Should a chest X-ray be ordered for a patient with pulmonary embolism (PE) and wheezing?

Chest X-ray in Pulmonary Embolism with Wheezing

A chest X-ray should be ordered for a patient with pulmonary embolism and wheezing as it helps exclude alternative diagnoses, though it is not diagnostic for PE itself. 1

Role of Chest X-ray in PE Diagnosis

• Chest X-ray is typically performed in suspected PE because the differential diagnosis is broad, and it helps evaluate for alternative causes of symptoms 2
• Chest X-ray is rarely diagnostic for PE but is valuable for excluding other causes of dyspnea and chest pain such as pneumonia, pneumothorax, heart failure, or tumor 1
• The main utility of chest X-ray is to aid in the interpretation of ventilation-perfusion scans, as abnormalities on chest X-ray can affect V/Q scan interpretation 1

Common Chest X-ray Findings in PE

• Pleural effusion is present in 46% of PE cases 1, 3
• Atelectasis or infiltrate is found in 49% of PE cases 1, 4
• Decreased pulmonary vascularity (Westermark sign) is found in 36% of PE cases 1
• Elevated diaphragm is present in 36% of PE cases 1, 3
• Pleural-based wedge-shaped opacity (Hampton's hump) is present in 23% of PE cases 1
• Amputation of hilar artery is a more specific sign present in 36% of PE cases 1

PE and Wheezing: Clinical Considerations

• Wheezing is a possible but less common presentation feature of acute pulmonary embolism, occurring in approximately 9.1% of cases 5
• Wheezing may be more frequent in PE patients with previous cardiopulmonary disease, though it also occurs in those without such history 5
• Wheezing in PE may be associated with more severe presentations, with higher rates of dyspnea, cough, and respiratory failure 5
• Bronchial asthma-like symptoms can be induced by pulmonary embolism, making differential diagnosis challenging 6

Diagnostic Approach for PE with Wheezing

• CTPA (CT Pulmonary Angiography) is now the recommended initial lung imaging modality for non-massive PE, regardless of chest X-ray findings 2, 4
• Patients with a good quality negative CTPA do not require further investigation or treatment for PE 2
• D-dimer testing is useful as a screening tool for PE, but should not be performed in those with high clinical probability of PE 2
• A negative D-dimer test reliably excludes PE in patients with low or intermediate clinical probability 2

Clinical Algorithm for PE with Wheezing

1. Perform chest X-ray to exclude alternative diagnoses 2, 1
2. Assess clinical probability of PE using validated scoring systems 2
3. For low/intermediate probability: Perform D-dimer testing 2
4. If D-dimer positive or high clinical probability: Proceed to CTPA 2
5. If CTPA is contraindicated: Consider V/Q scan if chest X-ray is normal 2

Important Considerations

• Wheezing in a patient with dyspnea out of proportion to chest X-ray findings should raise suspicion for PE 7
• Do not rule out PE based on normal oxygen saturation, as up to 40% of patients may have normal arterial oxygen saturation 4
• Do not dismiss transient symptoms, as they can lead to delayed diagnosis or misdiagnosis 4
• All patients with possible PE should have clinical probability assessed and documented 2
• An alternative clinical explanation should always be considered at presentation and sought when PE is excluded 2