Abstract

At Atlantis The Palm - Dolphin Bay, a 10 year old female Indopacific bottlenose dolphin (Tursiops aduncus) presented with occasional episodes of mild leukocytosis (8,500 to 10,000 cells/mm3) with no associated clinical signs. Her white blood cell count was consistently on the high end of the average values observed in the collection. In April 2012 an acute leukocytosis (up to 24,700 cells/mm3 with a total count of neutrophils of 20,000/mm3) was observed and showed no response to antibiotic therapy with levofloxacin (7 mg/kg PO SID) but slowly responded over a period of 10 days to ceftriaxone (20 mg/kg IM SID) and amikacin (7 mg/kg IM BID) and maintained response with azithromycin (7–5 mg/kg PO SID).

During September 2012, a set of radiographs were performed to evaluate the lungs and abdominal cavity. A radiopaque triangular-shaped foreign body was identified, ventral to lumbar spine. The adjacent lumbar vertebras presented with bony proliferation, narrowing of disc spaces and irregularity of the end plates. The imaging of the structure showed that it was deep in paraspinal musculature and surrounded by a small halo of anechoic fluid but also seemed to extend to the retroperitoneal space.

During November, 2012 a CT scan was performed to better evaluate the location and extension of the affected areas. The exam confirmed the mineralized structure revealing a two layer structure with a central linear core and a circumferential second mineralized layer. The foreign body was located caudal to the kidney, partially within the left ventral paraspinal musculature (approximately 1/3 of length) and partially within the retroperitoneal space (approximately 2/3 of length).

The final diagnosis was a suspected migrating foreign body (possibly a stingray barb) with associated discospondylitis with osteitis. The calcification seemed to indicate a long term process and imaging of the area has shown its presence since 2010 but it had never been correlated to a disease process before.

The animal additionally presented with positive titers for Brucella (dolphin specific indirect enzyme-linked immunosorbent assay [iELISA]) and is currently under long term doxycycline therapy (2.5 mg/kg PO BID) with stable blood results and behaviorally normal.

Future steps will involve possible fine needle aspirate under ultrasound guidance to identify if an infectious agent is associated with the foreign body, a retrospective serial study of Brucella seroprevalence and antibiotic rotation. Surgery to remove the foreign body is not under consideration at this time. Local antibiotic impregnated-biodegradable microspheres based on culture results might be a promising local therapy in long term disease management.

This case has shown that, despite an otherwise asymptomatic state, subtle blood changes should always be taken in consideration and investigated with additional diagnostic tools. The isolation of an infectious agent and surgical intervention might be critical for the long term success of any therapy and control of vertebral disease progression.

* Presenting author