Middle lobe syndrome in children with asthma: review of 56 cases.

OBJECTIVE: Middle lobe syndrome (MLS) is one of the complications of asthma. Its signs and symptoms are often nonspecific, causing delay in appropriate treatment. We aimed to review our pediatric asthmatic patients and provide differential characteristics between MLS and asthma worsening in order to target early diagnosis. METHOD: File records of all asthmatics (n=3528) seen in our clinic during the last 2 years were retrospectively reviewed to identify the patients with MLS, and a case-control study was undertaken. Files of 56 asthmatic children diagnosed as MLS, with a total of 63 episodes, and 63 matched controls with asthma worsening were analyzed and compared. RESULTS: The incidence of MLS was 1.62% and half were below or at the age of 6. All cases with MLS were documented radiologically, and only 5 of the 63 episodes had physical findings suspicious for MLS. The most affected segments were right middle lobe (50%) and left lingula (26.2%). Although in all cases symptoms cleared, in 23 (36.5%) cases, atelectasis persisted radiologically. Compared to controls, patients with MLS included less atopics (34.9% vs. 59.4%, p<0.05) and fewer boys (52.4% vs. 71.4%, p<0.05), and they reported less frequent dyspnea (57.1% vs. 85.9%), more frequent sputum production (49.2% vs. 7.8%), and longer duration of complaints (22.0+/-6.23 vs. 2.4+/-0.31 days) (p<0.001, for each). Furthermore, the resolution of symptoms took significantly longer (45.2+/-9.3 vs. 3.3+/-0.4 days, p<0.001). CONCLUSION: We conclude that complicating MLS in childhood asthma is more frequent in younger ages, girls, and nonatopics. In most cases, physical findings are not informative, and chest radiographs diagnose most but not all cases. The most suggestive symptoms are unresolving/persisting symptoms during admission and/or following treatment.