Abstract

A six months old hooded seal (Cystophora cristata) was found stranded alive in a rocky shore of the Galician coast (NW Spain), in October 2001. After the clinical exploration and treatments for dehydration and a light respiratory affection, the animal was placed in a pool with other two hooded seals in rehabilitation.

At the end of January 2002, the seal decreased the food intake and the general activity. Blood collection for complete haematology and blood chemistry and a complete ultrasound examination were immediately performed. Moderate leukocytosis and hyperecoic ultrasound images into the stomach were the most remarkable findings. Gastric endoscopy and dorso-ventral radiographs were performed to obtain more information about the stomach contents. Results of both diagnostic procedures demonstrated the presence of seven rounded stones from 2 to 4 cm of diameter and one squared stone of 5 x 3 x 1 cm. All of them were in the pyloric portion of the stomach. A large amount of air into the intestine was also observed in the radiographs. At least three hooded seals in rehabilitation facilities in Spain during 2001 died because of foreign body ingestion: stones (2 cases) and sand (1 case).

The possibility of vomit induction was rejected to avoid oesophageal injuries due to the rough-surfaced squared stone, and surgical approach to the stomach and a gastrotomy to remove the stones were decided. A combination of Ketamine (4 mg/kg) and Midazolam (0'2 mg/kg) was used for sedation (I.M.) and 20 minutes later the same dosage was administrated as pre-anaesthesia (I.V.). An endotracheal tube was placed 15 min after the pre-anaesthesia administration and the surgical plane was maintained with halothane (3%).

The seal was placed in dorsal recumbency and the incision area was prepared aseptically for surgery. The abdomen was opened through the midline with a 15 cm incision from the caudal portion of the sternum towards the tail. The stomach was placed outside the abdominal cavity to prevent spilling gastric contents into it. The stomach and the portion of intestine placed out of the abdominal cavity were constantly moist with temperate saline solution. Severe congestion and some pre-necrotic areas were observed along the intestinal tube and mesentery. Mesenteric lymphatic nodes were enlarged and congestive. The stomach incision was made midway between the greater and lesser curvature of the stomach. The eight stones were easily removed with atraumatic forceps and a simple interrupted suture (with synthetic absorbable material, Vicryl 3/0) through all layers of the stomach wall was used for the incision closing.

The abdominal cavity was thoroughly lavaged with warm lactated Ringed solution to prevent the contamination by gastric spillage. Fur layer and skin were closed separately with a simple interrupted suture with synthetic absorbable material, Vicryl 2/0.

Intravenous fluid therapy with saline solution was given to the seal during the surgery and post-surgical period. An intravenous dosage of cephotaxime (40 mg/kg) was administrated at the end of the surgical procedures. The seal had a voluntary breathing during all the anaesthesia period and the seal recovered consciousness and motility one hour after the removal of the endotracheal tube. However, twelve hours after the surgery the seal died.

Histopathological, bacterial and viral analysis are being currently undertaken, but the vascular compromise and possible infection established in the gastrointestinal tract (due to the motility disorders produced by the presence of the stones and consequent bacterial overgrowth) seems to be the primary cause of the seal death as in the other three cases reported in Spain during 2001.

Although the immediate surgical action carried out in this case, and the similar clinical history and medical treatments described in the mentioned three cases, all of them resulted in the death of the seals. This fact strongly recommends quick and firm clinical actions when the first symptoms of foreign bodies ingestion appears. The possible reasons for ingestion of the stones are difficult to explain, but it has to be taken into account in the rehabilitation facilities design for this seal species.