Varicella-Zoster Virus (VZV)

Epidemiology

  • Most common complication of varicella in adults (occurs in 0.8-50% of cases): has highest mortality rate of any complication of varicella
  • Risk Factors for varicella pneumonia (in presence of varicella):
    • Immunosuppression:
    • AIDS:
    • Pregnancy:
    • Tobacco (15x increased risk in smokers):
  • Transmission: airborne droplets via person-to-person

Etiology

  • Varicella-Zoster Virus (VZV) infection

Physiology

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Pathology

  • Diffuse nodular (1-10 mm nodules) infiltrates

Diagnosis

Sputum GS/Cult+Sens:
ABG: hypoxemia
CXR/ Chest CT patterns:
1) Alveolar infiltrates (most common pattern):
-Nodular/ miliary densities may occur (miliary areas may remain as areas of “buckshot” calcification after resolution)
-Hilar adenopathy/small pleural effusions are sometimes seen
-Radiologic findings correlate with and follow the severity of skin rash
2) Nodular Interstitial infiltrates (less common pattern):
3) Miliary calcific pattern (on CXR): resembles old Histo


Clinical

Pulmonary Manifestations

  • Pneumonia (see [[Pneumonia]])
    • Dyspnea
    • Cough
    • Rales: correlate poorly with severity of illness
  • Interstitial Infiltrates (see [[Interstitial Lung Disease-Etiology]])
  • Miliary Nodular Pneumonia (see [[Lung Nodule or Mass]])
  • [[Diffuse Alveolar Damage]] -> [[Acute Lung Injury-ARDS]] or [[Diffuse Alveolar Hemorrhage]]

Dermatologic Manifestations

Other Manifestations

  • SIADH/ ARDS/ encephalitis/ Guillian-Barre syndrome/ GLN/ arthritis/ hepa-titis/ pancreatitis/ myocarditis/ DVT

Shingles

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Treatment

PO Acyclovir (800 mg/day PO x 5 days): effective, if given within 24 hours of onset of rash, to decrease fever/ tachypnea/ hypoxemia/duration of illness
-Effect on complications is unknown
-Risk/benefit ratio favors use in pregnant patients

IV Acyclovir (10 mg/kg IV q8 hrs x 7 days): for VZV pneumonia or VZV in an immunocompromised host
IV Foscarnet (40 mg/kg IV q8 hrs x 10 days): indicated for Acyclovir-resistant VZV
Post-Exposure Prophylaxis (indicated for Varicella-seronegative hosts with close and prolonged exposure): VZV immune globulin
Infection control: airborne precautions


Treatment

  • Resolves over days-weeks

References

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