acute disseminated encephalomyelitis (ADEM); headache worsened; nausea; photosensitivity; vomiting; lethargic; speaking in tongues as if she was possessed; extremely disoriented; could not follow commands or respond appropriately; diffuse hyperreflexia; ankle clonus bilaterally; short-term memory and balance; some problems with balance; Initial information received on 30-Oct-2019 regarding an unsolicited valid serious case from a Literature article.  Abstract:  Case Presentation: A 62 year old woman with a history of hypertension suddenly developed a headache starting 3 days after receiving the influenza vaccine. The headache worsened and was associated with nausea, photosensitivity and vomiting. The next day she was lethargic, and that night, her husband states she sat up in bed and started "speaking in tongues" as if she was "possessed". He brought her to the emergency room where she was extremely disoriented, could not follow commands or respond appropriately. Temperature was 101.2F on presentation, and remained afebrile afterward. She had diffuse hyperreflexia with ankle clonus bilaterally; otherwise exam was unremarkable. Serum white blood count was 12.2, ESR 51, CRP 3.40; anticardiolipin IgM and beta-2-glycoprotein were elevated. The remainder of serological studies were unremarkable, including anti-NMDA antibodies, tick borne infections, autoimmune and viral studies. CT head and CTA of the head and neck were unremarkable. Lumbar puncture showed protein of 57, 87 white blood cells and 36 red blood cells; glucose was normal. Other cerebrospinal fluid tests including herpes virus and oligoclonal bands were negative. MRI brain demonstrated multifocal ovoid and serpiginous areas of diffusion restriction and T2/FLAIR hyperintensities in the bilateral mesial temporal lobes, frontoparietal white matter, thalamus, putamen, and globus pallidus; this was thought most consistent with acute disseminated encephalomyelitis (ADEM). She was briefly treated with IV acyclovir (until HSV PCR was found to be negative), and IV steroids for 5 days followed by prednisone taper over about 1 month. Her mental status improved dramatically each day; score on montreal cognitive assessment (MOCA) test was 19/30 on discharge. At follow up 1 month after presentation, she complained of some problems with short-term memory and balance, but was otherwise back to normal. Examination demonstrated MOCA of 26/30, difficulty with tandem gait, and mild hyperreflexia without clonus; neurologic exam was otherwise normal. Cardiolipin IgM was borderline-positive, ESR 13, CRP 2.2, and beta-2-glycoprotein was negative. Repeat MRI demonstrated resolution of diffusion restriction and improvement in the size and number of T2/FLAIR hyperintensities without any new lesions. Discussion: ADEM is an inflammatory demyelinating disease of the central nervous system. The assumed mechanism is immunemediated demyelination triggered by infection, or, rarely, vaccination. For most vaccines, incidence rates of ADEM are as low as 0.1 to 0.2 per 100,000 vaccinated individuals. A search from 1979 to 2013 showed only 3 cases of seasonal influenza vaccine associated with ADEM. As such, there have been no large population studies with estimated incidence rates yet. Lesion patterns often seen in ADEM include widespread, multifocal lesions in the white and deep grey matter, as seen in our patient. Conclusions: 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  This case involves a 62 years old female patient who experienced acute disseminated encephalomyelitis (adem) (Acute disseminated encephalomyelitis), short-term memory (Amnesia) and balance (Balance disorder), while she received vaccine INFLUENZA VACCINE.  The patient's past medical history, medical treatment(s), vaccination(s) and family history were not provided. At the time of the event, the patient had ongoing Hypertension.   On an unknown date, the patient received a dose of suspect INFLUENZA VACCINE produced by unknown manufacturer lot number not reported via unknown route in unknown administration site.  On an unknown date, The patient developed a serious acute disseminated encephalomyelitis (adem) (acute disseminated encephalomyelitis) (3 days latemcy), short-term memory and balance (amnesia) (latency: 1 month), some problems with balance (balance disorder) (latency: 1 month), headache worsened (headache) (3 days latemcy), nausea (nausea), photosensitivity (photosensitivity reaction), vomiting (vomiting), lethargic (lethargy), speaking in tongues as if she was possessed (verbigeration), extremely disoriented (disorientation), ould not follow commands or respond appropriately (abnormal behaviour), diffuse hyperreflexia (hyperreflexia), ankle clonus bilaterally (clonus) Unknown latency following the administration of INFLUENZA VACCINE. Other than amnesia and balance disorder, all other events was assessed as medically significant. The patient was hospitalized for these events.  Relevant laboratory test results included: Beta-2 glycoprotein antibody - On an unknown date: elevated [elevated] Body temperature - On an unknown date: 101.2 F [101.2] C-reactive protein - On an unknown date: 3.40 [3.40]; on an unknown date: 2.2 [2.2] Cardiolipin antibody - On an unknown date: elevated [elevated]; on an unknown date: positive [positive] Lumbar puncture - On an unknown date: 57 [57] Montreal cognitive assessment - On an unknown date: 19/30 [19/30]; on an unknown date: 26/30 [26/30] Red blood cell count - On an unknown date: 36 [36] Red blood cell sedimentation rate abnormal - On an unknown date: 51 [51]; on an unknown date: 13 [13] Tandem gait test - On an unknown date: abnormal [abnormal] White blood cell count - On an unknown date: 12.2 [12.2]; on an unknown date: 87 [87]  (Other relevant tests included glucose was normal. The remainder of serological studies were unremarkable, including anti-NMDA ntibodies, tick borne infections, autoimmune and viral studies. CT head and CTA of the head and neck were unremarkable. Other cerebrospinal fluid tests including herpes virus. and oligoclonal bands were negative. MRI brain emonstrated multifocal ovoid and serpiginous areas of diffusion restriction and T2/FLAIR hyperintensities in the bilateral mesial temporal lobes, frontoparietal white matter, thalamus, putamen, and globus pallidus; this was thought most consistent with acute disseminated encephalomyelitis (ADEM)..)  Final diagnosis was some problems with balance, short-term memory and balance and acute disseminated encephalomyelitis (adem).   The patient was treated with ACYCLOVIR [ACICLOVIR] (ACYCLOVIR [ACICLOVIR]) for Product used for unknown indication and PREDNISONE (PREDNISONE) for Product used for unknown indication.  The patient outcome was not reported.  The information on the batch number was requested.; Sender's Comments: Patient experienced acute disseminated encephalomyelitis, amnesia, balance disorder along with other events after vaccination. Time to onset is compatible with the role of vaccine. However, further information including patient's concomitant medications, previous vaccination and tolerance would be needed to fully assess this case. Based on available information the role of vaccine cannot be assessed.