Herpes ZOSTER - CLASS NOTES Flashcards
Where does herpes zoster virus lay dormant after primary varicella infection?
Sensory nerve ganglia
After chickenpox, VZV migrates to these sensory nerve ganglia and establishes lifelong latency. VZV reactivation typically occurs in elderly people, however it can be predisposed in younger adults due to weakened immune system.
What causes reactivation of herpes zoster?
Reactivation can be triggered by:
Advanced age
Trauma
Stress
Immunosuppression
Transmission of infection can occur by direct contact with skin lesions or airborne route if there is presence of disseminated herpes zoster.
Describe how varicella turns to herpes zoster?
What is the clinical presentation of herpes zoster?
Herpes zoster is characterized by a painful, unilateral vesicular eruption, which usually occurs in a single or two contiguous, dermatomes
Prodromal symptoms (1-5 days before rash appears) may include malaise, headaches, fatigue or fever. Pain, itching, tingling in the area where rash will develop
Describe the Shingles rash?
Involves 1 – 2 adjacent dermatomes on one side of the body, generally not crossing the body’s midline.
The rash forms blisters that typically scab over in 7 – 10 days and clears up within 2 – 4 weeks. The rash can be hemorrhagic in immunosuppressed people and people of advanced age.
In rare cases, the rash may be more widespread or affect the eye
Prodromal systemic symptoms as mentioned above may continue throughout the infection.
Scarring and hypo- or hyperpigmentation may persist months to years after herpes zoster has resolved. The development of new lesions more than a week after presentation should raise concerns regarding possible underlying immunodeficiency.
Although the rash can occur in any dermatome, the thoracic and lumbar dermatomes are most commonly involved.
The most common complication of shingles is postherpetic neuralgia (PHN), a nerve pain that persists after the rash has resolved and can last from weeks to years.
What are some non-pharm management strategies for shingles?
- Keep rash clean and dry to reduce risk of bacterial superinfection
- Prevent transmission of the virus
- Keep fluid-filled blisters and rash covered
- Wash hands often
- Do not touch or scratch the rash
- Avoid use of topical antibiotics and dressing with adhesives
- May cause irritation and delay rash healing
- Use sterile wet dressings to relieve discomfort in some patients
When should antivirals be initiated after rash onset for shingles?
Initiated within 72 hours of rash onset, reduces duration of viral shedding, acute pain and the appearance of new lesions. After 72 hours, efficacy of anti-virals is NOT well-established hence pain managment remains the mainstay of therapy unless there is ocular involvement.
Treat ocular zoster even if rash has been present for up to 7 days
Refer for ophthalmological assessment
What drugs should be used to treat shingles rash?
Acyclovir 800mg 5X daily for 7 days
Valacyclovir 1000mg TID for 7 days
Famciclovir 500mg TID for 7 days
Describe the three types of neuralgias that can occur with Shingles rash?
- Acute pain (within 30 days)
- Subacute pain (between 30 days and 90 to 120 days of rash onset)
- Postherpetic neuralgia (beyond 120 days of rash onset)
Approximately 10 to 15 percent of patients with herpes zoster will develop postherpetic neuralgia. Individuals older than 60 years of age account for 50 percent of these cases. Immunosuppressed patients also have a higher incidence.
Vaccinated adults are less likely to develop postherpetic neuralgia, even if HZ infection occurs.
Significant pain is considered a pain level 3 or higher on a pain scale of 1 to 10.
Sensory symptoms can also include numbness, dysesthesias, pruritus, and allodynia in the affected dermatome
Antiviral treatment does not reduce risk of postherpetic neuralgia
What % of patients with herpes zoster develop post herpetic neuralgia?
About 10 to 15 percent of patients with herpes zoster will develop postherpetic neuralgia
Individuals older than 60 years of age account for 50 percent of these cases. Immunosuppressed patients also have a higher incidence
Does vaccination reduce the chance of developing poster herpetic neuralgia?
YES! Evenif HZ infection occurs.
What is considered significant pain regarding shingles pain?
Pain level of 3 or higher on a pain scale of 1 to 10.
What type of symptoms occur with neuralgia?
Sensory symptoms can include numbness, dysesthesias, pruritus and allodynia in the affected dermatome
Does antiviral treatment reduce the risk of post herpetic neuralgia?
No!
What is herpes zoster opthalmicus?
A potentially sight-threatening condition which is defined as herpes zoster involvement of the ophthalmic division of the fifth cranial nerve. Incidence of this complication range from 8-20%. Unilateral pain or hypesthesia in the affected eye, forehead, and top of the head may precede or follow the prodromal symptoms.
What is ramsay hunt syndrome (herpes zoster oticus)?
- Ipsilateral facial paralysis, ear pain and vesicles in auditory canal or on the auricle
- Ipsilateral altered taste perception and tongue lesions, hearing abnormalities (decreased hearing, tinnitus, hyperacusis), and lacrimation occur in some patients; vestibular disturbances (vertigo) are also frequently reported. Note that the facial paralysis seen in Ramsay Hunt syndrome is often more severe than Bell’s palsy attributed to HSV, with increased rates of late neural denervation and a decreased probability of complete recovery.
