Shortness of Breath: History Taking and Differential Diagnoses

History of Presenting Complaint

Overview

With each symptom, always (if relevant) ask about:

• When did it start?
• Did it come on suddenly or gradually?
• Is it continuous or intermittent?
• Has this ever happened before?

Shortness of breath

• Onset – how did it start?
  • A sudden onset suggests something potentially life-threatening (e.g. pulmonary embolism, heart failure, myocardial infarction)
• Timeline and variability:
  • How long has this been going on?
  • Does this change throughout the day?
  • Is it intermittent or progressively getting worse?
• Exacerbating factors?
  • Exertion?
  • Pollen/chemicals at work? – suggests asthma
  • Orthopnoea?
• Alleviating factors?
• Severity?
  • How far can they walk until they get short of breath?
  • Do they struggle walking upstairs?
  • Are they short of breath at rest?
• Have they recently been ill?
• Has this impacted their daily life and if so, how?

Review of systems

• Screen for other cardiorespiratory symptoms:
  • Cough:
    • Dry or productive?
    • What are they coughing up?
      • Blood?
        • Fresh/bright red blood?
        • Dark clots or ground-up coffee?
      • What is the sputum like?
        • Offensive smell?
        • Colour? – may be white, yellow, green, or pink
  • Chest pain:
    • Assess using SOCRATES
  • Palpitations
  • Syncope
  • Wheezing
  • Stridor
  • Orthopnoea
  • Paroxysmal nocturnal dyspnoea
  • Peripheral oedema
• Screen for red flags of malignancy:
  • Haemoptysis, weight loss, night sweats, hoarse voice

Past Medical History

Questions include:

• Do they have any other medical conditions?
• Have they ever had any previous surgery?
• Do they take any regular medications?
  • Some medications that can cause shortness of breath include NSAIDs, methotrexate, beta-blockers, and amiodarone
• Do they take any over-the-counter medications, herbal remedies, or supplements?

Family History

• Is there any family history of anything similar?
  • Atopy:
    • Eczema
    • Asthma
    • Hayfever
  • Heart disease
  • Lung problems including lung cancer

Allergy History

• Are they allergic to anything?
  • What happens during the allergic reaction?

Social History

• Do they smoke?
  • If so, how much and how long?
• Do they drink alcohol?
  • If so, how much and how long?
• Do they use any illicit drugs?
  • If so, how much and how long?
• What is their occupation?
• Who’s at home?
  • What support do they have?
• How has this impacted their activities of daily living?
• Has there been any recent foreign travel?

Physical Examinations

Overview

Physical examinations to perform are:

• Vital signs may show:
  • Tachycardia, tachypnoea, and hypotension suggest shock
  • Pulsus paradoxus can suggest cardiac tamponade
  • Normal vital signs are not enough to exclude cardiorespiratory problems, as patients can still have normal oxygen saturations despite having an acute myocardial infarction, asthma, pulmonary embolism, COPD etc.
• Respiratory examination may show:
  • Cyanosis
  • Clubbing:
    • Suggests lung cancer, interstitial lung disease, bronchiectasis
  • Facial oedema:
    • Suggests anaphylaxis
  • Tracheal deviation:
    • Suggests tension pneumothorax
  • Stridor:
    • Suggests upper airway obstruction (e.g. foreign body, anaphylaxis)
  • Wheezing:
    • Suggests asthma, COPD, anaphylaxis
  • Hoarseness:
    • Suggests laryngeal tumours, laryngeal palsy secondary to lung cancer
  • Barrel chest:
    • Suggests COPD
  • Unilateral dullness to percussion:
    • Suggests pneumonia, pleural effusion, foreign body aspiration, tumours
  • Unilateral decreased/absent breath sounds:
    • Suggests pneumothorax, pleural effusion, foreign body aspiration
  • Crackles:
    • Suggest heart failure, pneumonia, interstitial lung disease
• Cardiovascular examination may show:
  • Elevated jugular venous pressure:
    • May suggest heart failure, COPD, tension pneumothorax, cardiac tamponade
  • Arrhythmia
  • Abnormal heart sounds/murmurs
  • Peripheral oedema

Investigations

Overview

When suggesting investigations in an OSCE, the BOXES (Blood tests, orifice tests, x-rays, ECGs, special tests) mnemonic is useful for deciding the order of investigations:

• Blood tests:
  • Full blood count (FBC):
    • May identify anaemia which can cause shortness of breath
    • May show leukocytosis suggesting infection
    • May show eosinophilia suggesting asthma
  • Urea and electrolytes (U&Es):
    • May show hyponatraemia in heart failure, chronic kidney disease, liver failure, or hypothyroidism
  • Liver function tests:
    • May show elevated bilirubin in liver failure or congestive heart failure
  • C-reactive protein:
    • Non-specific marker of inflammation, may be elevated
  • Venous/arterial blood gases:
    • May show derangements in pH, pO₂, pCO₂, bicarbonate, and base excess depending on the underlying cause
  • Cardiac enzymes (troponins):
    • If acute coronary syndrome is suspected
  • NT-proBNP:
    • Elevated in congestive heart failure
  • D-dimer:
    • For pulmonary embolism/deep vein thrombosis
  • Blood culture:
    • If severe pneumonia/sepsis suspected 
• Orifice tests:
  • Sputum culture and gram stain:
    • May identify causative agent if infection suspected
  • Urinary Legionella antigen:
    • If Legionella pneumonia suspected
• X-rays:
  • Chest X–ray:
    • To screen for pneumothorax
    • May show opacifications
    • May show signs of congestive heart failure (e.g. cardiomegaly)
• ECGs:
  • ECG:
    • If chest pain or palpitations are present, or acute coronary syndrome suspected
• Special tests:
  • Echocardiogram:
    • May show structural heart defects 
  • CT pulmonary angiography or V/Q scan:
    • For pulmonary embolism
  • High-resolution CT chest:
    • For pulmonary fibrosis
  • CT coronary angiography:
    • For angina or acute coronary syndrome
  • Spirometry:
    • For asthma or COPD

Differential Diagnoses (Acute/Subacute)

Pneumothorax

• A history may reveal:
  • Shortness of breath is sudden in onset
  • Unilateral chest pain (often pleuritic)
  • There may be a history of pre-existing lung disease, tall and asthenic build, non-invasive ventilation 
• A physical exam may reveal:
  • Unilaterally reduced/absent breath sounds, unilateral hyperresonance on percussion
• Investigations may reveal:
  • Chest x-ray:
    • Collapsed lung and absent lung markings

Tension pneumothorax

• A history may reveal:
  • Shortness of breath is sudden in onset
  • Unilateral chest pain (often pleuritic)
  • There may be a history of penetrating trauma (e.g. stabbing), pre-existing lung disease, tall and asthenic build, non-invasive ventilation 
• A physical exam may reveal:
  • Unilaterally reduced/absent breath sounds, unilateral hyperresonance on percussion
  • Tracheal deviation away from the affected side, elevated jugular venous pressure, hypotension and tachycardia
• Investigations may reveal:
  • Insertion of large bore cannula into 2^nd or 5^th intercostal space in the midclavicular line:
    • Hiss heard as decompression occurs
  • If suspected, urgent needle decompression should be performed – do not wait for imaging
    • A chest X-ray should not be waited for as this can delay treatment and lead to cardiac arrest

Pulmonary embolism

• A history may reveal:
  • Sudden onset shortness of breath
  • Pleuritic chest pain may be present
  • Haemoptysis may be present
  • There may be a history of risk factors such as prothrombic state (e.g. pregnancy, inadequate coagulation, malignancy), prolonged immobilisation (e.g. long-haul flights), recent surgery, or oral oestrogens (e.g. combined oral contraceptive pill or combined oral hormone replacement therapy)
• A physical exam may reveal:
  • Tachycardia, tachypnoea
  • Crackles and fever may be seen
• Investigations may reveal:
  • Chest x-ray – done to screen for other pathologies such as pneumothorax
    • Usually clear
    • May show wedge-shaped opacification
  • ECG:
    • Sinus tachycardia is the most common feature
  • D-dimer:
    • Elevated
  • CT angiography or V/Q scan:
    • Diagnostic

Acute coronary syndrome

• A history may reveal:
  • There may be chest pain or chest crushing/squeezing
  • The chest pain may radiate to the shoulder/jaw
  • Shortness of breath may happen in isolation in atypical presentations (especially in female patients and people with diabetes mellitus)
  • Associated pallor and diaphoresis
• A physical exam may reveal:
  • Pallor, tachycardia, sweatiness, clamminess
• Investigations may reveal:
  • ECG:
    • May show ST elevation, ST depression, Q wave changes or no changes
  • Cardiac enzymes (troponins):
    • Elevated in myocardial infarction
    • Normal in unstable angina
  • Coronary angiography:
    • Shows occlusion of coronary artery

Acute heart failure

• A history may reveal:
  • Exertional shortness of breath that is worsening quickly
  • Orthopnoea, paroxysmal nocturnal dyspnoea
  • Ankle swelling
• A physical exam may reveal:
  • Elevated jugular venous pressure, crackles, S3 gallop rhythm, peripheral oedema
• Investigations may reveal:
  • Chest x-ray:
    • May show cardiomegaly, bilateral lobe shadowing, Kerley B-lines
  • ECG:
    • May show axis deviation
  • Echocardiogram:
    • Identifies structural abnormalities such as valve disease or wall motion abnormalities
  • NT-proBNP:
    • Elevated

Cardiac tamponade

• A physical exam may reveal:
  • Beck’s triad – raised jugular venous pressure, hypotension, and muffled heart sounds
  • Pulsus paradoxus may be present – abnormally large drop in blood pressure during inspiration
• Investigations may reveal:
  • ECG:
    • May show electrical alternans
  • Pericardiocentesis is urgently needed

Aortic dissection

• A history may reveal:
  • Sudden severe ‘tearing’ or ‘ripping’ chest pain that may radiate to the back
  • There may be a history of hypertension
• A physical exam may reveal:
  • >20 mmHg difference in systolic blood pressure between the arms
  • Pallor, tachycardia, hypotension
• Investigations may reveal:
  • Chest x-ray:
    • Widened mediastinum
  • If stable: CT angiography:
    • Shows false lumen
  • If unstable: transoesophageal echocardiography
    • Shows double lumen or dissection flap

Acute asthma exacerbation

• A history may reveal:
  • Progressively worsening wheezing, cough, chest tightness
  • Increased use of reliever inhaler
  • History of atopy (e.g. eczema/hayfever)
• A physical exam may reveal:
  • Wheezing, tachycardia, tachypnoea, difficulty completing sentences, cyanosis, accessory muscle use, altered consciousness, coma depending on the severity
• Investigations may reveal:
  • Peak expiratory flow rate (PEFR):
    • Decreased compared to best or predicted

Acute COPD exacerbation

• A history may reveal:
  • Progressively worsening shortness of breath, cough, and wheezing
  • There may be increasing amounts of sputum production
  • A history of smoking
• A physical exam may reveal:
  • Fever, crackles, wheezing, hypoxaemia
  • Cyanosis, chest hyper-expansion, facial plethora
• Investigations may reveal:
  • Chest x-ray:
    • May show lung hyper-expansion and flattened hemidiaphragm
  • Arterial blood gas:
    • May show hypoxaemia with or without hypercapnia

Pneumonia

• A history may reveal:
  • Subacute onset of fever, cough, shortness of breath, pleuritic chest pain
  • Cough may be productive
• A physical exam may reveal:
  • Fever, tachycardia, crackles
  • Focal consolidation and dullness of percussion
• Investigations may reveal:
  • Full blood count:
    • May show leukocytosis
  • Legionella urinary antigen:
    • For Legionella pneumonia
  • Blood cultures:
    • Identifies likely pathogen
  • Urea and electrolytes (U&Es):
    • Prognosis is worse if urea is elevated (CURB-65)
  • Chest x-ray:
    • Shows opacification

Sepsis

• A history may reveal:
  • Features of a specific infection, fever, rigours, nausea, vomiting, confusion
  • Risk factors such as immunosuppression
• A physical exam may reveal:
  • Tachycardia, tachypnoea, hypotension, fever, reduced urine output
  • Mottled skin, prolonged capillary refill time, altered mental state
• Investigations may reveal:
  • Sepsis 6 – BUFALO:
    • Blood cultures
    • Urine output
    • Fluids – IV fluids
    • Antibiotics – broad-spectrum IV antibiotics
    • Lactate – serum lactate
    • Oxygen

Anaphylaxis

• A history may reveal:
  • Exposure to an allergen such as food, stings from bees/wasps, or insect bites
  • Choking, shortness of breath, wheezing, rash, tongue and lip swelling
  • Nausea, vomiting, and diarrhoea may be present
• A physical exam may reveal:
  • ABC:
    • Airway problems – stridor and hoarse voice
    • Breathing problems – wheezing and shortness of breath
    • Circulation problems – hypotension and tachycardia
• Investigations may reveal:
  • Diagnosis is clinical but serum tryptase is measured to confirm anaphylaxis after treatment

Foreign body aspiration

• A history may reveal:
  • Coughing and choking, ingestion of food
  • Recurrent pneumonia
• A physical exam may reveal:
  • Unilateral wheezing, stridor, focal dullness to percussion
• Investigations may reveal:
  • Chest x-ray:
    • May identify object

Arrhythmia

• A history may reveal:
  • Shortness of breath with palpitations, weakness, pre-syncope or syncope
  • A history of heart disease
• A physical exam may reveal:
  • Tachycardia or bradycardia, depending on arrhythmia
  • Pallor, sweating, peripheral oedema, altered mental state
• Investigations may reveal:
  • ECG:
    • Identifies arrhythmia
  • Holter monitoring:
    • If initial ECG did not identify arrhythmia

Myocarditis

• A history may reveal:
  • Usually a younger patient following a viral infection
  • Chest pain, shortness of breath, and arrhythmia
• A physical exam may reveal:
  • Palpitations, crackles, elevated jugular venous pressure, tachycardia, S3 gallop
• Investigations may reveal:
  • C-reactive protein:
    • Elevated
  • Cardiac troponins:
    • Elevated
  • NT-proBNP:
    • Elevated
  • ECG:
    • Tachycardia
    • Arrhythmia
    • ST elevation and T wave inversion

Pericarditis

• A history may reveal:
  • Shortness of breath and pleuritic chest pain that may be worse when lying and improves when sitting or leaning forwards
  • Fever, malaise, non-productive cough
  • A history of viral infection, tuberculosis, chronic kidney disease, heart disease, radiotherapy, or malignancy 
• A physical exam may reveal:
  • Tachycardia
  • Pericardial friction rub 
• Investigations may reveal:
  • ECG:
    • Saddle-shaped ST elevation and PR depression
  • Echocardiography:
    • May show effusion and evidence of cardiac tamponade
  • C-reactive protein:
    • May be elevated
  • Troponins:
    • May be elevated

Panic attack

• A history may reveal:
  • A choking sensation, discomfort, fear, anxiety
  • A history of anxiety, phobias, depression
• A physical exam may reveal:
  • Tachycardia, tachypnoea, sweating
• Investigations may reveal:
  • Clinical diagnosis
  • Arterial blood gas:
    • Respiratory alkalosis

Haemothorax

• A history may reveal:
  • Blunt or penetrating chest trauma
• A physical exam may reveal:
  • Hypotension, tachycardia, tachypnoea, shock
• Investigations may reveal:
  • Chest x-ray:
    • Fluid in pleural space, blunting of costophrenic angle
  • Ultrasound:
    • Identifies fluid in pleural space suggestive of blood

Superior vena cava obstruction

• A history may reveal:
  • Shortness of breath, swelling of face, neck, and arms, and periorbital oedema may be seen
  • Head fullness and headaches – worse in the mornings
  • Visual disturbances 
• A physical exam may reveal:
  • Elevated jugular venous pressure, facial swelling and plethora
• Investigations may reveal:
  • Chest x-ray:
    • Identifies tumour compressing superior vena cava
  • CT angiography:
    • Confirms superior vena cava narrowing

Carbon monoxide poisoning

A history may reveal:

• Classically questions may hint at badly maintained housing (e.g. poor boiler function or furnaces)
• Other household members may have similar symptoms
• Pets may be unwell
• Headaches are an early feature, nausea, vomiting, confusion, and weakness follow

• A physical exam may reveal:
  • Tachypnoea, poor coordination, reduced consciousness
• Investigations may reveal:
  • Oxygen saturation – may be normal
  • Arterial blood gases – carboxyhaemoglobin:
    • 3% or more in people who do not smoke
    • 10% in people who smoke 

Methaemoglobinaemia

• A history may reveal:
  • The use of sulphonamides, nitrates (including recreational nitrates)
  • Headaches, nausea, anxiety
• A physical exam may reveal:
  • Cyanosis, arrhythmia
  • Reduced oxygen saturations
• Investigations may reveal:
  • Co-oximetry:
    • Elevated methaemoglobin
  • Arterial blood gases:
    • pO2 may be normal despite low oxygen saturation

Myasthenia gravis (myasthenic crisis)

• A history may reveal:
  • Extraocular muscle weakness and diplopia, ptosis, dysphagia, and general weakness that is worse towards the end of the day
• A physical exam may reveal:
  • May identify fatigue with repetitive movements
• Investigations may reveal:
  • Pulmonary function test:
    • FVC low
  • Serum acetylcholine receptor antibodies (anti-AChR):
    • Usually positive
  • Muscle-specific tyrosine kinase antibodies (anti-MuSK):
    • Single-fibre EMG
  • CT chest in all new patients:
    • To detect thymoma

Differential Diagnoses (Chronic)

Asthma

• A history may reveal:
  • Wheezing, cough, chest tightness
  • Increased use of reliever inhaler
  • History of atopy (e.g. eczema/hayfever)
• A physical exam may reveal:
  • Wheezing, tachycardia, tachypnoea, difficulty completing sentences, cyanosis, accessory muscle use, altered consciousness, coma depending on the severity
• Investigations may reveal:
  • Peak expiratory flow rate (PEFR):
    • Decreased compared to best or predicted
  • Spirometry with bronchodilator reversibility:
    • FEV1/FVC ratio 0.7 or less with reversibility
  • Fractional exhaled nitric oxide test (FeNO):
    • Increased

COPD

• A history may reveal:
  • Shortness of breath, cough, and wheezing
  • Sputum production
  • A history of smoking
• A physical exam may reveal:
  • Fever, crackles, wheezing, hypoxaemia
  • Cyanosis, chest hyper-expansion, facial plethora
• Investigations may reveal:
  • Spirometry with bronchodilator reversibility:
    • FEV1/FVC ratio 0.7 or less without reversibility

Stable Angina

• A history may reveal:
  • Dull chest pain or discomfort that is relieved with rest
  • No associated nausea, vomiting, pallor, shortness of breath 
• A physical exam may reveal:
  • Nothing – an examination may be normal
• Investigations may reveal:
  • ECG:
    • No acute changes
  • Troponins
    • Not elevated
  • CT coronary angiography:
    • Confirms diagnosis

Bronchiectasis

• A history may reveal:
  • Chronic cough productive of foul, offensive, copious amounts of sputum
  • Shortness of breath
  • Recurrent infection
  • Severe infection in childhood
• A physical exam may reveal:
  • Crackles, wheezing, clubbing
• Investigations may reveal:
  • Chest x-ray:
    • Thickened airways
  • High-resolution CT chest:
    • Tram-tracking and bronchial dilation

Interstitial Lung Disease

• A history may reveal:
  • Slow, progressive shortness of breath and dry cough
  • There may be a history of exposure to chemicals, radiotherapy, chemotherapy, some drugs (e.g. nitrofurantoin, methotrexate, amiodarone), asbestos, tuberculosis, ankylosing spondylitis, silicosis, sarcoidosis
• A physical exam may reveal:
  • Dry crackles, clubbing
• Investigations may reveal:
  • Pulmonary function tests:
    • Shows restrictive pattern
  • High-resolution CT scan:
    • Ground glass appearance

Hypersensitivity Pneumonitis

• A history may reveal:
  • May present acutely within 4-8 hours after exposure with fever, chills, cough (may be productive)
  • May present more slowly weeks-months after exposure with lethargy, productive cough, weight loss
  • A causative trigger may be identified such as pet birds
• A physical exam may reveal:
  • Crackles
• Investigations may reveal:
  • Chest x-ray:
    • May show fibrosis
  • CT chest:
    • May show fibrosis

Lung Cancer

• A history may reveal:
  • Cough, haemoptysis, unexplained weight loss, hoarseness, chest pain
  • Features of paraneoplastic syndromes
• A physical exam may reveal:
  • Focal wheezing, dullness, decreased breath sounds
• Investigations may reveal:
  • Chest x-ray:
    • Mass present
  • CT chest:
    • Mass present
  • Biopsy:
    • Histologically confirms lung cancer

Pulmonary tuberculosis (TB)

• A history may reveal:
  • Cough, fever, weight loss, night sweats, haemoptysis
  • HIV/immunosuppression
  • Travel to an endemic area
• A physical exam may reveal:
  • Fever, tachypnoea
• Investigations may reveal:
  • Chest x-ray:
    • May show bilateral hilar lymphadenopathy, may show upper lobe cavitation
  • Sputum culture:
    • Diagnostic

Pleural Effusion

• A history may reveal:
  • Progressive shortness of breath and a dull ache may be present
• A physical exam may reveal:
  • Dullness to percussion, reduced breath sounds, reduced chest expansion
• Investigations may reveal:
  • Chest x-ray:
    • Shows effusion and blunting of costophrenic angles

Anaemia

• A history may reveal:
  • Shortness of breath on exertion, chest pain, palpitations, lethargy, pre-syncope/syncope 
• A physical exam may reveal:
  • Conjunctival pallor, jaundice if haemolytic anaemia
  • Features of specific anaemia types (e.g. koilonychia in iron deficiency anaemia)
• Investigations may reveal:
  • Full blood count:
    • Haemoglobin low

Sarcoidosis

• A history may reveal:
  • Fever, arthritis, erythema nodosum, weight loss, malaise
• A physical exam may reveal:
  • Wheezing, dry crackles
• Investigations may reveal:
  • Chest x-ray:
    • Bilateral hilar lymphadenopathy
  • Serum ACE:
    • Elevated
  • Serum calcium:
    • Elevated
  • Lung biopsy:
    • Non-caseating granuloma

Hypertrophic Obstructive Cardiomyopathy

• A history may reveal:
  • Syncope following exercise, angina, exertional shortness of breath
  • There may be a family history of sudden cardiac death
• A physical exam may reveal:
  • Ejection systolic murmur louder with Valsalva manoeuvre and quieter when squatting, pansystolic murmur, double apex beat
• Investigations may reveal:
  • ECG:
    • Shows axis deviation and left ventricular hypertrophy
  • Echocardiogram:
    • MR SAM ASH:
      • MR – mitral regurgitation
      • SAM – systolic anterior motion
      • ASH – asymmetric hypertrophy

Mesothelioma

• A history may reveal:
  • Asbestos exposure around 20-40 years before the onset of symptoms 
  • Dry cough, fatigue, fever, weight loss, night sweats
• A physical exam may reveal:
  • Decreased breath sounds, dullness to percussion on the affected side due to pleural effusion
• Investigations may reveal:
  • Chest x-ray:
    • May show pleural thickening, pleural effusion
  • CT chest:
    • Shows pleural thickening

Phaeochromocytoma

• A history may reveal:
  • Episodic headaches, sweating, tachycardia and palpitations, and feeling panicky
• A physical exam may reveal:
  • Severe hypertension
• Investigations may reveal:
  • 24-hour urinary metanephrines:
    • Elevated

Kyphoscoliosis and pectus excavatum

• A history may reveal:
  • Pectus excavatum, poor posture, neuromuscular disease, vertebral body destruction (e.g. fractures), ankylosing spondylitis
• A physical exam may reveal:
  • Pectus excavatum may be seen, kyphosis may be seen, scoliosis may be seen
• Investigations may reveal:
  • Spinal x-ray:
    • Shows abnormal spine/sternum shape