A 37-year-old nonsmoker man without any known comorbidity presented with complaints of dull aching pain on the left side of the chest for 2 months and dry cough associated with shortness of breath for 7 days. He was a villager and a farmer by occupation. Respiratory system examination revealed an air–fluid level in the left hemithorax indicated by the presence of shifting dullness and succession splash. The chest radiograph confirmed the presence of hydropneumothorax on the left side. Intercostal tube drainage was done. The complete hemogram showed mild leukocytosis with an absolute eosinophil count of 980/ml. The metabolic panel, including renal and liver function tests, was normal. Pleural fluid was serous, exudative, and eosinophilic with adenosine deaminase of 23 units/L. Repeat chest X-ray revealed a cavity in the left mid and lower zone containing a crumpled membrane-like structure that seemed to float at a fluid level [Figure 1]. Computed tomography of the chest showed a cystic lesion in the left lower lobe with a wavy membranous structure floating in the air–fluid interface, suggesting collapsed endocyst. This is named as water-lily or camolette sign [Figure 2]. This is one of the characteristic radiological signs of a ruptured hydatid cyst. In a serological study, enzyme-linked immunosorbent assay (ELISA) detecting immunoglobulin G (IgG) against antigen B was positive. The patient underwent cystotomy plus capitonnage along with decortication. He was put on oral albendazole therapy at a dose of 400 mg twice daily.
Hydatid cyst or echinococcosis is a zoonotic disease caused due to infestation by the larval form of the parasite Echinococcus. Humans are the accidental host as they get infected by ingesting contaminated water or vegetables. The lung is the second-most common organ involved, following the liver. Cysts are usually detected incidentally as they are slow growing. Larger cysts cause compressive symptoms such as chest pain, dry cough, and dyspnea. Sudden-onset dyspnea, cough, severe chest pain, fever, and anaphylactic reactions may indicate cyst rupture. In our case, the cyst might be present for a longer time, but the rupture was suggested by acute-onset dry cough and dyspnea. The rupture of a cyst may be partial or complete. Following complete rupture, a cyst may communicate with bronchus or pleural cavity, leading to partially or fully emptying its content. Pleural rupture leads to the development of hydrothorax or hydropneumothorax. In rare instances, acute pulmonary embolism has been described after rupturing of the cyst. Imaging characteristics aided by serological tests usually make the diagnosis. Various characteristic radiological signs have been described in the context of a ruptured cyst [Table 1].[2,3] ELISA and indirect hemagglutination tests are the most commonly applied methods for detecting anti-Echinococcus antibodies. It is reported that echinococcal IgG ELISA is the most sensitive test for the detection of hydatidosis. The differential diagnoses usually include lung abscess, cavitary tuberculosis, infected benign cysts, and cavitating neoplasms. In these conditions, rupture into the pleural cavity may also lead to hydropneumothorax or pyopneumothorax. Surgical removal of the cyst is the treatment of choice for the ruptured cyst. The operative intervention should be applied soon after the diagnosis is confirmed. The surgical interventions usually target either removal of the content of pericyst or complete cyst excision with an aim to preserve the lung parenchyma. The conservative surgical approach is cystotomy with capitonnage. The posterolateral or lateral thoracotomy approach is used to remove endocyst and other remnants. Albendazole therapy should be considered postoperatively for 6 months to prevent a recurrence. The usual dose is 15 mg/kg daily in two divided doses along with a fatty meal. Since rupture of pulmonary hydatid cyst is seen in up to 90% of cases, the clinicians must be aware of such presentation and management of the pulmonary hydatid disease.
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The authors certify that they have obtained appropriate patient consent form. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
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The authors followed applicable EQUATOR Network guidelines, notably the CARE guideline, during the conduct of this report.
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