医学精品课件：17 chickenpox.ppt

1、Varicella(chickenpox)is the primary infection caused by varicella-zoster virus(VZV).Varicella is characterized by the appearance on the skin and mucous membranes of successive crops of typical vesicles,generally accompanied by a mild constitutional reaction.Varicella-zoster virus(VZV)Family:Herpesvi

2、ridae Subfamily:Alpha herpesvirinae Serotype:Only onelatent infection-reactivation Locations:Patients respiratory secretions,blood,vesicle fluid Resistance:Sensitive to heat,acid and disinfectant Infectious sources:Patients The infective stage is from about 24 hr before the appearance of the rash to

3、 all lesions are crusted Routes of transmission:Respiratory transmission:spread by droplet、Direct contact、Mother-to-fetus Population susceptibility：90%of reported patients are under 10-yr of age.The peak age of incidence is 2-6 yr.Peak seasons:winter and spring regional lymph nodes viremia viremia,s

4、kin,characteristic change of pathology：Multinucleated giant cells and intranuclear inclusions 1.Maculopapule2.Vesicles3.Cloudy vesicles(pustules)4.CrustAngiotelectasis in dermisBallooning degeneration in celllayerApocytes invade in fluid fluid absorbed the incubation period varies from 10-21 days,bu

5、t the average is 13-17 days.there may be slight fever,malaise,or anorexia.Rash Features:1.rash development process:maculopapule-“tear-drop”vesicles-cloudy vesicles(pustules)-crusts 2.rash characteristics:lappear in batches(development of several crops of rash)lfour kinds of rash at the same timelcon

6、centric distributionlmucosa involvement 3.rash sequence:trunk-face and scalp-extremities rash pruritus the skin lesions is the most common complication.Such as impetigo,erysipelas,cellulitis、surgical scarflet fever Varicella encephalitis the most common central nervous system complication.Overall mo

7、rtality rates vary from 5-25%.About 15%of survivors have permanent sequelae of seizures,mental retardation,or behavior disturbances.Guillain-Barre syndromeReye syndromeTransverse myelitisFacial palsyOptic neuritis,ect.MyocarditisLeukocytopeniaNephritis,ect.Blood routine:a mild leukocytopenia Multinu

8、cleated giant cells:it can be demonstrated in scrapings from the floors of fresh vesicles.serological study Virus isolation:virus can be isolated in human tissue culture cell lines.Epidemiologic dataAgeSeasonsHistory of contact with patientHistory of inoculationClinical data:Typical rash The diagnos

9、is is usually made from the characteristic clinical picture,and laboratory confirmation is rarely needed.1.Hand-foot-and-mouth disease2.Urticaria papulosa1.Symptomatic treatment Wear mittens and keeping nails short Daily changes of clothes2.Antiviral therapy:AcyclovirInterferon-3.Complication treatm

10、ent:antibiotic therapy if there is a superinfection with bacteriaCortical hormone is forbiddedSalicylic acid agent is not be used as possible1)Control of sources of infectionsThe patient will be isolated until all lesions are crustedThe susceptible contacts will be isolated for clinical observation

11、for 3 weeks after exposure.2)Abrupt the ways of transmission3)Protect the susceptiblepassive immunization zoster immune globulin(ZIG).given within 72 hr of exposure.125-625U/10kgactive immunization Varicella Attenuated Live Vaccine Efficacy:85%-95%,more than ten yearsThe prognosis is usually goodFatalities occur from the complicationsClinical Manifestations of typical varicellaComplications of varicellaDiagnosis and differential diagnosis of varicellaThanks