Interesting case of incidental diagnosis of pulmonary embolism by endobronchial ultrasonography

Background

Pulmonary embolism (PE) is the obstruction of the pulmonary arteries or their branches by a material, most commonly a thrombus that originates elsewhere in the body. PE is the third most common cause of mortality from cardiovascular causes, after coronary disease and stroke.1 2 Untreated PE can carry a significant mortality risk, especially in patients with malignancy or in patients presenting with signs of right heart strain.3–5

Here, we present the case of a man in his 40s who was referred to the pulmonology clinic for the evaluation of a lung nodule discovered incidentally during a dysphagia workup. Endobronchial ultrasonography (EBUS) revealed findings suggestive of PE. EBUS is not a modality used to diagnose PE. Therefore, the diagnosis was confirmed using chest CT angiography (CTA). Anticoagulation therapy was initiated. The patient had no classic signs and symptoms of PE, and the diagnosis would have been easily missed. PE was diagnosed during EBUS, which resulted in prompt treatment and helped avoid further complications.

Case presentation

A man in his 40s with no significant medical history, except coronavirus disease in 2020, was referred to our pulmonology clinic for the evaluation of a right upper lobe lung nodule. Two weeks before presentation, the patient developed discomfort while swallowing, which he described as a pressure sensation. There was no odynophagia or a feeling of food getting stuck. A week later, he developed dry cough and wheezing. He felt pressure during deep breathing. He denied chest pain, chest tightness, dyspnoea or haemoptysis. There was no history of aspiration, fever, chills, seizures or weight loss. The patient had no history of smoking. He also developed calf pain. He visited his primary care physician who performed chest radiography, which revealed abnormal peribronchial and interstitial thickening of the right lung and septal lines in the periphery. There was a 9×4 mm nodule over the right upper lobe. Chest CT showed a 2.1 cm nodule in the superior aspect of the right lower lobe, which was lobulated and spiculated and showed mediastinal and hilar adenopathy. Small pleural effusion, peribronchial interlobular septal thickening, pleural thickening and interstitial markings were noted in the right lower lobe. Lower extremity Doppler was also performed and was negative for deep vein thrombosis (DVT).

On physical examination, the patient’s vital signs were within the normal limits. He was not in any distress. He had no thyromegaly and tenderness of the neck. There was no lymphadenopathy in the neck and supraclavicular area. On auscultation of the chest, an end-expiratory wheeze was heard on the right side during forced expiration, but no crackles. The findings of cardiac examination were unremarkable. The abdomen was non-distended, soft and non-tender with no palpable organomegaly.

The differential diagnoses at this point were broad and included inflammation, infection and malignancy. The patient was offered the option of empiric antibiotics with short-term follow-up or positron emission tomography (PET) CT. The decision was made for PET CT, which was performed the next week and showed a hypermetabolic right lower lobe nodule, hypermetabolic mediastinal adenopathy, right hilar adenopathy and hypermetabolic bone lesions in the right clavicle and sternum. The findings were concerning for a neoplastic aetiology; however, an infectious aetiology could not be excluded. These findings necessitated bronchoscopy and EBUS.

A week later, bronchoscopy with transbronchial needle aspiration, brushing, endobronchial biopsy, bronchoalveolar lavage (BAL) and EBUS was were performed. Airway inspection revealed mild diffuse erythema and thickening of the airway mucosa on the right side. Extrinsic compression of the right lower lobe subsegments was observed. Left EBUS revealed a thrombus in the left pulmonary artery (figure 1). Endobronchial biopsy of the lymph nodes was also performed. Because of the findings suggestive of PE, the patient was hospitalised for further workup and management.

Investigations

On hospital admission, his vital signs were stable, and his physical examination findings were unchanged.

The complete blood count was unremarkable. Serum electrolytes and the renal function test results were within the normal limits. Serum troponin was negative. Chest CTA showed filling defects consistent with acute PE in the right upper and left lower lobes. Extensive ground glass opacities were observed in the bilateral lung fields with right pleural effusion (figure 2). Duplex ultrasound of the lower extremity veins revealed DVT in the bilateral lower extremity veins. This was a new finding compared with the negative duplex ultrasound performed 3 weeks prior. A right thoracentesis was performed. An echocardiogram showed unremarkable findings. He was admitted to the hospital, and continuous cardiac monitoring showed normal sinus rhythm.

Treatment

Anticoagulation therapy was initiated with enoxaparin 1 mg/kg two times per day because at that point it had not yet been ascertained whether the patient could afford the more expensive direct-acting oral anticoagulant (DOAC) therapy. On discharge, enoxaparin was stopped, and apixaban was started at 10 mg two times per day for a week, followed by 5 mg two times per day.

Outcome and follow-up

A 1-week follow-up was recommended, and by then, the findings of the endobronchial biopsy, BAL and thoracentesis were available. Pleural fluid cytology and right endobronchial biopsy were positive for adenocarcinoma. The subcarinal, right lower paratracheal and right interlobar lymph nodes were positive for adenocarcinoma of lung origin. The patient was referred to the oncology clinic. At the time of writing, he is undergoing chemotherapy. Anticoagulation therapy was continued indefinitely. The patient had no DVT or PE complications.