Spontaneous rupture of lung echinococcal cyst causing anaphylactic shock and respiratory distress syndrome.

A 21 year old woman was admitted to hospital with a persistent productive cough, dyspnoea, and fever. There was no history of sweats or haemoptysis. At admission a chest radiograph showed a 6 cm lesion at the base of the left lower lobe with an air fluid level (fig 1A) and an additional cavitary lesion in the left apex. The blood count was within the normal range with 0.7% eosinophils. Five days later the patient developed severe respiratory distress and her oxygen saturation on room air fell to 82%. She was intubated and mechanically ventilated. At this time the eosinophil count had increased to 10%. Over the following few hours the patient developed shock with a blood pressure of 85/40 and worsening hypoxaemia (saturation 75% on 100% oxygen). The mode of ventilation was changed to pressure control without significant improvement in blood oxygenation. The eosinophil count reached 16.9% (total 12 800) and the chest radiograph showed bilateral infiltrates compatible with ARDS (fig 1B). Fibreoptic bronchoscopy with bronchoalveolar lavage (BAL) showed no evidence of bronchial obstruction. Multiple blood and BAL cultures were negative for microorganisms, but pathological examination of the BAL fluid revealed numerous echinococcal scolices (fig 2). A combined regimen of albendazole and praziquantel was started together with high dose intravenous steroids. Four weeks later she was discharged in a stable condition on albendazole for 3 months. The patient then