Spontaneous rupture of giant hydatid cyst of lung into left bronchus: Preoperative diagnosis and treatment

Introduction: Hydatid disease is a parasitic infestation caused by Echinococcus granulosus in which human is accidental intermediate host. Lung is the most common site involved in children unlike adults, where liver is involved. Case report: 13-year-old girl who was asymptomatic, was found to have reduced air entry on left side during health checkup. Chest radiography (CXR) was suggestive of radio-opaque lesion obscuring left cardiac border and left dome of diaphragm. CT chest report was suggestive of intrapulmonary hydatid cyst. However, few hours after admission, she developed anaphylactic reaction which was managed successfully with adrenaline and steroids. Repeat chest readiograph was suggestive of decreased opacity, air fluid level noticed on dependent part of left lung. Rupture of the cyst was suspected. She underwent left thoracotomy and evacuation of hydatid cyst was done. Intra-operative findings were suggestive of broken endocyst, thoracic cavity filled with fluid with multiple bronchial openings. Conclusion: Hydatid cyst despite of its thick covering layers, undergoes spontaneous rupture occasionally. Anaphylactic shock due to rupture of cyst is a life threatening complication.