Microbiology 2 Flashcards by Joanne McEwan

what causes chickenpox and shingles?

varicella zoster virus
chickenpox = varicella
shingles = zoster or herpes zoster

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how does chickenpox present?

macules which then become papules which then become vesicles
vesicles then scab over and begin to recover
lesions can vary in density - either in clusters or spread out
Occurs on first exposure

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what complications can arise from chickenpox and who are these common in?

secondary bacterial infection
varicella pneumonia
haemorrhagic rash (darker)
encephalitis
scarring
more common in adults/very young or immunocompromised

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what is neonatal varicella zoster virus?

secondary infection in newborn due to chickenpox in mother during late pregnancy (within 5 days of birth)
high mortality

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can neonatal VZV be prevented?

yes

varicella zoster immune globulin given to susceptible women

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what is shingles?

reactivation of varicella zoster virus later in life

usually in elderly or immunocompromised

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how does shingles present?

same as chickenpox - macules > papules > vesicles > scabs
limited to a single dermatome
associated neuralgic pain

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what is post hepatic neuralgia and when is it more likely?

when the neuralgic pain associated with shingles lasts for more than 4 weeks
more common in elderly and if the shingles is on the face (trigeminal)

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does scarring occur in shingles?

usually not

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what is ophthalmic zoster?

when shingles occupies the ophthalmic division of the trigeminal nerve (upper corner of face)
urgent ophthalmic referral indicated

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when is ophthalmic zoster common?

can happen in children if they contract the virus in utero or if immunocompromised

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what can it indicate if newborn/very young babies contract zoster virus?

in utero infection

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what dermatomes are likely to be affected in adults and children by the herpes zoster virus?

adults - lower thoracic, upper lumbar, trigeminal

children - dermatomes supplied to cervical and sacral nerves (legs etc)

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can the varicella zoster virus still occur if the patient has had the varicella vaccine?

yes

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what is Ramsey-Hunt Syndrome?

vesicular rash in the auditory canal and throat

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what are the symptoms of ramsey-hunt syndrome?

facial palsy (7th nerve palsy)
irritation of 8th cranial nerve causing deafness, vertigo and tinnitus

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what is ramsey hunt syndrome also known as?

geniculate or otic herpes zoster

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what can ramsey hunt syndrome often be mistaken for and what is the difference?

Bells Palsy

both causes by same virus and facial paralysis but Bells doesn’t have the vestibulocochlear symptoms of ramsey-hunt

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is there a vaccination for chickenpox?

yes

live attenuated vaccine is available but not really used in the UK, only for susceptible healthcare workers

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is there a vaccination for shingles?

yes
same as chickenpox but in a much higher titre
used in elderly to reduce impact of shingles

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what does the herpes simplex virus cause on first exposure?

primary gingivostomatitis causing extensive ulceration in and around mouth in pre-school children
lasts around a week

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how does the herpes simplex virus recur?

recurs as a blistering rash at vermillion border of lips

can the herpes simplex virus be spread?

yes

e.g - to finger or eczema

what does herpes simplex virus type 1 cause?

oral lesions
genital herpes
encephalitis

what does herpes simplex virus type 2 cause?

occasionally causes oral lesions genital herpes encephalitis/disseminated infection

how is HSZ and VZV treated?

acticlovir (analogue of guanosine)

how does acticlovir work?

analogue of guanosine incorporated into viral DNA chain inhibiting replication doesn't clear the virus but shortens the infection

how are VZV and HSV diagnosed?

swab

what is erythema multiforme?

target lesions with erythema | most are drug induced but can be caused by HSV or mycoplasma pneumoniae

what is molluscum contagiosum?

fleshy, firm nodules with a central punctum ("belly button") | common in children or sexually transmitted

how is molluscum contagiosum treated?

local liquid nitrogen | self limiting but may take months

what are warts?

benign tumours triggered by the Human Papilloma Virus | can cause verrucas on feet

how are warts treated?

self limiting but can be treated with topical salicylic acid or liquid nitrogen

what diseases can HPV cause?

genital warts cervical cancer head and neck cancer - so now vaccinated against in males

what is herpangina?

blistering rash of the back of the mouth caused by enterovirus (like coxackie or echovirus)

how is herpangina diagnosed and treated?

swab of lesion PCR of stool sample self limiting

what is hand, foot and mouth disease?

enterovirus infection causing blisters on hands, feet and buttocks

what can cause death in hand foot and mouth disease?

pulmonary oedema

what is erythema infectiosum?

slapped cheek disease caused by parovirus B19 | often causes arthritis

what are some complications of parovirus B19?

spontaneous abortion sudden anaemia chronic anaemia

how is parovirus B19 diagnosed?

antibody testing

what is orf?

virus of sheep | causes firm, fleshy nodules on hands of farmers

what is syphilis?

sexually transmitted treponema pallidum bacterium infection

what are the 3 phases of syphilis infection?

``` primary = chancre (painless ulcers at entry site) secondary = whole body rash (esp. on palms and soles) with mucous membrane snail track ulcers tertiary = CNS, cardiovascular and gummatous symptoms ```

how is syphilis diagnosed and treated?

``` diagnosis = blood test or chacre swab for PCR treatment = penicillin injections ```

how is syphilis incidence changing?

increasing

what is a serious complication of syphilis?

aneurysm

what is lyme disease?

bacterial infection by borrelia burgdoferi | carried by ticks

how does lyme disease present?

``` early = erythema migrans late = heart block, nerve palsy, arthritis ```

how is lyme disease treated?

doxy or amoxy

what is the Zika virus?

spread by mosquitoes in tropical areas | causing fever, rash, headaches, arthralgia, myalgia and conjunctivitis

does everyone that's infected with Zika virus get symptoms?

no only 1 in 5

what are some complications of Zika?

microcephaly | gullain barre syndrome