Respiratory medicine is an estimated 6% of the MCCQE Part I, about 14 of 230 questions. It covers asthma, COPD, pneumonia, pulmonary embolism, pneumothorax, pleural effusion, lung cancer and nodules, tuberculosis, interstitial disease, respiratory failure, sleep apnea and smoking cessation. Marks come from grading severity, choosing the first treatment and knowing when to escalate. The weight is an editorial estimate.
Weight and scope
Fourteen questions is about twenty minutes. Respiratory stems are usually short and structured: a breathless patient, a set of observations, sometimes a chest X-ray description or a blood gas. Because the block is small, efficiency pays. Learn the severity grading and the first-line treatment for the common conditions, and the domain becomes some of the most reliable marks in the paper. Respiratory stems also appear in emergency, pediatric and critical-care questions.
The MCC publishes no discipline weights. The 6% figure is our editorial estimate from the MCC Examination Objectives and clinical presentations, and the count is rounded because some items in each section are unscored. Questions from this domain are also spread across the four dimensions of care and the four physician activities.
What is tested
- Airways disease. Asthma diagnosis, control assessment and stepwise therapy; COPD diagnosis, exacerbation management and long-term therapy; bronchiectasis and cystic fibrosis in adults.
- Infection. Community-acquired pneumonia and severity scoring, hospital-acquired and aspiration pneumonia, tuberculosis diagnosis, treatment and contact follow-up.
- Pleural and vascular disease. Pulmonary embolism with pretest probability, D-dimer and imaging; pneumothorax; pleural effusion with transudate versus exudate.
- Respiratory failure. Oxygen therapy, non-invasive ventilation and the recognition of hypercapnia.
- Chronic and occupational disease. Interstitial lung disease, sarcoidosis and obstructive sleep apnea.
- Symptoms and cancer. Chronic cough, hemoptysis and dyspnea work-up; lung cancer presentations and the work-up of a pulmonary nodule.
- Tobacco. Smoking cessation counselling and pharmacotherapy, which also sits in the prevention dimension.
Canadian points to anchor your answers
- Canadian Thoracic Society. The CTS publishes the Canadian asthma and COPD guidance. Learn the stepwise ladder and the exacerbation approach from its current documents. We do not quote thresholds on this page.
- Lung cancer screening. The 2016 task force statement recommends annual low-dose CT for up to three consecutive years in people aged 55 to 74 with at least a 30 pack-year history who currently smoke or quit within the last 15 years, as a weak recommendation in expert settings. It advises against chest X-ray screening. Check for newer statements.
- Tuberculosis. Reportable diseases are set provincially. Learn the principle of notifying public health and tracing contacts, and confirm the list in the provincial source.
- Tobacco and public health. The task force published guidance on tobacco in adults in 2025. Learn that counselling and pharmacotherapy are offered at every visit.
- Units. Blood gases may be in kPa or mmHg, and the stem gives the unit. Use salbutamol and acetaminophen.
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How the questions are framed
Respiratory stems tend to give you three things: the picture, a severity marker and a test result. The task is usually to grade severity, choose the first treatment or decide the setting of care. For asthma and COPD, the exam favours the stepwise approach and the safe immediate response. For pneumonia, it favours severity assessment and antibiotic stewardship. For thromboembolism, it favours risk stratification and the correct order of tests. For pleural disease, it favours the choice between observation, aspiration and drainage.
Look for the detail that moves the patient into a different category: exhaustion or drowsiness, a rising carbon dioxide level, home oxygen, pregnancy, a history of cancer or recent surgery.
Three typical traps
- Giving high-flow oxygen to a patient at risk of carbon dioxide retention. The expected answer is controlled oxygen with a target range. Learn the range from the current Canadian source.
- Using the wrong test for suspected pulmonary embolism. The correct step depends on the pretest probability and on contraindications such as renal impairment or pregnancy. Know the sequence your guideline uses.
- Treating primary and secondary pneumothorax the same way. Management depends on the underlying lung disease, size and symptoms. Read the history for COPD or another lung condition.
How to revise it
- Write a severity ladder for acute asthma, COPD exacerbation and pneumonia, with the first action at each level.
- Make a pleural table for pneumothorax, effusion and empyema: history, test, first treatment and referral.
- Do chest X-ray and blood gas drills for ten minutes a day until patterns are automatic.
- Revise inhalers and oxygen as prescribing topics. Know the device, the drug and the common error.
- Finish with timed blocks of 20 questions mixed with emergency and pediatric stems.
Pair this domain with the emergency and critical care, infection, hematology and oncology and pediatrics pages, where bronchiolitis, croup and pediatric asthma appear.
Subtopic checklist
Our blueprint lists these 15 subtopics for this domain. Tick each one only when you can state the presentation, the first investigation and the first management step without notes.
- Asthma: diagnosis, control assessment and stepwise therapy
- COPD: diagnosis, exacerbation and long-term therapy
- Community-acquired pneumonia and severity scoring
- Hospital-acquired and aspiration pneumonia
- Pulmonary embolism: pretest probability, D-dimer and imaging
- Pneumothorax
- Pleural effusion: transudate versus exudate
- Lung cancer presentations and work-up of a pulmonary nodule
- Tuberculosis diagnosis, treatment and contact follow-up
- Interstitial lung disease and sarcoidosis
- Respiratory failure, oxygen therapy and non-invasive ventilation
- Bronchiectasis and cystic fibrosis in adults
- Obstructive sleep apnea
- Chronic cough, hemoptysis and dyspnea work-up
- Smoking cessation counselling and pharmacotherapy
How the four dimensions of care show up
Every question in this domain is classified under one dimension of care, so revise respiratory in four ways, not one.
- Health promotion and illness prevention. Prevention: smoking cessation, pneumococcal and influenza vaccination and lung cancer screening eligibility.
- Acute care. Acute: severe asthma, COPD exacerbation, pneumonia, pulmonary embolism and tension pneumothorax.
- Chronic care. Chronic: asthma control reviews, COPD staging, home oxygen decisions and sleep apnea follow-up.
- Psychosocial aspects. Psychosocial: tobacco dependence, occupational exposures, housing and mould, and the impact of chronic breathlessness.
When you review a wrong answer, note which dimension the question belonged to as well as the topic. A pattern, such as repeated errors on the prevention items, tells you more than a topic score.
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Frequently asked questions
How many respiratory questions are in the MCCQE Part I?
The MCC publishes no weights. Our editorial estimate is about 6%, roughly 14 of 230, with more respiratory content inside emergency and pediatric stems.
Which asthma and COPD guidelines apply?
Use the Canadian Thoracic Society. Learn the stepwise ladder and the exacerbation approach from its current documents.
Is lung cancer screening tested?
It can be, in the prevention dimension. The 2016 task force statement is a weak recommendation for expert settings. Check for a newer statement before relying on an age or pack-year figure.