HSV Flashcards
Define herpes simplex virus.
Disease resulting from HSV1 or HSV2 infection.
What is HSV1 AKA and what does it cause?
Cold sores
- Herpes labialis - lips
- Herpetic whitlow - painful infection on fingers
What is HSV2 AKA and what does it cause?
Genital herpes
How is HSV1 spread?
Respiratory droplets
Saliva
How does HSV1 present?
- Gingivostomatitis, cold sores (herpes labialis)
- Herpetic whitlow
- Eczema herpeticum
- Herpes simplex meningitis, encephalitis
- Systemic infection
- Keratoconjunctivitis
How does HSV2 present?
- Genital herpes (chronic-life long)
- flu-like prodrome
- vesicles/papules around genitals, anus
- shallow ulcers
- urethral discharge
- dysuria
- fever and malaise
How common is HSV1?
Very common
90% of adults seropositive for HSV1 by age 30yrs (can be asymptomatic)
How is HSV2 spread?
- Sexual contact
- Perinatal
What is the aetiology of HSV1 and 2?
- Virus becomes dormant following primary infection - trigeminal/sacral root ganglia
- Reactivation may occur in response to stress or immunosuppression
List the herpesvirus classification.
What kind of viruses are HSV1 and 2?
Large, enveloped, double-stranded DNA viruses.
What are the two phases of HSV?
Has a latent and lytic phase:
Latent phase - chronic infection where infectious virons are not produced –> asymptomatic
Lytic phase - viral replication and transport of virus to skin and mucosal surfaces–> active infection
Describe the pathophysiology of herpes simplex virus.
- Acquired at mucosal surfaces or breaks in the skin
- Virus replicates in epidermis then infects sensory or autonomic nerve ending and travels via retrograde axonal transport to sensory ganglia.
- It then enters latent phase, evading the immune system to cause lifelong infection
- Periodic reactivation of the virus produces lytic replication when the virus travels by anterograde transport doen axons to the mucosal or cutaneous surface.
- Reactivation may lead to asymptomatic shedding of virus –> neuropathic tingling and burning to recurrent ulceration
- Timing and source is often diffucult to determine because virus is asymptomatic in when acquired
- HSV is associated with CD4+ and CD8+ T cells and antibodies.
What investigations would you do fos HSV infection?
Usually clinical diagnosis
May consider viral culture and HSV PCR, glycoprotein G based type specific serology.
- Viral culture - highest yield if vesicles can be unroofed and the base of an ulcer can be scraped with a Dacron swab
- HSV PCR - as above; higher sensitivity than viral culture
How do you manage HSV infection?
- oral aciclovir, valaciclovir or famciclovir *
- symptomatic treatment - paracetamol, lidocaine 5% topical,
- topical antiviral - docosanol topical 10%
*IV if there is disseminated visceral involvement (pneumonitis, hepatitis or SN involvement)
