Varicella-Zoster Pneumonia

Source:  Varicella-Zoster Pneumonia    Tag:  disseminated varicella zoster
A man with  Day 3 chicken pox complicated with cough.


 Day 1 admission CXR. Consolidation in retrocardiac region.

Day 3 admission. 

  • Patchy diffuse air-space consolidation predominantly near hila and lung bases.
  • Widespread ill-defined nodular opacities (acinar nodular pattern).



 Day 7 admission. 
Improved. No lung scarring.

DISCUSSION:

Varicella-zoster virus (VZV) most commonly is a self-limited benign disease (chickenpox) in children. However, in adults it tends to cause significant complications such as VZV pneumonia. 



2 types of pathologic reactions and radiologic aspects can be observed:
             (1) usual, long-standing, or insidious course of pneumonia; and
             (2) rapidly progressive or virulent pneumonia.

Radiological changes:
  • radiographic manifestations usually appear 2-5 days after the rash does.
  • tend to clear in 3-5 days in mild disease and take up to several weeks or months to clear in widespread disease.
  • Patchy, diffuse air space consolidation
  • Tendency to coalesce near hila
  • Widespread nodules can occur (30%) appearing as ill-defined, 5- to 15-mm nodular opacities (acinar nodular pattern). The nodules are seen in the lung periphery (bases), coalescing near the hila;
  • Tiny calcifications remain in 2% (DDX is histoplasmosis, alveolar microlithiasis).
  • CT images may show nodules with a surrounding halo of ground-glass opacity, patchy ground-glass opacity, and coalescence of nodules.
  • Unique complication consists of the late appearance (years after onset of pneumonia) of 2- to 3-mm dense calcifications, which are well defined, scattered, and predominant in the lower half of the lungs. 
11% mortality rate.

Pneumonia due to bacterial superinfection is segmental in distribution, it affects 1 or both lower lobes, and it is frequently associated with atelectasis. The presence of a dense opacity is more suggestive of a bacterial etiology (88%) than a viral etiology (36%).