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DIAGNOSING PULMONARY EMBOLISM ON ENDOBRONCHIAL ULTRASOUND

      TOPIC: Pulmonary Vascular Disease
      TYPE: Medical Student/Resident Case Reports
      INTRODUCTION: Untreated acute pulmonary embolism (PE) is associated with mortality rate as high as 30%, whereas the death rate of diagnosed and treated PE is 8%. Hence, timely diagnosis of pulmonary embolism is important. CT angiogram of pulmonary arteries is the gold standard of imaging. However, other modalities such as ventilation perfusion scan and deep vein thrombosis scans are used sometimes as well depending upon the patient presentation and comorbidities. We hereby present a case of incidental diagnosis of pulmonary embolism on Endobronchial Ultrasound (EBUS).
      CASE PRESENTATION: A 72-year-old male was admitted to the medicine service for acute cholecystitis, with a previous history significant for 100 pack years smoking, subcarinal mass from mycobacterium avium infection that was treated with appropriate therapy in the past and left upper lobe (LUL) mass of the lung that was treated with stereotactic body radiation therapy 2 years ago. Hospital course was complicated by acute hypoxic respiratory failure prompting a CT scan of chest that showed an enlarged LUL mass, stable mediastinal lymphadenopathy and new ovoid reverse halo consolidation at lateral right middle lobe measuring 4.5*1.8cm. PET-CT scan was done to further evaluate the condition which revealed hypermetabolic mediastinal lymph nodes and new focal uptake in distal esophagus. We thus decided to pursue EBUS guided biopsy. While taking sample from station 4L, a filling defect was seen incidentally in the pulmonary artery at that location (Image A). We took samples from 7, 11R and immediately after the procedure sent patient for CTA of pulmonary arteries that confirmed large saddle pulmonary embolism involving left and right pulmonary arteries (Image B). Patient was immediately started on appropriate anticoagulation.
      DISCUSSION: EBUS is commonly used in diagnosis and staging of lung cancer, obtaining mediastinal lymph node biopsy, sampling of bronchial or peribranchial mass and as guide in therapeutic procedures such as airway stenting. Major vascular structures such as pulmonary artery can easily be seen on EBUS and hence, can be used as a modality to diagnose pulmonary embolism in the right patient population such as patients with renal failure, anaphylaxis to contrast, inconclusive CTA results, pregnant females, and unstable patient in ICU since EBUS can be done at bedside in ICU setting.
      CONCLUSIONS: EBUS is an expensive and invasive modality compared to the other available techniques for diagnosing pulmonary embolism. However, if used in right subpopulation, it can be helpful in decreasing mortality by early and accurate diagnosis of pulmonary embolism similar to the aforementioned patient.
      REFERENCE #1: Abuserewa ST, Duff R. Incidental diagnosis of pulmonary embolism in asymptomatic patient using endobronchial ultrasound (EBUS) during mediastinal lymphadenopathy assessment. Cureus. 2021;13(2):e13404.
      REFERENCE #2: Segraves JM, Daniels CE. Pulmonary embolus diagnosed by endobronchial ultrasound. Respir Med Case Rep. 2015;16:104-105.
      REFERENCE #3: Sachdeva A, Lee HJ, Malhotra R, Shepherd RW. Endobronchial ultrasound diagnosis of pulmonary embolism. J Bronchology Interv Pulmonol. 2013;20(1):33-34.
      DISCLOSURES: No relevant relationships by Umama Adil, source=Web Response
      No relevant relationships by Himanshu Bhardwaj, source=Web Response
      No relevant relationships by FNU RABEL, source=Web Response