Pulmonary Embolism Diagnosed During Endobronchial Ultrasound in a Patient With Major Trauma

Pulmonary embolism (PE) is a serious condition that often poses a diagnostic challenge. We report a case of a 57-year-old man with tobacco dependence who presented with multiple trauma, with chest imaging findings concerning for malignancy. While performing bronchoscopy with endobronchial ultrasound (EBUS), an echogenic material was incidentally found in the left pulmonary artery. Computed tomography pulmonary angiography (CTPA) was immediately obtained and confirmed the diagnosis of PE. This case illustrates the utility of routine pulmonary artery examination during EBUS procedures in patients at risk of PE and the importance of prompt management including confirmation with CTPA.


Introduction
Pulmonary embolism (PE) is a common and potentially life-threatening disease, which often poses a significant diagnostic challenge. Once diagnosed, prompt interventions such as therapeutic anticoagulation are indicated. While computed tomography pulmonary angiography (CTPA) is considered the standard diagnostic modality for PE [1], endobronchial ultrasound (EBUS) has been shown to have the ability to detect clinically significant thrombus in pulmonary arteries [2]. However, it has not been well studied how to utilize EBUS for the diagnosis of PE, or what would be the best approach for patients incidentally diagnosed with PE during EBUS. We present a case of PE incidentally diagnosed during EBUS performed for a patient with multiple trauma.

Case Presentation
A 57-year-old man was admitted to the hospital after a fall resulting in fractures of the right femur, left scaphoid, and multiple lumbar vertebrae. Pulmonary consultation was requested for abnormal findings on chest computed tomography (CT) performed during the initial evaluation for trauma. He reported a twomonth history of blood-tinged sputum and weight loss but had no fever, cough, dyspnea, or chest pain symptoms. His past medical history was unremarkable. His social history was notable for current cigarette smoking (49 pack-year) and occupational asbestos exposure while he was in military service, as well as one prior incarceration. The chest CT with contrast showed right upper lobe patchy consolidation with central cavitation and necrosis, left upper lobe nodular consolidation (Figure 1), and mildly enlarged right hilar and paratracheal lymph nodes.

CT: computed tomography
Bronchoscopy was performed with EBUS-guided transbronchial needle aspiration (TBNA) of the hilar and mediastinal lymph nodes, and transbronchial biopsy followed by bronchial brush and bronchoalveolar lavage (BAL) at the right upper lobe lesion. While visualizing the left hilar region with EBUS, the bronchoscopists found an echogenic material in the left pulmonary artery concerning a thrombus ( Figure 2).

EBUS: endobronchial ultrasound
Consequently, the patient underwent CTPA, confirming new pulmonary emboli in the left main pulmonary artery extending into the left upper and lower lobar branches ( Figure 3). While transthoracic echocardiogram showed mildly elevated estimated pulmonary arterial systolic pressure (46 mmHg), right heart size and systolic function were normal and troponin I and N-terminal pro-brain natriuretic peptide levels were normal. Doppler ultrasound of the lower extremities revealed acute deep venous thrombosis in the right popliteal vein. For the venous thromboembolism likely provoked by the trauma, he was started on continuous intravenous infusion of heparin followed by a subcutaneous therapeutic dose of enoxaparin. He remained hemodynamically stable and did not have overt hemoptysis. The anticoagulant was switched to oral apixaban for at least three months upon hospital discharge.

CTPA: computed tomography pulmonary angiography
The EBUS-TBNA samples from bilateral paratracheal, subcarinal, and right hilar lymph nodes showed cellular evidence of lymph nodes without malignant cells. A transbronchial lung biopsy of the right upper lobe lesion showed fragments of lung parenchyma with chronic inflammation, interstitial thickening, and reactive pneumocytes. The bronchial brush showed hemosiderin-laden macrophages, and the bronchial brush and BAL fluid specimens were negative for bacteria, mycobacteria, or fungi. While the exact etiology for the abnormal chest CT findings remained unclear, malignancy appeared less likely and therefore a decision was made to manage pulmonary contusion and possible infection. He was given amoxicillinclavulanate for seven days and a repeat chest CT in six weeks was recommended. Because he resided more than 100 miles away, he elected to follow up with outside medical providers near his home.

Discussion
To the best of our knowledge, the present case is the first report of PE in a patient with multiple trauma incidentally diagnosed with EBUS. It illustrates two potential implications in clinical practice.  [4], pulmonary sarcoidosis [5], pulmonary histoplasmosis [6], and pulmonary tuberculosis [7]. Erer et al. found that among 548 patients undergoing EBUS for various reasons, four were incidentally diagnosed with PE [8]. Given the short time required to perform pulmonary artery examination during EBUS, the minimal risk associated with the evaluation, and the clinical implications of making a diagnosis of PE, the careful vascular examination should be part of every EBUS as a complete evaluation to catch incidental findings such as noted in this case.
Second, if an incidental diagnosis of PE was made with EBUS, prompt confirmation with CTPA would be reasonable. Recent case reports describe that EBUS can be used as a primary diagnostic test in critically ill patients who are too unstable to undergo CTPA. This includes a patient in cardiac arrest who improved with intravenous thrombolysis therapy for massive PE diagnosed with bedside EBUS [9], and patients on extracorporeal membrane oxygenation [10]. However, there has yet to be a consensus on the diagnostic accuracy of EBUS for PE and current guidelines for PE do not mention EBUS as a diagnostic modality [1]. Almost all case reports describing PE initially diagnosed with EBUS note that CTPA was later performed to confirm the diagnosis [2,[4][5][6][7][8]10]. Therefore, unless contraindicated, confirmation with a better-established diagnostic modality such as CTPA would likely be the best approach.

Conclusions
We describe a case of PE incidentally diagnosed during EBUS performed for a patient with multiple trauma.
Bronchoscopists should consider performing a pulmonary artery examination routinely during EBUS procedures, particularly in patients who are at high risk of developing PE. If EBUS findings are concerning for PE, confirmation with better-studied modalities such as CTPA would be reasonable as long as it can be immediately performed. Future studies are desired to further establish the role of EBUS in the diagnosis of PE.

Additional Information Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.