What is the appropriate management for a patient with new onset shortness of breath (dyspnea) with exertion?

Management of New Onset Exertional Dyspnea

Begin immediately with vital signs including pulse oximetry, respiratory rate, pulse rate, blood pressure, and temperature, followed by targeted diagnostic testing to differentiate between cardiac, pulmonary, and other causes. 1, 2

Immediate Assessment

• Measure oxygen saturation via pulse oximetry as the "fifth vital sign" - SpO2 <90% requires immediate supplemental oxygen 2
• Obtain respiratory rate, pulse rate, and blood pressure to establish baseline hemodynamic status 1, 2
• Continue pulse oximetry monitoring until the patient is stable 1

Critical History Elements to Elicit

• Timing and onset: Acute (minutes to hours) versus chronic (>4-8 weeks) helps narrow the differential 2
• Quality descriptors: "Chest tightness" suggests bronchoconstriction; "air hunger" indicates restrictive mechanics or heart failure; "effort/suffocation" may suggest panic disorder 2
• Associated symptoms requiring urgent evaluation: Palpitations with dizziness warrant aggressive investigation for cardiac arrhythmias including supraventricular tachycardia, atrial fibrillation, or ventricular tachycardia 1
• Risk factors: Smoking history, chemical exposures, medication use 3

Physical Examination Priorities

• Breathing pattern observation: Pursed-lip breathing, accessory muscle use, tripod positioning 2
• Cardiac assessment: Jugular venous distention, heart sounds, murmurs, gallops to identify heart failure or valvular disease 2
• Pulmonary auscultation: Wheezing (bronchoconstriction), crackles (pulmonary edema/fibrosis), diminished sounds (effusion/pneumothorax) 2, 3
• Percussion: Dullness (consolidation/effusion) versus hyperresonance (pneumothorax/emphysema) 2

First-Line Diagnostic Testing

Order the following initial panel for all patients with exertional dyspnea: 2, 3

• Chest radiograph (posteroanterior and lateral preferred) to assess for cardiomegaly, pulmonary pathology 2, 3
• Electrocardiogram to identify arrhythmias, ischemia, or conduction abnormalities 2, 3
• Brain natriuretic peptide (BNP) or NT-proBNP - this is the single most important test when initial evaluation is unrevealing, with BNP <100 pg/mL having 96-99% sensitivity for ruling out heart failure 1, 4
• Complete blood count to assess for anemia 1, 3
• Basic metabolic panel to evaluate for metabolic acidosis 2, 3
• Spirometry to identify obstructive or restrictive lung disease 2, 3

Critical Differential Diagnoses in Young/Middle-Aged Adults

Do not overlook cardiac causes, particularly in women who are at risk for underdiagnosis: 1

• Supraventricular tachycardia causes exercise-induced breathlessness with palpitations, dizziness, and diaphoresis 1
• Complete heart block manifests as dyspnea on exertion, syncope, dizziness, or fatigue 1
• Hypertrophic cardiomyopathy presents with dyspnea and chest pain that improve with beta-blockers and carries risk of sudden death 1
• Heart failure with preserved ejection fraction (HFpEF) is particularly common in middle-aged women and may present with normal systolic function but diastolic dysfunction 4

Algorithm Based on BNP Results

If BNP ≥100 pg/mL:

• Proceed to transthoracic echocardiography to assess left ventricular ejection fraction, diastolic parameters, valve function, right ventricular systolic pressure, and identify structural abnormalities including hypertrophic cardiomyopathy, valvular disease, or cardiomyopathies 1, 4
• Refer to cardiology if echocardiography reveals valvular disease requiring intervention, HFpEF, or if cardiac etiology remains suspected 4

If BNP <100 pg/mL:

• Consider cardiopulmonary exercise testing (CPET) to distinguish between cardiac, pulmonary, vascular, and deconditioning causes when resting tests are normal 1, 4
• CPET is the definitive test to identify exercise-induced limitations, deconditioning, exercise-induced bronchoconstriction, or exercise-induced arterial hypoxemia 4

Additional Testing When Initial Workup is Unrevealing

• Exercise challenge or bronchoprovocation testing if exercise-induced bronchoconstriction is suspected, as it may not be detected on resting pulmonary function tests 5, 4
• CT chest to evaluate for interstitial lung disease, pulmonary vascular abnormalities, or subtle parenchymal disease not visible on chest radiography 4
• Pulmonary function studies to identify emphysema and interstitial lung diseases 3

Common Pitfalls to Avoid

• Do not assume a negative cardiac stress test excludes all cardiac causes - it primarily rules out obstructive coronary disease but not HFpEF, valvular disease, or pulmonary hypertension 4
• Clinical evaluation alone has high specificity (96%) but low sensitivity (59%) for cardiac causes, making biomarker testing essential 4
• Do not delay evaluation of unexplained dyspnea - it is associated with increased all-cause mortality and may represent early manifestations of serious disease 4
• One-third of patients have multifactorial etiology requiring evaluation of multiple organ systems 3

Age-Specific Considerations

• Patients >50 years with smoking history should be assumed to have COPD if they are long-term smokers with chronic breathlessness on minor exertion and no other known cause 2
• Target oxygen saturation of 88-92% for patients with known or suspected COPD to avoid CO2 retention 2

Referral Indications

• Refer to pulmonology for consideration of interstitial lung disease, pulmonary vascular disease, or if CPET suggests pulmonary limitation 4
• Refer for psychological evaluation when hyperventilation and anxiety disorders are in the differential diagnosis 5