Micro: Genital Ulcers Flashcards Preview

Block 8 - Endo & Repro > Micro: Genital Ulcers > Flashcards

Flashcards in Micro: Genital Ulcers Deck (19)

How would you go about lab testing for various genital ulcers?

everyone gets HIV testing
HSV: viral culture, DFA, PCR
Chancroid: PCR - not routinely available
these and syphilis are "US"


What are general features of the Herpes virus?

large, enveloped, icosahedral capsids
dsDNA, linear
lytic, persistent, and latent inf (EBV --> immortalizing)


What is the pathogenesis of HSV?

inf and replication in mucoepithelial - lytic inf, persistent inf in lymphocytes and macrophages
inf of innervating neuron - retrograde back to ganglion for latent (sacral and trigeminal)


How does HSV reactivate?

triggered by stress, trauma, fever, sunlight, menses, etc.
virus returns to initial site of inf - asymptomatic or vesicular lesions w virions


How does HSV evade immune system?

obstruct pathway leading to CD8 T cell recognition
spreads directly cell to cell, avoiding Ab neutralization


What are big differences in HSV-1 vs. HSV-2?

glycoprotein gG1 vs. gG2
higher seroprevalence vs. lower
most acquired by 30 as saliva (families, kids) vs. most acquired in adolescence/early adulthood as STD
prior partial immunity to HSV-1 provides partial protection to HSV-2


What are the primary and relapsing symptoms seen in HSV1?

primary: incubation 6-8 days, oral mucosa replication, mild fever and sore throat, ascends sensory nerves to trigeminal ganglion
Relapse: at vermillion border, often prodrome of itching, burns, pins and needles


What are the primary and relapsing symptoms seen in HSV2?

primary: incubation 3-7 days, painful vesicles, regional LAD, maybe systemic symptoms, ascends sensory nerves to sacral root ganglia, duration 2 wks
relapse: frequent, shorter duration than first episode, prodrome common


What syndromes are associated with HSV1?

gingivostomatitis, orolabial herpes, keratitis, encephalitis, aseptic meningitis, esophagitis (HIV), hepatitis, whitlow


What syndromes are associated with HSV2?

genital, oropharyngeal and neonatal herpes, aseptic meningitis, autonomic neuropathy, Mollaret's meningitis


What is neonatal herpes?

mostly during childbirth
higher risk in moms who acquire HSV2 near term, lower risk in those w recurrent lesions and Abs
skin/eye/mouth dz, meningoencephalitis, multiorgan dissemination


How is HSV diagnosed?

clinical appearance of lesions, viral culture w typing, Tzanck smear
type specific serology: primary inf or epidemiology, recurrence doesn't correlate w rise in titers


How is genital herpes managed?

antiviral chemo - doesn't treat latent virus but helps w recurrences
acyclovir, valacyclovir, famciclovir


How do the drugs against herpes work?

all are phosphorylated by viral thymidine kinase - incorporate into viral DNA and prevent elongation
resistance if mutations in viral thymidine kinase
second line = foscarnet, cidofovir


What is chancroid?

incubation 5-7 days
painful papules that ulcerate w/i 48 hrs (kissing lesions)
tender regional lymphadenopathy - spontaneous rupture, purulent drainage


What causes chancroid?

Haemophilus ducreyi = gram- coccobacillus, chocolate agar, high CO2, gram stain = "school of fish"


What are the CDC definitions of haemophilus ducreyi?

definite: culture +
probable: one or more painful genital ulcers, no evidence of T. pallidum 7 days after onset, clinical picture, HSV testing negative


What is the epidemiology of chancroid?

mostly Asia and Africa, uncommon in U.S.
if here, mostly from returning travelers


What causes granuloma inguinale?

klebsiella granulomatosis
difficult to culture - diagnosis requires seeing intracellular inclusions (Donovan bodies = "safety pins")