S8) Cystic Fibrosis and Bronchiectasis Flashcards
What is bronchiectasis?
Bronchiectasis is the chronic irreversible dilatation of one or more bronchi wherein the bronchi exhibit poor mucus clearance and there is predisposition to recurrent/chronic bacterial infection
Inflammation causes destruction of elastic and muscular compenents of the bronchial wall and peribronchial fibrosis
Variety of underlying causes with common underlying mechanism of inflammation:
- Identify 5 causes of bronchiectasis
- Post infective e.g. whooping cough, TB
- Immune deficiency e.g. hypogammaglobulinaemia
- Obstruction e.g. foreign body, tumour, extrinsic lymph node
- Inhalation of toxic chemicals/gases
- Secondary immune deficiency e.g. HIV, malignancy
Identify 5 genetic causes of bronchiectasis
Mucociliary clearance defects:
- Cystic fibrosis
- Primary ciliary dyskinesia
- Young’s syndrome (bronchiectasis, sinusitis, reduced fertility)
- Kartagener syndrome (bronchiectasis, sinusitits, situs inversus)
Alpha-1-antitrypsin deficiency
Identify 5 causative organisms of bronchiectasis
- Haemophilus influenzae
- Streptococcus pneumoniae
- Fungi e.g. aspergillus, candida
- Non-tuberculous mycobacteria
- Pseudomonas aeruginosa
Describe the management of bronchiectasis
- Treat underlying cause / exclude immunodeficiency
- Physiotherapy/airway clearance for mucus clearance (essential! want to remove stagnant purulent mucous)
- Antibiotics according to routine sputum cultures
- Flu vaccine - against haemophilus influenzae & Strep pneumoniae
What is cystic fibrosis?
Cystic fibrosis is a multisystem, autosomal recessive disease occurring due to a mutation in the CFTR molecule which is characterised by thickened secretions
(mutation on long arm of chromosome 7)
How does cystic fibrosis present?
- Meconium ileus – intestinal obstruction by sticky secretions (bilous vomiting & abdominal distension)
- Intestinal malabsorption (90%) – severe deficiency of pancreatic enzymes secondary to blockage of exocrine glands
- Recurrent chest infections
- Pateints living long enough develop diabetes mellitus - endocrone part of pancreas damged by chronic inflammation
How does one confirm the diagnosis of Cystic fibrosis?
- 1/more characteristic phenotypic features
- History of CF in a sibling
- Positive newborn screening test result
- Increased sweat [Cl-] (>60 mmol/L) - sweat test
- Identification of two CF mutations (genotyping)
Identify 6 common cystic fibrosis complications and describe how they are treated
- Respiratory Infections – aggressive therapy with physio and prophylactic antibiotics
- Low body weight – pancreatic enzyme replacement therapy, high calorie intake and extra supplements
- Distal Intestinal Obstruction Syndrome (DIOS)
- CF Related Diabetes
- Heart: cardiac failute, arthritis, joints and bones
- Liver & Biliary tree: chronic liver disease, portal hypertension, gall stones
Describe the management of cystic fibrosis
- Avoid smoking
- Avoid other CF patients - idividuals colonised with pseudomonas with different resistance to antibiotics, dont want sharinf of pseudomonas
- Avoid jacuzzis (pseudomonas)
- Annual influenza immunisation
- Sodium chloride tablets in hot weather / vigorous exercise
Describe the clincial management of CF?
- Complex - led by CF specialist centres / MDTs
- Holistic care / multisystem focus
- Up to date vaccines
- Key is maintaining lung health - clear lungs out 2/3 times a day
- Optimal nutritional state
What is the most common mutation for CF?
- Phe508del CFTR protein - causes:
- Defective intracellular processing and trafficking
- Decreased stability, which drastically reduces the quantiity of CFTR protien at the apical surface
- Also exhibits defective channel gating, which further limits anion transport
What are the clinical signs of bronchiactasis?
- Pulse oximetry may reveal hypoxaemia
- Fever relatively common
- Haemoptysis (50%)
- Fine crackels
- Rhonchi
- High pitched inspiraotry squeaks
- Sometimes both crackles and wheezing = lung sounds from CF patient w/ bronchiectasis
- Systemic - weight loss
What are the clinical symtpoms of bronchiectasis?
- Very common: chronic cough, daily mucopurulent sputum production (varient in quantity colour & consitency)
- Common: Breathlessness on exertion, intermittent haemoptysis, chest paib, fatigue
- Less common: wheeze
What radiological techniques are used to diagnose bronchiectasis?
- CXR: - usually abnormal but may be normal in early disease - inadequate in diagnosis or quantificaiton of disease
- CT: - gold standard diagnostic investigation - specifically high resolution CT - demonstrates bronchial dialtion bigger than adjacent blood vessels, bronchial wall thickening
What signs do you see on CXR for bronchiectasis?
- Tram track sign - represents thick walled dilated bronchi
What signs do you see on a CT for bronchiectasis?
Signet ring sign - dilated bronchus and accompanying pulmonary artery are seen in cross-section
In healthy lung bronchus slightly smaller than artery, in bronchiectasis the bronchus is markedly dilated
