K22 Varicella
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Transcript of 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.