Varicella zoster (I) Flashcards
What is VZV also known as?
Human Alpha Herpes Virus
What disease does VZV primarily cause?
Chickenpox (varicella)
What infection does primary vs secondary infection by VZV cause?
- primary infection (acute) –> chickenpox
- secondary infection –> shingles
When does primary acute VZV (chickenpox) normally present?
Chickenpox normally presents in childhood and is usually self-limiting
Who does VZV infect?
Exclusively human virus - over 80% of people have been infected by the age of 10 years
Which groups are at high risk of VZV complications? (4)
- adults
- pregnant women
- immunocompromised patients
- neonates
- (including pneumonia, neurological sequelae, hepatitis, secondary bacterial infection and death)
How is VZV transmitted?
Direct contact with lesions (vesicular secretions) or through airborne spread from respiratory droplets
What is the incubation period for VZV?
14 days (9 to 21 days)
What happens after primary infection with VZV?
- can become latent in dorsal root ganglia and trigeminal ganglia
- later in life: in 1/3 of cases it may reactivate –> shingles
- increased risk if HIV or immunocompromised (e.g. steroid use or chemotherapy)
What is Ramsay-Hunt Syndrome (VZV)?
- LMN facial nerve palsy due to reactivation of VZV in geniculate ganglion of facial nerve
- Sx - first auricular pain –> then unilateral facial nerve palsy and vesicular rash around ear +/- blisters on anterior 2/3 of tongue
- Rx - oral acyclovir and corticosteroids (prednisolone)
What is Herpes Zoster Ophthalmicus (VZV)?
- reactivation of VZV in area supplied by ophthalmic division of trigeminal nerve
- Sx - vesicular rash around eye + Hutchinson’s sign (rash on tip/side of nose) indicates likely ocular involvement e.g. anterior uveitis
- Rx - urgent ophthalmology review + oral antivirals 7-10d
What are the clinical features of chickenpox - VZV? (7)
- fever
- vesicular rash - appears centrally first then spreads to extremities
- vesicles on mucous membranes e.g. nasopharynx
- pruritus
- headache
- fatigue/malaise (prodromal)
- sore throat
Describe the rash in chickenpox (VZV).
- macular papular rash evolving into vesicles with areas of weeping (exudate) and crusting
- as vesicles sweep and crust over new ones appear
- scabs fall off without leaving a scar
How does the rash spread in chickenpox (VZV)?
Starts centrally (face and trunk) then spreads to extremities (and oropharynx, conjunctivae, GU tract)
What are the clinical features of shingles - VZV?
- acute, unilateral, painful, blistering rash - erythematous, macular, vesicular rash
- prodromal period of burning/tingling pain over affected dermatome for 2-3 days
Describe the rash in shingles (VZV).
Acute, unilateral, painful, blistering
Erythematous, macular, vesicular
When are patients with shingles infectious until (VZV)?
Until vesicles have crusted over - usually 5-7 days from onset
What is the treatment for shingles (VZV)? (3)
- paracetamol
- NSAIDs
- can give antivirals within 72h
Which groups should those with shingles avoid?
Pregnant women and immunocompromised whilst infectious
What are the clinical features of Ramsay-Hunt Syndrome in order (VZV)?
- first auricular pain
- then unilateral facial nerve palsy and vesicular rash around ear +/- blisters on anterior 2/3 of tongue
What are the clinical features of Herpes Zoster Ophthalmicus (VZV)?
- vesicular rash around eye
- Hutchinson’s sign (rash on tip/side of nose) –> indicates likely ocular involvement e.g. anterior uveitis
What are the risk factors for chickenpox - VZV? (5)
- exposure to VZV
- age 1-9y
- unimmunised status
- occupational exposure
- immunocompromised
What are the risk factors for shingles - VZV? (4)
- primary VZV Hx
- adults >50y
- immunocompromised
- stress –> reactivation
How is VZV usually diagnosed?
Clinical diagnosis
What are the first-line investigations for VZV?
- PCR - positive for VZV DNA
- ultrasound in pregnant women - screen for foetal consequences of VZV
- vesical fluid - electron microscopy, direct immunofluorescence (DFA), cell culture, viral PCR
What is the main investigation done for VZV?
PCR - positive for viral DNA
What investigation do we do in pregnant women with VZV?
US - screen for foetal consequences of VZV infection
What investigation would we consider in VZV chickenpox in adults?
HIV testing
What are some differential diagnoses for VZV? (4)
- smallpox - fever, centrifugal distribution (face and extremities)
- HSV infection - mucous membranes of oral / genital region
- SJS-TEN - targetoid lesions that become flaccid blisters, erythema, positive Nikolsky’s sign
- monkeypox - travel to Africa, exotic pets, palms/soles, lymphadenopathy
What kind of disorder is chickenpox usually?
Self-limiting
How is chickenpox in children usually managed (VZV - low risk of severe disease)?
Supportive care - paracetamol, skin emollients, antihistamines (diphenhydramine), hydration, calamine lotion (itching)
What do we give for VZV - risk of moderate/severe disease?
Oral acyclovir
What do we give for VZV - high risk of severe disease?
IV antiviral therapy (acyclovir)
(Underlying pulmonary disease, long-term salicylates, short-course/intermittent oral corticosteroids)
How do we manage VZV (chickenpox and shingles) in adults?
Acyclovir if elderly, immunocompromised or ophthalmic involvement + simple analgesia
Which groups of patients should take post-exposure prophylaxis for VZV? (3)
- significant exposure to chickenpox or VZV
- immunosuppressed, neonate, pregnant
- no antibodies to VZV
What is VZV prophylaxis?
Varicella zoster immunoglobulin (VZIG) –> immunosuppressed and pregnant women exposed to VZV
Chickenpox vaccine - live attenuated VZV vaccine
What do we give for a common complication of shingles?
Antivirals to reduce chances of post-hepatic neuralgia, especially in elderly
How do we manage Ramsay-Hunt Syndrome - VZV? (2)
Oral acyclovir + corticosteroids (prednisolone)
How do we manage Herpes Zoster Ophthalmicus - VZV? (2)
- urgent ophthalmology review
- oral antivirals for 7-10d
What are some complications of VZV? (5)
- Varicella pneumonia
- encephalitis
- meningitis
- hepatitis
- severe infection in newborn
Describe the prognosis of VZV.
Typically self-limiting disease
In up to 1/3, VZV reactivates later as shingles or Herpes Zoster
