Major viral pathogens Flashcards
what are the causes of necrotizing retinitis?
HSV and VZV
what is the most common cause of acute, sporadic encephalitis? what are the signs?
HSV encephalitis
fever and focal signs (temporal lobe enhancement)
what should be considered in recurrent meningitis associated with reactivation of HSV?
mollaret syndrome
what constitutes the clinical diagnosis for HSV?
painful vesicular lesions with a surrounding erythematous base
what constitutes the cytologic diagnosis for HSV?
Tzanck smear - intranuclear inclusions and multinucleated giant cells (suggestive)
what is the gold standard test for HSV diagnosis?
culture / PCR on direct specimens
route and dose/duration treatment for HSV is dependent upon what factors?
- primary infection or reactivation?
- deep / visceral or superficial, or CNS
- immunocompromised host?
what is the main drug used to treat HSV?
acyclovir
what visceral involvement is seen in VZV infection?
CNS
pneumonitis
hepatitis
what are the clinical manifestations of VZV infection?
exanthema and enanthem
bacterial skin superinfection
visceral involvement
disseminated
what is the most common visceral complication of VZV infection?
varicella pneumonia
what are the risk factors associated with varicella pneumonia?
smoking
pregnancy
immunosuppression
what is herpes zoster?
reactivation of latent VZV in sensory DRG
which DRGs are commonly associated with herpes zoster?
T3-L3
what antiviral is used to treat VZV?
acyclovir
what are the diagnostic lab tests for VZV?
Tzanck
culture
PCR
serology (previous infection)
zoster treatment depends on what?
complicated or uncomplicated infection
what drugs are used for herpes zoster treatment?
acyclovir
valacyclovir
famcyclovir
foscarnet
does EBV have a cytopathic effect?
no
what are the clinical manifestations of EBV? when do symptoms resolve?
- fever, adenopathy, pharyngitis
- splenomegaly (50%)
- rash (50%)
most symptoms resolve in 3 weeks
what are the lab diagnostic tests for EBV?
- heterophil antibodies
- atypical lymphocytosis
- EBV specific antibodies
- PCR for viral DNA, not in healthy hosts
what is the treatment for EBV?
- supportive care
- avoid contact sports
- steroids only for limited situations
- acyclovir
what is the transmission for CMV?
childhood
sexual
transfusion / transplant
what is diagnostic for CMV?
histology - owl’s eye inclusions
what are the clinical manifestations of CMV?
- exudative pharyngitis and cervical adenopathy rare as opposed to EBV
- ampicillin induced rash
- alk phos and transaminases usually elevated
what constitutes diagnosis for CMV?
- viral isolation (PCR)
- serology (antibodies)
- PCR for CMV DNA
does a positive PCR prove CMV disease?
no
what is the treatment for CMV?
gancyclovir / valgancyclovir
foscarnet
what is the MOA of gancyclovir / valgancyclovir?
selective inhibitor of CMV DNA pol mojor toxicity - neutropenia
which drug is effective in gangcyclovir resistant strains?
foscarnet
