Microbiology 2 Flashcards

1
Q

what causes chickenpox and shingles?

A

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

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2
Q

how does chickenpox present?

A

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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3
Q

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

A
secondary bacterial infection
varicella pneumonia
haemorrhagic rash (darker)
encephalitis
scarring
more common in adults/very young or immunocompromised
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4
Q

what is neonatal varicella zoster virus?

A

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

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5
Q

can neonatal VZV be prevented?

A

yes

varicella zoster immune globulin given to susceptible women

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6
Q

what is shingles?

A

reactivation of varicella zoster virus later in life

usually in elderly or immunocompromised

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7
Q

how does shingles present?

A

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

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8
Q

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

A

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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9
Q

does scarring occur in shingles?

A

usually not

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10
Q

what is ophthalmic zoster?

A

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

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11
Q

when is ophthalmic zoster common?

A

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

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12
Q

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

A

in utero infection

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13
Q

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

A

adults - lower thoracic, upper lumbar, trigeminal

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

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14
Q

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

A

yes

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15
Q

what is Ramsey-Hunt Syndrome?

A

vesicular rash in the auditory canal and throat

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16
Q

what are the symptoms of ramsey-hunt syndrome?

A
facial palsy (7th nerve palsy)
irritation of 8th cranial nerve causing deafness, vertigo and tinnitus
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17
Q

what is ramsey hunt syndrome also known as?

A

geniculate or otic herpes zoster

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18
Q

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

A

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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19
Q

is there a vaccination for chickenpox?

A

yes

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

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20
Q

is there a vaccination for shingles?

A

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

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21
Q

what does the herpes simplex virus cause on first exposure?

A

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

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22
Q

how does the herpes simplex virus recur?

A

recurs as a blistering rash at vermillion border of lips

23
Q

can the herpes simplex virus be spread?

A

yes

e.g - to finger or eczema

24
Q

what does herpes simplex virus type 1 cause?

A

oral lesions
genital herpes
encephalitis

25
Q

what does herpes simplex virus type 2 cause?

A

occasionally causes oral lesions
genital herpes
encephalitis/disseminated infection

26
Q

how is HSZ and VZV treated?

A

acticlovir (analogue of guanosine)

27
Q

how does acticlovir work?

A

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

28
Q

how are VZV and HSV diagnosed?

A

swab

29
Q

what is erythema multiforme?

A

target lesions with erythema

most are drug induced but can be caused by HSV or mycoplasma pneumoniae

30
Q

what is molluscum contagiosum?

A

fleshy, firm nodules with a central punctum (“belly button”)

common in children or sexually transmitted

31
Q

how is molluscum contagiosum treated?

A

local liquid nitrogen

self limiting but may take months

32
Q

what are warts?

A

benign tumours triggered by the Human Papilloma Virus

can cause verrucas on feet

33
Q

how are warts treated?

A

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

34
Q

what diseases can HPV cause?

A

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

35
Q

what is herpangina?

A

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

36
Q

how is herpangina diagnosed and treated?

A

swab of lesion
PCR of stool sample
self limiting

37
Q

what is hand, foot and mouth disease?

A

enterovirus infection causing blisters on hands, feet and buttocks

38
Q

what can cause death in hand foot and mouth disease?

A

pulmonary oedema

39
Q

what is erythema infectiosum?

A

slapped cheek disease caused by parovirus B19

often causes arthritis

40
Q

what are some complications of parovirus B19?

A

spontaneous abortion
sudden anaemia
chronic anaemia

41
Q

how is parovirus B19 diagnosed?

A

antibody testing

42
Q

what is orf?

A

virus of sheep

causes firm, fleshy nodules on hands of farmers

43
Q

what is syphilis?

A

sexually transmitted treponema pallidum bacterium infection

44
Q

what are the 3 phases of syphilis infection?

A
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
45
Q

how is syphilis diagnosed and treated?

A
diagnosis = blood test or chacre swab for PCR
treatment = penicillin injections
46
Q

how is syphilis incidence changing?

A

increasing

47
Q

what is a serious complication of syphilis?

A

aneurysm

48
Q

what is lyme disease?

A

bacterial infection by borrelia burgdoferi

carried by ticks

49
Q

how does lyme disease present?

A
early = erythema migrans
late = heart block, nerve palsy, arthritis
50
Q

how is lyme disease treated?

A

doxy or amoxy

51
Q

what is the Zika virus?

A

spread by mosquitoes in tropical areas

causing fever, rash, headaches, arthralgia, myalgia and conjunctivitis

52
Q

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

A

no only 1 in 5

53
Q

what are some complications of Zika?

A

microcephaly

gullain barre syndrome