A case of fulminant Epstein-Barr virus encephalitis in an immune-competent adult.

A 21-year-old female presented with headache, nausea and vomiting, dysarthria, difficulty finding words, vertigo, episodical diplopia and an abnormal gait since 2 days. Additionally, we found marked ataxia and disturbed liver chemistry whilst her infection parameters were low. Her head CT scan was unremarkable, but her MRI scan showed leptomeningeal enhancement along the cerebellar folia. A lumbar punction revealed mononuclear leucocytosis and increased protein in her cerebrospinal fluid. She was admitted on a working diagnosis of herpes simplex encephalitis. Shortly after admission, she had a generalised seizure. She was tested for a wide range of viruses, bacteria and auto-immune antibodies and treated empirically with aciclovir, ceftriaxone, doxycycline and intravenous immunoglobulins. All tests continued to come back negative until the fifth day of admission, when repeat Epstein-Barr virus (EBV) serology showed evidence of an acute EBV infection, even though negative tests were acquired at admission. EBV encephalitis is a rare complication of EBV infection that is usually restricted to children and immune-compromised individuals. This is only the fifth case describing EBV encephalitis in an immune-competent adult, presenting with unique clinical features including a lack of fever and leptomeningeal enhancement on MRI investigation. Most interestingly, she tested negative for EBV until a few days after admission, underlining the need for repeated investigations in suspected virological encepahlitis. Even though our patient did not receive the often recommended glucocorticosteroids, she made a good neurological recovery.