CCFP priority topic 89 of 105
Shortness of Breath on the CCFP exam
4 key features, the mistakes that cost marks, and a practice question.
Checked by a Canadian family physician, MD, CCFP. Updated October 20, 2026.
What the exam tests
Key features
The CFPC’s 4 key features for Shortness of Breath. Each one below has how the exam asks it, the common mistakes and the approach.
Practice question
Try one before you read
A real case from the bank, in the new short-menu format. Answer it first. Then read the key features.
Key feature 1 of 4
Look wider
Ask enough questions to find causes outside the heart and lungs.
CFPC skill Clinical reasoningPhase Hypothesis generation, historySources Canadian Thoracic Society
On the exam
A drowsy girl breathing fast and deep; her brother has a cold and her parents have headaches. Expect a short menu (pick several from a list) of history questions.
Pick the questions that find the cause.
Common mistakes
Chasing the brother's cold, prematurity or past wheeze when she has no cough and a clear chest.
Approach
- Ask beyond the heart and lungs: bleeding or heavy periods, fitness, reflux, panic, and exposures at home and work.
- Ask who else at home is unwell. A shared illness points to a shared source, such as carbon monoxide.
- Ask about fuel-burning heaters, generators, ovens used for heat, and cars running in an attached garage.
- Deep, fast breathing with a clear chest suggests acid in the blood, as in diabetic ketoacidosis or poisoning.
- Ask about work. About 36% of asthma that starts in adulthood is probably or possibly linked to work.
| Cause | Examples | Ask about |
|---|---|---|
| Blood | Anemia | Bleeding, heavy periods, black stools, tiredness |
| Environment | Carbon monoxide, work exposures | Others unwell at home, fuel-burning heaters, the job |
| Metabolic | Diabetic ketoacidosis, poisoning | Thirst, vomiting, drowsiness, pills or chemicals in the home |
| Mind | Panic, over-breathing | Tingling, fear, past attacks; only after other causes are excluded |
| Fitness and gut | Deconditioning, reflux | Less activity, weight gain, heartburn, cough when lying down |
Key feature 2 of 4
Life threats first
Wherever you see a breathless patient, think first of the causes that can kill.
CFPC skill SelectivityPhase Hypothesis generationSources Choosing Wisely Canada
On the exam
Sudden breathlessness in a patient seen at the office or at home. Expect a short menu (pick several from a list) of diagnoses not to miss.
Pick the diagnoses you must exclude today.
Common mistakes
Booking routine tests for next week because the setting feels low-risk. Ordering a computed tomography (CT) scan for a clot before a decision rule is wrong too.
Approach
- In every setting, think first of a clot in the lung, heart attack, anaphylaxis, and an inhaled object in a child.
- A child who choked, then started coughing or wheezing, has an inhaled object until proven otherwise.
- Breathlessness with hives, lip swelling or low blood pressure after a food, sting or drug is anaphylaxis. Treat it at once.
- A heart attack can show up as breathlessness alone, with no chest pain.
- Suspected clot: apply a decision rule first, such as Wells or PERC (pulmonary embolism rule-out criteria).
- Then get a D-dimer, a blood test for clot breakdown, when the rule calls for it. Only then order a CT of the lung arteries or a ventilation-perfusion (VQ) scan.
- Where no rule has been tested, as in some high-risk groups, use your clinical judgment.
Key feature 3 of 4
When treatment fails
When known breathlessness worsens, find what changed, recheck the diagnosis and look for another illness.
CFPC skill Clinical reasoningPhase Hypothesis generation, historySources Canadian Thoracic Society, Choosing Wisely Canada
On the exam
A girl of 7 with asthma, in hospital and not improving on oral steroids. Expect a short menu (pick several from a list) of questions, then one best answer for the next step.
Pick the questions that explain the failure.
Common mistakes
Asking about night symptoms and missed school, then adding more asthma drugs. Stepping up before checking inhaler technique and adherence is wrong too.
Approach
- Before stepping up, check adherence, inhaler technique, and whether the inhaler is empty.
- Ask what changed: a new pet, smoke or vaping at home, a new job or workplace exposure.
- Look for illnesses that worsen or mimic asthma: sinus disease, reflux, vocal cords that close on breathing in, anxiety, depression.
- Question the label. From age 6, a breathing test (spirometry) showing blockage that reverses is the preferred proof. A normal result does not rule asthma out.
- Think of a second illness on top: pneumonia, or an inhaled object.
- A one-sided wheeze or a choking spell at onset points to an inhaled object. A focal finding or a long course justifies imaging a wheezy child.
| Question | Check | Example |
|---|---|---|
| What changed? | Adherence, technique, empty inhaler, new exposures | A new cat, a smoker in the home, a new job |
| Was the diagnosis right? | Objective proof of the first diagnosis | Asthma never confirmed by spirometry; an inhaled object |
| Is there a second illness? | Infection, or a condition that worsens symptoms | Pneumonia, reflux, sinus disease, anxiety |
Key feature 4 of 4
Anxious patients
When a breathless patient is anxious, find a physical cause before blaming nerves.
CFPC skill Clinical reasoning, selectivityPhase Hypothesis generationSources Canadian Thoracic Society, Choosing Wisely Canada
On the exam
A young woman with known panic attacks, breathless with a fast pulse. Expect one best answer for the next step.
Pick the best next step.
Common mistakes
Calling it another panic attack and teaching breathing exercises. Her history makes it tempting, but a clot, asthma or an abnormal heart rhythm can look the same.
Approach
- Rule out physical causes first: a clot in the lung, asthma, an abnormal heart rhythm, anemia, an overactive thyroid.
- A low oxygen level, a fever or abnormal chest findings are not explained by anxiety.
- Suspected clot: apply a decision rule, then a D-dimer when indicated, before a CT or VQ scan for the clot.
- Anxiety can sit alongside lung disease. The asthma guideline lists it among illnesses to check when asthma is poorly controlled.
- Anxiety, depression and other psychiatric illness raise the risk of a near-fatal asthma attack. Take these patients more seriously, not less.
- Call it panic only when the work-up is clear and the story fits. Tell the patient what you ruled out.
Flashcards
Answer it first, then check.
KF 1What share of asthma that starts in adulthood is probably or possibly linked to work?
About 36%. Take a full work history in every adult with new asthma. Source: Canadian Thoracic Society
KF 1Name four causes of breathlessness outside the heart and lungs.
Any four of: anemia, carbon monoxide, diabetic ketoacidosis, panic, deconditioning, reflux.
KF 2You suspect a clot in the lung. What comes before a CT?
A decision rule such as Wells or PERC, then a D-dimer when the rule calls for it. Source: Choosing Wisely Canada
KF 3Asthma keeps flaring despite treatment. What do you check before stepping up?
Adherence, inhaler technique, an empty inhaler, triggers at home or work, and other illnesses. Source: Canadian Thoracic Society
KF 3From what age is spirometry the preferred test to confirm asthma?
From 6 years. A normal result does not rule asthma out. Source: Canadian Thoracic Society
KF 3Asthma is poorly controlled. Which other illnesses do you look for?
Sinus disease, reflux, vocal cords that close on breathing in, anxiety and depression. Source: Canadian Thoracic Society
KF 4Does an anxiety disorder lower your concern in a breathless patient with asthma?
No. Anxiety and depression raise the risk of a near-fatal asthma attack. Source: Canadian Thoracic Society
FAQ
Which guideline covers shortness of breath?
None covers it as a symptom. The exam tests reasoning: a wide list, life threats first, and a fresh look when treatment fails. Disease guidelines, such as the Canadian asthma guideline, guide each cause.
Do I need to know the Wells score?
Know that a decision rule comes first. Choosing Wisely Canada advises Wells or PERC, then a D-dimer when indicated, before a CT or lung scan for a suspected clot.
Does every wheezy child need a chest X-ray?
No. For typical asthma, bronchiolitis, croup or a first wheeze, X-rays rarely help. Get one for low oxygen, a focal finding, a long illness or severe distress. Think about one when a wheeze has no clear allergy or cold behind it.
Sources
Written from the CFPC Assessment Objectives and Canadian guidelines first. Checked by a Canadian family physician, MD, CCFP.
Last reviewed October 20, 2026For exam study. Not advice for a patient in front of you.
- Assessment Objectives for Certification in Family Medicine, 2nd editionCollege of Family Physicians of Canada · 2020
- Respiratory guideline libraryCanadian Thoracic Society
- Choosing Wisely recommendationsChoosing Wisely Canada