genital%20herpes
GENITAL HERPES
Genital herpes is a recurrent lifelong disease with no cure, caused by herpes simplex virus (HSV).
HSV-2 is usually the cause but HSV-1 may occur in up to 1/3 of new cases.
HSV-1 tends to cause fewer recurrences & milder disease than HSV-2.
The incubation period is 2 days-2 weeks after exposure.

Classification

Classification of Genital Herpes Simplex Virus Infection

  • Initial Episode
    • Primary HSV
      • First infection with either HSV-1 or HSV-2 in individuals who do not have antibodies to either HSV-1 or HSV-2
      • Associated with more extensive genital lesions, systemic symptoms, complications, and duration of symptoms
      • More severe infections (ie duration >35 days) have 2x more often recurrent episodes with shorter interval from 1st recurrence
    • Non-primary HSV
      • First infection with either HSV-1 or HSV-2 in individuals who have previously existing antibodies against HSV-2 and HSV-1 respectively
      • Less likely to develop constitutional or severe symptoms
  • Recurrent HSV
    • Results from reactivation of latent virus
    • Milder, more localized, lesser viral shedding and shorter duration as opposed to primary infection
    • After symptomatic 1st episode of genital HSV infection, median recurrence rate is 0.34 recurrences/month for HSV-2, and is 4 times more common than in HSV-1 infected patients
    • Rate of recurrences decreases over time in most patients
    • Usually brought about by triggering factors (eg UV light, immunosuppression, trauma, stress)

Physical Examination

Clinical Manifestations

  • Infection is frequently asymptomatic
  • Local symptoms: Pain, itching, dysuria, vaginal and urethral discharge and tender inguinal lymphadenopathy
  • Systemic symptoms: Fever, headache, myalgia, abdominal pain
  • Lesions may be present in varying stages (vesicles, blisters or ulcers)
    • Can occur on the vulva, cervix, vagina, urethral or perianal skin and extragenital areas (eg buttocks, thighs or perineum)
    • Painful and contains large amount of infectious viral particles which are excreted over 3 weeks
  • More severe infections and higher rate of complications in women during the primary infection
    • May be due to larger surface area affected in females and ability of the virus to easily spread over moist surfaces
  • Systemic complications: Urinary retention syndrome, aseptic meningitis, transverse myelitis, sacral radiculopathy, extragenital lesions (buttocks, perineum or thighs), disseminated infections and superinfection with bacteria or fungi
  • Mean duration of symptoms: 16.5-22.7, 15.5, and 9.3-10.6 days in primary, non-primary, and recurrent episodes, respectively

Clinical Manifestations that may Require Hospitalization

  • Urinary retention
  • Severe constitutional symptoms
  • Disseminated infection
  • Meningitis

Laboratory Tests

Viral Detection

  • Should be done to all patients with suspected genital herpes who were not previously diagnosed with HSV
  • Performed best with early lesions
  • Lack of HSV detection does not indicate absence of HSV infection because viral shedding is intermittent
    • As HSV shedding is intermittent, testing swabs for routine diagnosis is not recommended in asymptomatic patients as confirmation of carrier status is unlikely

Viral Culture

  • Isolate of HSV in cell culture
  • Both sensitive and specific, but sensitivity is lower for recurrent lesions and decreases as lesions heal (70% from ulcers, 94% from vesicles)
  • Virus isolates can be distinguished and tested for antiviral susceptibility
  • However, results are slow and labor intensive

Cytological Exam

  • Eg Tzanck and Papanicolaou smears
  • with moderate specificity and sensitivity
  • Not recommended for diagnosis except in limited-resource settings

Viral Antigen Detection Tests

  • Eg Direct immunofluorescence assay (IFA) or enzyme immunoassay (EIA)
  • Less sensitive than virus culture and generally not recommended except in limited-resource settings
  • EIA may be used as a rapid alternative diagnostic test in symptomatic patients where laboratory facilities are limited
  • Reports HSV type when test is positive

Polymerase Chain Reactions (PCR)

  • Test for HSV DNA; allows viral typing
    • HSV DNA is considered the diagnostic gold standard 
  • HSV detection rates are increased compared with virus culture
  • Highly sensitive and specific, but costly, inaccessible, and labor intensive
  • Test of choice in diagnosing CNS HSV infection

Type-Specific Serologic Tests (TSST)

  • Type-specific assay for HSV antibodies, eg Western blot
  • Not routinely recommended in asymptomatic patients but useful in recurrent or atypical genital symptoms with negative direct virus detection methods; clinical diagnosis of genital herpes without laboratory evidence; 1st-episode genital herpes where primary and established infection differentiation guides disease management; for patients with genital herpes-infected partner or sexual partners of genital herpes-infected patient; and for seroepidemiological studies
  • Do not distinguish anogenital from orolabial infection in the presence of HSV-1 antibodies
  • Detection of HSV-2 antibody in most cases indicates anogenital infection
  • Repeat serologic testing after 3 months is advised in patients with suspected recent infection who have negative HSV antibody early after presentation
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