From: Subject: Best Dx/Best Rx: Herpes Zoster Date: Wed, 3 Jun 2009 21:22:26 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0192_01C9E491.6456A2C0" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0192_01C9E491.6456A2C0 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.acpmedicine.com/acp/newrxdx/rxdx/dxrx0726.htm Best Dx/Best Rx: Herpes Zoster



Herpes = Zoster

Martin S. Hirsch, M.D.
Harvard = Medical=20 School

Defin= ition/Key=20 Clinical Features
Diffe= rential=20 Diagnosis
Best = Tests
Best = Therapy
Best = References

Definition/Key Clinical=20 Features

  • Herpes zoster (also known as shingles) is = caused by=20 reactivation of varicella-zoster virus (VZV), a human = herpesvirus=20
  • Higher incidence in those who are > 60 yr,=20 immunosuppressed, or have neoplasms=20
  • Likelihood of reactivation related to age and = immune=20 status=20
  • Attacks are often preceded by pain lasting 1 = to several=20 days before lesions appear=20
  • Unilateral vesicular eruption, most commonly = on the=20 thorax and limited to 1-3 dermatomes; vesicles are surrounded by = erythematous=20 base=20
  • Superinfections common=20
  • Scarring often occurs=20
  • Complications=20
    • Postherpetic neuralgia most common=20
    • Segmental myelitis=20
    • Acute retinal necrosis=20
    • Ramsay Hunt syndrome=20
    • VZV encephalitis

3D""=20=20 bac= k to=20 top

Differential = Diagnosis

  • Herpes simplex virus infection=20
  • Impetigo=20
  • Insect bites=20
  • Scabies
    3D""=20=20 bac= k to=20 top

    Best=20 Tests

    • Physical examination usually sufficient for=20 diagnosis=20
    • Laboratory testing for definitive = diagnosis=20
      • Virus isolation=20
      • Direct immunofluorescence of lesions=20
      • PCR detection of viral DNA=20
      • Demonstration of fourfold rise in antibodies = by viral=20 antigens (more rapid and greater than that which occurs during=20 varicella)
    3D""=20=20 bac= k to=20 top

    Best=20 Therapy

    • I.V. acyclovir (first choice)=20
      • Dose: 10 mg/kg q. 8 hr for 7 days =
    • Oral acyclovir (alternative)=20
      • Dose: 800 mg 5 times/day for 7 days=20
      • Cost/30 tablets: $25
    • Valacyclovir=20
      • Dose: 1 g p.o., t.i.d., for 7 days=20
      • Cost/30 tablets: $280
    • Famciclovir=20
      • Dose: 500 mg t.i.d. for 7 days=20
      • Cost/30 tablets: $256
    • Foscarnet: for acyclovir-resistant VZV = infections in=20 immunocompromised patients=20
      • Dose: 40 mg/kg I.V. q. 8 hr =
    • Concomitant use of corticosteroids and = acyclovir may be=20 justified in patients > 50 yr with no contraindications (e.g., = diabetes,=20 hypertension, glaucoma)
    • Treatment of VZV-related postherpetic = neuralgia=20
      • Topical anesthetics=20
      • Oral analgesics=20
      • Tricyclic antidepressants=20
      • Gabapentin=20
      • Intrathecal methylprednisolone = acetate
    • Prevention=20
      • Live attenuated VZV vaccine (Varivax) for = prevention=20 of chickenpox=20
        • Single dose for ages 1=9612 yr=20
        • Two doses, 4=968 wk apart, for susceptible = adolescents=20 and adults
      • Higher-dose VZV vaccine (Zostavax) for = reduction in=20 incidence of herpes zoster in patients ≥ 60 yr=20
        • Single dose=20
        • Contraindications=20
          • Immunodeficiency states
          • Untreated tuberculosis=20
          • History of anaphylactoid reactions to = vaccine=20 components
      3D""=20 bac= k to=20 top

      Best = References

      Dworkin, et al: Clin Infect Dis 44:S1, 2007 = [PMID=20 17143845]

      MMWR Morb Mortal Wkly Rep 55:209, 2006 [PMID=20 16511443]

      Oxman, et al: N Engl J Med 352:2271, 2005 [PMID = 15930418]

      March=20 2007


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