Respiratory Pathologies (Remember CXR)

Question 1

Describe the pathophysiology of asthma

Answer 1

• narrowing of the airway due to bronchial muscle contraction
• inflammation caused by degranulation of mast cells
• increased mucus production

Question 2

What diagnostic approach would you take if you suspected asthma?

Answer 2

• order peak flow readings
• prescribe salbutamol
• if FEV1 (forced expiratory volume) shows significant improvement with salbutamol then asthma is likely

Question 3

Describe the pharmacological steps of asthma prescribing

Answer 3

Step 1: short-acting inhaled B2-agonist (eg. salbutamol)
Step 2: add low-dose inhaled corticosteroid (ICS)
Step 3: add long-acting B2-agonist (eg. salmeterol)
- Step 4: trial oral leukotriene receptor antagonist with high-dose steroid and oral B-2 agonist

Question 4

What test results would you expect in COPD (spirometry, bloods, ABG and CXR?)

Answer 4

Spirometry: FEV <80% of predicted, FEV1/FVC <0.7

Bloods: polycythaemia
ABG: reduced PaO2 and/or raised PaCO2

CXR: hyperinflated chest, bullae, decreased peripheral vascular markings, flattened hemidiaphragms

Question 5

How would you manage a tension pneumothorax?

Answer 5

• ABCDE
• give high-flow oxygen (15L/min) through a non-rebreather mask
• emergency decompression inserting a canula into the second intercostal space mid-clavicular line on the affected side

Question 6

What tests would you order in a suspected pulmonary embolism?

Answer 6

• CT pulmonary angiogram (diagnostic) - shows defect in vasculature
• D-dimer, FBC, CRP, LFTs (assess liver in anticipation of administering anticoagulation), Us and Es

Question 7

What are the ABG findings in respiratory alkalosis?

Answer 7

• increased pH
• decreased pCO2
• decreased HCO3-