HSV

Question 1

Define herpes simplex virus.

Answer 1

Disease resulting from HSV1 or HSV2 infection.

Question 2

What is HSV1 AKA and what does it cause?

Answer 2

Cold sores

• Herpes labialis - lips
• Herpetic whitlow - painful infection on fingers

Question 3

What is HSV2 AKA and what does it cause?

Answer 3

Genital herpes

Question 4

How is HSV1 spread?

Answer 4

Respiratory droplets

Saliva

Question 5

How does HSV1 present?

Answer 5

• Gingivostomatitis, cold sores (herpes labialis)
• Herpetic whitlow
• Eczema herpeticum
• Herpes simplex meningitis, encephalitis
• Systemic infection
• Keratoconjunctivitis

Question 7

How does HSV2 present?

Answer 7

• Genital herpes (chronic-life long)
• flu-like prodrome
• vesicles/papules around genitals, anus
• shallow ulcers
• urethral discharge
• dysuria
• fever and malaise

Question 8

How common is HSV1?

Answer 8

Very common

90% of adults seropositive for HSV1 by age 30yrs (can be asymptomatic)

Question 10

How is HSV2 spread?

Answer 10

• Sexual contact
• Perinatal

Question 11

What is the aetiology of HSV1 and 2?

Answer 11

• Virus becomes dormant following primary infection - trigeminal/sacral root ganglia
• Reactivation may occur in response to stress or immunosuppression

Question 12

List the herpesvirus classification.

Answer 12

Question 13

What kind of viruses are HSV1 and 2?

Answer 13

Large, enveloped, double-stranded DNA viruses.

Question 14

What are the two phases of HSV?

Answer 14

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

Question 16

Describe the pathophysiology of herpes simplex virus.

Answer 16

• 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.

Question 17

What investigations would you do fos HSV infection?

Answer 17

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

Question 18

How do you manage HSV infection?

Answer 18

• 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)

Question 19

What is most likely to predict future eye involvement?

Answer 19

• Involvement of the tip of nose