Westermark’s Sign and Palla’s Sign in Pulmonary Embolism
Abstract
A 90-year-old man with atrial fibrillation and dementia presented with sudden-onset dyspnea, which began one hour before admission. The patient had not been receiving anticoagulation therapy due to prior discussions with his physician. Physical examination revealed tachypnea and tachycardia.
Chest radiography demonstrated two rare radiologic findings:
- Westermark’s sign – absence of pulmonary vasculature in the right lung fields, indicating an area of oligemia distal to an embolism.
- Palla’s sign – enlargement of the right descending pulmonary artery, another rare indicator of pulmonary embolism.
Further evaluation showed T-wave inversions on ECG, elevated D-dimer levels, and computed tomography (CT) pulmonary angiography confirmed bilateral pulmonary emboli, predominantly affecting the right side. CT imaging also displayed oligemia in the right lung parenchyma.
The patient was treated with apixaban, leading to rapid clinical improvement. At his five-month follow-up, he remained in stable condition.