Traumatic amputation may occur in marine mammals due to fighting, interactions with predators or due to human interaction (boat strike, entanglement). Below is an example of traumatic amputation in an elephant seal weaner. This radiograph was taken during a recheck examination following surgical debridement of the digit. The right hind flipper is labeled with a radiopaque ‘right’ marker. The distal and middle phalanges of the 1st digit of the left flipper are absent.

Young California sea lions tend to get themselves in trouble! This young male sea lion was received into rehabilitation with a large swelling of the left inguinal region and hind flippers. An inguinal hematoma was the diagnosis (note the soft tissue swelling on the right of the image). Inguinal abscesses and hernias have also presented similarly. Ultrasound was used to guide the needle for fine needle aspirate of the lesion and to ensure that no intestinal loops could be identified within the swelling.

California sea lions are particularly inquisitive and playful with objects they find. They aren’t shy to steal a meal from someone else! The example below is a radiograph taken of an adult, male sea lion who had partially swallowed a fishing line....probably after trying to steal the fish off of it. The line including several hooks are lodged in the esophagus. Below the radiograph is how he appeared at the time of rescue.

Verminous pneumonia in California sea lions is usually caused by Parafilaroides decorum, although Otostrongylus circumlitus infection has also recently been described in this species. The hair-like worms can be readily identified on necropsy evaluation of the lungs by scraping a cut lung surface. Clinical signs are most evident in yearlings although all age groups post-weaning are usually infected.

Radiographically, signs include a bronchointerstitial pattern with a miliary nodular component representing inflammation in response to the worms with small parasitic granulomas evident within the interstitium or close examination. Secondary bacterial pneumonia may follow and alveolar infiltrates are often readily discernible.

In this case, the animal had been heard to cough and had harsh lung sounds on auscultation. Note the marked, diffuse bronchointerstitial pattern throughout all lung fields with air bronchograms in the left cranial lung lobe (on the right of the image) indicating an additional lobar alveolar pattern. The lucent lines through the long bones of the pectoral flippers are physes and confirm this animal is skeletally immature.

ALVEOLAR DISEASE AND PLEURAL EFFUSION IN A NORTHERN ELEPHANT SEAL

Northern elephant seals normally have rounded lung margins and poor cardiac margins (see Normal radiographic anatomy). However pleural effusion may be seen due to pleuropneumonia or in animals with Otostrongylus infection. Below is a radiograph demonstrating the appearance of both pleural effusion (red arrow) and a pulmonary alveolar pattern (either due to consolidation or possibly atelectasis, blue arrows). Air bronchograms indicate an alveolar pattern and are evident in both caudal lung lobes, but are most evident on the left. The right side of the animal is on the left of the image. At necropsy this seal had Otostrongylus which results in pulmonary thromboemboli, pulmonary hemorrhage and heart failure.

POSITIVE CONTRAST STUDIES

ESOPHAGEAL MOTILITY DISORDER

Below are radiographs of an adult pacific harbor seal. She had been regurgitating. Plain radiographs were suspicious for megaesophagus. After a period of training, the seal would voluntarily accept a feeding tube for barium administration. Radiographs were taken using conventional film-screen and digitized by taking a digital photo at high resolution while the film was hung on a lightbox. The VD view was taken 1 minute post barium administration (right side of the animal is to the left of the image), and the lateral taken at 3 mins post barium administration (the head is towards the left side of the image). Barium has reached the stomach, but a significant quantity has remained within the thoracic esophagus. Several filling defects are evident and consistent with fish chunks given as part of her behavioral training.

Food and liquid boluses pass down the esophagus via peristalsis. Primary peristalsis should propel the food to the caudal esophagus and if insufficient to clear food into the stomach, secondary peristalsis is stimulated. While a small volume of barium remaining adhered to mucosal folds is normal in such a study, the retention of large volumes of barium (and fish) in the esophagus so long after administration is not. It indicates motility dysfunction. In addition in this case the small intestines are uniformly gas filled throughout. This is indicative of a functional ileus as opposed to a mechanical ileus due to obstruction. The final diagnosis for this individual is still pending but a diffuse motility disorder such as dysautonomia is being considered. Other differentials include diffuse severe inflammation, hypocalcemia and toxic ingestion such as lead or zinc.

Note also the irregularity of the middle phalanx of the Rt 2nd digit with subtle soft tissue swelling surrounding it - this may be an old fracture or osteomyelitis. The reduced joint space between the middle and distal phalanx indicates either subluxation or loss of articular cartilage. Collimated, orthogonal projections would be needed for further evaluation.