HSV, Chickenpox, Shingles - Block 3 Flashcards
What is the only known resevoir for HSV?
HUmans
How does the etiology of HSV1 and 2 differ?
HSV1: cold sores
HSV2: Genital ulceration
Can cause clinically indistinguishable infections in humans
Describe the cycle of HSV infection?
- Initial mucosal or dermal infection
- Ganglia infection
- Establishment of latency
- Reactivation
- Recurrent infection
Clinical presentation for facial HSV?
- Gingivostomatitis and pharyngitis (first episode of HSV1)
- Recurrent herpes labialis (reactivated HSV1)
Clinical presentation of genital HSV?
- Itching
- Discomfort
- Paresthesia
- Local lymphadenopathy
Intubation period for genital HSV?
2-14 days
Define first episode (primary) of HSV?
Initial genital infection in individuals who lack HSV-1 or HSV-2 antibodies
Define first episode (non-primary) of HSV?
Initial genital infection in individuals with clinical or serologic evidence of prior HSV infection (usually HSV-1)
Define recurrent HSV infection?
Genital lesions following the healing of 1st episode infection
Sx associated with first episode of genital hepres?
- Multiple painful pustular or ulcerative lesions on external genitalia over 7-10 days
- Flu-like sx
- Local itching, pain, discomfort, vaginal/urethral discharge, paresthesia
Severity of recurrent genital HSV are most common in what populations?
- Higher severity in females
- Higher severity and more prolonged in IC patients
How do you diagnose HSV?
- Viral culture
- PCR assay Preferred
- HSV subtyping should immediately follow HSV detection
Tx options for HSV? Out of the options which ones are preferred?
Acyclovir
Valacyclovir (prodrug of acyclovir)
Famciclovir (prodrug of penciclovir)
Valacyclovir and faiciclovir is more preferential due to superior PK/PD
ADR of Acyclovir?
- Acute kidney injury
- Neurotoxicity
- GI intolerance
Acyclovir interactions?
VZV vaccine: Avoid use of acyclovir within 24hrs prior to VZV vaccine and 14 days after vaccination
Zoster: Acyclovir may decrease effect
Counseling of Acyclovir?
- Take w or w/o food
- Avoid rapid IV infusion over 1 hr to prevent kidney damage
- Rotate injection sites to prevent phlebitis
Warnings of valacyclovir?
- Renal impairment
- Appropriate use: ASAP after 1st s/s
ADR of valacyclovir?
- Acute kidney injury
- Neurotoxicity
- GI intolerance
Valacyclovir interactions?
VZV vaccine: Avoid use of acyclovir within 24hrs prior to VZV vaccine and 14 days after vaccination
Zoster: Acyclovir may decrease effect
Counseling for valacyclovir?
- Take PO medication with or w/o food
- Maintain adequate hydration during therapy.
Warning of famicyclovir?
Renal impairment
ADR of famicyclovir?
GI intolerance
Interactions of famciclovir?
VZV vaccine: Avoid use of acyclovir within 24hrs prior to VZV vaccine and 14 days after vaccination
Zoster: Acyclovir may decrease effect
Counseling for famciclovir?
Take PO with or w/o food
When do you need to consider tx dc for HSV tx?
Suppressive therapy: Consider discontinuation of treatment after one (1) year to assess frequency of recurrence.
What is the difference between varicella and zoster?
Varicella: chickenpox
Zoster: shingles
Incubation period of VZV?
10-21 days
Infectious 48 hrs before onset vesicular rash, during vesicle fomration, untill all vescicles crust over
Complications of VZV?
- Secondary bacterial SSTI
- CNS involvment
- Varicella pneumonia
How do we confirm VZV diagnosis?
- Isolation of VZV from tissue culture
- Demonstration of seroconversion or ≥4-fold increase in antibody titer
- Detection of VZV DNA by PCR assay
What is the preferred diagnostic method for VZV?
PCR assay
What is the most frequently used & most-sensitive serology tests for assessing host response?
- FAMA test
- ELISA test
What OTC product should be avoided in children with VZV?
Aspirin due to Reye’s syndrome
Tx for VZV?
- Acyclovir
- Valacyclovir
- Famicyclovir
Tx for pedatric with VZV?
Acyclovir PO for 5 days
Immunocompromised patients with VZV ?
Acyclovir IV for 7 days
Who should get the VZV vaccine?
- All children > 1 year old (up to 12 years old) who have NOT had chickenpox
- Adults known to be seronegative for VZV.
2 doses SC
CI of VZV?
- Pregnancy
- Immunocompromised
- Avoid aspirin 6 weeks affter vaccination to avoid Reye’s syndrome
ADRs of live vac?
- Fever
- Inj site reaction
- Rash
If a patient has recieved blood, plasma, Ig products , when can they get the VZV vaccine?
- Administered ≥2 weeks BEFORE receipt of blood product OR
- Should be delayed 3–11 months AFTER receipt of blood product
When should VZIG be administered?
Within 96 hrs (preferablly within 72 hrs) but can be given up to 10 days
Who should recieve anti-viral prophylaxis?
- Recommended for individuals at high-risk who are ineligible for vaccination
- Beyond 96-hour time window after direct contact
When does VZV prophylaxis provide the most benefit?
7 days after exposure
Agents used fo VZV prophylaxis?
- Acylovir
- Valacylovir
- Famciclovir
What population has the highest incidence for Zoster?
> 60 YO
Presentations of Zoster?
- Unilateral vesicular dermatomal eruption
- Erythematous maculopapular rash -> vesicular lesions
Onset of zoster?
48-72 hrs
Duration of dx: 7-10 days
Skin healing: 2-4 weeks
Complications of Zoster?
- Ophthalimicus
- Post herpetic neuralgia
Tx for Zoster?
- Acyclovir
- Valacyclovir
- Famiclovir
Tx for post herpatic neuralgia?
- Systemic agents: gabapentin, pregabalin, amitriptyline
- Lidocaine pathces
Who should get the Zoster vax?
- Immunocompetent >50YO
- Immunocompromised >19YO
Counselign for RZV use?
Do NOT administer RZV to patients who are experiencing an acute episode of herpes zoster, as it does NOT treat herpes zoster.
Dosing of RZV?
2 doses IM separated by 2-6 months