Course 04: Respiratory Medicine and Infectious Disease
Lesson 1 of 14. Explore the diagnostic and management frameworks, work through the case, and finish the linked 10-question practice set. Urgent presentations require an emergency-care pathway and review of local professional scope.
Immediate clinical priorities
- Rapidly evaluate airway patency, speech, work of breathing, respiratory rate, oxygen saturation, heart rate, blood pressure, mental status and perfusion; respiratory distress may precede desaturation.
- Cyanosis, exhaustion, confusion, silent chest, stridor, severe hypoxemia, shock or inability to speak in full sentences require emergency activation and airway-ready assessment.
- Distinguish hypoxemia from hypoventilation: pulse oximetry measures peripheral oxygen saturation, not carbon dioxide or ventilation; a normal SpO2 cannot exclude hypercapnia.
Focused history and differential
- Characterize acute versus chronic symptoms, fever, sputum, hemoptysis, pleuritic pain, orthopnea, wheeze, exposures, smoking, vaping, occupational risks, medications and thromboembolic risks.
- Acute dyspnea differentials: asthma/COPD exacerbation, pneumonia, pulmonary edema, PE, pneumothorax, anaphylaxis, upper-airway obstruction, metabolic acidosis and anemia.
- Chronic cough differentials include asthma, upper-airway cough syndrome, reflux, ACE inhibitor effects, smoking, bronchiectasis and malignancy; investigate red flags rather than labeling all cough as reflux.
Examination and first tests
- Inspect breathing pattern, accessory muscle use and symmetry; percuss and auscultate for crackles, wheeze, absent breath sounds, stridor and signs of fluid overload.
- Use chest radiography for appropriate suspected pneumonia, pneumothorax, heart failure or malignancy; choose ultrasound, CT or CT pulmonary angiography based on clinical probability and the question asked.
- Spirometry: FEV1, FVC and FEV1/FVC with quality control; confirm obstruction and assess variability; restriction requires lung-volume assessment rather than low FVC alone.
Oxygenation, blood gases and safe handoff
- ABG can clarify pH, PaCO2 and oxygenation in a deteriorating patient; rising or normalizing PaCO2 during severe asthma may indicate fatigue rather than improvement.
- Target oxygen delivery to disease and clinical setting; patients at risk of hypercapnic failure may need controlled oxygen and blood-gas reassessment rather than unmonitored high-flow oxygen.
- Communicate symptom onset, observed work of breathing, current vitals and SpO2, relevant risk factors, interventions and treatment response during emergency transfer.
Applied clinical case
A 56-year-old presents with abrupt breathlessness, pleuritic pain, tachycardia and mild hypoxemia after prolonged immobilization. Lung examination is largely clear.
Show model clinical reasoning and disposition
Pulmonary embolism is a dangerous possibility despite a relatively normal lung examination. Assess stability immediately, use clinical probability, and send for urgent imaging/evaluation as appropriate; do not attribute unexplained dyspnea to anxiety.
Clinical self-check
- Why can normal auscultation be misleading?
- When is ABG more informative than pulse oximetry?
- Which features favor PE over a viral URI?
Current guidance and further learning
- Canadian Thoracic Society guideline library (external)
- Choosing Wisely Canada: Respiratory medicine (external)