A Cluster of Cases of Intervertebral Disc Disease (IVDD) in a Family of Asian Small-Clawed Otters (Aonyx cinereus)
Intervertebral disc disease is characterized by degeneration of discs between the vertebrae resulting in bulging or herniation of disc material which can compress the spinal cord or spinal nerves resulting in clinical signs. It is a multifactorial disease process influenced by genetic and environmental factors. In humans, it is estimated that genetic factors contribute about 75% to IVDD etiology.1
Four Asian small-clawed otters (Aonyx cinereus) presented with acute paraparesis to paraplegia of both hind legs. In all cases there was no known trauma. The first animal to demonstrate clinical signs was the patriarch of the group and three out of his six offspring have subsequently shown similar clinical signs. Age of onset was 11 years for the sire and 6–7 years for the offspring. Gender did not appear to be a risk factor as cases were equally split between males and females. Three of these cases resolved with medical management consisting of exercise restriction and intravenous (15 mg/kg methylprednisolone sodium succinate once) or oral corticosteroids (tapering dose of prednisolone starting at ∼0.5 mg/kg BID). The fourth case exhibited minimal motor movement of the hind end with no appreciable improvement after 24 hours with medical management. She was anesthetized for MRI which confirmed disc extrusion and spinal cord compression at T14-L1 and a hemilaminectomy was performed. Post-operatively, she showed progressive clinical improvement and regained full motor function within 6 weeks.
The authors would like to thank the Animal Health and Husbandry Department at SeaWorld Orlando for their dedication and assistance in these otters’ care and Affiliated Veterinary Specialists in Maitland, FL for their assistance with imaging and surgery.
* Presenting author
1. Martirosyan NL, Patel AA, Carotenuto A, Kalani M, Belykh E, Walker CT, Preul, MC, Theodore N. 2016. Genetic alterations in intervertebral disc disease. Front Surg. 3:59.