Radiologic Subtypes and Treatment Outcome of Unclassifiable Type Mycobacterium avium Complex Pulmonary Disease

Methods@#Ninety-six patients with unclassifiable type MAC-PD who initiated a macrolidecontaining regimen from 2001 to 2020 were identified at a tertiary referral center in South Korea. Among these 96 patients, 1-year culture conversion rate was analyzed for 48 patients who received standard treatment (three-drug oral-antibiotic combination with or without an injectable agent) for ≥ 1 year. @*Results@#The mean age of the 96 patients was 65.4 ± 10.8 years, and 72.9% of them were male. These patients were classified into four major radiologic subtypes; the most common subtype was the focal cavity subtype (n = 31, 32.3%), followed by the focal mass or nodule (n = 23, 24.0%), consolidation upon emphysema (n = 21, 21.9%), and bronchiolitis (n = 21, 21.9%) subtypes. For the 48 patients who received standard treatment for ≥ 1 year, the overall rate of culture conversion at 1-year was 93.8%. All patients in the focal cavity subtype and focal mass or nodule subtype categories achieved 1-year culture conversion. Additionally, 1-year culture conversion rate was 92.9% in consolidation upon emphysema subtype and 75.0% in bronchiolitis subtype. @*Conclusion@#Unclassifiable type MAC-PD can be radiologically further categorized into four major radiologic subtypes. The treatment outcome of all of these subtypes seems to be favorable.

Respiratory Viruses in Acute Exacerbations of Bronchiectasis

Background@#Bacterial infections are well known factors underlying acute exacerbations in bronchiectasis. However, viral infections may also contribute to acute exacerbations. We aimed to assess the rate of viral detection in acute exacerbations of bronchiectasis, and the associated clinical factors. @*Methods@#Diagnostic tests for viral and bacterial etiologies were performed in 792 patients with bronchiectasis who visited the emergency room or the respiratory care inpatient unit in a tertiary referral center in South Korea. All patients were diagnosed with bronchiectasis by chest computerized tomography and were prescribed antibiotics for a minimum of 3 days. @*Results@#Viral pathogens were detected in 202 of the 792 enrolled patients (25.5%). The most common viral pathogen isolated was influenza A virus (24.8%), followed by rhinovirus (22.4%), influenza B virus (9.8%), respiratory syncytial virus B (8.9%), and human metapneumovirus (6.1%). In 145 patients, a viral, but not bacterial, pathogen was detected, whereas no pathogens were found in 443 patients with exacerbations. Multivariable analysis revealed that female sex and chronic heart disease as a comorbidity were positively associated with viral detection in acute exacerbations of patients with bronchiectasis, whereas the presence of radiographic infiltration was negatively associated. @*Conclusion@#Respiratory viruses were identified in approximately 25% of the acute exacerbations observed among patients with bronchiectasis. Of the viruses detected, influenza viruses and rhinovirus made up over 50%. More attention to viruses as possible causative pathogens for acute deteriorating symptoms in patients with bronchiectasis is warranted.

Respiratory Viruses in Acute Exacerbations of Bronchiectasis

Background@#Bacterial infections are well known factors underlying acute exacerbations in bronchiectasis. However, viral infections may also contribute to acute exacerbations. We aimed to assess the rate of viral detection in acute exacerbations of bronchiectasis, and the associated clinical factors. @*Methods@#Diagnostic tests for viral and bacterial etiologies were performed in 792 patients with bronchiectasis who visited the emergency room or the respiratory care inpatient unit in a tertiary referral center in South Korea. All patients were diagnosed with bronchiectasis by chest computerized tomography and were prescribed antibiotics for a minimum of 3 days. @*Results@#Viral pathogens were detected in 202 of the 792 enrolled patients (25.5%). The most common viral pathogen isolated was influenza A virus (24.8%), followed by rhinovirus (22.4%), influenza B virus (9.8%), respiratory syncytial virus B (8.9%), and human metapneumovirus (6.1%). In 145 patients, a viral, but not bacterial, pathogen was detected, whereas no pathogens were found in 443 patients with exacerbations. Multivariable analysis revealed that female sex and chronic heart disease as a comorbidity were positively associated with viral detection in acute exacerbations of patients with bronchiectasis, whereas the presence of radiographic infiltration was negatively associated. @*Conclusion@#Respiratory viruses were identified in approximately 25% of the acute exacerbations observed among patients with bronchiectasis. Of the viruses detected, influenza viruses and rhinovirus made up over 50%. More attention to viruses as possible causative pathogens for acute deteriorating symptoms in patients with bronchiectasis is warranted.

Treatment Outcomes after Discontinuation of Ethambutol due to Adverse Events in Mycobacterium avium Complex Lung Disease

BACKGROUND@#Long-term administration of ethambutol (EMB) for Mycobacterium avium complex lung disease (MAC-LD) sometimes leads to permanent discontinuation of EMB due to various adverse events. This study aimed to investigate treatment outcomes after discontinuation of EMB.@*METHODS@#Among patients diagnosed with MAC-LD between January 2001 and December 2014, 508 patients whose treatment was initiated with standard regimen until May 2018 were enrolled at a tertiary referral center in Korea. Of these 508 patients, 60 (11.8%) discontinued EMB due to various adverse effects. Among these 60 patients, treatment outcomes were analyzed for 44 patients by comparing their outcomes with those of matched subjects who received the standard treatment regimen without EMB discontinuation.@*RESULTS@#The mean age of the 60 patients who discontinued EMB was 64.4 years. Ocular toxicity was the most common cause of discontinuation of EMB (75.0%, 45/60). The mean duration of EMB administration before its discontinuation was 7.0 ± 4.6 months. The treatment failure rate of the 44 patients with EMB discontinuation analyzed for treatment outcome was 29.6%, which was higher than that of the matched patients who received the standard regimen (18.3%), although the difference was not significant (P = 0.095). Of these 44 patients, EMB was substituted with later-generation fluoroquinolone in 23 patients, and the treatment failure rate of these 23 patients was significantly higher than that of the matched patients who received the standard regimen (39.1% vs. 19.3%, P = 0.045).@*CONCLUSION@#These findings suggest that treatment outcomes are unsatisfactory in patients with MAC-LD who discontinue EMB owing to adverse events. Notably, there was a statistically significant high failure rate in patients who were prescribed fluoroquinolone to replace EMB.

Treatment Outcomes after Discontinuation of Ethambutol due to Adverse Events in Mycobacterium avium Complex Lung Disease

BACKGROUND: Long-term administration of ethambutol (EMB) for Mycobacterium avium complex lung disease (MAC-LD) sometimes leads to permanent discontinuation of EMB due to various adverse events. This study aimed to investigate treatment outcomes after discontinuation of EMB.METHODS: Among patients diagnosed with MAC-LD between January 2001 and December 2014, 508 patients whose treatment was initiated with standard regimen until May 2018 were enrolled at a tertiary referral center in Korea. Of these 508 patients, 60 (11.8%) discontinued EMB due to various adverse effects. Among these 60 patients, treatment outcomes were analyzed for 44 patients by comparing their outcomes with those of matched subjects who received the standard treatment regimen without EMB discontinuation.RESULTS: The mean age of the 60 patients who discontinued EMB was 64.4 years. Ocular toxicity was the most common cause of discontinuation of EMB (75.0%, 45/60). The mean duration of EMB administration before its discontinuation was 7.0 ± 4.6 months. The treatment failure rate of the 44 patients with EMB discontinuation analyzed for treatment outcome was 29.6%, which was higher than that of the matched patients who received the standard regimen (18.3%), although the difference was not significant (P = 0.095). Of these 44 patients, EMB was substituted with later-generation fluoroquinolone in 23 patients, and the treatment failure rate of these 23 patients was significantly higher than that of the matched patients who received the standard regimen (39.1% vs. 19.3%, P = 0.045).CONCLUSION: These findings suggest that treatment outcomes are unsatisfactory in patients with MAC-LD who discontinue EMB owing to adverse events. Notably, there was a statistically significant high failure rate in patients who were prescribed fluoroquinolone to replace EMB.

Treatment Outcomes after Discontinuation of Ethambutol due to Adverse Events in Mycobacterium avium Complex Lung Disease

BACKGROUND@#Long-term administration of ethambutol (EMB) for Mycobacterium avium complex lung disease (MAC-LD) sometimes leads to permanent discontinuation of EMB due to various adverse events. This study aimed to investigate treatment outcomes after discontinuation of EMB.@*METHODS@#Among patients diagnosed with MAC-LD between January 2001 and December 2014, 508 patients whose treatment was initiated with standard regimen until May 2018 were enrolled at a tertiary referral center in Korea. Of these 508 patients, 60 (11.8%) discontinued EMB due to various adverse effects. Among these 60 patients, treatment outcomes were analyzed for 44 patients by comparing their outcomes with those of matched subjects who received the standard treatment regimen without EMB discontinuation.@*RESULTS@#The mean age of the 60 patients who discontinued EMB was 64.4 years. Ocular toxicity was the most common cause of discontinuation of EMB (75.0%, 45/60). The mean duration of EMB administration before its discontinuation was 7.0 ± 4.6 months. The treatment failure rate of the 44 patients with EMB discontinuation analyzed for treatment outcome was 29.6%, which was higher than that of the matched patients who received the standard regimen (18.3%), although the difference was not significant (P = 0.095). Of these 44 patients, EMB was substituted with later-generation fluoroquinolone in 23 patients, and the treatment failure rate of these 23 patients was significantly higher than that of the matched patients who received the standard regimen (39.1% vs. 19.3%, P = 0.045).@*CONCLUSION@#These findings suggest that treatment outcomes are unsatisfactory in patients with MAC-LD who discontinue EMB owing to adverse events. Notably, there was a statistically significant high failure rate in patients who were prescribed fluoroquinolone to replace EMB.