Iatrogenic deadly pulmonary trauma and pneumomediastinum in a young sea lion

Abstract

A young male South American sea lion (Otaria byronia) of three years old died eight days after starting of molting hair. Along those days the animal did not eat showing weakness and dehydratation. Treatment consisted on glucose serum orally and subcunateously, antibiotics and cortisone. The previous day to its death, subcutaneous emphysema was clearly noticed in the head and the thorax. A complete necropsy was carried out only 4 hours postmortem. Tissue samples were fixed in 10% buffered formalin and embedded in paraffin, sectioned and stained with Haematoxylin and Eosin for a routine light microscopical study. During necropsy, distension of the pulmonary visceral pleura associated with a severe pneumomediastinum which extended craneally, as well as subcutaneous emphysema, was observed. No inflamatory, degenerative or neoplastic lesions were detected. Virological and bacteriological analysis were negative. Gas samples were taken with a five mililitres vacutainer without additives and analyzed using the same method as described previously by Pierucci G. & Gherson G. in 1968 for the corresponding analysis. Microscopical studies revealed severe interstitial and alveolar emphysema in both lung lobules involving some subpleural areas. Results from gas analyses were similar to the definition of air embolism stablished by (Pierucci G. & Gherson G.,1968; Pedal et al., 1987; Bajanowski et al., 1998). Morphological diagnosis was defined as a severe diffuse pneumomediastinum caused by the distension of the pulmonary visceral pleura during forced intraesophagic intubation when trying to feed the sea lion. Pneumomediastinum and subcutaneous emphysema due to intubation have been previously described in humans, dogs and cats. We report a case of diffuse severe deadly interstitial emphysma and pneumomediastinum iatrogenically caused in a young sea lion. In order to demonstrate the air nature of the gas trapped in those mentioned anatomical areas, gas analysis was additionally done.