Hydatidothorax.

A 12-year-old boy presented with cough, chest pain and fever for 15 days. Chest X-ray showed left hydropneumothorax [Figure 1a]. Intercostal tube drainage (ICD) was performed which drained pus. He was treated with antibiotics, with which he showed improvement in symptoms. Computed tomography of the thorax was performed [Figure 1b].

Figure 1a

Chest X-ray showing left hydropneumothorax

Figure 1b

CT thorax showing left hydropneumothorax, pleural thickening and hydatid membranes floating in the pleural fluid “serpent sign”

Q1. What is the likely diagnosis based on CT thorax?

ANSWER

CT thorax showed hydropneumothorax with pleural thickening. Additionally, “serpent sign”[1] suggestive of floating hydatid membranes was noted. Immune hemagglutination (IHA) against Echinococcus granulosus was positive. Albendazole 10 mg/kg was initiated and the patient was referred for surgical management. Open thoracotomy was performed; fluid evacuation with removal of hydatid membranes [Figure 1c] was followed by decortication. Patient had an uneventful recovery.

Figure 1c

Hydatid membranes removed from the pleural space

Intrapleural rupture of pulmonary hydatid cysts is relatively rare. Rupture of a hydatid cyst results in a pneumothorax or a hydropneumothorax. Over time, the pleural effusion gets infected resulting in empyema and pleural thickening. The diagnosis at this stage is difficult as there are no clinical symptoms or signs suggestive of hydatid disease. CT scan may be diagnostic as in this case. Serological investigations are positive in 60% of cases. Surgery is the treatment of choice.