Varicella, Emergency Medicine

Basics

Description

Commonly known as chickenpox
Most common in late winter and early spring
Vaccine has reduced incidence by 85%
Adults have a 15 times greater risk for death from varicella than children

Etiology

DNA virus:
- Latency in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia with periodic reactivation
- Presents as herpes zoster or shingles decades after primary infection
- Virus is transmitted by respiratory route and direct contact with skin lesions
- Humans are only known reservoir

Diagnosis

Signs and Symptoms

Varicella causes a spectrum of disease
Classic childhood illness:
- Usually affects children ages 1 " 9
- Low-grade fever (100 " 103 °F), headache, malaise, usually precedes rash by 1 " 2 days
- Pruritus, anorexia, and listlessness
- 10 " 21 day incubation period
- Infectious from 48 hr before vesicle formation until all vesicles are crusted, typically 3 " 7 days after onset of rash
- Classic exanthem:
  - Lesions begin on the face, spreading to the trunk and extremities
  - Papules, vesicles, or pustules, on erythematous base
  - Lesions in varying stages of evolution, which is hallmark of Varicella
  - "Dewdrop on rose petal "
  - Vesicles 2 " 3 mm in diameter
  - Duration of vesicle formation 3 " 5 days
  - May involve conjunctival, oropharyngeal, or vaginal mucosa
  - Skin superinfection with group A streptococcus or staphylococcus in 1 " 4% of healthy children
Adolescents and adults:
- Similar presentation to children but greater risk of severe disease:
  - Extracutaneous manifestations in 5 " 50%, particularly pneumonia
Immunocompromised patients:
- HIV, transplant patients, leukemia patients at highest risk for disseminated form
- Patients on chemotherapy, immunosuppresants, and long-term corticosteroid therapy at high risk
- More numerous lesions that may have hemorrhagic base
- Healing may take longer
- Pneumonia common in these patients
Pregnant patients:
- Prevalent in young expectant women
- More severe disease presentation:
  - Risk to fetus greatest in 1st half of pregnancy
  - Risk to mother greatest if infection in 2nd half of pregnancy
- Perinatal disease can occur from 5 days predelivery to 48 hr postdelivery
Congenital varicella syndrome
Occasionally follows maternal zoster infection
Limb hypoplasia or paresis
Microcephaly
Ophthalmic lesions
Extracutaneous manifestations:
- Pneumonitis:
  - 25 times more common in adults
  - Highest risk in adult smokers and immunocompromised children
  - Occurs 3 " 5 days after onset of rash
  - Signs: Continued eruption of new lesions, and new-onset cough
  - Tachypnea, dyspnea, cyanosis, pleuritic chest pain, and hemoptysis
- Cerebellar ataxia:
  - May develop 5 days after rash
  - Ataxia, vomiting, slurred speech, fever, vertigo, tremor
- Cerebritis:
  - Develops 3 " 8 days after start of rash
  - Duration about 2 wk
  - Progressive malaise
  - Headache, meningismus, vomiting, fever, delirium, seizures
- Reye syndrome risk

Increased risk of extracutaneous manifestations
Lower immunity allows for reactivation as herpes zoster

No aspirin for treatment of fever, possible association with Reye syndrome:
- Acetaminophen " is recommended antipyretic treatment
Parents need to be cautioned regarding risk for secondary bacterial infection and possible progression to sepsis

Pregnant women with no childhood history of varicella and no antibodies to varicella zoster virus (VZV) require varicella zoster immunoglobulin (VZIG)
Varicella pneumonia in pregnancy is medical emergency, associated with life-threatening respiratory compromise and death (mortality can be 10 " 45%)
Likely to occur in 3rd trimester

History

Thorough history:
- Fever, systemic symptoms
- Immunization history
- Immunocompetent vs. immunocompromised

Physical Exam

Thorough physical exam:
- Characterize rash spread and extent
- Evaluate for any extracutaneous manifestations

Essential Workup

History and physical exam are sufficient in uncomplicated cases
Pneumonitis:
- CXR shows 2 " 5 mm peripheral densities, may coalesce and persist for weeks
Reye syndrome:
- Ammonia level peaks early
- LFTs will be elevated
- PT, PTT
Cerebritis:
- Lumbar puncture demonstrates lymphocytic pleocytosis and elevated levels of protein

Diagnosis Tests & Interpretation

Lab

Viral culture (results in 3 " 5 days), polymerase chain reaction (PCR), or direct fluorescent antibody using skin scrapings from crust or base of lesion
Serologic tests for varicella antibodies
PCR is diagnostic method of choice, but uncomplicated patients need no labs

Imaging
Not generally indicated unless there is concern for extracutaneous manifestations
Diagnostic Procedures/Surgery
Liver biopsy definitive test for Reye syndrome

Differential Diagnosis

Impetigo
Disseminated herpes
Disseminated coxsackievirus
Measles
Rickettsial disease
Insect bites
Scabies
Erythema multiforme
Drug eruption (especially Stevens " Johnson syndrome)

Treatment

Pre-Hospital

Nonimmune transport personnel must avoid respiratory or physical contact with patients
Transport personnel who have varicella or herpes zoster should not come in contact with immunocompromised or pregnant patients

Initial Stabilization/Therapy

Airway management and resuscitate as indicated:
- Protect airway if obtunded

Ed Treatment/Procedures

Generally, acetaminophen and antipruritics are the keys to treating classic childhood illness
Closely cropped nails and good hygiene help prevent secondary bacterial infection
Infants/children ≤12 yr of age:
- Acyclovir:
  - Recommended in children taking corticosteroids, long-term salicylate therapy, or chronic cutaneous or pulmonary diseases
  - Modest benefit, reduces lesions by 25% and fever by 1 day
  - Should be given within 24 hr of symptom onset
  - NOT recommended in uncomplicated Varicella in healthy children
- Prophylaxis with VZIG in susceptible patients:
  - Immunocompromised children at high risk for complication with significant exposure
  - Susceptible children in the same household as person with active chickenpox or herpes zoster
- In 2012 FDA extended period for VZIG administration to 10 days after exposure
- VZIG in short supply, difficult to obtain
Adolescents/adults:
- Acyclovir now recommended in adults with uncomplicated varicella initiated within 24 hr to decrease progression to disseminated disease
- Symptomatic treatment with antipyretics and antipruritics
Pregnant women:
- If exposed to Varicella, no childhood history of varicella, no antibodies to VZV, need VZIG
- 80 " 90% immune from prior infection, need antibody testing prior to administration of VZIG
- Acyclovir or Valacyclovir prophylaxis especially during 2nd or 3rd trimesters:
  - Safe during pregnancy (category B)
- IV acyclovir for pneumonitis/other complications:
  - Respiratory, neurologic, hemorrhagic rash, or continued fever >6 days
Immunocompromised patients:
- IV Acyclovir recommended, poor PO bioavailability
- PO valacyclovir better bioavailability, approved in 2008 for lower risk immunocompromised patients
- Should be started within 24 hr of onset to maximize efficacy
- Foscarnet for acyclovir-resistant disease
- Prophylaxis with VZIG for the susceptible immunocompromised patient
Extracutaneous:
- IV acyclovir or foscarnet if resistant
Vaccine:
- Children:
  - Routine vaccination for all susceptible children at 12 mo and older, 2 doses
- Adolescents and adults:
  - Age 13 and older without history of varicella need vaccine
  - 2 doses separated by 4 " 8 wk
  - Recommended in high-risk groups: Health care workers, family member of immunocompromised person, susceptible women of childbearing age, teachers, military, international travelers
- Post exposure prophylaxis:
  - Susceptible patients 12 mo or older, given with 72 " 120 hr, with 2nd dose at age appropriate interval
  - Will produce immunity if not infected
- Immunocompromised persons:
  - Most immunocompromised persons should not be immunized

Medication

Acyclovir:
- Uncomplicated: Adults: 800 mg PO QID for 5 days; Adolescents (13 " 18 yr old): 20 mg/kg per dose QID for 7 days; Peds: 20 mg/kg suspension PO QID for 5 days [max. 800 mg PO QID])
- Immunocompromised: Adults: 10 mg/kg IV q8h infused over 1 hr, or 800 mg PO 5 times a day for 7 days. Peds: 10 " 12 mg/kg IV q8h infused over 1 hr, or 500 mg/m2/day IV q8h for 7 " 10 days
Valacyclovir: 1 g PO TID for 5 " 7 days
Famciclovir: 500 mg PO TID for 7 days
Foscarnet: Adults: 90 mg/kg q12h IV over 90 " 120 min for 2 " 3 wk; Peds: 40 " 60 mg/kg q8h over 120 min for 7 " 10 days; Foscarnet is not FDA approved
Hydroxyzine: Adults: 25 " 50 mg IM or PO q4 " 6h. Peds: 0.5 mg/kg q4 " 6h suspension (supplied as 10 and 25 mg/5 mL)
Diphenhydramine: Adults: 25 " 50 mg IV, IM, or PO q4h. Peds: 5 mg/kg/d elixir
VZIG: Adults: 625 IU IM. Peds: 1 vial per 10 kg IM to a max. of 5 vials [each vial contains 125 IU])

Follow-Up

Disposition

Admission Criteria

Patients with pneumonia require admission:
- ICU for respiratory observation or support
Immunocompromised patients: ICU vs. ward, depending on severity of illness
All admitted patients must be kept in isolation

Discharge Criteria

Immunocompetent children without evidence of Reye syndrome or secondary bacterial infection
Adults with no evidence of extracutaneous disease

Followup Recommendations

Patients who are discharged need close follow-up with PCP to assure resolution without complications

Pearls and Pitfalls

Patients with varicella are infectious from 48 hr before vesicle formation until all vesicles are crusted
Immunocompromised patients with Varicella need careful consideration and admission in most cases
Varicella pneumonia is medical emergency, particularly in pregnancy

Additional Reading

Abramowicz M, Zuccotti G, Pflomm JM, eds. Drugs for non-HIV viral infections. Treatment Guidelines from The Medical Letter. New Rochelle: The Medical Letter, Inc. 2010;8:71 " 82.
Albrecht MA. Treatment of varicella-zoster infection: Chickenpox. www.uptodate.com. Dec 12, 2012.
American Academy of Pediatrics. Varicella-Zoster infections. In: Pickering L, ed. Red Book: 2012 Report of the Committee on Infectious Diseases, 29th ed. Elk Grove Village, IL: American Academy of Pediatrics, 2012:774 " 779.
Flatt A, Breuer J. Varicella vaccines. Br Med Bull. 2012;103:115 " 127.
Roderick M, Finn A, Ramanan AV. Chickenpox in the immunocompromised child. Arch Dis Child. 2012;97:587 " 589.
van Lier A, van der Maas N, Rodenburg GD, et al. Hospitalization due to varicella in the Netherlands. BMC Infect Dis. 2011;11:85.

Codes

ICD9

052.9 Varicella without mention of complication
053.9 Herpes zoster without mention of complication
053.21 Herpes zoster keratoconjunctivitis
052.1 Varicella (hemorrhagic) pneumonitis
052.7 Chickenpox with other specified complications
052.8 Chickenpox with unspecified complication

ICD10

B01.9 Varicella without complication
B02.9 Zoster without complications
B02.31 Zoster conjunctivitis
B01.2 Varicella pneumonia
B01.89 Other varicella complications

SNOMED

38907003 varicella (disorder)
4740000 Herpes zoster (disorder)
410509003 Herpes zoster conjunctivitis
195911009 chickenpox pneumonia (disorder)
423333008 Exanthem due to chicken pox (disorder)
90433002 Congenital varicella infection

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