Journal of the College of Physicians and Surgeons Pakistan 2012, Vol. 22 (3): 189-191 189 INTRODUCTION Primary spontaneous pneumothorax occurs commonly in young females. Spontaneous pneumothorax during pregnancy is quite uncommon, with only 56 cases reported till now. 1 Pneumothorax in a pregnant patient secondary to ruptured pulmonary hydatid cyst is extremely rare and only two such cases are reported in the literature. 2,3 During pregnancy, oxygen consumption is increased by about 20%. In addition, physiological anaemia of pregnancy and a relatively low partial pressure of oxygen in the umbilical vein of the fetus (approximately 35 mmHg) has little reserve if maternal partial pressure of oxygen starts to decrease. 4 Any impairment of ventilation during pregnancy may have serious consequences for both the mother and her fetus. Herein, we report a case of ruptured pulmonary hydatid cyst leading to pneumothorax in a pregnant patient and its management. CASE REPORT A 19-year-old female patient presented to the emer- gency room with one-day history of progressive shortness of breath and pain on the right side of the chest. She also gave history of productive cough with on and off low-grade fever for the last 2 months. Chest radiograph taken with abdominal shielding showed a right-sided large pneumothorax (Figure 1). A right-sided chest tube was inserted and connected to a closed suction device. It showed a large air leak followed by intermittent air leak. The patient had immediate clinical improvement, and her respiratory rate dropped to 20 / minute and pulse to 94 / minute and she was maintaining oxygen saturation of 98% at room air. She was admitted to the ward and treated as a case of right-sided spontaneous pneumothorax. Repeated chest X-ray showed incomplete lung expansion. Patient was assessed by the Obstetrician and obstetrical ultrasound examination showed a single viable fetus with parameters corresponding to a gestational age of 20 weeks. On the 6th postadmission day, the patient developed low-grade fever along with a rise of white cell count to 18000/mm 3 . The drainage of the chest tube changed from serous to turbid fluid with persistent intermittent air leak. A CT scan of the chest with abdominal shield was performed. It showed a cavitating lesion in the right middle lobe, surrounded with patchy fibrotic changes. It measured 4.5 x 1.5 cm in transverse and antero- posterior diameters respectively. It was communicating laterally with the pleural space and medially with lateral segment of the right middle lobe, thus creating a ruptured focal lesion, with formation of bronchopleural fistula (Figure 2). Based on these findings, the differential diagnosis was ruptured hydatid cyst, necrotizing infection (tuber- culosis or fungal), or a cavitating malignant lesion. ABSTRACT Hydatid disease in pregnancy is a rare condition. Ruptured pulmonary hydatid cyst with pneumothorax during pregnancy is potentially serious for both the patient and the fetus. Diagnosis, treatment, and the mode of delivery of the infant all present complex problems related to this event. We describe here a case of pneumothorax occurring during pregnancy secondary to ruptured pulmonary hydatid cyst with a good outcome for both the mother and the fetus. Key words: Pulmonary hydatid cyst. Rupture. Pneumothorax. Pregnancy. Department of Thoracic Surgery, King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia. Correspondence: Dr. Iftikhar Ahmed, Department of Thoracic Surgery, King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia. E-mail: iftikhardoc90@hotmail.com Received April 20, 2011; accepted September 29, 2011 Pneumothorax in Pregnancy Secondary to Ruptured Pulmonary Hydatid Cyst Iftikhar Ahmed, Waseem Hajjar, Ahmed Nageeb Alakeed, Salah Rahal, Zohair Alhariri and Sami Alnassar CASE REPORT Figure 1: Large right-sided pneumo- thorax with collapsed lung. Figure 2: Cavitatory lesion middle lobe.