Ectopic pregnancy with associated gestational choriocarcinoma in a California sea lion (Zalophus californianus).

A wild-born, captive-reared, 14 yr old, primiparous female California sea lion Zalophus californianus presented for anorexia of 14 d duration and abdominal distention. Routine complete blood cell count revealed leukocytosis with a neutrophilia, and serum chemistry revealed hypoalbumenemia and hyponatremia. Treatment with broad spectrum antibiotics and non-steroidal anti-inflammatories were started, but the animal continued to decline. Abdominal radiographs revealed a mature mineralized fetal skull and spine in the caudal abdomen and abdominal ultrasound revealed ascites but could not confirm the fetus. The patient was taken to surgery where a full term fetus was found outside of the uterus but within the fetal membranes, representing a secondary ectopic pregnancy. The patient passed away during surgery and was taken to necropsy. Gross necropsy revealed a diffuse peritonitis with yellow deposits over the serosal surfaces of the abdominal organs. The uterus appeared intact grossly and the ovaries appeared abnormal. The mesenteric, renal, and sub-lumbar nodes were enlarged and edematous. Histopathology revealed choriocarcinoma in the right uterine horn with evidence of chronic uterine rupture and protrusion of the placental tissue into the abdomen. The choriocarcinoma had metastasized locally as well as to the liver, spleen and lung. Choriocarcinoma is a highly malignant trophoblastic neoplasm that is rare in domestic animals. This case represents, to the authors' knowledge, the first report of gestational choriocarcinoma causing secondary ectopic pregnancy in a California sea lion and presents questions regarding pregnancy monitoring and management in a population of captive, minimally trained California sea lions.

INTRAPERITONEAL DEXTROSE ADMINISTRATION AS AN ALTERNATIVE EMERGENCY TREATMENT FOR HYPOGLYCEMIC YEARLING CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS).

The Marine Mammal Center (TMMC) cares for malnourished California sea lion (CSL) (Zalophus californianus) pups and yearlings every year. Hypoglycemia is a common consequence of malnutrition in young CSLs. Administering dextrose during a hypoglycemic crisis is vital to recovery. Traditional veterinary approaches to treat hypoglycemia pose therapeutic challenges in otariids, as vascular access and catheter maintenance can be difficult. The current approach to a hypoglycemic episode at TMMC is to administer dextrose intravenously (i.v.) by medically trained personnel. Intraperitoneal (i.p.) dextrose administration is an attractive alternative to i.v. administration because volunteer staff with basic training can administer treatment instead of waiting for trained staff to treat. This study compares the effects of i.v., i.p., and no dextrose administration on serum glucose and insulin in clinically healthy, euglycemic CSL yearlings. Three groups of animals, consisting of five sea lions each, were treated with 500 mg/kg dextrose using one of the following routes: i.v., i.p., or no dextrose (control). A jugular catheter was placed, and blood samples were collected at times 0, 5, 15, 30, 60, 120, 180, and 240 min after dextrose administration. I.v. dextrose administration resulted in an increase of serum glucose concentrations from a baseline level of approximately 150 mg/dl to a peak of approximately 350 mg/dl. The resulting hyperglycemia persisted for approximately 2 hr and was associated with an attenuated plasma insulin response compared with most terrestrial mammals. Intraperitoneal dextrose administration resulted in increases of serum glucose to approximately 200 mg/dl, which gradually declined to baseline by 2 hr after dextrose administration. These data suggest that the initial treatment of a hypoglycemic crisis in young malnourished CSLs can be accomplished with i.p. dextrose, thus enabling minimally trained volunteer staff to respond immediately to a crisis. Further studies are needed to determine the most appropriate long-term treatment.

Algal toxin impairs sea lion memory and hippocampal connectivity, with implications for strandings.

Domoic acid (DA) is a naturally occurring neurotoxin known to harm marine animals. DA-producing algal blooms are increasing in size and frequency. Although chronic exposure is known to produce brain lesions, the influence of DA toxicosis on behavior in wild animals is unknown. We showed, in a large sample of wild sea lions, that spatial memory deficits are predicted by the extent of right dorsal hippocampal lesions related to natural exposure to DA and that exposure also disrupts hippocampal-thalamic brain networks. Because sea lions are dynamic foragers that rely on flexible navigation, impaired spatial memory may affect survival in the wild.

Inflation and deflation pressure-volume loops in anesthetized pinnipeds confirms compliant chest and lungs.

We examined structural properties of the marine mammal respiratory system, and tested Scholander's hypothesis that the chest is highly compliant by measuring the mechanical properties of the respiratory system in five species of pinniped under anesthesia (Pacific harbor seal, Phoca vitulina; northern elephant seal, Mirounga angustirostris; northern fur seal Callorhinus ursinus; California sea lion, Zalophus californianus; and Steller sea lion, Eumetopias jubatus). We found that the chest wall compliance (CCW) of all five species was greater than lung compliance (airways and alveoli, CL) as predicted by Scholander, which suggests that the chest provides little protection against alveolar collapse or lung squeeze. We also found that specific respiratory compliance was significantly greater in wild animals than in animals raised in an aquatic facility. While differences in ages between the two groups may affect this incidental finding, it is also possible that lung conditioning in free-living animals may increase pulmonary compliance and reduce the risk of lung squeeze during diving. Overall, our data indicate that compliance of excised pinniped lungs provide a good estimate of total respiratory compliance.