RESUMEN
Approximately 300 million people worldwide were living with chronic hepatitis B virus infection as of 2016, however, this number does not account for those who might be living with occult hepatitis B virus infection due to difficulty diagnosing this condition. The multiple genotypes and the ability of the hepatitis B virus to acquire mutations that down-regulate its expression make occult hepatitis B virus infection a very elusive diagnosis. This is especially worrisome when there is a need to start immunosuppressive therapies, since there is a risk of reactivation in undiagnosed patients. We present a case of female patient who was referred to the consultation because she was about to start chemotherapy with an anti-CD20 agent and had a positive anti-HBc and anti-HBs. During routine workup an occult hepatitis B virus infection was diagnosed. Upon further study mutations in the PreCore and Basal Core Promoter regions were identified, as well as, a double genotype D/C. Therapy with tenofovir was initiated before the patient was started on chemotherapy. This case highlights the importance of comprehensive studying of patients who present with apparently resolved chronic hepatitis B virus infection, especially when they are about to start immunosuppressive therapies.
RESUMEN
Herpes simplex virus (HSV) can affect the central nervous system causing meningitis, encephalitis and, rarely, acute retinal necrosis. We present a case of a 46-year-old man, previously healthy complaining of a 5-day persistent headache and sudden loss of vision of his left eye that progressed to the right. We started ceftriaxone, methylprednisolone and acyclovir for suspected encephalitis with vasculitis. HSV-1 was identified in vitreous and aqueous humour. Therapy with acyclovir was maintained and two intravitreous boluses of foscarnet were administered, without improvement. Usually being a benign infection, HSV can, in rare cases like this, have catastrophic effects in the optic tract.
