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Varicella Zoster Presented by Roopa Rani Halder

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Varicella Zoster Presented by Roopa Rani Halder Powered By Docstoc
					By Roopa Rani Halder
Under the guidance of
       Dr. Venkatesh
  Contents
 Introduction
 Definition
 Etiology
 Clinical Manifestations
 Pathogenesis And Pathology
              Primary Infection
             Recurrent Infection
• Differential Diagnosis
• Laboratory Findings
Continued…
 Complications
 Epidemiology
 Transmission
 Prevention
 Facts
 Conclusion
 Reference
Definition
 Varicella Zoster is a virus which is
  responsible for two distinct clinical
  entities: Varicella(chicken pox) and
  Herpes zoster (Shingles)
 This virus is one among the Human
  Herpes Viruses and is considered as HHV
  type-3.
Etiology
 A clinical association between varicella
  and Herpes zoster has been recognized for
  nearly 100 years.
 Viral isolates from patients with chicken
  pox and herpes zoster produced similar
  alterations in tissue culture.
 These results suggested that the viruses
  were biologically similar.
continued
 VZV is a member of
  the family Herpes
  viridae.
 It has a lipid
  envelope
  surrounding a
  nucleocapsid with
  icosahedral
  symmetry.
 Diameter: 180-2oonm
 Centrally located
  double stranded DNA
Chicken pox
 It is a Primary
  infection which
  usually occurs in
  childhood with the
  virus entering the
  mucosa of the upper
  respiratory tract.
 This virus remains
  latent in the dorsal
  root and cranial nerve
  ganglia.
 Years later it may be
  reactivated.
Clinical features
 Symptoms are
  usually mild in
  children but can be
  severe in adults.
 Lesions are present
  on the palate before
  the rash appears.
 Characteristic rash
  appears on the trunk
  on the second day of
  the illness.
Continued….
 Then on the face and finally the limbs are
  involved.
 Macules appear first and within a few hours
  the lesions become papular then vesicular
  and within 24 hours, pustular.
 Whether or not the pustules rupture, they dry
  up in a few days to form scabs.
Herpes zoster
 It is a Sporadic disease that results from
  reactivation of latent VZV from dorsal root
  ganglia.
 It occurs at all ages but its incidence is
  highest among individuals in the 6th
  decade.
Continued…
 Herpes zoster is
  characterized by
  a unilateral
  vesicular eruption
  within a
  dermatome.
 Dermatomes
  involved are T3 to
  L3.
Pathogenesis and pathology


    Primary
   infection   Recurrent
               infection
          Transmission occurs readily by respiratory route


  Localized replication of the virus at an undefined site (Nasopahrynx)


             Seeding of the reticulo endothelial system


                       Development of Viremia


Viremia is reflected in the diffuse and scattered nature of the skin lesions


    Vesicle formation and the vesicular fluid becomes cloudy.

The vesicle either rupture and release their fluid or are gradually
                           reabsorbed.
Differential diagnosis
 The diagnosis of chickenpox is not
  difficult.
 Varicella can be confused with
 HIV infection with atopic Dermatitis.
 Coxsackievirus infection.
 Echovirus infection.
 Atypical measles.
 Smallpox sometimes.
 More commonly with Rickettsialpox.
Continued…
 Rickettsialpox can be distinguished easily
  by detection of the “Herald spot” at the
  site of the mite bite and there will be
  development of Head ache.
 Serologic testing is also useful in
  differentiating Rickettsialpox from
  Varicella and can confirm it.
 The lesions of Small pox are larger than
  those of chickenpox.
 Smallpox    Chickenpox
 Rickettsialpox    chickenpox
Laboratory findings
 Laboratory diagnosis is rarely required as
  clinical signs are clear-cut.
 The most rapid and sensitive means of
  diagnosis is examination of vesicle fluid
  under electronic microscope which shows
  round particles.
 Scrapings of floor of vesicles show
  multinucleated giant cells.
 Serology is used mainly for
  epidemiological surveys.
Epidemiology
 Humans are the only known reservoir for
  VZV.
 Chicken pox is highly contagious.
 Persons of both sexes and all races are
  infected equally often.
 The virus is endemic in the population at
  large.
 Children 5-9 yrs old are most commonly
  affected.
transmission
 Chicken pox is transmitted from person to
  person by droplet infection and by droplet
  nuclei.
 Most patients are infected by Face to face
  contact.
 The Portal of entry of the virus is the
  respiratory tract.
 Fomites play a significant role in
  transmission
 The virus can cross the placental barrier
  and infect the foetus.
Complications
 Complications
    include Pneumonia.
   More common in
    adults and can result
    in adult respiratory
    distress syndrome.
   Cerebellar syndrome.
   Encephalitis occurs
    1 in 100 cases.
   Death may occur.
prevention
 VARICELLA ZOSTER
  IMMUNOGLOBULIN
  (VZIG) given within
  72 hours of exposure
  has been
  recommended in
  Immunosuppressed
  persons.
 VZIG is given by IM
  injection in a dose of
  12.5 units/kg weight
  with a repeat dose in
  3 weeks.
Continued…
 A live attenuated
  varicella virus
  vaccine is safe and
  currently
  recommended for
  children between 12-
  18 months of age.
 All susceptible
  adolescents and
  adults should be
  immunized, with
  special emphasis on
  high risk groups.
faCts….
 The lesions of
  Herpes resembles
  the hood of the
  snake and is always
  the same.
 There is a
  superstitious belief
  that Herpes is due to
  the Curse of
  NAGADEVATA due to
  the resemblance of
  the pustular lesion
  with that of snake.
conclusion
References
 API text book of medicine.
 Textbook of Pathology by HARSHMOHAN
 HARRISON’s
 Preventive and Social Medicine by K.PARK
 DAVIDSON’s
 VAIDYALOKA magazine
 WIKIPEDIA through Internet..