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)
