Herpes Viruses

Question 1

What herpes viruses are there?

Answer 1

Herpes 1, 2, 3, 4, 5, 6, and 8

Question 2

What is herpes virus 1 and 2?

Answer 2

Herpes simplex virus 1 and 2 (HSV1, HSV2)

Question 3

What is herpes virus 3?

Answer 3

Varicella zoster virus

Question 4

What is herpes virus 4?

Answer 4

Epstein-Barr virus (EBV)

Question 5

What is herpesvirus 5?

Answer 5

Cytomegalovirus (CMV)

Question 6

Which is more common, HSV1 or HSV2?

Answer 6

HSV1 - 2/3 of world’s population are infected.

HSV2 - around 11% of world’s population

Question 7

Explain pathology of HSV.

Answer 7

Viruses multiple in epithelial cells of mucosal surface producing vesicles or ulcers.

There is a lifelong latent infection when virus enters sensory neurons at infection site.

They can then reactivate, replicate and infect surrounding tissue.

Question 8

When might disseminated infection happen in HSV?

Answer 8

If there is impaired T cell immunity leading to pneumonitis, hepatitis and colitis.

Question 9

Presentation of primary HSV infection.

Answer 9

Subclinical or sensory nerve tingling

Vesicles and shallow ulcers

Systemic features might occurs such as fever, malaise and lymphadenopathy.

Question 10

How long does it take for primary HSV infection to heal?

Answer 10

8-12 days

Question 11

Where might HSV infect? (Anatomy-wise)

Answer 11

Herpes labialis - cold sores at lip border (HSV1)

Genital herpes (HSV2)

Gingivostomatitis

Keratoconjunctivitis with corneal dendritic ulcers. (Avoid steroids in this)

Herpetic whitlow - painful vesicles on distal phalanx

Herpes encephalitis

Question 12

Explain herpes encephalitis.

Answer 12

This is the most treatable encephalitis.

There is transfer of virus from peripheral site to brain via neuronal transmission.

This is predominantly in HSV1 and generally affects temporal lobe.

Question 13

Presentation of herpes encephalitis.

Answer 13

Fever, malaise, headache and nausea.

There is then encephalopathy involving general and focal neurological signs and dysfunction.

Psychiatric symptoms

Seizures

Memory loss

Question 14

Secondary infection of HSV.

Answer 14

HSV infection of eczematous skin like eczema herpeticum

Question 15

Diagnosis of HSV.

Answer 15

Clinical diagnosis.

Confirmation is needed if there is encephalitis, keratoconjunctivitis or immunosuppression.

This is then done with viral PCR of CSF, swab or vesicle scraping.

Culture, immunofluorescence and serology can also be done.

Question 16

Treatment of HSV.

Answer 16

Aciclovir - will reduce symptoms and viral shedding. It will however not prevent latent infection.

In herpes encephalitis empirical IV aciclovir should be done.

Question 17

What is Varicella zoster virus (VZV)?

Answer 17

Primary infection transmitted by respiratory droplets.

The incubation period is 14-21 days.

Question 18

Pathology of VZV.

Answer 18

It invades the respiratory mucosa and replicates in lymph nodes.

It then disseminates via mononuclear cells to infect skin epithelial cells.

The virus is then contained in vesicles = chicken pox.

The virus then lies dormant in sensory nerve roots.

Question 19

What is dermatomal reactivation of dormant VZV called?

Answer 19

Shingles

Question 20

Presentation of chicken pox.

Answer 20

1-2 days of fever, malaise, headache and abdo pain.

Then the rash comes which is a pruritic, erythematous macules going to vesicles.

Crust develops in 48h from onset of rash.

Patient is then infectious 1-2 days prior to onset of symptoms and 5 days post rash development.

Question 21

Complications of chicken pox.

Answer 21

This is usually only the case in immunosuppresion.

Encephalitis with cerebellar ataxia

VZV pneumonia

Transverse myelitis

Pericarditis

Purpura fulminans/DIC

Question 22

Presentation of shingles.

Answer 22

Painful hyperaesthetic area in one dermatome.

There is then a macular rash going vesicular in one dermatome.

The patient is infectious until scabs appear.

There is also a risk of causing chicken pox in a non-immune contact.

This means that someone with shingles can infect a non-immune causing them to have chicken pox.

Question 23

Complications of shingles.

Answer 23

Disseminated infection

Post-herpetic neuralgia

Ramsay-Hunt syndrome.

Question 24

Diagnosis of VZV.

Answer 24

Clinical diagnosis unless the patient is immunosuppressed.

Then you go for viral PCR, culture and immunofluorescence.

Question 25

Treatment of VZV.

Answer 25

Oral aciclovir/valaciclovir for uncomplicated chicken pox/shingles in adults. Aim to give within 48h of the onset of rash.

IV aciclovir should be given if pregnant, immunosuppressed or there is severe/disseminated disease.

Question 26

Prevention of VZV.

Answer 26

Vaccination - this is not routine in children in UK.

It is given at aged 70 to prevent shingles reactivation.

VZV immunoglobulin if non-immune exposure is also given in immunosuppression, prengancy and neonates.

Question 27

What is EBV?

Answer 27

Epstein-Barr virus is a virus that targets circulating B lymphocytes leading to a lifelong latent infection.

It also targets squamous epithelial cells of oropharynx.

Question 28

Presentation of EBV.

Answer 28

Usually asymptomatic infection in childhood.

There is infectious mononucleosis in around 50% of adults, this is the primary infection.

Sore throat, fever, anorexia, lymphadenopathy, palatal petechiae, splenomegaly, hepatomegaly and jaundice.

The malaise will be prominent.

Resolution is usually within 2 weeks.

Chronic active infection and recurrence is rare.

Question 29

Diagnosis of EBV.

Answer 29

Blood film with lymphocytosis. There are atypical lymphocytes that are large and irregular nuclei.

Heterophile antibody tests to detect non-EBV heterophile antibodies. They are present in 85% of infectious mononucleosis sera.
You might get false +ves in pregnancy, autoimmune disease, lymphoma and leukaemia.

Serology - IgM to EBV viral capsid antigen in acute infection, IgG if past infection.

Reverse transcriptase viral PCR

Question 30

Complications of EBV.

Answer 30

Burkitt’s lymphoma

Hodgkin’s lymphoma

B-cell lymphoma in immunosuppression

Gastric cancer

Nasopharyngeal cancer

Post-transplantation lymphoproliferative disease.

Question 31

Treatment of EBV.

Answer 31

Supportive

Seek expert help if there is severe disease or immunosuppression.

Question 32

What is CMV?

Answer 32

Cytomegalovirus is a herpes virus.

50-100% of adults are seropositive depending on socioeconomic and sexual risk.
This means that it is an extremely common virus to carry around but not noticing due to it usually being asymptomatic.

There is a latent infection that is periodic and asymptomatic.

It transmissible via blood transfusion, transplantation and bodily fluids.

Question 33

Presentation of CMV.

Answer 33

Asymptomatic in almost all cases.

However there is severe disease if the patient is immunosuppressed.

Oesophagitis, gastritis, colitis, retinitis, pneumonitis, hepatitis and encephalitis.

Infection in pregnancy is associated with congenital abnormalities.

Question 34

Diagnosis of CMV.

Answer 34

Primary infection in immunocompetent should be diagnosed by IgM.
In immunosuppressed quantitative nucleic acid amplification testing (QNAAT) is done.

In invasive disease tissue QNAAT and histopathology is done.

Question 35

Treatment of CMV.

Answer 35

Treatment is only given in severe disease and immunosuppressed.

Ganciclovir or valganciclovir.

Pre-emptive treatment in transplant patients is done depending on their QNAAT result.

Use CMV-ve irradiated blood for transfusion if immunosuppressed and at risk such as HIV, transplant and leukaemia.