Hind limb paresis in a South African fur seal

Abstract

A 19 year old, female, South African fur seal (Arctocephalus pusillus pusillus) was initially evaluated in April of 2007 for intermittent right forelimb lameness. Upon physical examination, the patient reacted painfully when the right forelimb was palpated proximally, but no external lesions were present. No other abnormalities were found at that time. Subsequent radiographs of her right forelimb and vertebral column showed no significant abnormalities. The condition was minimally responsive to pain medications. In January 2008, she had an acute onset of paraparesis with no conscious movement present in either hind limb. Nocioception was also absent in the hind limbs. The paraparesis was not responsive to anti-inflammatory, antibiotic, or antifungal medications. Radiographs of her vertebral column showed no abnormalities, but a thoracic radiograph revealed a large mass of soft tissue opacity cranial to the heart at the area of the thoracic inlet. MRI confirmed the presence of this mass. Due to declining condition and a poor prognosis, the patient was euthanized and submitted for necropsy. A large soft tissue mass was found at the area of the thoracic inlet. The mass was infiltrating the tissues of the right forelimb, and was also causing an extradural compression of the spinal chord by penetrating through the C6-C7 intervertebral foramen. A histopathologic diagnosis has not yet been obtained.