This case was reported in a literature article and described the occurrence of acute disseminated encephalomyelitis in a 62-year-old female patient who received Influenza vaccine for prophylaxis. On an unknown date, the patient received Influenza vaccine at an unknown dose. On an unknown date, 3 days after receiving Influenza vaccine unspecified season, the patient experienced acute disseminated encephalomyelitis (serious criteria hospitalization and GSK medically significant), photosensitivity (serious criteria hospitalization), speech disorder (serious criteria hospitalization), fever (serious criteria hospitalization), disorientation (serious criteria hospitalization), hyperreflexia (serious criteria hospitalization), clonus of limbs (serious criteria hospitalization), hyperintensity in brain deep nuclei (serious criteria hospitalization), brain lesion (serious criteria hospitalization), headache (serious criteria hospitalization), vomiting (serious criteria hospitalization), lethargy (serious criteria hospitalization), short-term memory impairment, balance disorder and gait disturbance. The patient was treated with NOS Steroids and prednisone. On an unknown date, the outcome of the acute disseminated encephalomyelitis, hyperintensity in brain deep nuclei and brain lesion were recovering/resolving and the outcome of the photosensitivity, speech disorder, fever, disorientation, hyperreflexia, clonus of limbs, headache, vomiting and lethargy were recovered/resolved and the outcome of the short-term memory impairment, balance disorder and gait disturbance were unknown. The reporter considered the acute disseminated encephalomyelitis, photosensitivity, speech disorder, fever, disorientation, hyperreflexia, clonus of limbs, hyperintensity in brain deep nuclei, brain lesion, headache, vomiting, lethargy, short-term memory impairment, balance disorder and gait disturbance to be possibly related to Influenza vaccine. Additional information was provided. This case was reported in a literature article and described the occurrence of acute disseminated encephalomyelitis (ADEM) in 62-year-old female patient who was vaccinated with unspecified influenza vaccine (manufacturer unknown) for prophylaxis. No information on patient's medical or family history or concurrent condition or concomitant medication was provided. On an unspecified date, the patient received unspecified influenza vaccine (administration route and site unspecified, dosages unknown, batch number not provided). The age of vaccination was not provided. On an unspecified date, 3 days after vaccination, the patient suddenly developed headache which worsened and was associated with photosensitivity and vomiting. The next day, the patient was lethargic. The same night, the patient's husband reported that, she sat up in bed and started "speaking in tongues" as if she was "possessed". The patient was brought to the emergency room. The patient was extremely disoriented and could not followed commands. The patient was presented with 101.2 degree F temperature but remained afebrile afterwards. The patient had diffuse hyperlexia with ankle clonus bilaterally. The patient examination was unremarkable. The patient serum white blood count was 12.2; erythrocyte sedimentation rate (ESR) was 51; C-reactive protein (CRP) was 3.40; anti-cardiolipin IgM and beta-2-glycoprotein were elevated. The remainder of serological studies including anti-NMDA antibodies, tick borne infections, autoimmune and viral studies were unremarkable. The patient's computed tomography angiography (CTA) of head and neck was unremarkable. The lumbar puncture showed protein of 57; 87 white blood cells and 36 red blood cells; glucose was normal, negative viral studies; negative oligoclonal bands. The patient magnetic resonance imaging (MRI) of brain showed hyperintensities in the bilateral mesial temporal lobes, frontoparietal white matter, and basal ganglia. Subsequently, the patient was diagnosed with ADEM. The patient was treated with IV steroids for 5 days followed by prednisone taper over about 1 month. The patient's mental status improved dramatically each day. At the time of discharge, the patient's score on Montreal cognitive assessment (MOCA) test was 19/30. At 1 month follow up after presentation, the patient complained of some problems with short-term memory and balance, but was otherwise back to normal. The examination demonstrated MOCA of 26/30, difficulty with tandem gait, and mild hyperreflexia without clonus. The patient's neurologic exam was found to be normal. The patient Cardiolipin IgM; ESR CRP and beta-2-glycoprotein were all decreased. Repeat MRI demonstrated resolution of diffusion restriction and improvement in the size and number of hyperintensities without any new lesions. This case has been considered serious due to hospitalisation. The author's comment on the relationship between the event of ADEM and unspecified influenza vaccine: "Significant spontaneous recovery is the expected outcome in most cases of vaccine-induced ADEM, usually occurring within 1-6 months. Based on the current literature, it is difficult to predict who may be at risk. The risk must be balanced by the fact that influenza infection itself is a risk factor for ADEM, which is likely more common than that triggered by the vaccine. We do not advocate avoiding any vaccinations, but wish to promote awareness of this potential complication, as early identification and treatment may improve outcomes, and avoid unnecessary testing and treatment". Lab Comments: Lab tests were performed on unspecified dates. The patient magnetic resonance imaging (MRI) of brain showed hyperintensities in the bilateral mesial temporal lobes, frontoparietal white matter, and basal ganglia; this was consistent with acute disseminated encephalomyelitis. The patient's mental status improved dramatically each day. At the time of discharge, the patient's score on Montreal cognitive assessment (MOCA) test was 19/30. At 1 month follow up after presentation, the patient complained of some problems with short-term memory and balance, but was otherwise back to normal. The examination demonstrated MOCA of 26/30, difficulty with tandem gait, and mild hyperreflexia without clonus. The patient's neurologic exam was found to be normal. Repeat MRI demonstrated resolution of diffusion restriction and improvement in the size and number of hyperintensities without any new lesions.