Acute Painful Tetraparesis in a Dog

History

A 6-year-old spayed Shih Tzu was presented with a one-day history of an acute progressive weakness affecting all limbs. The dog had not showed a similar event previously and had been systemically healthy. The dog was routinely vaccinated and up-to-date on parasite prophylaxis. There was no access to toxins that the owners were aware of and no known traumatic event. However, the owners noted that the dog would frequently jump on and off their bed, occasionally falling when doing so.

Physical Examination

The rest of the examination was unremarkable.

Neurologic Examination

• Mentation – Appropriate but depressed.

• Posture – A ventroflexed neck was noted, suggestive of cervical weakness or pain.

• Gait – The dog was ambulatory with assistance but exhibited a profound tetraparesis with frequent collapse of the thoracic limbs. No ataxia was noted but was difficult to assess due to the dog’s inability to move with reasonable strength.  There was more profound weakness noted on the dog’s right side.

• Postural reactions – The dog’s proprioceptive placing was reduced to absent in all limbs and was, again more severe on the right side.

• Cranial nerves – All intact and unremarkable.

• Spinal reflexes – The thoracic limbs both had reduced tone and flexor withdrawal reflexes that were worse on the right. The pelvic limbs had increased tone and intact to exaggerated reflexes.

• Spinal pain – The dog exhibited pain on neck palpation but was comfortable on palpation of the thoracolumbar spinal column.

Where would you localize this Lesion to? 

Lesion Localization:

C6-T2 spinal cord segments

Differential Diagnoses (acute painful C6-T2 spinal cord lesion):

• Degenerative disc disease and type-I extrusion

• Trauma (causing fracture or luxation of the vertebrae or even hemorrhage)

• Inflammatory disease

• Possible neoplasia of the vertebra, meninges, or spinal cord.

The latter two are not frequently so acute in onset; however, they may be perceived as acute by the owners or may cause hemorrhage, resulting in sudden onset of clinical signs.

Diagnostics

• Minimum database of hematology, serum biochemistry urinalysis, and thoracic radiographs. These were all considered to be normal.

• Survey radiographs of the cervical spinal column, also considered to be normal.

• A CSF tap at the atlanto-occipital cistern after the dog was anesthetized. The tap was analyzed and reported to be within normal limits.

• A cervical MRI revealing a large compressive lesion at the C6-C7 intervertebral disc space situated ventrolaterally on the right. The signal characteristics and the lesion location were compatible with an acute intervertebral disc extrusion.

Outcome

A ventral slot surgery was performed to decompress the spinal cord. Copious amounts of disc material were removed from the canal and the cord was visible following this decompression. The dog was ambulatory without assistance within 24 hours of the surgery. The dog was strictly rested for a month and treated with pain relievers for 7 days postsurgery. Sutures were removed 10 days after surgery and the dog was reported to be ambulatory with minimal deficits present in the pelvic limbs. The dog went on to make a full recovery over the following 2 months.