Tuesday 8 January 2013

Genital Herpes Simplex


7.06 Genital Herpes Simplex

Presentation
The patient may be distraught with severe ganital pain or just concerned about paresthesias and subtle genital lesions, desirous of pain relief during a recurrence, or suffering complications such as superinfection or urinary retention. Instead of the classic grouped vesicles on an erythematous base, herpes in the genitals usually appears as groupings of 2-3mm ulcers, representing the bases of abraded vesicles. Resolving lesions are also less likely to crust on the genitals. Lesions can be tender, and should be examined with gloves on, because they shed infectious viral particles.
What to do:



If necessary for the diagnosis, perform a Tzanck prep, by scraping the base of the vesicle (this hurts!), spreading the cells on a slide, drying, and staining with Wrights or Giemsa stain. The presence of multinucleate giant cells with nuclear molding confirms the diagnosis of herpes. Alternatively, use this sample for herpes virus culture, if available.



Send a serologic test for syphilis and culture any cervical or urethral discharge in search of other infections requiring different therapy.



Prescribe acyclovir (Zovirax) 200mg q4h (5x daily) for 10 days (dispense 50 tablets) or 5 days (25 tablets) for recurrent infections.



Prescribe anti-inflammatory analgesics (Motrin to Percodan) for pain.



Warn the patient that:



lesions and pain can be expected to last 2 weeks during the initial attack (usually less in recurrences);



although acyclovir reduces shedding, he should assume he is contagious whenever there are open lesions (and can potentially transmit the virus other times as well);



he should be careful about touching lesions and washing hands, because other skin can be inoculated, and



recurrences can be triggered by any sort of local or systemic stress, and will not be helped by topical acyclovir.



Try sitz baths for comfort.
Discussion
Currently there is no role for topical acyclovir in the treatment of genital herpes. Oral prophylaxis has been shown to be effective. Acyclovir is activated by phosphorylation inside infected cells and acts by blocking viral DNA replication, but it is ineffective once viral latency is established. Latent herpes virus DNA already residing in the sensory ganglia can cause recurrences with impunity, and topical acyclovir only decreases the amount of viral shedding. Famcyclovir is currently being used tid for zoster and is in clinical trials for herpes simplex.
References:



Benedetti J, Corel L, Ashley R: Recurrence rates in genital herpes after symptomatic first-episode infection. Ann Intern Med 1994;121:847-854.


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