Chickenpox + Shingles Flashcards
which of the following is false regarding human herpesviruses
1. there is a property of latency with specific host cells
2. different viruses may exhibit different clinical sx
3. chicken pox is caused by varicella zoster virus 3
4. there are 6 herpes viruses that routinely infect only humans
4- there are 8
acute infection with varicella zoster causes
chickenpox/ varicella
reactivation with varicella zoster causes
shingles or herpes zoster
how can the herpes simplex 1 virus be reactivated
fever, sunlight to face, menstruation, stress, etc
how can the varicella virus be reactivated
age, x ray irradiation
herpes zoster begins as _______ which evolve into ______ that coalesce into ______________ with _________ component
erythematous papules
evolve into vesicles
coalesce into large confluent blisters with hemorrhagic component
herpes zosters lesions continue to form over
3-5d
healing of herpes zoster lesions occurs over
2wks
what are some permanent changes that may happen after herpes zoster
scarring and discoloration
what are the most commonly affected dermatomes by herpes zoster
T1-L2
hallmark characteristic of herpes zoster is
unilateral- does not cross body’s midline
~20% patients have systemic sx from herpes zoster, including
fever, HA, malaise, fatigue
herpes zoster is diagnosed ________
clinically
why might confirmatory lab tests be used for herpes zoster dx
to differentiate from HSV (dep on location of rash) or in pts with typical pain but no rash
3 lab tests you can use for herpes zoster dx
PCR
immunohistochemistry
viral culture from vesicular fluid
describe immunohistochemistry for herpes zoster dx
cells scraped from base of lesion + stained with fluorescein conjugated monoclonal Abs to detect viral glycoprotein
which is more sensitive
1 .immunohistochemistry
2. culture
1
list 3 differential dx for herpes zoster
herpes simplex virus
contact dermatitis
impetigo
cellulitis
candidiasis
dermatitis herpetiformis (skin manifestation of celiac disease)
drug eruptions
what is the most common complication of HZ
post herpetic neuralgia
3 major risk factors for HZ
> 50yrs
HIV
other immunosuppression (ex- CS, chemo)
which of the following is true
1.HIV increases the risk of HZ by 10x
2. there is an increasing trend of shingles in the US
3. there is a decreasing trend of shingles in Japan
4. being >40yrs is a major RF for HZ
2
acute herpetic neuralgia is
pain preceding or accompanying rash that persists up to 30 days from onset
subacute herpetic neuralgia is
pain that persists beyond rash healing but resolves within 3-4mths
what is post herpetic neuralgia
pain >3-4mths from initial onset rash
pain preceding or accompanying rash that persists up to 30 days from onset
acute herpetic neuralgia
pain that persists beyond rash healing but resolves within 3-4mths
subacute herpetic neuralgia
incidence of PHN increases with
1. age
2. worse initial shingles pain
3. larger area of initial shingles
4. all of the above
4
3 types of PHN
constant pain without stimulus
intermittent pain without stimulus
evoked pain (allodynia and/or hyperalgesia)
PHN can persist for
mths-yrs
4 major RF for PHN
older age, severe acute pain, greater rash severity, immunosuppressive conditions
list 3 nonpharm ways to prevent spread of HSV/ comfort measures
Keep rash clean + dry to reduce risk of bacterial superinfection
Prevent transmission of virus to another person: keep fluid filled blisters/rash covered, wash hands often, do not touch or scratch rash
Avoid topical antibiotics and dressing with adhesives- can cause irritation + delay rash healing
Sterile wet (hydrocolloid) dressings to ↓ discomfort in somepts (Ex- Tegaderm (3M), bandaid)
Wear loose fitting clothing for comfort
systemic antivirals if started within 72hrs of rash can
Reduce acute pain
Accelerate rash healing by 1-2 days and decrease formation of new lesions
Reduce period for viral shedding
T or F: antivirals prevent PHN
insufficient evidence- may reduce intensity, duration, incidence of prolonged pain by decreasing neural damage (inhibits viral replication)
which 3 antivirals are used in HZ
famciclovir
valacyclovir
acyclovir
rank the antivirals on worst to best resolution of pain
famciclovir
acyclovir
valacyclovir
acyclovir < famciclovir = valacyclovir
SEs of HZ antivirals
generally well tolerated- nausea, HA most common sx
fam/vala/ acyclovir are _________ eliminated
renally
T or F: herpes zoster vaccines are used to protect against infection with virus
F- already infected, only intended to boost T cell immunity to avoid reactivation
how is famciclovir dosed for HZ
500mg TID F7d
how is valacyclovir dosed for HZ
1000mg TID F7d
how is acyclovir dosed for HZ
800mg 5x/d F7d
in pts presenting <72hrs since rash onset, cost benefit favors tx of pts:
> 50yrs, esp those with severe pain and large area of skin involved
optional for younger pts with mild pain/ limited skin involved
in pts presenting >72hrs since rash, should they receive antivirals?
consider if continued new vesicles, immuncomp, or has complications (ex- ocular, motor, neuro)
tx of mild acute HZ pain
NSAIDs, APAP
tx of mod acute HZ pain
tramadol (can adjuvant w/ gabapentin or TCAs)
tx of severe acute HZ pain
opioids, CS
PHN tx for pain
TCAs
SNRIs (venla)
gabapentin or pregabalin
opioids
topical lido
cannabinoids
Studies show _________________________or _______________________________yield greater reductions in PHN pain than either alone
gabapentin + nortrityline
gabapentin + morphine
ramsay hunt sx can cause
facial paralysis and hearing loss in affected ear
