Intrathoracic rupture of hepatic hydatid cyst is a rare clinical pathology with a reported frequency of 0.6 to 1.6% in adult population [4]. The rupture into the pleural cavity is less common than in the bronchial tree [5]. Several factors explain this complication: the negative intrathoracic pressure which tends to aspirate the hepatic hydatid cyst, the mechanical compression exerted by the cyst on the diaphragm leading to muscles erosion, the infection of the cyst leading to muscle necrosis, and in the case of biliary fistulas, the caustic feature of the bile caused a chemical erosion of the diaphragm, lung, and pleura [6]. This complication results from the long evolution of a hydatid cyst of the hepatic dome and generally reported in young adults [3, 7]. Caustic action on the lung or bronchial tree caused by the bile will damage the pulmonary parenchyma with lesions ranging from simple hydatid pneumonia to the constitution of a cave. Once the cyst gets through the diaphragm, different lesional aspects may result, classified according to Mestiri et al. into 4 types and 9 subtypes [8]. Referring to this classification, our patients are classified respectively as type IVb and Ib.
Intrathoracic rupture is usually revealed through respiratory and thoracic symptoms. Hydatic vomica and pathognomonic hydatidoptysis of hydatid disease are less commonly reported [3].
Chest X-ray is not very helpful. It shows a right lower lobe opacity or pleural effusion. An ultrasound exam is essential for some authors as it shows the hepatic hydatid cyst and its close connection with thoracic lesions, visualizes the diaphragmatic discontinuity, highlights thoracic lesions, and explores the biliary tract [3]. However, CT scan is more effective than ultrasound in assessing pulmonary pleural and parenchymal lesions [3]. In our patients, the chest X-ray showed right sided pleural effusion. The lack of clinical improvement leads us to suspect lung hydatid cyst rupture in the pleural cavity as our patients come from an endemic echinococcosis area. We completed this by CT scan to establish our diagnosis.
The surgical approach to treat hepatic hydatid cyst with thoracic involvement is controversial [3, 4, 9]. Surgery can be performed by thoracotomy only, thoraco-phrenolaparotomy, laparotomy only, or associated with thoracotomy [7]. The abdominal approach enables to treat the liver cyst, to evacuate the pleural cavity through the diaphragmatic breccia and to restore the diaphragm [9]. The treatment of pleuropulmonary lesions have been reported to represent the limitation of this approach in adult because the important lesions of the pulmonary parenchyma required a regulated resection such as lobectomy or segmentectomy [3, 7]. The thoracic approach offering adequate access to treat both thoracic and abdominal lesions is defended by some authors [4, 5, 10, 11].
In pediatrics population, surgery must be conservative and most of pulmonary lesions caused by hepatic hydatid rupture are minimal and located on the lower or middle pulmonary lobe [5, 7]. That is why we prefer abdominal approach only to treat hepatic hydatid cyst with thoracic involvement. For our first patient, given the absence of significant pleuro-pulmonary lesions, the abdominal approach proved to be effective and safe. For the second patient bronchial fistulas treatment was impossible by the laparotomy which required additional thoracic approach.
Medical adjuvant treatment is indicated when hydatid disease dissemination and total cysts resection is not possible. Albendazole (10 mg/kg/day given b.i.d) for 6 months is the current recommended therapy when indicated. Prophylactic measures should always be taken in endemic areas [11].
Despite diagnosis and therapeutic progress, this complication has high mortality and recurrence rate (7.5%; 16%) [3,4,5].
