What is the recommended workup for an elderly female patient with exertional dyspnea (shortness of breath upon exertion)?

Workup for Elderly Female with Exertional Dyspnea

Begin with immediate vital signs assessment including oxygen saturation, respiratory rate, pulse rate, blood pressure, and temperature, followed by targeted history for cardiac versus pulmonary causes, then proceed to transthoracic echocardiography and brain natriuretic peptide testing as the primary diagnostic tests. 1

Initial Assessment and Vital Signs

• Measure oxygen saturation via pulse oximetry immediately in all patients presenting with breathlessness 1
• Record pulse rate, respiratory rate, blood pressure, and temperature as part of the initial ABC assessment 1
• Continue pulse oximetry monitoring until the patient is stable 1

Focused History: Key Red Flags

Cardiac indicators:

• Orthopnea is a hallmark symptom indicating elevated pulmonary capillary pressure and pulmonary edema 1, 2
• Paroxysmal nocturnal dyspnea suggests left ventricular dysfunction 1
• Peripheral edema indicates heart failure 1
• History of ischemic heart disease, diabetes mellitus, and hypertension represents a high-risk profile for heart failure 1, 2
• In elderly patients with established ischemic heart disease, dyspnea frequently substitutes for typical anginal symptoms 1, 2

Pulmonary indicators:

• Chronic breathlessness on minor exertion in patients over 50 years who are long-term smokers suggests COPD 1
• Wheezing during vigorous exercise may indicate exercise-induced bronchoconstriction 1

Initial Laboratory Testing

• Brain natriuretic peptide (BNP) levels to help exclude heart failure 1
• D-dimer testing if pulmonary embolism is suspected 1
• Transferrin saturation >55% may indicate iron overload cardiomyopathy in the appropriate clinical context 1

Initial Imaging Studies

• Chest X-ray in all patients with dyspnea to assess for pulmonary edema, cardiomegaly, or pulmonary pathology 1
• ECG to identify arrhythmias, ischemia, or conduction abnormalities 1
• Transthoracic echocardiography (TTE) as the primary imaging modality when a cardiac cause is suspected 3, 1

Specific TTE Indications:

• TTE is mandated in all patients with suspected heart failure to confirm or exclude diagnosis, quantify chamber volumes, assess systolic and diastolic function, and identify etiology 1
• TTE identifies heart failure with preserved, mid-range, or reduced ejection fraction 1
• TTE is the primary imaging modality when SOB with suspected valvular heart disease based on history or examination (e.g., systolic murmur) 1
• TTE is fundamental for diagnosis and classification of hypertrophic, dilated, arrhythmogenic, or restrictive cardiomyopathies 1

Advanced Diagnostic Testing When Initial Evaluation is Inconclusive

Cardiopulmonary exercise testing (CPET) is the definitive test to distinguish between cardiac, pulmonary, vascular, and deconditioning causes when the initial evaluation is inconclusive 3, 1, 4

Key CPET Parameters:

• Peak VO2 (percent-predicted) to assess functional capacity 1
• VE/VCO2 slope and PETCO2 to identify ventilation-perfusion abnormalities suggesting pulmonary vasculopathy 1
• Peak exercise VE/MVV ratio to assess ventilatory limitation 1
• A decrease in FEV1 >15% post-exercise suggests exercise-induced bronchoconstriction 1

CPET Diagnostic Patterns:

• Cardiac dysfunction presents with reduced peak VO2, low O2 pulse, steeper heart rate-VO2 relationship, and early anaerobic threshold 4
• Pulmonary vascular disease demonstrates reduced peak VO2, low anaerobic threshold, and high VE/VCO2 ratio even during light physical activities 4

Spirometry and Pulmonary Function Testing

• Perform spirometry and detailed pulmonary examination to determine whether shortness of breath with exercise is associated with underlying conditions such as COPD or restrictive lung conditions (obesity, skeletal defects, diaphragmatic paralysis, or interstitial fibrosis) rather than exercise-induced bronchoconstriction 3
• Cardiopulmonary exercise testing should be performed with close observation to assess the clinical presentation 3

Critical Pitfalls to Avoid

• In patients with COPD or risk factors for hypercapnic respiratory failure, target oxygen saturation of 88-92% rather than normal saturation 1
• Excessive oxygen therapy (PO2 >10 kPa or 75 mmHg) in COPD patients causes CO2 retention and respiratory acidosis 1
• If respiratory acidosis develops from excessive oxygen, step down to 28% or 35% Venturi mask or 1-2 L/min nasal cannula rather than discontinuing oxygen abruptly 1

Special Consideration: Unrecognized Heart Failure

Elderly primary care patients with shortness of breath on exertion often have unrecognized heart failure, mainly with preserved ejection fraction (HFpEF) 5. Diastolic dysfunction is a major cause of shortness of breath on exertion in elderly primary-care patients who often are suffering from unrecognized heart failure (16%), more often from HFpEF (12%) than from heart failure with reduced ejection fraction (3%) 3.