K22 Varicella

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    V RI ELL(Chicken pox)

    Infectious and Tropical Pediatric Division,

    Department of Child Health,Medical Faculty, University of Sumatera Utara

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    Definition: Varicella is a common contagious

    disease caused by primary infection with

    varicella-zoster virus (VZV). It ischaracterized by a short or absent

    prodromal period and by a pruritic rash

    consisting of crops of papules, vesicles,pustules, and crusting

    Etiology: Varicella zoster virus (VZV)Herpesvirus group

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    Epidemiology: worldwide distribution,

    usually endemic in large cities. The mostly

    age distribution is 5-9 year old.Transmission by direct contact, droplet.

    The patient can transmit the disease 1 day

    before the rash appeared until crusted wasdried. In mild cases, crusted was

    completed until 5 days, and in severe

    cases until 10 days.

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    Epidemiology of primary varicella

    90% of cases occur at

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    Pathogenesis:

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    Primary varicella

    Days 2-4: initial viral replication in

    regional lymph nodes

    Days 4-6: primary viremia

    Subsequent second round of viral

    replication in liver, spleen, other organs

    Secondary viremia seeds capillariesand then epidermis by day 14-16

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    Herpes zoster

    VZV spreads from skin/mucosa intosensory nerve endings

    Virus travels to dorsal root ganglion andbecomes latent

    Reactivation occurs with decreased cell-mediated immunity

    Initial replication occurs in affected DRGafter reactivation

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    Ganglionitis ensues, with inflammation

    and neuronal necrosis

    Pain ensues with travel of the virusdown the sensory nerve

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    Clinical manifestations:

    Incubation period 14-16

    days (10-21 days). The

    disease begins withlow-grade fever,

    malaise, and the

    appearance of rash. In

    children the exanthemand symptoms usually

    occur simultaneously.

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    Rash: The typicalvesicle of chickenpoxis superficially locatedin the skin. The lesionappear in crops thatgenerally involve thetrunk, scalp, face, andextremities. The

    distribution typicallycentral especially ontrunk and face.

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    The rash is more profuse on the proximal partsof the extremities than on the distal parts. A

    distinctive manifestation of the eruption is thepresence of lesions in all stages in any onegeneral anatomical area; macules, papules,vesicles, pustules, and crusts are usually

    located in proximity to each other. Insummary, the rash characterized by (1) arapid evolution of macule to papule to vesicleto pustule to crust, (2) a central distribution of

    lesions that appear in crops, and (3) thepresence of lesions in all stages in any oneanatomical area.

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    Fever: The height of the fever usually

    paralels the severity of the rash. When the

    eruption is sparse, the temperature isusually normal or slightly elevated.

    Other symptoms: headache, malaise, and

    anorexia usually accompany the fever.The most distressing symptom is pruritus,

    which is present during the vesicular stage

    of the disease.

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    Unusual manifestations:

    Hemorrhagic, progressive, and disseminated

    varicella in immunompromised host and apotencially fatal outcome. Our department hadbeen reporting 3 cases with varicellahemorrhagic, two in immunocompromised

    child and the other in normal child.Congenital varicellasyndrome is extremely rare.

    Manifestations of this syndrome include a

    hypoplastic extremity, zosteriform skinscarring, microphthalmia, cataracts,choreoretinitis, and abnormalities of the CNS.

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    Severe or fatal

    varicella in 5 to 10

    day-old infants may

    occur when their

    mothers have

    varicella 5 days or

    less before delivery.

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    Diagnosis:

    1. Confirmatory clinical factors, (1)development of a pruritic papulovesicular

    eruption concentrated on the face and trunk

    associated with fever and mild constitutionalsymptoms;

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    (2) the rapid progression of macules to

    papules, vesicles, pustules, and crusts; (3)

    the appearance of these lesions in crops,with a predominant central distribution

    including the scalp; (4) the presence of

    shallow white ulcers on the mucousmembranes of the mouth; and (5) the

    eventual crusting of the skin lesions.

    2. Detection of the causative agent from

    vesicular fluid

    3. Serological tests : ELISA, FAMA, RIA, LA

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    Differential diagnosis:

    Impetigo

    Insect bites, papular urticaria, and urticaria

    Scabies

    Dermatitis herpetiformis

    Rickettsialpox

    Eczema herpeticum and other forms of HSV

    infection

    Steven-Johnson syndrome

    Smallpox

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    Chickenpox versus smallpox

    CHICKENPOX

    14-21 day incubation

    Mild to no precedingillness

    Lesions most numerouson trunk

    Palms and soles spared

    Lesions at varying stagesof development

    Scabs form 4-7 days afterrash appears

    Vesicles do collapse onpuncture

    SMALLPOX

    7-17 day incubation

    Fevers, severe systemicsymptoms precede rash

    by 2-3 days Lesions most numerous

    on face, arms, legs

    Palms and soles involved

    Lesions at same stage of

    development Scabs form 10-14 days

    after rash appears

    Vesicles do not collapseon puncture

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    Complications: are not common

    Secondary bacterial infection

    Encephalitis

    Varicella pneumonia

    Reyes syndrome

    Disseminated varicella

    Prognosis: usually a benign disease, clearsspontaneously without sequaelae.

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    Complications and mortality in

    varicella

    In healthy children aged 1-14,

    mortality rate estimated at 2/100,000[Mehta PN (2004) eMedicine online]

    Bacterial superinfection is most

    common complication; Staph

    exotoxin can result in bullous

    varicella [Melish ME (J Pediatr (1973) 83, 1019-21]

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    CNS is most common extracutaneous site;

    symptoms include Reyes syndrome, acute

    cerebellar ataxia, encephalitis, myelitis [McKendall and

    Kiawans (1978) Handbook of clinical neurology. Elsevier Press]

    Rare complications: myocarditis, appendicitis,

    glomerulonephritis, hepatitis, pancreatitis,

    vasculitis, arthritis, keratitis, iritis, optic neuritisWhitney RJ (1990) Antiviral agents and viral diseases of man. Raven

    Press, NY]

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    Immunity : an attack of chickenpox usuallyconfers lasting immunity.

    Treatment: self limited disease

    1. Symptomatic acetaminophen for high

    fever; oral antihistamines and localapplications of of calamine lotion may helpcontrol the itching. Fingernails should bekept short and clean in an attempt to

    minimize secondary skin infections. Forsame reason, daily bathing alsorecommended during chickenpox.

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    2. Treatment of complications :

    (1) bacterial infections

    (2) encephalitis

    3. Specific antiviral : 20 mg/kg of acyclovir four

    times daily for 5 days (max 800 mg)

    Preventive measures:

    Zoster immunoglobulin (ZIG) 5 ml/IM within

    72 hours of a household exposure to

    children with underlying leukemia.

    Live attenuated varicella vaccine.