Bronchiectasis

Question 1

What is the definition of bronchiectasis?

Answer 1

• Recurrent episodes of chronic wet cough
• Recurrent is >=3 episodes per year
• Chronic cough is >4 weeks of cough
• Radiographic features on HRCT

Question 2

What is the definition of protracted bacterial bronchitis?

Answer 2

• Chronic wet cough (>4 weeks)
• Absence of specific signs and symptoms (no cough pointers = nothing pointing to a specific diagnosis)
• Resolution within 2-4 weeks with an appropriate oral antibiotic (typically amox-clav). For the majority of children, there is resolution within 2 weeks of antibiotic. (This is why we typically treat a CF exacerbation with 2 weeks of antibiotics)

Question 3

What is the spectrum of suppurative lung disease? What differentiates bronchiectasis from chronic suppurative lung disease?

Answer 3

• PBB–>chronic suppurative lung disease–>bronchiectasis

- Bronchiectasis is differentiated by the HRCT finding of irreversible bronchial dilatation

Question 4

When should you worry about patients having bronchiectasis?

Answer 4

• > =3 episodes of chronic wet cough per year
• persistent wet cough that doesn’t respond to >4 weeks of antibiotics
• persistent CXR abnormality after >4 weeks of antibiotics

Question 5

What are the airway and vascular changes that happen in bronchiectasis?

Answer 5

• eventually, the airway’s elastic tissue, muscle and cartilage is destroyed and there is just scar tissue–>loose bag of scar tissue (mucous filled saccular airway)
• increased bronchial artery blood flow, can get anastomoses between bronchial and pulmonary circulation
• hypoxia–>pulmonary hypertension

Question 6

How do you interpret nasal nitric oxide for the purpose of diagnosing PCD?

Answer 6

● Role of nasal nitric oxide in diagnosis
● Low nasal nitric (<77 nL/min) is quite consistent in PCD, though other things can also result in low nasal nitric oxide (viral illness, sinusitis, cystic fibrosis)
● Low nasal NO is relatively sensitive (90% range) and specific (90% range) for PCD
● But nasal NO is not well studies in children <5 years of age
● Recommendation: in a child >=5 years of age with a clinical phenotype of PCD and CF excluded, low NO on 2 separate occasions can make a presumptive diagnosis of PCD
○ Key point: 2 separate occasions

Question 7

What are the subtypes of subtypes?

Answer 7

• ultrastructural defect - most common is outer dynein arm defect
• other types:
• dynein arm defect
• radial spoke defect
• microtubular transposition defect
• functional defect

Question 8

Draw the structure of cilia

Answer 8

See PCD chapter

Question 9

Management of PCD?

Answer 9

• Regular airway clearance
• Consider antibiotics during pulmonary exacerbations, regular sputum cultures
• Ensure appropriate nutrition and growth
• Immunizations–>influenza, routine, pneumovax
• Avoid smoking
• ENT: audiology assessment, ?hearing aids, referral to ENT physician
• Genetic testing and counselling
• Sibling screening

(from OSCE discussion)

Question 10

What are the bare minimum investigations for bronchiectasis?

Answer 10

• CT chest (so that bronchiectasis can be diagnosed)
• CBC
• IgG, A, M, E
• vaccine titres
• sweat chloride

Question 11

Differential diagnosis for bronchiectasis?

Answer 11

• idiopathic (most common)
• impaired host defences
  
  • cystic fibrosis (CF) (most common cause in children)
  • primary ciliary dyskinesia, e.g. Kartagener syndrome, Young syndrome
  • primary immunodeficiency disorder, e.g. common variable immunodeficiency, hypogammaglobulinaemia, chronic granulomatous disease
  • HIV/AIDS 15,16
• postinfective (most common known non-CF cause in adults)
  
  • bacterial pneumonia and bronchitis, e.g S. aureus, H. influenzae, B. pertussis
  • mycobacterial infection, e.g. tuberculosis, Mycobacterium avium-intracellulare complex
• allergic and autoimmune
  
  • allergic bronchopulmonary aspergillosis (ABPA)
  • connective tissue disease, e.g. rheumatoid arthritis 6, Sjögren syndrome, systemic lupus erythematosus (SLE) 7
  • inflammatory bowel disease
• obstruction
  
  • severe obstructive lung disease: asthma or chronic obstructive pulmonary disease (COPD)
  • neoplasm, e.g. bronchial carcinoid, bronchogenic carcinoma
  • inhaled foreign bodies
• congenital
  
  • bronchial tree malformations, e.g. Mounier-Kuhn syndrome, Williams-Campbell syndrome, pulmonary sequestration, bronchial atresia
  • alpha-1-antitrypsin deficiency
• others
  
  • chronic aspiration
  • traction bronchiectasis due to diffuse lung disease, e.g. pulmonary fibrosis
  • radiation-induced lung disease
  • post-transplantation

Question 12

CXR findings in bronchiectasis

Answer 12

• Tram track opacities in cylindrical bronchiectasis
• Air fluid levels in cystic bronchiectasis
• Ring shadows (from seeing bronchi end on)
• Increased bronchovascular markings

Question 13

CT findings for bronchiectasis

Answer 13

• bronchus visualised within 1 cm of pleural surface
  
  • especially true of lung adjacent to costal pleura
  • most helpful sign for early cylindrical change
• lack of tapering
• increased bronchoarterial ratio
• bronchial wall thickening: normally wall of bronchus should be less than half the width of the accompanying pulmonary artery branch
• mucoid impaction
• air-trapping and mosaic perfusion
  Signs described on CT include:
• tram-track sign
• signet ring sign

Question 14

For what bronchoarterial ratio do you consider a diagnosis of bronchiectasis?

Answer 14

> 1-1.5 in adults

Question 15

review differential diagnosis of bronchiectasis as based on location

Answer 15

See note on Bronchiectasis (Radiology)