Bronchiectasis and CF Flashcards
Differential for cough with sputum
Upper respiratory tract infection Acute bronchitis (cough, sputum, SOB, wheeze, general malaise, crackles that clear with coughing) Pneumonia Acute exacerbation of COPD Bronchiectasis TB
Causes of bronchiectasis
Causes:
1) Previous severe LRTI such as pneumonia, pertussis, pulmonary tuberculosis, mycoplasma, influenza, and other viral infections. = MOST COMMON
2) Gastric or foreign body aspiration
3) Disorders of mucociliary clearance, or immunodeficiencies, that facilitate bacterial colonization of the LRT
4) Endobronchial tumours
5) Allergic bronchopulmonary aspergillosis (ABPA)
6) Rheumatoid arthritis
7) Ulcerative colitis
8) Yellow nail syndrome
9) Congenital defects of large airways e.g. Williams-Campbell, Mounier-Kuhn, Marfan’s
What is bronchiectasis?
Persistent or progressive condition characterized by dilated, thick-walled bronchi due to inflammatory damage to the airways
IRREVERSIBLE
Symptoms of bronchiectasis
Persistent productive cough - large volumes of purulent sputum
Breathlessness
Haemoptysis
Chest pain
Young age, history over many years, non-smoker
Signs of bronchiectasis
Coarse crackles, especially in the lower lung zones.
Wheeze.
Large airway rhonchi (low pitched snore-like sounds).
Finger clubbing.
Cyanosis
Chest hyperinflation
Pathology of bronchiectasis
Cause e.g. infection such as TB or CF
- -> can’t clear airways (obstruction) causes stagnation which creates bacteria OR there is infection in first place
- -> purulent sputum blocks bronchi and bronchioles
- -> obstruction and destruction of airways due to inflammatory processes
- -> dilation of the airways usually in lower lobes.
Genetics of cystic fibrosis and how it leads to lung disease
Autosomal recessive disorder
Involves mutation of CFTR (cystic fibrosis transmembrane conductance regulator) gene
This codes for the CFTR protein
This protein is a channel protein that pumps chloride ions into secretions, which draws water into the secretions + thins them out
In CF, the CFTR gene is misfolded and can’t migrate from endoplasmic reticulum to the cell membrane, so lack of CFTR protein on surface so can’t pump chloride ions out, so secretions are overly thick.
Mucociliary action defective due to thick mucus
–> bacteria colonises lung, can cause CF exacerbations
Also causes bronchiectasis due to obstruction and infection, which can lead to resp failure.
Most common CF mutation
Delta F508 mutation
= 508th amino acid (phenylalanine) is deleted from CFTR gene
Pathological effect and clinical consequences of CF in non-pulmonary organs
Meconium ileus in neonatal period - thick first stool blocks bowel, surgical emergency
Pancreatic insufficiency - thick secretions block pancreatic ducts, so digestive enzymes can’t get to small intestine so protein and fat aren’t absorbed –> failure to thrive, steatorrhoea. Also these backed up digestive enzymes damage pancreas —> pancreatitis, diabetes.
Infertility - due to lacking vas deferens.
Clubbing
Nasal polpys
Liver disease
Organisms that exacerbate bronchiectasis
Haemophilus influenzae
Pseudomonas aeruginosa
Klebsiella spp.
Streptococcus pneumoniae
Organisms that exacerbate CF
Staphylococcus aureus
Pseudomonas aeruginosa
Burkholderia cepacia*
Aspergillus
Investigations to confirm CF
Infant screening (blood spot immunoreactive trypsin test) Sweat test for children/YA Gene tests for adults
Investigations to confirm bronchiectasis
Sputum culture
Chest X-ray
Post-bronchodilator spirometry
High-resolution CT or thin section scanning
Significance of isolation of pseudomonas
Needs specialist follow up
Hard to treat - it produces a biofilm which protects it from abx, plus low abx susceptibility, easily develops acquired resistance
Isolation is associated with increased severity of disease, greater airflow obstruction and poorer quality of life = marker of severity
Role of abx prophylaxis
Refer people with three or more infective exacerbations a year, or fewer if causing significant morbidity, to a respiratory specialist.
