What is the next best step to confirm the diagnosis in a patient with shortness of breath (SOB) and leg swelling?

From the Guidelines

The next best step to confirm the diagnosis in a patient with shortness of breath and leg swelling is to obtain a comprehensive evaluation starting with a thorough history and physical examination, followed by basic laboratory tests including complete blood count, comprehensive metabolic panel, brain natriuretic peptide (BNP), and a chest X-ray. These symptoms commonly suggest heart failure, but could also indicate pulmonary embolism, kidney disease, or liver dysfunction. An electrocardiogram (ECG) should be performed to assess for cardiac rhythm abnormalities or evidence of ischemia 1. If heart failure is suspected, an echocardiogram would be essential to evaluate cardiac structure and function, including ejection fraction and valve abnormalities. For suspected pulmonary embolism, a D-dimer test followed by CT pulmonary angiography may be necessary, as suggested by the British Thoracic Society guidelines for the management of suspected acute pulmonary embolism 1. Lower extremity ultrasound can help evaluate for deep vein thrombosis if the swelling is asymmetric. Pulmonary function tests might be indicated if underlying lung disease is suspected.

According to the 2023 ACC expert consensus decision pathway on management of heart failure with preserved ejection fraction, a stepwise approach to assessment of individuals with shortness of breath and/or edema should be applied, considering noncardiac mimics and HFpEF mimics 1. This systematic approach allows for accurate diagnosis of the underlying cause, which is crucial for implementing appropriate treatment strategies. It is also important to identify relevant comorbidities contributing to the presentation that warrant treatment, such as kidney disease, liver disease, or chronic venous insufficiency.

In terms of specific tests, the choice of diagnostic modality depends on the clinical probability of pulmonary embolism, as well as the presence of alternative diagnoses. For example, if the clinical probability of pulmonary embolism is low, a negative D-dimer test can exclude the diagnosis, whereas a high clinical probability may require further imaging with CT pulmonary angiography or other modalities 1. Similarly, if heart failure is suspected, an echocardiogram can provide valuable information on cardiac structure and function, including ejection fraction and valve abnormalities 1.

Overall, a comprehensive evaluation is necessary to confirm the diagnosis in a patient with shortness of breath and leg swelling, and to guide appropriate treatment strategies. A thorough history and physical examination, followed by basic laboratory tests and targeted diagnostic modalities, is the best approach to confirm the diagnosis and improve patient outcomes.

From the Research

Next Best Steps to Confirm Diagnosis

To confirm the diagnosis in a patient with shortness of breath (SOB) and leg swelling, the following steps can be considered:

• A thorough history and physical examination to differentiate causes of leg swelling, as proposed in the diagnostic algorithm by 2
• Assessment and resuscitation of the patient with SOB, following an algorithm that incorporates simultaneous evaluation and management, as discussed in 3
• Use of clinical decision rules to determine the pre-test probability of pulmonary embolism (PE), and referral for D-dimer test or chest imaging if PE is suspected, as outlined in 4
• Evaluation of pulmonary vascular obstruction and its consequences, such as raised pulmonary arterial pressure and chest pain, which are associated with dyspnoea in PE, as found in 5
• Consideration of left atrial function and exercise stress testing for a comprehensive diastolic heart failure workup in patients with SOB, as suggested in 6

Diagnostic Considerations

When evaluating a patient with SOB and leg swelling, it is essential to consider multiple potential causes and to use a systematic approach to differential diagnosis. This may involve:

• Laboratory and imaging evaluations to assess for conditions such as PE, diastolic heart failure, and lymphatic system dysfunction
• Assessment of symptoms such as chest pain, breathing variability, and anxiety or depression, which can influence the sensory-affective domain of dyspnoea
• Use of diagnostic algorithms and clinical decision rules to guide evaluation and management

Further Evaluation

Further evaluation may be necessary to confirm the diagnosis and to guide management. This may involve:

• Referral for specialized testing, such as echocardiography or ventilation-perfusion scanning
• Consultation with specialists, such as cardiologists or vascular specialists
• Use of anticoagulant therapy, such as direct oral anticoagulants, if PE is diagnosed, as discussed in 4