What is the initial management approach for a 55-year-old female patient presenting with exertional dyspnea and bilateral wheezing, normal blood investigations, and electrocardiogram (ECG) showing sinus tachycardia?

Initial Management of Exertional Dyspnea with Bilateral Wheezing in a 55-Year-Old Female

Begin with inhaled bronchodilator therapy (short-acting beta-agonist such as albuterol) immediately while simultaneously pursuing diagnostic evaluation to differentiate between asthma, cardiac causes, and other etiologies of wheezing and dyspnea. 1

Immediate Therapeutic Intervention

• Administer a short-acting beta-agonist (albuterol 2.5 mg via nebulizer) as first-line therapy for the bilateral wheezing, which can provide both therapeutic benefit and diagnostic information based on response 2, 3
• Monitor the patient's response to bronchodilator therapy within 15-30 minutes, as improvement in wheezing and dyspnea supports a bronchospastic component 4
• Ensure oxygen saturation monitoring with pulse oximetry to assess for hypoxemia requiring supplemental oxygen 5

Critical Diagnostic Considerations

Rule Out Cardiac Causes First

The combination of exertional dyspnea, sinus tachycardia, and bilateral wheezing raises significant concern for "cardiac asthma" (cardiogenic pulmonary edema with reflex bronchoconstriction) rather than primary pulmonary disease 1:

• Obtain B-natriuretic peptide (BNP) or NT-proBNP immediately as the single most important diagnostic test, with BNP <100 pg/mL having 96-99% sensitivity for ruling out heart failure 1, 6

• Order transthoracic echocardiography urgently to assess for:

  • Left ventricular systolic and diastolic function 1
  • Valvular abnormalities (particularly mitral stenosis or regurgitation) 1
  • Right ventricular function and pulmonary hypertension 1
  • Elevated left ventricular filling pressures 1

• Obtain chest radiography to evaluate for pulmonary edema, cardiomegaly, or pleural effusions that would support cardiac etiology 6

Distinguish From Primary Pulmonary Disease

• Perform spirometry with bronchodilator response testing once acute symptoms are controlled to identify obstructive lung disease patterns 1, 5
• Consider that normal blood investigations do not exclude significant cardiac or pulmonary pathology 1
• The presence of sinus tachycardia may indicate compensatory response to heart failure, pulmonary embolism, or severe bronchospasm 1

Algorithmic Approach Based on BNP Results

If BNP is Elevated (>100 pg/mL):

• Treat as heart failure with preserved or reduced ejection fraction until echocardiography clarifies 6
• Initiate diuretic therapy cautiously while awaiting echocardiography 1
• Continue bronchodilator therapy as cardiac asthma often has bronchospastic component 1
• Avoid ACE inhibitors if left ventricular outflow tract obstruction is suspected (particularly in hypertrophic cardiomyopathy) 1

If BNP is Normal (<100 pg/mL):

• Pursue primary pulmonary causes more aggressively with pulmonary function testing 5
• Consider exercise-induced bronchoconstriction or asthma as primary diagnosis 1
• Evaluate for vocal cord dysfunction syndrome, which commonly mimics asthma with wheezing sounds 3
• Consider less common causes: pulmonary arteriovenous malformations, vascular rings, or exercise-induced laryngomalacia 1

Additional Diagnostic Testing

• Perform stress echocardiography or cardiopulmonary exercise testing if diagnosis remains unclear after initial workup, particularly to assess for:

  • Exercise-induced elevation of left ventricular filling pressures (E/e' ratio >14 with exercise) 1
  • Exercise-induced pulmonary hypertension (systolic pulmonary artery pressure >43 mmHg with exercise) 1
  • Diastolic dysfunction with preserved ejection fraction 1

• Consider D-dimer testing if pulmonary embolism is in the differential, though the presentation is less typical 7

Common Pitfalls to Avoid

• Do not assume wheezing equals asthma in a middle-aged female with exertional symptoms and tachycardia; cardiac causes must be excluded first 1, 3
• Do not rely solely on normal blood work to exclude serious pathology; BNP and echocardiography are essential 1, 6
• Do not miss cardiac dysrhythmias (including supraventricular tachycardia) that can present with dyspnea and wheezing 1
• Recognize that patients may underreport symptoms by unconsciously limiting activity; objective exercise testing may be needed 1
• Be aware that respiratory sounds from vocal cord dysfunction are frequently mischaracterized as wheezing and lead to misdiagnosis of asthma 3

Immediate Management Summary

The priority is to provide symptomatic relief with bronchodilator therapy while urgently obtaining BNP and echocardiography to distinguish cardiac from pulmonary causes. 1, 6 The combination of exertional dyspnea, bilateral wheezing, and sinus tachycardia in a 55-year-old female warrants high suspicion for cardiac dysfunction presenting as "cardiac asthma" rather than primary bronchospastic disease 1. Treatment decisions should be guided by BNP results and echocardiographic findings rather than empiric asthma therapy alone 6.