ABSTRACT BACKGROUND: Asthma is a chronic inflammatory disease with airway hyperresponsiveness. Spirometry is the most commonly used test among asthmatic patients. Another functional test used for diagnosing asthma is the bronchial challenge test. The aim of this study was to analyze the accuracy of spirometry for detecting asthma in the general population. DESIGN AND SETTING: Cross-sectional study with data analysis to evaluate the accuracy of spirometry through calculating sensitivity, specificity and predictive values and through the kappa agreement test. METHODS: Subjects who constituted a birth cohort were enrolled at the age of 23 to 25 years. Spirometric abnormality was defined as reduced forced expiratory volume in one second, i.e. lower than 80% of the predicted value. Measurement of bronchial responsiveness was performed by means of the bronchial challenge test with methacholine. The gold-standard diagnosis of asthma was defined as the presence of bronchial hyperresponsiveness in association with respiratory symptoms. RESULTS: Asthma was detected in 200 subjects (10.4%) out of the sample of 1922 individuals. Spirometric abnormality was detected in 208 subjects (10.9%) of the sample. The specificity of spirometric abnormality for detecting asthma was 90%, sensitivity was 23%, positive predictive value was 22%, and negative predictive value was 91%. The kappa test revealed weak agreement of 0.13 (95% confidence interval, CI: 0.07-0.19) between spirometry and the diagnosis of asthma. CONCLUSION: Spirometry, as a single test, has limitations for detecting asthma in the general population.

Cistos aéreos que emergem anormalmente da traquéia e/ou brônquios de maior calibre são doença extremamente rara. Na literatura encontram-se poucas descrições de casos isolados de cistos paratraqueais associados a pneumopatias crônicas. Relatamos dois casos dessa entidade clínica, rara, em membros de uma mesma família: o pai das pacientes faleceu dessa doença com 43 anos de idade e as duas filhas encontram-se em tratamento. O quadro clínico é semelhante ao da supuração pulmonar crônica. O diagnóstico foi firmado através de broncovideoscopia e tomografia computadorizada de tórax com reconstrução em 3D e broncoscopia virtual. As pacientes estão sob observação e tratamento clínico paliativo.

Air cysts abnormally emerging from the trachea and/or larger bronchi is an extremely rare disease. Only a few isolated cases of paratracheal air cysts associated with chronic lung diseases have been described in the literature. The aim of this communication is to describe two cases of this rare, clinical entity in members of the same family. The father of the patients died from this disease at 43 years of age and his two daughters are currently under treatment. The clinical findings are similar to those of chronic pulmonary suppuration syndrome. The diagnosis was established by bronchovideoscopy, axial CT with 3D reconstitution and virtual bronchoscopy. The patients are under observation and palliative treatment is being administered.