VZV-related community-acquired pneumonia linked to morbidity, mortality

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The hospital and ICU mortality rates of critically ill patients with VZV-CAP were 24% and 17%, respectively.
The hospital and ICU mortality rates of critically ill patients with VZV-CAP were 24% and 17%, respectively.

Varicella-zoster virus-related community-acquired pneumonia (VZV-CAP), frequently resulting in invasive mechanical ventilation, can be linked to significant rates of morbidity and mortality in adults, according to a recent study published in Critical Care.1

"It is estimated that about 200 million cases of viral CAP occur annually, accounting for 17% to 39% of CAP," wrote Emmanuel Canet, MD, from the Hôpital Saint-Louis, AP-HP, in Paris, France, and colleagues. The researchers cited a much earlier study2 that noted a 16.3% incidence rate of VZV-CAP in adult patients. Therefore, Dr Canet and colleagues aimed to evaluate clinical characteristics, treatment options, and outcomes in a large cohort of critically ill patients with VZV-CAP.

An observational study enrolled 102 patients with VZV-CAP (mean age, 39 years; interquartile range [IQR], 32-51 years). Participants were admitted to 29 intensive care units (ICUs) between January 1996 and January 2015; 52% were immunocompromised. All patients were treated with acyclovir 10 mg/kg per 8 hours. To assess the effects of steroid therapy, the patients who received steroids (n=10) were matched 1:6 to patients in a control group (n=60).

Investigators identified a seasonal distribution of VZV-CAP cases, with more cases occurring during the spring and winter months. A typical chickenpox skin rash preceded the onset of respiratory symptoms in 96% of patients. Time to ICU admission from the onset of respiratory symptoms was between 1 and 3 days (median, 2 days); 51% of patients received invasive mechanical ventilation (average length, 14 days; IQR, 7-21 days) within 1 to 2 days of ICU admission. The hospital mortality rate was slightly higher than the ICU mortality rate (24% vs 17%, respectively).

Compared with steroid-free control patients, patients who received steroids stayed longer in the ICU, had a higher rate of ICU-acquired infections, and received longer-duration mechanical ventilation. However, hospital mortality rates between the 2 groups were comparable (20% vs 20%).

"[R]espiratory disease severity, early bacterial co-infection, and other organ failures on ICU admission were independent risk factors for invasive mechanical ventilation," the researchers wrote. They further noted that early recognition of these factors and close monitoring of patients at risk may help secure timely treatment of those requiring intubation.

"Adjunctive steroid therapy did not influence mortality and increased the risk of superinfection," they concluded.

Study Limitations

  • Supportive care practices may have changed over the course of the retrospective study period.
  • No biological identification of VZV was available for patients included in the study; however, clinical signs and symptoms of chickenpox are "obvious in most cases," according to investigators.
  • Researchers were unable to identify independent predictors of hospital mortality because of to the limited number of deaths recorded.
  • VCV-CAP diagnoses were encoded by physicians, and as such, investigators cannot rule out that some patients with VZV-CAP may have been missed. 

References

  1. Mirouse A, Vignon P, Piron P, et al. Severe varicella-zoster virus pneumonia: a multicenter cohort study. Crit Care. 2017;21(1):137. doi: 10.1186/s13054-017-1731-0. 
  2. Weber DM, Pellecchia JA. Varicella pneumonia. Study of prevalence in adult men. JAMA. 1965;192(6):572-573. doi: 10.1001/jama.1965.03080190138035
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