Eventration in Green Iguana (Iguana iguana)

Abstract

Background : The reptile class could be considered one of the biggest vertebrate groups and are divided in orders and suborders according to their characteristics. These animals’ maintenance in captivity, either at home, captive bred or at zoos, can generate risk to their health, if the required cares are not given for each respective species. The lack of individual cares could lead to bone and muscular diseases and to traumatic lesions in soft tissues, mainly in the coelomic cavity. The report that is being presented aims to describe the case of a green iguana ( Iguana iguana ) that presented an increase of volume in the coelomic cavity. The animal belongs to the squad of the Zoo “Dr. Fabio de Sa Barreto”. Case : A green iguana arrived at the Zoo in February 2019 coming from another Zoo, with already an increase of volume in the coelomic cavity. The animal was put in quarantine and later on, it was put in display at a terrarium in the Zoo considered adequate to reptiles, with another seven green iguanas along with an argentine tegu ( Salvator rufescens ). Their feed was offered in the morning and was composed of fruits, vegetables and flowers like hibiscus. In the end of July 2019, it was reported by the attendant that the animal was presented with anorexia and prostration, and these symptoms progressed to neurologic signs, as it walked in circles. So, the animal was evaluated by the Zoo veterinarians and on exam they noticed lethargy, dehydration, absence of reflexes (pupillary, eyelid and painful), locomotion difficulty and when the iguana moves, it walks in circles. The increase in volume had the same size as reported in February and a soft consistency. After that, the animal was interned and treated according to the symptoms and the clinical evolution. Ten days after the hospitalization, the animal was still not eating, and locomotion stopped completely. It was performed in an ultrasonographic exam evaluating all the coelomic cavity, in which a great anechoic area was visualized, and a true hernia was diagnosed. However, the content of the hernia was not identified. In the next day, the animal died, and, in the necropsy, it was possible to verify that the increase in volume was actually a bladder eventration. The eventration occurred due to a laceration in the coelomic cavity musculature that allows the passage of the bladder to the subcutaneous space and its incarceration. So, the elimination of the urine and of nitrogen compounds was difficult and a large accumulation of uric acid from the bladder to the urodeo. Discussion : Iguana iguana is a uricotelic animal, which means that the main nitrogenous waste product is uric acid. Nevertheless, ammonia is also eliminated in less quantity, because of the excess of protein in the diet. These animals eliminate around 98 to 99% of the nitrogen compounds as uric acid and less than 1% as ammonia, which prove that it is possible for the accumulation of ammonia in reptiles, if any obstacle in its elimination exists. The excess of ammonia is extremely toxic to the organism, leading to emesis, irritability, lethargy, anorexia, ataxia, motor difficulties, behavioral and neurological changes, and could progress to coma or even death. The bladder incarceration reported in this case, made it impossible for the excretion of urine, uric acid and ammonia, and these compounds remained accumulated. So, the clinical signs, along with the necropsy findings, were suggestive of intoxication by ammonia accumulation which could be responsible for the signs presented by the animal and the evolution to neurologic symptoms, coma and death.