Asthma, CF, bronchiectasis Flashcards
(85 cards)
How do you check for bronchial hyperresponsiveness in asthma?
Bronchial challenge test
When may it be appropriate to check for bronchial hyperresponsiveness in asthma?
If clinical features are atypical or where the dx has important implications (defence force employment, athletes)
Unnecessary if variable airflow obstruction has already been documented
What does a high serum eosinophil count in asthma suggest?
Likely to be responsive to ICS or monoclonal ab
What does a high exhaled nitric oxide level mean in asthma?
Allergic inflammation
Likely to respond to steroids
What’s Samter’s triad?
Asthma
Aspirin intolerance - triggers asthma
Nasal polyps
How does allergic bronchial pulmonary aspergillus (ABPA) present?
Difficult to control asthma Recurrent pulmonary infiltrates Recurrent infections not responsive to abx Bronchiectasis with thick sputum Very high IgE (>1000IU/ml) Evidence of aspergillus hypersensitivity
What is allergic bronchial pulmonary aspergillus (ABPA)?
Hypersensitivity response to the fungus, aspergillus
Occurs in asthma and CF
Rx allergic bronchial pulmonary aspergillus (ABPA)
Steroids
How does eosinophilic granulomatosis with polyangiitis (EGPA) present?
Symptoms vary from mild to life threatening
But almost everyone has asthma +/- nasal polyps and high eosinophils
Multi-organ disease - peripheral neuropathy, mononeuritis multiplex, skin disease, cardiac disease
Rx eosinophilic granulomatosis with polyangiitis (EGPA)
Steroids
MTX, mycophenolate, cyclophosphamide
Mepolizumab (reduce eosinophils)
Explain the stepwise management of asthma
Step 1
ICS-fomoterol PRN
Step 2
Daily ICS-fomoterol + PRN same
Step 3
Daily low dose ICS-LABA + PRN SABA
Step 4
Daily medium dose ICS-LABA + PRN SABA
Step 5
Daily high dose ICS-LABA +/- add on therapy + PRN SABA
What are some potential add on therapies in severe asthma?
Tiotropium - useful in frequent exacerbations, airflow obstruction
Macrolides (azithromycin) - useful in frequent exacerbations, cough + sputum
Montelukast - useful in aspirin sensitive
Monoclonal abs - useful in frequent exacerbations
When is omalizumab indicated in asthma?
Targets IgE
Allergic asthma
Used in addition to ICS + LABA
When are mepolizumab and benralizumab used in asthma?
Targets IL5
Eosinophilic asthma
What is bronchiectasis?
Permanent dilation of bronchi and bronchioles due to destruction of airway muscles and elastic connective tissue
Causes of bronchiectasis
- Post-infectious (e.g. pertussis)
- ABPA
- COPD
- Traction secondary to fibrosis (radiological dx)
- Aspiration
- Obstruction
- Immunological defects (primary, secondary)
- Congenital defects (Marfan’s, ciliary defects, A1AT deficiency)
- Inflammatory - RA, coeliac disease, SLE, IBD
- Young’s syndrome
- Amyloidosis
- CF
Exacerbating comorbidities: GORD/aspiration, non-tuberculous mycobacterium, sinus disease
Investigations in bronchiectasis
- CT chest - look for tree and bud and granulomatous nodules - might indicate non-tuberculous mycobacterium
- Sputum x3 - AFB to look for non-tuberculous mycobacterium
- ABPA - IgE and aspergillus precipitants
- Immunoglobulins - if isolated level of IgG, can receive IV gammaglobulins which can reduce exacerbations
- 6MWT
- ABGs
Consider
- CF genotyping
- ECHO
- Bronchoscopy
- Immune test including HIV
- Nasal brushings to exclude coeliac syndrome
- Gastroscopy to exclude GORD
What are the organisms commonly implicated in bronchiectasis?
- Pseudomonas - important player. Very hard to eradicate.
- Non-tuberculous mycobacterium
- Aspergillus
- Stenotrophomonas nalophilia
- Staph aureus
Rx bronchiectasis
- Treat the cause
- Improve airway clearance/chest physio/pulmonary rehab
- Treat infection (acute and chronic) - PO ciprofloxacin or IV beta-lactam +/- aminoglycoside
- Treat airway obstruction - salbutamol +/- ICS. 2nd line ICS/LABA, theophylline, tiotropium.
- Treat chronic inflammation - erythromycin, azithromycin. 2nd line doxycycline. 3rd line nebulised tobramycin.
- Inhaled hypertonic saline - can be trialled in frequent exacerbators or has significant symptoms due to viscous mucous (be careful if FEV<1L due to bronchospasm)
Less common
- Surgical resection
- Lung transplant
- Bronchial artery embolization for significant haemoptysis
What must you monitor if using macrolides long-term for bronchiectasis?
Monitor sputum for resistance and increased non-tuberculous mycobacterium
Monitor ECG for prolonged QT
Pathophysiology of CF
Defect in the cystic fibrosis transmembrane conductance regulator (CFTR)
CFTR is blocked in CF –> can’t transport Cl out of cell –> Enac tries to compensate by transporting Na into cell to neutralise Cl –> dehydrated airways + viscous mucous
What are the 6 functional classifications of CFTR mutations?
1) No protein
2) No traffic (most common phenotype due to homozygous DF508 genotype)
3) No function (gate doesn’t open properly) due to G551D genotype
4) Less function
5) Less protein (minor abnormality)
6) Less stable (minor abnormality)
How is CF diagnosed?
1) Meconium ileus at birth
2) Heal prick test - high sensitive, low specificity
3) Sweat test - chloride >60mmol/L, borderline 40-60mmol/L
4) Gene testing - 50 panel test; but >2000 mutations
How does CF affect the lungs?
CFTR protein defect –> unable to secrete chloride –> sodium follows and stays inside cell –> thick secretions –> infection –> inflammation –> bronchiectasis –> lung destruction