Mycoplasma pneumoniae infection. A follow-up study of 50 children with respiratory illness

Abstract

Fifty children with a previous history of Mycoplasma pneumoniae respiratory tract infection were assessed clinically, and pulmonary function tests carried out after an interval ranging from 1 1/2 to 9 1/2 years (median 2 1/2). 23 suffered from recurrent wheezy bronchitis or asthma, and in 5 the index illness appeared to precipitate the wheezing tendency. All were symptom-free when respiratory function tests were performed. Simple tests of ventilatory function (PEFR, FEV, and FVC) were within normal limits. Increased bronchial reactivity after excercise (a fall in PEFR > 15% resting value) was demonstrated only in children known to have asthma. Maximum expiratory flow rates in air at 50% of vital capacity (V max50) were within the normal range in all patients with the exception of two. The response in flow rate at 50% of vital capacity after inhalation of an 80% helium and 20% oxygen mixture (Δ V max50) was reduced (P<0.001) in asymptomatic patients with a history of M. pneumoniae respiratory infection, when compared with normal data from 48 healthy schoolchildren without a background of significant respiratory illnesses. These findings indicate impairment of small airways function, even in totally symptom-free children in the study group.