Bronchiectasis and Cystic Fibrosis Flashcards
What is bronchiectasis?
Chronic and irreversible dilation of one or more bronchi
What are the consequences of bronchi dilation?
- exhbit poor mucus clearance
- predisposition to recurrent or chronic bacterial infection
What is the aetiology of bronchiectasis?
-chronic inflammation
leads to destruction of elastic fibres and muscle fibres that give elasticity and movement to bronchi but once destroyed they permanently dilate the bronchi
How do you diagnose bronchiectasis?
High resolution CT scan
What would you find?
dilated bronchi and thickened walls
-bronchus is larger than its pulmonary arteriole
What is the key defining feature of bronchiectasis ?
signet ring - due to the bronchus being larger than its accompanying pulmonary arteriole
What are the clinical symptoms of bronchiectasis?
- daily sputum production
- breathless on exertion
- intermittent haemoptysis
- chronic cough
What are the clinical signs?
- hypoxaemia (seen with pulse oximetry)
- history of intermittent fevers
- fine crackles on exam
- sometimes have wheezing
- high pitched inspiratory squeaks
- history of weight loss (hyper metabolic state due to chronic inflammation)
What are the causes of bronchiectasis?
- TB
- immune deficiency
- CF
- alpha 1 anti trypsin deficiency
- obstruction
- toxic insult (aspiration of gastric acid)
- HIV
- malignancy
- RA
- IBD
what are the common organisms causing bronchiectasis?
- haemophillus influenzae
- pseudomona aeruginosa
- mycobacterium tuberculosis
Why does bronchiectasis need to be controlled?
bronchial dilation leads to mucous accumulation –>impaired ciliary function and increased risk of infection –> leads to inflammation if infection is caught –>loss of more bronchial elastic fibres and smooth muscle –> more dilation
What would you find if you did lung functions tests on someone with bronchiectasis?
- obstructive patten
- reduced FEV 1
- normal diffusing capacity
Why is the diffusing capacity the same even though there is an accumulation of mucus which increases the diffusion distance?
-the mucus accumulation occurs in the bronchi which is not in the respiratory conducting portion as gaseous exchange takes place in the alveoli
What are the differences between bronchitis and bronchiectasis?
- bronctis is due to mucous gland hyperplasia due to tobacco smoke
- bronchiectasis is due to chronic infections that cause airway dilation and scarring
What is a purulent sputum?
green/yellow sputum
-maybe even smell
How does bronchiectasis management?
- physio with airways clearance 2/3 times a day
- exclude immunodeficiency
- long-term therapies
- immunisations up to date
- sputum sampling
What is an exacerbation in bronchiectasis?
a person with bronchiectasis with a deterioration in 3 or more key symptoms for at least 48 hrs
- cough
- sputum volume
- sputum purulence
- breathlessness
- fatigue
- haemoptysis
What is the most common identifiable cause of bronchiectasis? (in europe / UK)
CF
What is cystic fibrosis?
- autosomal recessive disorder
- mutantation of gene located on chromosome 7
- leads to abnormal function of CFTR (key role in maintaining lung epithelium)
- characterised by thickened secretions of mucus
What does CFTR stand for and what is it?
Cystic fibrosis transmembrane conductance regulator - epithelial chloride channel
- transmembrane protein that transport cl- and bicarbonate and regulates ENAC
- it enables Cl- to be transported out of cells into airways controlling the moment of water
What co-morbidites are caused because of epithelial cell destruction?
- malabsorption (pancreas)
- billiary cirrhosis (liver)
- heat shock (sweat glands release Cl- and NA+)
- infertility (vas deferens)
So if the CFTR gene is mutated, what happens?
reduced cl- transport across membrane so water doesn’t leave epithelium to hydrate the mucus so you get thick mucus production which blocks ducts
How is CF diagnosed?
- history of CF in a sibling
- positive new born screening result
- increases sweat chloride conc
- genotyping
