Varicella zoster Flashcards
What is chickenpox
Chickenpox is caused by primary infection with varicella zoster virus.
What is shingles
Shingles is a reactivation of the dormant virus in dorsal root ganglion
What is the transmission
spread via the respiratory route
can be caught from someone with shingles
What is the infectivity and incubation
infectivity = 4 days before rash, until 5 days after the rash first appeared*
incubation period = 10-21 days
What are the clinical features
Fever
itchy, rash starting on head/trunk before spreading. Initially macular then papular then vesicular
systemic upset is usually mild
What is the management of chicken pox
keep cool, trim nails
calamine lotion
When children be excluded
he most infectious period is 1–2 days before the rash appears, but infectivity continues until all the lesions are dry and have crusted over (usually about 5 days after the onset of the rash).
what should immunocompromised patients and newborns with peripartum exposure receive
Varicella zoster immunoglobulin
What is a secondary complication
bacterial infection of the lesions - INCREASED RISK WITH nsaids
What can occur as a result of bacterial infection
whilst this commonly may manifest as a single infected lesion/small area of cellulitis, in a small number of patients invasive group A streptococcal soft tissue infections may occur resulting in necrotizing fasciitis
What are the rare complication
pneumonia
encephalitis (cerebellar involvement may be seen)
disseminated haemorrhagic chickenpox
arthritis, nephritis and pancreatitis may very rarely be seen
What is shingles
acute, unilateral, painful blistering rash caused by reactivation of the varicella-zoster virus (VZV), the virus lies dormant in the dorsal root or cranial nerve ganglia.
What are the risk factors for shingles
increasing age
HIV: strong risk factor, 15 times more common
other immunosuppressive conditions (e.g. steroids, chemotherapy)
What are the most affected dermatomes
T1-L2
What occurs during the prodromal period
burning pain over the affected dermatome for 2-3 days
pain may be severe and interfere with sleep
around 20% of patients will experience fever, headache, lethargy
What is the rash like in shingles
initially erythematous, macular rash over the affected dermatome
quickly becomes vesicular
characteristically is well demarcated by the dermatome and does not cross the midline. However, some ‘bleeding’ into adjacent areas may be seen
What is advised to shingles patients
remind patients they are potentially infectious
may need to avoid pregnant women and the immunosuppressed
should be advised that they are infectious until the vesicles have crusted over, usually 5-7 days following onset
covering lesions reduces the risk
What analgesia should be given in shingles
paracetamol and NSAIDs are first-line
if not responding then use of neuropathic agents (e.g. amitriptyline) can be considered
oral corticosteroids may be considered in the first 2 weeks in immunocompetent adults with localized shingles if the pain is severe and not responding to the above treatments
When to give anti virals in shingles
in practice, they recommend antivirals within 72 hours for the majority of patients, unless the patient is < 50 years and has a ‘mild’ truncal rash associated with mild pain and no underlying risk factors
What are the benefits of giving anti virals
reduced incidence of post-herpetic neuralgia, particularly in older people
What are the antivirals used in shingles
aciclovir, famciclovir, or valaciclovir are recommended
What is the most common complication
Post hepatic neuralgia
What is herpes zoster opthalmicus
shingles affecting affecting the ocular division of the trigeminal nerve) is associated with a variety of ocular complications
What is heroes zoster optics
Ramsay Hunt syndrome): may result in ear lesions and facial paralysis
