Bronchiectasis is a chronic respiratory disease characterized by permanent, abnormal dilation and thickening of the bronchi resulting from a self-perpetuating cycle of airway infection, inflammation, impaired mucociliary clearance, and progressive structural lung damage (the so-called vicious vortex). It may be idiopathic or arise secondary to prior severe respiratory infection, cystic fibrosis, primary ciliary dyskinesia, immunodeficiency, allergic bronchopulmonary aspergillosis, or chronic obstructive airway disease. Affected individuals experience chronic productive cough, recurrent respiratory infections, and progressive airflow obstruction, with acute exacerbations driving stepwise decline in lung function.
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name: Bronchiectasis
creation_date: '2025-12-04T16:57:31Z'
updated_date: '2026-04-26T23:00:50Z'
category: Respiratory Disease
description: >-
Bronchiectasis is a chronic respiratory disease characterized by permanent, abnormal
dilation and thickening of the bronchi resulting from a self-perpetuating cycle of airway
infection, inflammation, impaired mucociliary clearance, and progressive structural lung
damage (the so-called vicious vortex). It may be idiopathic or arise secondary to prior
severe respiratory infection, cystic fibrosis, primary ciliary dyskinesia, immunodeficiency,
allergic bronchopulmonary aspergillosis, or chronic obstructive airway disease. Affected
individuals experience chronic productive cough, recurrent respiratory infections, and
progressive airflow obstruction, with acute exacerbations driving stepwise decline in lung
function.
parents:
- Chronic Lung Disease
- Inflammatory Lung Disease
prevalence:
- population: Adults
percentage: Unknown
- population: Children
percentage: Unknown
progression:
- phase: Onset
age_range: Childhood to Adulthood
pathophysiology:
- name: Chronic Infection and Inflammation
description: Persistent microbial infections and inflammation damage airway
walls, leading to dilation and thickening.
evidence:
- reference: DOI:10.1183/16000617.0055-2024
reference_title: 'Pathophysiology and genomics of bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: The presence of airway infection together with chronic inflammation,
airway mucociliary dysfunction and lung damage are key components of the
vicious vortex model that better describes its pathophysiology.
explanation: Vicious vortex model centers on chronic infection plus
inflammation as the core pathophysiology of bronchiectasis.
downstream:
- target: Airway Dilation
- name: Airway Dilation
description: Destruction of elastin and cartilage in the bronchial walls causes irreversible dilation of bronchi.
downstream:
- target: Impaired Mucociliary Clearance
- target: Fixed Airflow Obstruction
description: Irreversible structural destruction and dilation of the bronchial
walls produces the progressive, fixed airflow limitation seen in
bronchiectasis.
- target: Dyspnea
description: Airway structural damage and airflow limitation manifest
clinically as breathlessness.
- target: Wheezing
description: Distorted, dilated airways and luminal narrowing during airflow
produce wheeze.
- target: Hemoptysis
description: Bronchial wall destruction with hypertrophied, fragile bronchial
arteries predisposes to airway bleeding.
- name: Impaired Mucociliary Clearance
description: Damage and dilation of airways hinder effective clearance of mucus, allowing for accumulation and further infection.
downstream:
- target: Recurrent Respiratory Infections
description: Failure to clear mucus and trapped microbes permits persistent
and recurrent airway infection.
- target: Chronic Cough
description: Retained, hyperconcentrated airway secretions stimulate the cough
reflex.
cell_types:
- preferred_term: airway epithelial cell
term:
id: CL:0002368
label: respiratory tract epithelial cell
- preferred_term: ciliated epithelial cell
term:
id: CL:0000067
label: ciliated epithelial cell
biological_processes:
- preferred_term: mucociliary clearance
term:
id: GO:0003351
label: epithelial cilium movement involved in extracellular fluid movement
- preferred_term: cilium movement
term:
id: GO:0003341
label: cilium movement
locations:
- preferred_term: bronchus
term:
id: UBERON:0002185
label: bronchus
- name: Neutrophil-Driven Inflammation
description: Excessive neutrophil recruitment, degranulation, and NET
formation release proteases (neutrophil elastase, proteinase 3, cathepsin G)
that degrade extracellular matrix, impair ciliary function, and damage
epithelial barriers.
downstream:
- target: Protease-Antiprotease Imbalance
description: Excessive neutrophil serine protease release overwhelms airway
antiproteases, establishing the protease-antiprotease imbalance.
evidence:
- reference: DOI:10.1183/16000617.0179-2024
reference_title: 'Neutrophilic inflammation in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: The excessive release of neutrophil serine proteases, such as
neutrophil elastase, cathepsin G and proteinase 3, promotes a
protease–antiprotease imbalance that correlates with increased inflammation
in bronchiectasis and contributes to disease progression.
explanation: Direct evidence that neutrophil serine proteases drive
inflammation and disease progression in bronchiectasis.
- reference: DOI:10.1055/s-0041-1730891
reference_title: 'Pathophysiology of Bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Recent data show that neutrophil extracellular trap formation may be
the key mechanism leading to protease release and severe bronchiectasis.
explanation: Supports NET formation as a key mechanism for protease release
and disease severity.
cell_types:
- preferred_term: neutrophil
term:
id: CL:0000775
label: neutrophil
biological_processes:
- preferred_term: neutrophil degranulation
term:
id: GO:0043312
label: neutrophil degranulation
- preferred_term: neutrophil extracellular trap formation
term:
id: GO:0140645
label: neutrophil extracellular trap formation
- preferred_term: inflammatory response
term:
id: GO:0006954
label: inflammatory response
locations:
- preferred_term: bronchus
term:
id: UBERON:0002185
label: bronchus
- preferred_term: extracellular space
term:
id: GO:0005576
label: extracellular region
- name: Protease-Antiprotease Imbalance
description: Excess neutrophil serine proteases (NE, PR3, CatG) overwhelm
antiproteases (SLPI, A1AT), degrading structural proteins and perpetuating
tissue damage.
downstream:
- target: Airway Dilation
description: Protease-driven destruction of airway-wall elastin and collagen
drives the irreversible bronchial dilation.
evidence:
- reference: DOI:10.1183/16000617.0179-2024
reference_title: 'Neutrophilic inflammation in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: The excessive release of neutrophil serine proteases, such as
neutrophil elastase, cathepsin G and proteinase 3, promotes a
protease–antiprotease imbalance that correlates with increased inflammation
in bronchiectasis and contributes to disease progression.
explanation: Directly supports protease-antiprotease imbalance as a
neutrophil serine protease-driven mechanism linked to inflammation and
bronchiectasis progression.
biological_processes:
- preferred_term: proteolysis
term:
id: GO:0006508
label: proteolysis
locations:
- preferred_term: extracellular space
term:
id: GO:0005576
label: extracellular region
- name: Goblet Cell Hyperplasia and Mucus Hypersecretion
description: Increased goblet cell numbers and overproduction of gel-forming
mucins (MUC5AC, MUC5B) lead to mucus hyperconcentration and impaired
clearance.
downstream:
- target: Sputum Production
description: Overproduction of gel-forming mucins generates the copious,
often purulent sputum characteristic of bronchiectasis.
- target: Chronic Cough
description: Excess airway mucus stimulates the cough reflex, producing the
productive chronic cough.
evidence:
- reference: DOI:10.1055/s-0041-1730891
reference_title: 'Pathophysiology of Bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Mucus symptoms arise through goblet cell hyperplasia and metaplasia
and reduced ciliary function through dyskinesia and loss of ciliated cells.
explanation: Direct support for goblet cell hyperplasia as a source of mucus
symptoms in bronchiectasis.
cell_types:
- preferred_term: goblet cell
term:
id: CL:0000160
label: goblet cell
biological_processes:
- preferred_term: mucus secretion
term:
id: GO:0070254
label: mucus secretion
locations:
- preferred_term: bronchus
term:
id: UBERON:0002185
label: bronchus
- name: Inflammasome Activation and IL-1beta Signaling
description: NLRP3 inflammasome activation drives IL-1beta production, which
directly impairs ciliary function, disrupts tight junctions, promotes mucus
hyperconcentration, and is associated with severe disease and Proteobacteria
enrichment.
evidence:
- reference: DOI:10.1183/13993003.01966-2023
reference_title: 'Airway IL-1β is related to disease severity and mucociliary function in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: A subset of stable bronchiectasis patients show increased airway
IL-1β, suggesting pulmonary inflammasome activation is linked with more
severe disease, airway infection, mucus dehydration and epithelial
dysfunction.
explanation: Cohort study (n=269) directly links airway IL-1beta to
inflammasome activation, severity, and epithelial dysfunction.
- reference: DOI:10.1183/13993003.01966-2023
reference_title: 'Airway IL-1β is related to disease severity and mucociliary function in bronchiectasis'
supports: SUPPORT
evidence_source: IN_VITRO
snippet: Chronic IL-1β treatment reduced the functionality of cilia and
tight junctions of epithelial cells
explanation: In vitro mechanistic evidence that IL-1beta directly impairs
ciliary and tight-junction function in airway epithelial cells.
biological_processes:
- preferred_term: interleukin-1 beta production
term:
id: GO:0032611
label: interleukin-1 beta production
cellular_components:
- preferred_term: NLRP3 inflammasome complex
term:
id: GO:0072559
label: NLRP3 inflammasome complex
cell_types:
- preferred_term: airway epithelial cell
term:
id: CL:0002368
label: respiratory tract epithelial cell
locations:
- preferred_term: bronchus
term:
id: UBERON:0002185
label: bronchus
- name: Microbiome Dysbiosis
description: Reduced microbial diversity with Proteobacteria dominance,
particularly Pseudomonas aeruginosa and Haemophilus influenzae, drives
chronic infection, exacerbations, and disease progression.
downstream:
- target: Recurrent Respiratory Infections
description: Proteobacteria-dominant dysbiosis with persistent pathogen
colonization drives chronic and recurrent airway infection.
evidence:
- reference: DOI:10.1055/s-0041-1730891
reference_title: 'Pathophysiology of Bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Loss of diversity of the normal lung microbiota and dominance of
proteobacteria such as Pseudomonas and Haemophilus are features of severe
bronchiectasis and link to poor outcomes.
explanation: Direct support for Proteobacteria dominance as a feature of
severe disease.
- reference: DOI:10.1186/s12931-024-02931-x
reference_title: 'The clinical impacts of lung microbiome in bronchiectasis with fixed airflow obstruction: a prospective cohort study'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Patients with bronchiectasis, with or without FAO, had similar
microbiome profiles characterized by reduced alpha diversity and a
predominance of Proteobacteria
explanation: Confirms reduced alpha diversity and Proteobacteria predominance
via 16S rRNA sequencing of BAL samples.
locations:
- preferred_term: bronchus
term:
id: UBERON:0002185
label: bronchus
- preferred_term: respiratory tract mucus
term:
id: UBERON:0000912
label: mucus
genetic:
- name: CFTR
association: Modifier gene
notes: CFTR ion channel dysfunction contributes to airway surface liquid dehydration and mucus abnormalities in non-CF bronchiectasis, though the role is debated.
- name: SCNN1A
association: Modifier gene
notes: ENaC (epithelial sodium channel) alpha subunit; hyperactivity causes airway surface dehydration and increased mucus viscosity, impairing mucociliary clearance.
phenotypes:
- category: Respiratory
name: Chronic Cough
frequency: VERY_FREQUENT
diagnostic: true
phenotype_term:
preferred_term: Chronic Cough
term:
id: HP:0034315
label: Chronic cough
evidence:
- reference: DOI:10.1183/16000617.0179-2024
reference_title: 'Neutrophilic inflammation in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Patients with clinically significant bronchiectasis have chronic
cough and sputum production, as well as recurrent respiratory infections,
fatigue and impaired health-related quality of life.
explanation: Chronic cough is a defining clinical feature of bronchiectasis.
- category: Respiratory
name: Sputum Production
frequency: VERY_FREQUENT
notes: Often purulent and copious
phenotype_term:
preferred_term: Sputum Production
term:
id: HP:0033709
label: Increased sputum production
evidence:
- reference: DOI:10.1183/16000617.0179-2024
reference_title: 'Neutrophilic inflammation in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Patients with clinically significant bronchiectasis have chronic
cough and sputum production, as well as recurrent respiratory infections,
fatigue and impaired health-related quality of life.
explanation: Sputum production is a defining clinical feature of
bronchiectasis.
- category: Respiratory
name: Dyspnea
frequency: FREQUENT
phenotype_term:
preferred_term: Dyspnea
term:
id: HP:0002094
label: Dyspnea
- category: Respiratory
name: Hemoptysis
frequency: OCCASIONAL
notes: Blood in cough due to airway damage
phenotype_term:
preferred_term: Hemoptysis
term:
id: HP:0002105
label: Hemoptysis
- category: Respiratory
name: Recurrent Respiratory Infections
frequency: FREQUENT
phenotype_term:
preferred_term: Recurrent Respiratory Infections
term:
id: HP:0002205
label: Recurrent respiratory infections
evidence:
- reference: DOI:10.1183/16000617.0179-2024
reference_title: 'Neutrophilic inflammation in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Patients with clinically significant bronchiectasis have chronic
cough and sputum production, as well as recurrent respiratory infections,
fatigue and impaired health-related quality of life.
explanation: Recurrent respiratory infections are a hallmark clinical feature
of bronchiectasis.
- category: Respiratory
name: Fixed Airflow Obstruction
frequency: FREQUENT
notes: Progressive airflow limitation that may develop in bronchiectasis patients, associated with Proteobacteria-enriched microbiome
phenotype_term:
preferred_term: Chronic pulmonary obstruction
term:
id: HP:0006510
label: Chronic pulmonary obstruction
evidence:
- reference: DOI:10.1186/s12931-024-02931-x
reference_title: 'The clinical impacts of lung microbiome in bronchiectasis with fixed airflow obstruction: a prospective cohort study'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: compared to COPD and bronchiectasis without FAO, bronchiectasis with
FAO showed more severe disease and a higher risk of exacerbations.
explanation: Direct evidence that fixed airflow obstruction is a clinically
relevant phenotype in bronchiectasis with worse outcomes.
- category: Respiratory
name: Wheezing
frequency: OCCASIONAL
phenotype_term:
preferred_term: Wheezing
term:
id: HP:0030828
label: Wheezing
biochemical:
- name: C-Reactive Protein (CRP)
presence: Elevated
context: Indicates active inflammation and infection
- name: Sputum Culture
presence: Positive
context: Identification of pathogenic organisms
- name: Neutrophil Elastase (NE)
presence: Elevated
context: High sputum NE activity associates with severe bronchiectasis,
exacerbation risk, airway bacterial load, and disease progression;
mechanistic biomarker of neutrophil-driven inflammation
evidence:
- reference: DOI:10.1055/s-0041-1730891
reference_title: 'Pathophysiology of Bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Neutrophilic inflammation is characteristic of the disease, with
elevated levels of harmful proteases such as neutrophil elastase associated
with worse outcomes.
explanation: Supports elevated neutrophil elastase as a biomarker linked to
worse outcomes in bronchiectasis.
- name: Interleukin-1 beta (IL-1beta)
presence: Elevated
context: Subset of patients with high airway IL-1beta show severe disease,
mucus hyperconcentration, impaired ciliary function, and
Proteobacteria-enriched microbiome
evidence:
- reference: DOI:10.1183/13993003.01966-2023
reference_title: 'Airway IL-1β is related to disease severity and mucociliary function in bronchiectasis'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Patients with high sputum IL-1β had more severe disease, increased
caspase-1 activity and an increased T-helper type 1, T-helper type 2 and
neutrophil inflammatory response compared with patients with low IL-1β.
explanation: Cohort study links elevated airway IL-1beta to greater severity
and amplified inflammatory response.
- name: Neutrophil Extracellular Traps (NETs)
presence: Elevated
context: NET complexes in sputum associate with higher disease severity, exacerbations, and mortality; include MPO, NE, resistin, and azurocidin
diagnosis:
- name: High-Resolution CT Scan
notes: Reveals dilated bronchi and other structural changes typical of bronchiectasis.
- name: Pulmonary Function Test
notes: May indicate obstructive pattern due to airway dilation.
treatments:
- name: Airway Clearance Techniques
description: Physical therapies to enhance mucus clearance, such as chest physiotherapy.
treatment_term:
preferred_term: physical therapy
term:
id: MAXO:0000011
label: physical therapy
- name: Antibiotic Therapy
description: Used to treat and prevent bacterial infections in the airways.
treatment_term:
preferred_term: antibiotic therapy
term:
id: NCIT:C15620
label: Antibiotic Therapy
- name: Long-term Macrolide Therapy
description: Maintenance macrolide antibiotics such as azithromycin or
erythromycin reduce pulmonary exacerbations in selected patients, while
requiring attention to macrolide resistance risk.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: azithromycin
term:
id: CHEBI:2955
label: azithromycin
- preferred_term: erythromycin
term:
id: CHEBI:48923
label: erythromycin
evidence:
- reference: PMID:22901887
reference_title: 'Azithromycin for prevention of exacerbations in non-cystic fibrosis bronchiectasis (EMBRACE): a randomised, double-blind, placebo-controlled trial.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Azithromycin is a new option for prevention of exacerbations in
patients with non-cystic fibrosis bronchiectasis with a history of at
least one exacerbation in the past year.
explanation: EMBRACE was a randomized, double-blind, placebo-controlled
trial supporting azithromycin for exacerbation prevention.
- reference: PMID:23532242
reference_title: 'Effect of long-term, low-dose erythromycin on pulmonary exacerbations among patients with non-cystic fibrosis bronchiectasis: the BLESS randomized controlled trial.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Among patients with non-CF bronchiectasis, the 12-month use of
erythromycin compared with placebo resulted in a modest decrease in the
rate of pulmonary exacerbations and an increased rate of macrolide
resistance.
explanation: BLESS supports long-term macrolide therapy reducing
exacerbations while also documenting resistance risk.
- name: Brensocatib
description: Oral reversible dipeptidyl peptidase 1 inhibitor that reduces
neutrophil serine protease activity and pulmonary exacerbations.
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
target_mechanisms:
- target: Protease-Antiprotease Imbalance
treatment_effect: INHIBITS
description: Brensocatib inhibits DPP-1, targeting neutrophil serine
proteases that drive the protease-antiprotease imbalance.
evidence:
- reference: PMID:40267423
reference_title: 'Phase 3 Trial of the DPP-1 Inhibitor Brensocatib in Bronchiectasis.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase
1 (DPP-1), targets neutrophil serine proteases, key mediators of
neutrophilic inflammation.
explanation: The ASPEN trial abstract describes brensocatib's DPP-1
inhibition as targeting neutrophil serine proteases.
evidence:
- reference: PMID:40267423
reference_title: 'Phase 3 Trial of the DPP-1 Inhibitor Brensocatib in Bronchiectasis.'
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: Among patients with bronchiectasis, once-daily treatment with
brensocatib (10 mg or 25 mg) led to a lower annualized rate of pulmonary
exacerbations than placebo, and the decline in FEV1 was less with the
25-mg dose of brensocatib than with placebo.
explanation: ASPEN was a phase 3, double-blind trial demonstrating reduced
pulmonary exacerbations with once-daily brensocatib.
- name: Bronchodilators
description: Medications to open airways and improve breathing.
treatment_term:
preferred_term: bronchodilator therapy
term:
id: MAXO:0000316
label: bronchodilator therapy
- name: Inhaled Corticosteroids
description: Reduce inflammation in the airways.
treatment_term:
preferred_term: respiratory tract agent therapy
term:
id: MAXO:0000312
label: respiratory tract agent therapy
- name: Surgery
description: Rarely performed; may include removal of severely affected lung areas if localized and recurrent infections persist.
treatment_term:
preferred_term: surgical procedure
term:
id: MAXO:0000004
label: surgical procedure
- name: Vaccinations
description: Prevent respiratory infections and exacerbations.
treatment_term:
preferred_term: vaccination
term:
id: MAXO:0001017
label: vaccination
environmental:
- name: Pollution
notes: May worsen symptoms and progression.
exposure_term:
preferred_term: Air pollution exposure
term:
id: ECTO:8000036
label: exposure to air pollution
- name: Smoking
notes: Exacerbates lung damage and symptoms.
exposure_term:
preferred_term: Tobacco smoking exposure
term:
id: ECTO:6000029
label: exposure to tobacco smoking
notes: Bronchiectasis is characterized by a self-sustaining "vicious vortex" of mucociliary dysfunction, persistent infection with Proteobacteria-dominant dysbiosis (notably Pseudomonas aeruginosa), and chronic neutrophil-driven inflammation. Neutrophils release proteases (NE, PR3, CatG) and form NETs that degrade extracellular matrix, impair ciliary function, and damage epithelial barriers. Inflammasome activation with airway IL-1beta is associated with severe disease, mucus hyperconcentration, and epithelial dysfunction. The disease leads to irreversible bronchial dilation and progressive airflow limitation.
disease_term:
preferred_term: bronchiectasis
term:
id: MONDO:0004822
label: bronchiectasis
classifications:
harrisons_chapter:
- classification_value: RESPIRATORY
references:
- reference: DOI:10.1055/s-0041-1730891
title: Pathophysiology of Bronchiectasis
findings: []
- reference: DOI:10.1164/rccm.202306-1059oc
title: Airway “Resistotypes” and Clinical Outcomes in Bronchiectasis
findings: []
- reference: DOI:10.1183/13993003.01689-2023
title: 'Airway clearance management in people with bronchiectasis: data from the European Bronchiectasis Registry (EMBARC)'
findings: []
- reference: DOI:10.1183/13993003.01966-2023
title: Airway IL-1β is related to disease severity and mucociliary function in bronchiectasis
findings: []
- reference: DOI:10.1183/16000617.0038-2024
title: Infection and the microbiome in bronchiectasis
findings: []
- reference: DOI:10.1183/16000617.0055-2024
title: Pathophysiology and genomics of bronchiectasis
findings: []
- reference: DOI:10.1183/16000617.0179-2024
title: Neutrophilic inflammation in bronchiectasis
findings: []
- reference: DOI:10.1183/16000617.0234-2023
title: Biomarkers in bronchiectasis
findings: []
- reference: DOI:10.1186/s12931-024-02931-x
title: 'The clinical impacts of lung microbiome in bronchiectasis with fixed airflow obstruction: a prospective cohort study'
findings: []
- reference: PMID:22901887
title: 'Azithromycin for prevention of exacerbations in non-cystic fibrosis
bronchiectasis (EMBRACE): a randomised, double-blind, placebo-controlled
trial.'
findings: []
- reference: PMID:23532242
title: 'Effect of long-term, low-dose erythromycin on pulmonary exacerbations
among patients with non-cystic fibrosis bronchiectasis: the BLESS randomized
controlled trial.'
findings: []
- reference: PMID:40267423
title: Phase 3 Trial of the DPP-1 Inhibitor Brensocatib in Bronchiectasis.
findings: []
Pathophysiology description (concise knowledge-base narrative) Non‑CF bronchiectasis arises from a self-sustaining “vicious vortex” of mucociliary dysfunction, persistent infection with Proteobacteria-dominant dysbiosis (notably Pseudomonas aeruginosa), and chronic neutrophil-driven inflammation that releases proteases and NETs, injuring the epithelium and altering mucus rheology, thereby worsening clearance and perpetuating infection. Inflammasome activation with airway IL‑1β links to higher severity, mucus hyperconcentration, epithelial barrier dysfunction, and Proteobacteria enrichment. Excess NSP activity (NE, PR3, CatG) over antiproteases is a causative axis, validated by clinical benefit of DPP‑1 inhibition that reduces airway protease activity and exacerbations. Clinically, frequent exacerbators and those with chronic P. aeruginosa have worse outcomes; airway clearance use remains suboptimal despite guideline recommendations (keir2021pathophysiologyofbronchiectasis pages 2-2, perea2024pathophysiologyandgenomics pages 2-3, aogain2024infectionandthe pages 1-2, johnson2024biomarkersinbronchiectasis pages 1-2, johnson2024biomarkersinbronchiectasis pages 3-4, aogain2024infectionandthe pages 6-7, chen2024theclinicalimpacts pages 1-2).
References
(keir2021pathophysiologyofbronchiectasis pages 2-2): Holly R. Keir and James D. Chalmers. Pathophysiology of bronchiectasis. Seminars in Respiratory and Critical Care Medicine, 42:499-512, Jul 2021. URL: https://doi.org/10.1055/s-0041-1730891, doi:10.1055/s-0041-1730891. This article has 81 citations and is from a peer-reviewed journal.
(keir2021pathophysiologyofbronchiectasis pages 1-2): Holly R. Keir and James D. Chalmers. Pathophysiology of bronchiectasis. Seminars in Respiratory and Critical Care Medicine, 42:499-512, Jul 2021. URL: https://doi.org/10.1055/s-0041-1730891, doi:10.1055/s-0041-1730891. This article has 81 citations and is from a peer-reviewed journal.
(chalmers2025neutrophilicinflammationin pages 1-2): James D. Chalmers, Mark Metersky, Stefano Aliberti, Lucy Morgan, Sebastian Fucile, Melanie Lauterio, and Patrick P. McDonald. Neutrophilic inflammation in bronchiectasis. European Respiratory Review, 34:240179, Apr 2025. URL: https://doi.org/10.1183/16000617.0179-2024, doi:10.1183/16000617.0179-2024. This article has 20 citations and is from a peer-reviewed journal.
(perea2024pathophysiologyandgenomics pages 2-3): Lidia Perea, Rosa Faner, James D. Chalmers, and Oriol Sibila. Pathophysiology and genomics of bronchiectasis. European Respiratory Review, 33:240055, Jul 2024. URL: https://doi.org/10.1183/16000617.0055-2024, doi:10.1183/16000617.0055-2024. This article has 29 citations and is from a peer-reviewed journal.
(keir2021pathophysiologyofbronchiectasis pages 3-4): Holly R. Keir and James D. Chalmers. Pathophysiology of bronchiectasis. Seminars in Respiratory and Critical Care Medicine, 42:499-512, Jul 2021. URL: https://doi.org/10.1055/s-0041-1730891, doi:10.1055/s-0041-1730891. This article has 81 citations and is from a peer-reviewed journal.
(keir2021pathophysiologyofbronchiectasis pages 2-3): Holly R. Keir and James D. Chalmers. Pathophysiology of bronchiectasis. Seminars in Respiratory and Critical Care Medicine, 42:499-512, Jul 2021. URL: https://doi.org/10.1055/s-0041-1730891, doi:10.1055/s-0041-1730891. This article has 81 citations and is from a peer-reviewed journal.
(aogain2024infectionandthe pages 1-2): Micheál Mac Aogáin, Alison J. Dicker, Pontus Mertsch, and Sanjay H. Chotirmall. Infection and the microbiome in bronchiectasis. European Respiratory Review, 33:240038, Jul 2024. URL: https://doi.org/10.1183/16000617.0038-2024, doi:10.1183/16000617.0038-2024. This article has 24 citations and is from a peer-reviewed journal.
(aogain2024infectionandthe pages 4-5): Micheál Mac Aogáin, Alison J. Dicker, Pontus Mertsch, and Sanjay H. Chotirmall. Infection and the microbiome in bronchiectasis. European Respiratory Review, 33:240038, Jul 2024. URL: https://doi.org/10.1183/16000617.0038-2024, doi:10.1183/16000617.0038-2024. This article has 24 citations and is from a peer-reviewed journal.
(aogain2024infectionandthe pages 6-7): Micheál Mac Aogáin, Alison J. Dicker, Pontus Mertsch, and Sanjay H. Chotirmall. Infection and the microbiome in bronchiectasis. European Respiratory Review, 33:240038, Jul 2024. URL: https://doi.org/10.1183/16000617.0038-2024, doi:10.1183/16000617.0038-2024. This article has 24 citations and is from a peer-reviewed journal.
(chen2024theclinicalimpacts pages 1-2): Yen-Fu Chen, Hsin-Han Hou, Ning Chien, Kai-Zen Lu, Chieh-Hua Lin, Yu-Chieh Liao, Kuo-Lung Lor, Jung-Yien Chien, Chung-Ming Chen, Chung-Yu Chen, Shih-Lung Cheng, Hao-Chien Wang, Po-Ren Hsueh, and Chong-Jen Yu. The clinical impacts of lung microbiome in bronchiectasis with fixed airflow obstruction: a prospective cohort study. Respiratory Research, Aug 2024. URL: https://doi.org/10.1186/s12931-024-02931-x, doi:10.1186/s12931-024-02931-x. This article has 6 citations and is from a domain leading peer-reviewed journal.
(johnson2024biomarkersinbronchiectasis pages 3-4): Emma D Johnson, Merete B. Long, and James D. Chalmers. Biomarkers in bronchiectasis. European Respiratory Review, 33:230234, Jul 2024. URL: https://doi.org/10.1183/16000617.0234-2023, doi:10.1183/16000617.0234-2023. This article has 17 citations and is from a peer-reviewed journal.
(chalmers2025neutrophilicinflammationin pages 9-10): James D. Chalmers, Mark Metersky, Stefano Aliberti, Lucy Morgan, Sebastian Fucile, Melanie Lauterio, and Patrick P. McDonald. Neutrophilic inflammation in bronchiectasis. European Respiratory Review, 34:240179, Apr 2025. URL: https://doi.org/10.1183/16000617.0179-2024, doi:10.1183/16000617.0179-2024. This article has 20 citations and is from a peer-reviewed journal.
(johnson2024biomarkersinbronchiectasis pages 1-2): Emma D Johnson, Merete B. Long, and James D. Chalmers. Biomarkers in bronchiectasis. European Respiratory Review, 33:230234, Jul 2024. URL: https://doi.org/10.1183/16000617.0234-2023, doi:10.1183/16000617.0234-2023. This article has 17 citations and is from a peer-reviewed journal.