Iatrogenic gas embolism in a juvenile loggerhead sea turtle (Caretta caretta): clinical and pathological study

Abstract

Gas embolism in sea turtles is a clinical condition characterized by the appearance of nitrogen bubbles in the cardiovascular system and other tissues as a consequence of rapid decompression, whose effective treatment is hyperbaric oxygen therapy (HBOT). The usage of hyperbaric chambers for several treatments in human medicine is not exempt from risk; however, there is no description of similar accidents in sea turtles. The aim of this study was to describe from a clinical and pathological point of view an unusual case of iatrogenic gas embolism in a stranded juvenile loggerhead turtle (Caretta caretta). The stranded turtle showed buoyancy disorder and was very weak. A mild pneumocoelom was diagnosed using CT scan examination. An ultrasound-guided puncture allowed to extract 22 ml of gas, but the turtle got worse and HBOT was performed. After that, the turtle showed signs of subcutaneous emphysema and was found dead the next morning. Gross lesions included generalized subcutaneous emphysema, gas bubbles in the mesenteric, gastric and hepatic veins, and right atrium, a gas-filled saccular bulla emerging from left lung, and diffuse hemorrhages in cerebral hemispheres, optic lobes, and cerebellum. Histological lesions included gas emboli in the right atrium and blood vessels of spleen, thymus, lung, kidney, and intestinal serosa. Severe meningeal hemorrhages were observed in addition to presence of gas emboli in the lumen of meningeal blood vessels. This is the first description of iatrogenic gas embolism in a sea turtle. Two factors contributed to this outcome: the existence of a probably unresolved pneumoceloma, and the application of HBOT without an initial diagnosis that would accurately indicate its use. As in human medicine, the application of HBOT in sea turtles with lung lesions and pneumoceloma is therefore discouraged.