Virals Flashcards
What is HSV I associated with?
Oral cold sores
What does HSV 2 cause?
Genital herpes
What is the herpes virus that causes Kaposi’s sarcoma?
HSV-8
True or false: EBV is a herpes virus
True
True or false: CMV is a herpes virus
True
What is the genetic makeup of herpesviridae viruses?
dsDNA
Where do herpes viruses become latent?
Ganglions of sensory or autonomic nerves
What is the route of transmission for herpes viruses?
Exposure to virus at the skin or mucus membranes
What is the mechanism of transport for herpes viruses into and out of the ganglion?
intra axonal transport
Which more commonly reactivates: HSV-1 or HSV-2?
HSV1
True or false: transmission of herpes can only occur when there is an outbreak of vesicular lesions
False-viral shedding periods as well
What is the protein that does anterograde transport out of the neuron? Retrograde?
Anterograde = kinesin Retrograde = dynein
True or false: HSV-1 and HSV-2 can cause lesions at any site
True
Are primary or secondary s/sx of HSV more symptomatic?
Primary
How long do primary HSV lesions usually last for?
10-14 days (or longer)
What are the prodromal ssx of HSV reactivation? How long do these recurrences last for?
pain, burning, tingling, and pruritus
3 days-ish
What are the oro-facial ssx that can present with HSV-1 infections, besides herpes labialis?
- Gingivostomatitis
- Eczema herpeticum
- erythema multiforme
What are the s/sx that are associated with primary HSV-2 infections, besides the vesicular lesions of the genitalia?
Fever
HA
Malaise
myalgias
What are the s/sx of HSV proctitis?
Anorectal pain, discharge and tenesmus
Does HSV-1 or HSV-2 cause herpetic whitlow?
Both
What is Herpetic gladiatorum?
Herpes infection of the forearm, usually 2/2 wrestling
Why is herpetic eye infections an emergency?
Threaten sight
What are the strains of HSV that can cause necrotizing retinitis?
HSV or VZV
What is herpes simplex encephalitis?
Aseptic encephalitis caused by HSV–emergency
What are the CT findings of herpes encephalitis?
Temporal lobe enhancement
What is Mollaret syndrome?
Occasionally recurrent meningitis associated with reactivation of HSV
What is the survival rate of a pt who presents with HSV encephalitis with a GCS of less than 6?
Nearly 0%
Which has a worse prognosis: HSV encephalitis or meningitis?
Encephalitis
What are the s/sx of transverse myelitis caused by herpes?
Sacral-autonomic dysfunction
What cranial nerve can often be affected with HSV?
CN V (bell’s palsy)
What are the common visceral infections of HSV?
- Esophagitis
- Tracheitis
What immunocompromised patients are particularly susceptible to HSV recurrences?
Hematological malignancies, especially if on CD20 inhibitors (B cell lymphomas/leukemias)
How do you diagnose HSV infections?
Clinical picture + PCR or culture
What are the drugs that are used to treat herpes infections?
Acyclovir
Foscarnet
Ganciclovir
What is the MOA of acyclovir? HOw is this administered?
COnverted by thymidylate kinase, to then inhibit DNA polymerases
PO administration
What is the MOA of foscarnet? HOw is this administered?
a structural mimic of the anion pyrophosphate that selectively inhibits the pyrophosphate binding site[citation needed on viral DNA polymerases at concentrations that do not affect human DNA polymerases.
IV administration
What is the MOA of ganciclovir?
synthetic analogue of 2′-deoxy-guanosine. It is first phosphorylated to ganciclovir monophosphate by a viral kinase encoded by CMV.
This goes on to inhibit dGTP incorporation into DNA via DNA polymerases
What is the main MOA of resistance of HSV to acyclovir?
Lack of thymidine kinase
What is the major side effect of foscarnet?
Marrow suppression
What are the topical agents used for HSV eye infections?
Idoxuridine
Trifluridine
Vidarabine
True or false: VZV infections in adults is usually more severe than in children
true
When is VZV no longer contagious?
When the vesicles have crusted over
What is the characteristic of VZV lesions that is pathognomonic?
Vesicles are in all different stages
What is the incubation period for VSV?
10-21 days
What is the main complication of VZV infection?
Coinfection with staph or strep
Can VZV cause encephalitis?
Yes
What is the most common visceral involvement of VZV?
Pneumonia
What is the mortality rate of VZV pneumonia that requires ventilation?
50%
What are the risk factors for VZV pneumonia?
Smoking
Pregnant
Immunosuppression
What is the treatment for VZV?
Acyclovir, but need higher doses than other HSV infections
What is the difference of using acyclovir for VZV than for other HSV infections?
Need a higher dose sooner, since VZV is less susceptible to the drug
Is it okay to give the varicella vaccine to immunocompromised patients?
No
Is the VZV vaccine good for post-exposure prophylaxis?
Yes
What are the spinal segments that are commonly associated with VZV reactivation?
T3-L3
What is the major ophthalmic concern with VZV reactivation?
Herpes zoster ophthalmicus or retinal necrosis
What is Ramsey-Hunt syndrome?
facial paralysis and hearing loss 2/2 VZV reactivation
How do you diagnose zoster?
PCR, but tzanck smear too
When should treatment for zoster be initiated? Why?
Within 72 hours–only affects the incidence of postherpetic neuralgia
Do steroids affect the outcome of zoster?
Nah
What is the most common presentation of EBV infection?
Subclinical viral infection–not usually mono
How is EBV unlike other VZV infections?
Transforms its host cells–does not have a cytopathic effect
True or false: asymptomatic shedding of EBV is common
True
What are the classic s/sx of EBV? (4)
Fever
LAD
Exudative pharyngitis
Splenomegaly
What is the incidence of a rash in EBV infected patients if they are given Ampicillin?
90-100%
How long does EBV usually last?
3 weeks
What virus can cause or predispose to Guillain-Barre syndrome?
EBV
What is the cause of BUrkitt’s lymphoma?
EBV
What are the malignancies that EBV can cause?
- Lymphoproliferative disorders
- Nasopharyngeal CA
- T-cell lymphoma
How do you diagnose EBV infections? (3)
- Heterophile abs
- IgG or IgM
- PCR
What is the treatment for EBV?
- Supportive
- Avoid contact sports
- Acyclovir iff active infection
How is CMV transmitted?
Sexual
Transplants
What are the classic histological characteristics of CMV infections?
Owl-eyed cells (large cells)
What are the s/sx of CMV mononucleosis?
Exudative pharyngitis and cervical LAD
What is the most common pathogen that complicates transplants?
CMV
Who is prophylaxis for CMV given to?
Immunocompromised hosts
How do you diagnose CMV infections?
PCR
What are the histological characteristics of CMV infections?
Intranuclear inclusions
What is the treatment for CMV?
Ganciclovir/valganciclovir
Foscarnet