Post Herpetic Neuralgia

Question 1

how does shingles occur

Answer 1

varicella remains dormant in dorsal root ganglion and then is reactivated and presents as shingles

Question 2

transmission of shingles

Answer 2

cant give shingles to someone but can give someone chicken pox if they have never had it before

Question 3

symptoms of shingles and the progression

Answer 3

starts as a painful maculopapular rash that follows a dermatome and often stops at the midline
days - weeks rash will start to crust over
pain subsides as rash heals

Question 4

how long for shingles to resolve

Answer 4

2-4wks

Question 5

when should you treat wtih antivirals

Answer 5

within 72hr
can be later is new lesions present
no benefit once encrusted

Question 6

benefits of antiviral treatment

Answer 6

decrease transmission
help with pain
speed healing
prevent PHN?

Question 7

antiviral regimens

Answer 7

valacyclovir 100mg tid
famciclovir 500tid
for 7 days
very well tolerated, equal efficacy

Question 8

how should the pain be treated

Answer 8

analgesics scheduled

treat early

Question 9

why treat pain

Answer 9

prevent chronic pain
decrease acute pain
improve mood and sleep

Question 10

mild pain treatmetn

Answer 10

acetaminophen
codiene
tramadol

Question 11

moderate pain treatment

Answer 11

oxycodone 5-15mg q4-6hr

Question 12

what is post herpetic neuralgia

Answer 12

pain that lasts >3-4months after resolution of rash resulting for nerve damage due to inflammation form varicella
affects ADL, QOL

Question 13

risk factors for PHN

Answer 13

old age
allodynia
severe rash or pain
prodromal pain

Question 14

symptoms of PHN

Answer 14

rash resolved
burning, stinging, throbbing 
allodynia (pain from something not normally painful) 
numbness
parathesia

Question 15

how long does PHN last

Answer 15

unknown can spontaneously resolve

mean = 3.3years

Question 16

effectiveness of treatment

Answer 16

<50% of ppl experience more than a 50% pain reduction

Question 17

why is CBT so important in PHN

Answer 17

it is a potentially long lasting condition that affects QOL/ADL for which there is incomplete pain relief with medication

Question 18

reducing risk of PHN

Answer 18

vaccination

prompt, effective antiviral and acute analgesia

Question 19

problems with amitriptyline

Answer 19

anticholinergic burden
weight gain
sedation
do not use in glaucoma, urinary retention, cardiac issues

Question 20

dosing of ami and efficacy

Answer 20

nnt =2.6

10-25mg HS increased to 75-150mg

Question 21

gabapentin AE

Answer 21

edema
sedation
dizziness
falls

Question 22

dosing of gabapentin

Answer 22

100-300mg hs increase at weekly intervals up to 1800mg/day

Question 23

pregabalin > gabapentin

Answer 23

pregab reaches target faster
once daily dosing
more reliable target dose

Question 24

pregabalin AE

Answer 24

edema, sedation, dizziness

dry mouth

Question 25

dosing and efficacy of pregabalin

Answer 25

nnt = 4.2 50-150mg in 2 divided doses increase weekly by 50-150mg/day up to 300-600mg/day

Question 26

dosing and efficacy of lidocaine patch

Answer 26

apply tid prn | NNT=2

Question 27

side effects of lidocaine

Answer 27

redness

Question 28

issues with tramadol

Answer 28

NNT= 5 unknown long term efficacy dependence, constipation, drowsiness

Question 29

non pharms

Answer 29

``` pain diary cool compress exercise to improve mood CBT light loose clothing sleep hygiene ```

Question 30

monitoring

Answer 30

falls pain diary follow up in one day for side effect improved function

Question 31

benefits of specialty compounding

Answer 31

can target multiple MOA less systemic toxicity good for localized pain

Question 32

counseling for compounds

Answer 32

use gloves still can get systemic AE if too painful to apply spray is available

Question 33

what is immunosenescence

Answer 33

general reduction in immune response as patients age | reduces vaccine efficacy

Question 34

risk of shingles recurrence

Answer 34

6-10%

Question 35

efficacy of shingrix

Answer 35

treat 333 people will prevent 10 shingles outbreaks and 1 PHN

Question 36

dosing of shingrix

Answer 36

two doses 2-6month apart

Question 37

advantages of shingrix

Answer 37

easier storage better efficacy non live IM

Question 38

disadvantages of shingrix

Answer 38

increased AE - redness, flu like feeling for 1-2days | 2 doses