Inhaled N-Acetylcysteine as a Potential Adjunctive Therapy in Mucus Plug-Forming Asthma With Irpex lacteus Isolation: A Case Report.

A 68-year-old woman was hospitalized for hypoxemia during an asthma exacerbation with cough, highly tenacious sputum and exertional dyspnoea. Chest computed tomography revealed lower lobe-dominant mucus plugs. Irpex lacteus was identified from both sputum culture and environmental sampling from the patient's bedroom, although diagnostic criteria for allergic bronchopulmonary mycosis were not fulfilled. Wheezing improved after standard therapy; however highly tenacious sputum persisted. Following administration of inhaled N-acetylcysteine (NAC), sputum tenacity improved, followed by improvements in respiratory symptoms, pulmonary function test values and flow-volume curves and the resolution of mucus plugs. This case suggests that highly tenacious sputum may represent a treatable trait in mucus plug-forming asthma and that inhaled NAC may serve as a useful adjunctive therapy in selected patients. Further accumulation of cases is needed to clarify the clinical significance of Irpex lacteus colonisation.