Herpes Flashcards
What does neurotropic mean
Able to attack and infect nerve cells
dsDNA No animal reservoir Persistent latent phase in DRG Lytic infection of fibroblasts + epithelial cells Transmitted via muco-cutaneous contact
HSV 1 and 2
Sites of HSV 1 and 2 infection
Oral Genital Ocular Neonatal Encephalitis Skin
Oral HSV
Incubation 2-12 days Severe painful ulceration Tendency to coalesce Erythematous base Fever + submandibular lymphadenopathy DDx Herpangina (Coxsackie A0
Genital HSV
Incubation 4-7 days
Fever, dysuria, malaise, inguinal lymphadenopathy, Pain ++, vesicular rash
Herpes meningitis 1-2 weeks later in 4-8% of primary genital herpes
Sacral Radiculomyelitis - urinary retention (self limiting)
Ocular HSV
Herpetic keratits - unilateral/bilateral conjunctivitis + pre-auricular LNs
Acute retinal necrosis in immunocompetent
Progressive outer retinal necrosis in immunocompromised
Caused by VZV, EBV, CMV
Neonatal HSV
Primary infections in 1st and 2nd trimester - no risk to foetus
Primary infection in 3rd trimester presents greatest risk of transmission
Foetal loss
Skin eye and mouth lesions 7-12 days
Long term ocular and neural sequelae
Disseminated disease +/- vesicles 4-11 days post partum Risk of fulminant hepatits or multi organ failure - 80% mortality
Neurological disease +/- SEM (17-18 days post partum) - 50% mortality
Transmission: most often at delivery, more rarely infection in-utero, postnatally: mum with cold sores
Tx: oral/iv acyclovir, 6wks before EDD C-sec if primary infection
HSV Encephalitis
90 % HSV 1 (1 brain 2 eyes)
Flu-like pro drome for 2 weeks
FOcal neurology, fever, confusion, behavioural change, reduced consciousness, seizures, N&V, coma, death
50% cases in >60yo
Mollaret’s Meningitis - benign recurrent aseptic meningitis usually HSV2
Fronto-temporal and parietal lobes (lesions on CT/MRI)
CSF - lymphocytic pleiocytosis, may be normal cytology
Glucose normal, increased protein, negative PCR doesn’t exclude
Treatment: IV acyclovir stat (don’t wait for results)
10mg/kg tds then oral ACV for a total or 2-3 weeks
Skin HSV
Herpes gladiatorum - scrum pox (painful blisters + inguinal LNpathy, rugby players) Herpetic whitlow (painful red finger), erythema multiforme, HS Dermatitis, Eczema herpeticum, Zosteriform HS (painless)
Diagnosis - CLinical, culture, ELISA, Swab PCR (Blood PCR if dissemianted) Treatment Acyclic nucleoside analogues Ganciclovir Foscarnet Cidofivir
dsDNA
Droplet spread
Viral replication in LNs then liver + spleen then vesicular rash
Rash ~ 48 hours after infection, 2 weeks
Varicella zoster virus
Fever, malaise, ehadache
Characteristiccrops of rash (dew on a rose petal)
Lesions scab after 1 week (no longer contagious)
Complications - scarring, pneumonitis, haemorrhage, eye involvement, Reye’s sydrome, neurological (acute cerebellar ataxia, guillain barre, ramsay hunt sundrome (facial palsy, aurical vesicles, geniculate ganglion of CNVII (hearing loss and vertigo), encephalitis (vasculopathy), post-herpetic neuralgia
Chickenpox
Diagnosis of VSV
Exam - vesicles
Cytology - scrapings of multinucleated giant cells (Tzanck cells)
Immunofluorescence cytology cells from vesicles
PCR - especially if old rash, CNS and occular disease
CHickenpox in pregnancy
Congenital varicella syndrome: risk in early pregnancy: 0.4% if
Treatment for VZV
Acyclovir 800mg PO TDS 1 week
or
Valaciclovir 1g TDS
Indications - all adults with chicekpox, neonates, immunocompromised, eye involvement, all pts with pain
Post exposure prophylaxis for VZV
VZIG (immunocompromised and pregnant women)
Live vaccine against VZV
Attenuated Oka strain (contraindicated in pregnancy)
VZV reactivation (Dorsal root ganglion) - stress/ lowered immunity (immunocompromised, >50 years) painful rash with dermatomal spread
Shingles
Herpes zoster
Treatment for shingles
Symptomatic children OR (20/40 gravid
Acyclovir 800mg PO 5x daily or Famciclovir 250mg PO TDS or Valaciclovir 1000mg PO TDS
Topical eye drops plus oral for opthalmic
PEP 7-9 days for immunocompromised
