Resp11 - Bronchiectasis & Cystic Fibrosis

Question 1

What is bronchiectasis?

Definition
Aetiology
Infection Predisposition
Exacerbation
Management

Answer 1

1.) Definition - chronic, irreversible dilation of one or more bronchi

2. ) Aetiology - chronic inflammation (underlying cause)
   - destroys the elastic and muscular components of the bronchial wall and peribronchial fibrosis
3. ) Infection Predispostion - deformed bronchi have poor mucus clearance so susceptible to bacterial infections
   - infection –> more inflammation –> more dilation
   - common organisms - H. influenzae, pseudomonas aeruginosa, S. pneumoniae, fungi, mycobacteria TB, S.aureus (less common) + others
4. ) Exacerbation - deterioration in 3 or more key symptoms for at least 48 hours
   - cough, SOB, fatigue, haemoptysis, sputum volume and purulence
5. ) Management - daily airway clearance
   - vaccines for common organisms

Question 2

Causes of Bronchiectasis

Post Infective 
Immune Deficiency 
Mucociliary Clearance Defects
Obstruction 
Toxic Insult 
Others

Answer 2

1.) Post Infective - whooping cough (pertussis), TB

2. ) Immune Deficiency - increased infection risk
   - hypogammaglobulinaemia
   - secondary immune deficiency (HIV, malignancy)
3. ) Mucociliary Clearance Defects
   - cystic fibrosis (main)
   - primary ciliary dyskinesia, Young’s syndrome, Kartagener syndrome
4. ) Obstruction
   - foreign bodies, tumour, extrinsic lymph nodes
5. ) Toxic Insult
   - gastric aspiration, inhalation of toxic chemicals/gases
6. ) Others - alpha-1 antitrypsin deficiency, allergic bronchopulmonary aspergillosis,
   - IBD, RA (associated with bronchiectasis)

Question 3

Diagnosing bronchiectasis

Symptoms
Signs (systemic x2 and sounds x3)
History x3
3 Investigations

Answer 3

1. ) Symptoms - very common, common, less common
   - chronic cough and daily sputum production
   - SOB on exertion, chest pain, fatigue, haemoptysis,
   - wheeze (less common)
2. ) Signs
   - systemic signs: fever, weightloss
   - respiratory sounds: fine crackles (rales), rhonchi, crackles and wheezing in CF patients w/ bronchiectasis
3. ) History - think bronchiectasis if patients have:
   - lifelong/recurrent chest or sinus infections
   - severe chest infection in earlier life
   - asthma or COPD w/out any real evidence
4. ) Investigations
   - signet ring sign: dilated bronchus is larger than the accompanying pulmonary artery (high resolution CT)
   - sputum culture: +ve for common micro-organisms
   - pulmonary function tests: FEV1:FVC < 70%, elevated RV:TLC (air trapping), reduced diffusing capacity for CO in severe disease

Question 4

Managing cystic fibrosis

Aetiology
Diagnosis x3
Lifesyle Advice
Clinical Management

Answer 4

1.) Aetiology - autosomal recessive disorder caused by a defect in the CFTR gene on chromosome 7

2. ) Diagnosis - 1 phenotypic feature + 1 other feature
   - phenotypic features: CF in sibling, +ve screening test
   - sweat test: >60mM of Cl- in sweat
   - extended genotyping: 2 CF mutations
   - abnormal nasal potential difference (ion transport)

3.) Lifestyle Advice - no smoking, avoid other CF patients/ infectious people

4. ) Clinical Management - maintaining lung health (chest physio, infection management)
   - vaccinations, optimal nutritional state

Question 5

2 functions of the cystic fibrosis transmembrane conductance regulator (CFTR)

Answer 5

1. ) Hydrates Mucus - it transports chloride out of cells into airways, bringing water along with it
   - defect reduces airway surface liquid hydration –> thick, sticky mucous –> impaired muco-ciliary clearance

2.) Regulates Na Reasborption - regulates the epithelial sodium channel (ENaC)

Question 6

4 main cystic fibrosis clinical presentations

Answer 6

1. ) Meconium Ileus - occurs in newborn CF patients
   - bowel is blocked by sticky secretions causing intestinal obstructions
   - bilous vomiting, abdominal distenstion, delay in passing meconium (infant stool)
2. ) Intestinal Malabsorption - evident in infancy
   - due to severe deficiency of pancreatic enzymes
3. ) Recurrent Chest Infections
4. ) Newborn Screening

Question 7

Complications of Cystic Fibrosis

Respiratory Infections
Low Body Weight
Distal Intestinal Obstruction Syndrome
CF Related Diabetes
Others

Answer 7

1. ) Respiratory Infections - recurrent LRTIs
   - patients often receive prophylactic Abx
2. ) Low Body Weight - often due to intestinal malabsorption caused by pancreatic insufficiency
   - pancreatic enzyme replacement therapy
   - high-calorie intake, supplements, may need NG/PEG
3. ) Distal Intestinal Obstruction Syndrome
   - faecal obstruction in ileo-caecum due to thick, dehydrated faeces (due to pancreatic insufficiency)
   - palpable RIF mass, AXR shows faecal loading

4.) CF Related Diabetes

5. ) Others
   - chronic sinusitis, nasal polyps, bronchiectasis
   - cardiac failure, portal HTN, liver disease, gallstones
   - male infertility, arthritis, osteoporosis

Question 8

5 factors leading to impaired nutritional status in CF

Answer 8

1. ) Pancreatic Insufficiency
2. ) Chronic Malabsorption
3. ) Chronic Inflammation - leads to increased energy expenditure
4. ) Increased Energy Requirements of Breathing
5. ) Impaired Taste - leads to suboptimal nutrient intake