OUTCOME AFTER RIGHT MIDDLE LOBE SYNDROME

The long-term pulmonary consequences of right middle lobe syndrome (RM LS) in childhood are not known. Therefore, outcome was evaluated in 17 children with RMLS diagnosed in early childhood (mean age, 3.3 years; SD, 1.1 year), Mean age at follow-up was 10.1 years (SD, 2.6 years). RMLS was defined as atelectasis of the right middle lobe (RML) of at l east 1 month's duration and visible on the lateral view of the chest r adiograph as a wedge-shaped density extending from the hilum anteriorl y and downward. Seventeen children without personal history of allergy or respiratory tract disease were studied as control group, Five of 1 7 study group children had ongoing respiratory problems: symptoms of a sthma were present in 4 patients, and cylindrical bronchiectasis was p resent in one patient. Chest radiograph at follow-up was abnormal in s ix patients. Pulmonary function tests, including mean and SEM for vita l capacity (VC) (82% of predicted +/- 7 vs 94% predicted +/- 3), FEV(1 ) (77% of predicted +/- 12 vs 96%, of predicted +/- 4) and their ratio (75 +/- 5 vs 85 +/- 3) were significantly lower in patients with ongo ing respiratory symptoms than in the control children. The provocative dose causing a 20% decrease in FEV(1) (PD20) of methacholine was sign ificantly lower in patients with ongoing symptoms at follow-up than in control children and in patients without symptoms at follow-up (2.8 [ 2.2 to 3.1] vs 4.5 [2.2 to 8.8] and 9.2 [2.3 to 24] mg/mL; median and P25-75, p < 0.05). Age at initial diagnosis tended to be younger in pa tients with ongoing symptoms at follow-up (2.3 +/- 0.7 years vs 3.8 +/ - 0.4 years; p < 0.08).