Unilateral Pulmonary Edema, Westermark ’s Sign and Palla’s Sign in Pulmonary Embolism

A 54-year-old African American man presented with shortness of breath of two days duration. Physical examination revealed tachycardia with a heart rate of 113 bpm, oxygen saturation at 63% on room air and left sided crackles. Chest radiograph (Figure 1A) showed increased lucency of the right upper and middle lobes (Westermark ’s sign, blue arrow), enlarged right descending pulmonary artery (Palla’s sign, red arrow) and left lower zone pulmonary edema (black arrow). Computed tomography (CT) of chest (Figure 1B) with pulmonary angiogram confirmed extensive saddle pulmonary embolism (PE) at the right side with extension into left pulmonary artery branches. 2D echocardiogram revealed elevated right ventricular systolic pressure and a patent foramen ovale with right to left shunting. Hence, catheter directed thrombolysis with tissue-plasminogen activator (t-PA) was performed with significant improvement clinically and radiologically with reperfusion of the right lung lobes evident by restoration of vascular markings on the right and resolution of the left sided pulmonary edema. Here, we can see a perfect example of unilateral pulmonary edema after contralateral embolism and is likely secondary to increased hydrostatic pressure due to interruption of blood flow by PE.2

Source: QJM - February 17, 2017 Category: Internal Medicine Source Type: research