Chapter 17 Diagnosis of and Treatment Options for Disorders of the Spine 443Case Study 17.1 Acute onset tetraparesis
Signalment: 12‐y.o. M/N Australian Shepherd pre-
sented as acute asymmetrical, severely tetraparetic
emergency.
History: Patient is an active swimmer. Was swimming
in the client’s pool when he cried out and was taken
from the water by clients.
Examination: Patient bright and alert and not in sig-
nificant discomfort. Paresis very lateralized to the
right, involving right pelvic limb and left pelvic limb
to a much greater degree than left forelimb although
all four limbs were weaker than expected and patient
unable to stand.
Neurological examination:
● Bright and alert
● All cranial nerve reflexes WNL
● Tetraparetic with right side weaker than left
● Knuckling of feet evident in both pelvic limbs but
neither thoracic limb
● Right‐sided sympathetic palsy: Horner’s syndrome
● Increased tone in both thoracic limbs
● Stretch reflexes present and symmetrical in all four
limbs
● Response to noxious stimuli symmetrical and
appropriate in the pelvic limbs including percep-
tion and withdrawal
● Perception of noxious stimuli present in thoracic
limbs but withdrawal diminished.
Neuroanatomical localization: C6 to T2.Discussion: The acute nature of this incident makes an
infarction or intervertebral disc prolapse most likely.
Although the patient did not seem to be in any dis-
comfort, he did resist movement of his head and neck
to the left. The decrease in the withdrawal response
and the lateralization of these clinical signs would
make one consider a lesion, most likely localized to
the left side of the cervical intumescence. The Horner’s
syndrome is more commonly seen with acute spinal
cord disease, with severe spinal cord compression or
intramedullary disease.
The acute nature and severity of the clinical signs
would make one want to obtain a specific diagnosis.Outcome: This patient had an osteosarcoma of the sec-
ond thoracic vertebra (Figure 17.24). This was an unex-
pected outcome as the signs were acute and the dog
was not in very much pain. The localization was slightly
more caudal than would have been expected and there
was likely a shift of soft tissue (neoplasm) that occurred
while swimming. There was no obvious pathological
fracture. The neoplasm was surgically removed and
was followed with chemotherapy.
Osteosarcoma of the axial skeleton is often not as
aggressive as the same neoplasm affecting the limbs.
The author (HSS) has followed one dog for 4 years and
two dogs for more than 2 years, all with histological
diagnoses. All had surgical decompression and fol-
low‐up chemotherapy.(A) (B)Figure 17.24 (A) CT with contrast showing the spine at the level of T1 of a dog that became acutely tetraparetic
while swimming. (B) CT with contrast showing T2 of the same dog. Although his signs were acute it is obvious that
this osteosarcoma caused destruction of the vertebra over some period of time.