Clinical and virologic features of severe bronchiolitis requiring ventilatory support

Although bronchiolitis is usually a benign and self-limited disease, in a few cases it can be severe enough to require ventilatory support even in the absence of an underlying disease. The aim of this study was to examine the clinical and virologic features of previously healthy infants with bronchiolitis admitted to a PICU for ventilatory support. A cohort of 232 term infants within 12 months of age, with a diagnosis of bronchiolitis and no previous history of medical problems, admitted during three consecutive epidemics (2004-2007) was studied. Clinical, laboratory and radiologic data were recorded. Respiratory syncitial virus (RSV), rhinovirus, metapneumovirus, coronavirus, parainfluenzae viruses 1-2-3, bocavirus, influenzae viruses were detected by RT-PCR on nasal washings. Fourteen out of 232 (6%) infants required PICU admission for ventilatory support (11 non invasive and 3 invasive ventilation). As compared to infants admitted to the general pediatric ward, infants requiring intensive care were more likely to be younger (0.92 ± 0.8 vs 2.5 ± 2.1 months ± SD; p< 0.004), have lower birth weight (2.7 ± 0.45 vs 3.1 ± 0.5 kg ± SD; p<0.004), higher CRP levels (3.9 ± 4.7 vs 1.1 ± 1.9 mg/dL; p< 0.001), infection with RSV (72% vs 41%; p=0.05), and varying degrees of lung consolidation and air trapping on chest x ray (100% vs 14%; p<0.001). In contrast, there was no difference for gender and family history for atopy or asthma. Our data suggest, that in previously healthy infants, severe broncohiolitis requiring ventilator support occurs most frequently in younger infants secondary to RSV infection. Pulmonary consolidation and elevated CRP levels are main features of these cases.