Bronchiectasis and cystic fibrosis Flashcards
1
Q
What is bronchiectasis?
A
- Chronic irreversible dilatation of one or more bronchi
- Pathological condition can be caused by many diseases or be idiopathic
2
Q
What happens to the bronchioles in bronchiectasis?
A
- Results in abnormally enlarged bronchi
- Deformed bronchi exhibit poor mucus clearance
- Predisposition to recurrent or chronic bacterial infection
3
Q
What is the aetiology of bronchiectasis?
A
- Variety of underlying causes, with a common underlying mechanism of chronic inflammation
- Pertussis and TB used to be most common causes
- Now underlying congenital conditions are primary cause in UK
4
Q
What does inflammation of the bronchi result in?
A
- Destruction of elastic and muscular components of bronchial wall and peribronchial fibrosis + scarring
5
Q
What are the radiological findings in a patient with bronchiectasis?
A
- CXR - usually abnormal but may be normal in early disease
- Classic abnormality: dilated bronchi with thickened walls (tram-track sign)
6
Q
What is the gold-standard diagnostic investigation for bronchiectasis?
A
- High resolution CT
- Demonstrates bronchial dilation bigger than the adjacent blood vessel
- Bronchial wall thickening
7
Q
What is the signet ring sign?
A
- Dilated bronchus and accompanying pulmonary artery branch are seen in cross section
8
Q
What are the very common symptoms of bronchiectasis?
A
- Chronic cough
- Daily mucopurulent sputum production - can vary in quantity, colour, and consistency
- Accompanying halitosis
9
Q
What are the common symptoms of bronchiectasis?
A
- Breathlessness on exertion
- Intermittent haemoptysis
- Nasal symptoms
- Chest pain
- Fatigue
- Symptoms not very specific - history and risk factors are key to diagnosis
10
Q
What is a less common symptom of bronchiectasis?
A
- Wheeze
11
Q
What are the clinical signs of bronchiectasis?
A
- Hypoxaemia in advanced cases
- Fever
- Haemoptysis (usually mild)
- Fine crackles (rales)
- High-pitched inspiratory squeaks
- Rhonchi
- Sometimes can hear both crackles and wheezing
- Systemic signs e.g. weight loss
- Clubbing of digits is less common
12
Q
What are some of the causes of bronchiectasis?
A
- Post infective - pertussis, TB, measles
- Mucociliary clearance defects - cystic fibrosis
- Immune deficiency - hypogammaglobulinaemia
- Idiopathic causes
- Alpha-1 antitrypsin deficiency
13
Q
What is the vicious cycle of bronchiectasis?
A
- Bronchial dilation
- Leads to mucous accumulation, impaired ciliary function, increased risk of infection
- Infection leads to inflammation and loss of bronchial elastic fibres and smooth muscle
- More dilatation
14
Q
What are the common organisms that cause infection in bronchiectasis?
A
- Haemophilus influenzae
- Pseudomonas aeruginosa
- Moraxella catarrhalis
- Stenotrophomonas maltophilia
- Fungi - aspergillus, candida
15
Q
What makes it more likely that a patient has bronchiectasis?
A
- Asthma (particularly lifelong) without any great objective evidence
- ‘COPD’ but without risk factors or diminished breath sounds
- Severe chest infection earlier in life, lifelong/recurrent chest infections
- Sputum culture positive for common organisms such as haemophilus/pseudomonas/atypical mycobacterium
- Pt has IBS/rheumatoid arthritis
16
Q
What are the pulmonary function tests used to investigate bronchiectasis?
A
- Initial and follow up spirometry
- Obstructive airways disease evidenced by reduced FEV1 or FEV1/FVC ratio of <70%
- Elevated RV/TLC ratio consistent with air trapping
- Reduced capacity for CO in severe disease
17
Q
How is bronchiectasis differentiated from chronic bronchitis?
A
- Bronchitis caused by mucous gland hyperplasia, hypersecretion rather than airway dilatation or scarring
- Bronchitis due to tobacco smoke and air pollutants rather than infection
- Chronic bronchitis causes cough and a small amount of white sputum production but no intermittent fevers/haemoptysis
18
Q
How is bronchiectasis managed?
A
- Physio/airways clearance - daily clearance is essential for treatment success
- Sputum sampling - routine culture and Non Tuberculosis Mycoplasma
- Exclude immunodeficiency/treat identifiable causes
- Consider long-term therapies at future visits
- Annual flu & routine vaccinations
- An established MDT is key
19
Q
Which organisms do we need to vaccinate bronchiectasis patients against?
A
- Haemophilus influenzae
- Streptococcus pneumoniae
20
Q
How do we define exacerbation of bronchiectasis?
A
- A person with bronchiectasis with deterioration in 3 or more key symptoms for at least 48 hours
- Cough
- Sputum volume and/or consistency
- Sputum purulence
- Breathlessness and/or exercise tolerance
- Fatigue
- Haemoptysis
21
Q
What is cystic fibrosis?
A
- Autosomal recessive disorder
- Predominant mutation is Phe508del on long arm of chromosome 7
- Abnormal function of Cystic Fibrosis Conductance Regulator - has a key role in maintaining lung epithelial function
22
Q
What is the CFTR protein?
A
- Transmembrane protein that transports Cl- and HCO3- and regulates Na+ absorption into cells via ENAC channels
- Enables Cl - to be transported out of cells into airways - helps to control movement of water
- Plays critical role in hydration of mucus at surface of airway track
23
Q
What happens once the CFTR protein stops working properly?
A
- Reduced airway surface liquid hydration
- Thick and sticky mucus
- Muco-ciliary clearance is impaired
24
Q
How can mutations affect the CFTR protein?
A
- Manufacture of CFTR protein
- Transportation of CFTR
- CFTR processing function
- CFTR stability at cell membrane
25
Outline the effects of the Phe508del mutation?
- Defective intracellular processing and trafficking
- Decreased stability, which drastically reduces quantity of CFTR protein at apical surface of epithelial cells
- Also exhibits defective channel gating, which further limits anion transport
26
How is GF diagnosed?
- One or more of the characteristic phenotypic features
- Or history of CF in a sibling
- Or a positive newborn screening test result
AND
- An increased sweat chloride concentration - SWEAT TEST
- Or identification of 2 CF mutations - genotyping/EXTENDED GENOTYPING
27
What are the main CF clinical presentations?
- Meconium ileus
- Intestinal malabsorption
- Recurrent chest infections
- Newborn screening
28
What is a meconium ileus?
- Affects 15-20% of newborn CF infants
- Bowel is blocked by sticky secretions
- Bilious vomiting, abdominal distension, and delay in passing meconium
29
What is intestinal malabsorption?
- Over 90% of CF individuals are affected
- Evident in infancy
- Due to severe deficiency of pancreatic enzymes
- Secondary to blockage of exocrine glands
30
What kind of CF do patients who are diagnosed late have?
- Mutation associated with residual CFTR function
- Or heterozygous CFTR mutations - one severe + one mild
- Called atypical CF
- Need a high index of suspicion to diagnose
- Consider in cases of recurrent idiopathic pancreatitis, recurrent sinusitis and lung infections, infertility, allergic bronchopulmonary aspergillosis
31
What are the CF complications of the lungs?
- Bronchiectasis
- Pneumothorax
- ABPA
- Haemoptysis
- Respiratory failure
32
What are the CF complications of the nasal/upper respiratory tract?
- Chronic sinusitis
- Nasal polyposis
33
What are the CF complications of the GI tract?
- Pancreatic insufficiency
- Distal Intestinal Obstruction Syndrome
- Oesophageal reflux/oesophagitis
- Chronic liver disease
- Portal hypertension
- Gallstones
34
What are the CF complications of the heart?
- Cardiac failure
35
What are the CF complications of the joints and bones?
- Arthritis
- Osteoporosis
36
What are the CF complications of the reproductive tract?
- Male infertility
- Congenital bilateral absence of the vas deferens (CBAVD)
37
What lifestyle advice is given to patients with CF?
- No smoking
- Avoid other CF patients
- Avoid friends/relatives with colds/infections
- Avoid jacuzzies (pseudomonas)
- Clean and dry nebulisers thoroughly
- Annual influenza vaccine
- Pneumococcal vaccine
- Avoid compost, stables, rotting vegetation
38
What is the clinical management of CF?
- Complex - led by CF specialist centres/MDTs
- Holistic care/multisystem organ focus
- Up to date pneumococcal and haemophilus influenza vaccines
- Key is maintaining lung health
- Optimal nutritional state - pancreatic status, vitamin status, weight/BMI
39
Outline the role of nutrition in cystic fibrosis?
- Earliest manifestations of disease related to GI and nutritional derangements
- Impaired nutritional status:
- Pancreatic insufficiency
- Chronic malabsorption
- Chronic inflammation leading to increased energy expenditure
- Increased energy requirements of breathing
- Suboptimal nutrient intake related to impaired taste, fatigue, inflammatory mediated anorexia
40
How can lung function be improved in CF?
- Better nutritional status associated with better lung function
41
What are the 6 classes of CFTR mutation?
- No protein production
- Protein made but never gets to cell membrane
- Protein gets to membrane but doesn't work at all
- Protein made but only partially active
- Protein expressed at gene level but substantial reduction in mRNA and/or protein synthesis
- Protein gets to membrane but partially unstable
42
What is the cystic fibrosis survival like?
- Medications now being developed that target underlying disease mechanisms, not just complications
- Improvement of life-expectancy has been achieved due to:
- Augmenting airway clearance
- Aggressively treating infection
- Correcting nutrition deficits
- New drugs
