Background: We present a rare case of Epstein-Barr Virus (EBV) encephalitis in a 15-year-old immunocompetent male. EBV typically causes mild, self-limiting infection in adolescents and rarely spreads to the central nervous system in immunocompetent patients (0.4 – 7.5%). We therefore highlight this rarer cause of encephalitis as an important differential in cases of unclassified encephalopathy and outline its diagnosis and treatment.Case Presentation: This case report was compiled through a retrospective chart and imaging review. A 15-year-old previously well male presented to the Emergency Department with a sore throat, headache, and vomiting and was discharged, diagnosed with glandular fever (Monospot positive). He later developed seizures and a low GCS requiring intubation, PICU admission and treatment with ceftriaxone and aciclovir. His encephalopathy symptoms of confusion and retrograde amnesia persisted post-extubation.Results: The diagnosis of acute EBV infection was confirmed via: serology (IgG, IgM positive), PCR <1000IU/mL (log <3) and MRI showing symmetrical T2-FLAIR hyperintensity of the caudate and putamen nuclei as well as cytotoxic oedema. Of note, the patient’s CSF was EBV PCR negative with a WCC of 38. Given the patient’s symptoms, history, and investigations, a diagnosis of EBV encephalitis was made. This is consistent with international criteria for diagnosis as EBV encephalitis commonly does not have a positive signal in CSF.Given the patient’s good clinical response on IV acyclovir, we treated for a total of 2 weeks, with the second week taken orally as an outpatient.Discussion: EBV encephalitis commonly does not have a positive signal in CSF and this is in line with international criteria for diagnosis. There is no clear consensus on the benefit of treatment for EBV encephalitis, and the IDSA 2008 Guideline does not actually recommend treating with aciclovir. Importantly, this guideline may now be outdated or in need of revision and many case reports still advocate treatment with aciclovir despite the recommendation to do otherwise. In some cases, however, it is key to note that treatment with aciclovir was most likely started as empirical cover only for HSV, and that the course was completed anyway. Analysis of previous studies would prove beneficial to illuminate this discrepancy.Learning Points: EBV encephalitis while rare, should remain a differential for undifferentiated cases of encephalopathy, even in immunocompetent patients. Further research and a retrospective cohort analysis to correlate how EBV is most commonly being treated and the respective patient outcomes, is warranted to further characterize this area of paediatric infectious disease management.
