Imaging TYPE: Medical Student/Resident Case Reports INTRODUCTION: Acute disseminated encephalomyelitis (ADEM), is an autoimmune demyelinating disease of the central nervous system, with acute onset of encephalopathy and rapidly progressive multifocal neurologic deficits. ADEM is an uncommon illness in adults, thus the precise incidence is unknown. CASE PRESENTATION: 38 year old female with no prior history besides prior COVID infection 6 months ago, presented with 2 day history of nausea, intractable vomiting, ataxia, confusion, and generalized weakness.Initial MRI brain reported numerous white matter lesions supratentorially and infratentorially. LP demonstrated oligoclonal bands, WBC 14, no xanthochromia. She was diagnosed with multiple sclerosis (MS) and received 5 day course of Solumedrol, with no improvement. Her mental status worsened, and she required mechanical ventilation. She later developed rigidity of the neck and lower extremities, with meningeal signs and dystonia. EEG was done for dystonia but no epileptiform activity was captured. The HIV, syphilis Ig G antibody, ANA Ab, HSV and enterovirus PCR were negative. A continuous EEG for 48 hours did not capture any seizure activity.A repeat MRI Brain demonstrted worsening white matter lesions with symmetrical distribution through thalamus, basal ganglia, internal capsule, and brainstem (Figure 1). Spinal MRI revealed no abnormal enhancement. Given the large monophasic infratentorial and supratentorial lesions ADEM was suspected. Patient received IVIG treatment and plasmapheresis, with mild clinical improvement to date. DISCUSSION: ADEM is theorized to be an immunologically mediated demyelinating disease triggered by a febrile illness or recent vaccination, eliciting an inflammatory response affecting the central nervous system. Possible mechanisms may include either molecular mimicry or direct inflammatory damage to myelinated neurons. Radiographically, the T2/FLAIR (MRI) lesions of ADEM are diffuse, asymmetric, often irregular, patchy areas of homogeneous signal hyperintensities often involving both gray and white matter with over half of the cases involving infratentorial structures. ADEM diagnosis remains a challenge and is particularly difficult to differentiate from MS. In contrast to MS, ADEM should be suspected whenever a patient presents with a prodromal viral illness, fever, neck stiffness, ataxia and encephalopathy. Unlike MS, ADEM does not follow a relapsing-remitting course. Treatment involves high dose corticosteroids, intravenous immunoglobulin (IVIG), and plasmapheresis. CONCLUSIONS: The diagnosis of ADEM entails careful clinical assessment and characteristic imaging findings, as no clear criteria exist. It should be highly suspected in patients with atypical MS. REFERENCE #1: Nicole Mahdi, Peter A. Abdelmalik, Mark Curtis, Barak Bar, "A Case of Acute Disseminated Encephalomyelitis in a Middle-Aged Adult", Case Reports in Neurological Medicine, vol. 2015. REFERENCE #2: De Seze J, Debouverie M, Zephir H, et al. Acute fulminant demyelinating disease: a descriptive study of 60 patients. Arch Neurol 2007;64:1426. REFERENCE #3: Ceronie B, Cockerell OC. Acute disseminated encephalomyelitis in an older adult following prostate resection. eNeurologicalSci. 2018;14:40-42 DISCLOSURES: No relevant relationships by Jeannie Lee, source=Web Response No relevant relationships by Barbara Mantilla, source=Web Response No relevant relationships by Arunee Motes, source=Web Response No relevant relationships by Victor Test, source=Web Response No relevant relationships by Myrian Vinan Vega, source=Web Response