RESUMO
We describe three cases of female subjects (aged 16, 44 and 41 years) with no respiratory symptoms, who have alpha-1 antitripsyn mutation (PiSZ, PiZZ and PiZZ) and who performed traditional pulmonary function tests and the single breath nitrogen washout test. They still did not have chronic obstructive pulmonary disease (COPD) or any identifiable change in traditional pulmonary function tests but already have change in nitrogen washout tests. Alpha-1 antitrypsin deficiency is a genetic disorder associated with early-onset COPD. There is evidence that although patients who have well-preserved FEV1 may already have signs of emphysema associated with symptoms. Therefore, the nitrogen washout test is considered to have more sensitive outcomes than other pulmonary function tests for early investigation of small airways disease and could allow the monitoring pulmonary function and evaluating of therapeutic decision.
Assuntos
Pneumopatias , Doença Pulmonar Obstrutiva Crônica , Enfisema Pulmonar , Deficiência de alfa 1-Antitripsina , alfa 1-Antitripsina/genética , Adolescente , Adulto , Feminino , Humanos , Fenótipo , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Enfisema Pulmonar/diagnóstico por imagem , Deficiência de alfa 1-Antitripsina/complicações , Deficiência de alfa 1-Antitripsina/diagnóstico , Deficiência de alfa 1-Antitripsina/genéticaRESUMO
Introduction: Small airways are not evaluated with traditional pulmonary function tests. The aim of this study was to evaluate the small airways in patients with chronic obstructive pulmonary disease (COPD) with a nitrogen washout test and to verify whether there is a difference between patients with COPD due to smoking and those with COPD due to alpha-1 antitrypsin mutation. Methods: Sixteen patients with mutation in the SERPINA1 gene and 45 patients with no mutation were included in this cross-sectional study. All pulmonary function tests, including the single breath nitrogen washout test, were performed for all patients and alpha-1 antitrypsin dosage was assessed with immunonephelometry. Results: A comparison of patients with COPD due to smoking and those with COPD due to smoking and mutation revealed a significant difference in closure volume (%), which was the poorest in the mutation group. In the group with COPD and mutation, there was an inverse correlation between smoking and closure volume (%). We also verified that similar to forced expiratory volume in the first second (FEV1), the phase III slope (%) and ΔN2 750-1250 mL (%) could be used to differentiate the severity of airflow limitation. Conclusion: Our results suggest that both variables, phase III slope and the ΔN2 750-1250 mL (%), could be related to COPD severity. Therefore, alterations at the distribution of the location of the emphysema could alter the results of closer volume and that the nitrogen washout test is more sensitive when compared to traditional pulmonary function test in evaluating COPD patients.