Obstructive: Bronchiectasis Flashcards
What is bronchiectasis?
Permanent dilation of bronchioles and bronchi –
Loss of airway tone results in air trapping
Explain the pathogenesis of bronchiectasis
- Abnormal dilation of large airways via
- (Diffuse bronchiectasis) Inflammation of airways releases inflammatory mediators from intraluminal neutrophils.
The inflammatory mediators destroy elastin, cartilage, and muscle in larger airways, resulting in irreversible bronchodilation - (Focal bronchiectasis) Large airway becomes obstructed
Resulting inability to clear secretions leads to a cycle of infection, inflammation, and airway wall damage
- Causes loss of airway tone and air trapping
- Increase in dilation causes air to swirl
- Difficult to get air out
- Obstructed from emptying lung
How can we spot bronchiectasis histologically?
Larger airways
At periphery there isn’t large airways
Edge of lung is where the bronchiectasis is
What is the aetiology of bronchiectasis?
Due to necrotising inflammation with damage to airway wall dilating it
Occurs in patients who have a reason to have a chronic inflammation and infection such as those with:
- Cystic fibrosis –
Patients have thick secretions causing mucus plugging which increases risk of infection as you block the tube –
Infection causes damage to airway, leading to bronchiectasis - Kartagener syndrome – Autosomal recessive condition
Inherited defect of dynein arm of cilia
Primary ciliary dyskinesia (made worse by smoking) Necessary for ciliary movement –
Symptoms:
- Sinusitis:
Because cilia of resp epithelium isn’t functioning properly so you get sinusitis
- Infertility:
As cilia of sperm isn’t functioning properly
- Situs inversus:
Organs normally on one side of thorax are on the opposite side so eg heart is on right instead of left
Inflammation and infection of lung occurs because they don’t have cilia to move mucus out and clear lung - Tumour or foreign body – Causing compression/obstruction
- Necrotising infection –
ie bug that’s virulent - Allergic bronchopulmonary aspergillosis – Hypersensitivity reaction, in larger airways, triggered by aspergillus
Seen in asthmatics and those with cystic fibrosis, as these patients become hypersensitive to aspergillus,
when it comes into airways, it elicits this reaction, damaging airways resulting in bronchiectasis, due to inflammatory damage to airway
What are the clinical features/signs of bronchiectasis?
- Cough:
Large airway dilation causes mucus trapping so they’ll cough it out - Dyspnoea
- Fever
- Foul-smelling sputum: Loaded with inflammatory debris which has been sitting rotting in lung for a while
- Recurrent infections
- Haemoptysis
- Digital clubbing
What complications can occur due to bronchiectasis?
Abscess
Septic emboli
Hypoxemia (trapping of CO2) resulting in cor pulmonale and secondary amyloidosis HY!
- Amyloidosis: Deposition of a misfolded protein, can be localised (Deposits in one organ) or systemic (deposits in multiple organs)
- Systemic depositions are further divided into primary and secondary
- Primary:
Deposition of amyloid light chain due to plasma cell problem as they over-produce light chain, goes into blood and deposits in tissues as amyloid - Secondary:
Chronic infl producing acute phase reactant called SAA (serum amyloid A) overproduced in chronic infl
SAA is converted into AA which deposits as amyloid known as sec. amyloidosis with deposition of AA
How do you diagnose bronchiectasis?
CXR:
- Thickening of the airway walls and/or airway dilation
- Tram lines: Bronchial wall thickening
- Mucus plugging
Pulmonary Function Tests:
Bronchiectasis causes airflow limitation (reduced forced expiratory volume in 1 sec [FEV1] with reduction in the FEV1/FVC ratio)
Treatment for bronchiectasis?
Clear airway secretions (mucolytics)
Bronchodilators and sometimes inhaled corticosteroids if reversible airway obstruction is present
Antibiotics and bronchodilators for acute exacerbations
Smoking cessation
