Pulmonary hydatid cyst during pregnancy is extremely rare and life-threatening for the mother and fetus. Throughout pregnancy, hydatid cysts may enlarge due to the suppression of cellular immunity and steroids secreted from the placenta. In late pregnancy, the cysts can reach a huge volume with an increased risk for subsequent rupture due to the compression of the enlarging uterus and anaphylactic shock. Intrabronchial rupture is a rare and life-threatening complication of pulmonary hydatid cysts. It is vital to diagnose it as early as possible and manage patients with surgical intervention with aggressive medical treatment. Plain radiograph, computed tomography (CT) scan, and magnetic resonance imaging (MRI) can be used to identify pulmonary hydatid cysts. However, the diagnosis of hydatid cyst is quite challenging in pregnant patients due to concerns of radiation. Herein, we present a 26-week pregnant patient with acute respiratory failure. Bedside lung ultrasound was notable for thickened and severely broken pleural line with a large subpleural consolidation, and a giant fluid-filled cyst covered almost the entire left thorax, causing a mediastinal shift. In the present case, we highlighted that the bedside lung ultrasound in emergency (BLUE) protocol is an easy, safe, and fast way to identify pulmonary hydatid cyst. It should he the initial technique of choice for the diagnosis of pulmonary hydatid cysts in pregnant patients.
