Clinical characteristics
All patients were healthy previously, and the average age at the
diagnosis was 36 months. The sex distribution was eight males (67%) and
four females (33%). The racial/ethnic was Han. During the initial acute
lower respiratory tract infection, adenovirus antigen was positive in
four individuals by testing nasopharyngeal secretions, mycoplasma
pneumoniae was identified in four patients and measles virus in one
patient by serum IgM antibody tests, and the etiology was unknown in two
patients. In addition, one patient was infected with both adenovirus and
mycoplasma pneumoniae (Table 1). The diagnosis of PIBO was made on the
basis of the clinical and radiographic findings. The patients presented
with wheezing, cough, dyspnea, exercise intolerance, and frequent
respiratory illness. Physical examination findings were persistent moist
crackles, extensive wheezing and hypoxemia. In all twelve patients, HRCT
scans demonstrated mosaic perfusion pattern, air trapping and bronchial
wall thickening. In one patient, bronchial dilation was showed (Figure
1A and B).