Cervical Spondylomyelopathy : Wobbler

2. Cervical Spondylomyelopathy: Wobbler • Cervical spinal cord compression (C5-C7) as a result of caudal vertebral malformation or misarticulation. • Large breed dogs (Great danes and Dobermans) • Signs • Progressive hind-limb ataxia (wobbly gait) • Pelvic limbs cross each other when walking • Abduct widely/tend to collapse • May drag toes (wears dorsal surface of nails) • Impaired proprioception • Signs may also be present in front limb • Crouching stance with downward flexed neck • Rigid flexion of neck; may have neck pain

3. Cervical Spondylomyelopathy: Wobbler • Dx • Radiographs to show malalignment and narrowing of spinal canal • Myelogram is essential to locate the region of compression • CT and MRI if available

4. Cervical Spondylomyelopathy MYELOGRAM C6-C7

5. Cervical Spondylomyelopathy: Wobbler • Rx—without treatment, prognosis is poor • Medical • Anti-inflammatory doses of corticosteroids • Neck brace • Cage confinement • Surgical • Decompression of spinal cord by laminectomy • Stabilize vertebral column • screws and wire dorsally • spinal fusion ventrally

6. Cervical Spondylomyelopathy: Wobbler • Client info • Prognosis is guarded • Most likely a hereditary disease • Multiple levels of compression less favorable prognosis than a single area of compression • Surgery is risky and costly

7. Degenerative Myelopathy • Etiology—unclear • May be autoimmune response to antigen in nerv sys • Degeneration of white matter in ascending and descending tracts • ~ Multiple sclerosis - humans • Signs • Mainly in G Shep and Shep mixes (>5 yr) • Progressive ataxia and paresis of hind limbs (5-6 months) • Loss of proprioception is first sign • Dog “falls down” when trying to defecate • Muscle wasting of back muscles along caudal thoracic and lumbosacral areas • Symptoms progress until animal is unable to support weight on hind limbs

9. Degenerative Myelopathy • Dx— • Neurologic Exam • ↓ proprioception • ↑ patellar reflexes • Lack of pain • Normal sphincter tone; normal panniculus (pin prick) reflex • Radiographs usually normal • Rx—none; symptoms will progress to paralysis • Client info— • Degenerative myelopathy is a progressive, incurable disease • Although symptoms are similar at early stages, it is a different disease from hip dysplasia • When dog cannot support weight, quality of life should be evaluated

10. Degenerative Myelopathy

11. PERIPHERAL NERVOUS SYSTEM

12. Deafness 1) Damage to auditory pathway • chronic otitis • rupture of tympanic membrane • damage to middle ear (ossicles) 2) Damage to auditory nerve

13. Deafness 3) Hereditary or congenital • Bull terriers, Dobes, Rotts, Pointers, blue-eyed white cats, Dalmations, Aust Heelers, Aust shepherds, Eng setters, Catahoula 4) Related to drug therapy • Amimoglycosides (gentamicin, streptomycin, kanamycin • Topical polymyxin B • Chloramphenicol • Chlorhexidine w/ centrimide 5) Normal old age—usually due to atrophy of nerve ganglia or cochlear hair cells (also loud rock music)

14. Deafness • Dx— • Inability to rouse sleeping animal with loud noise (e,g,. blast from air horn) is diagnostic • Rx—No treatment is available in most cases • Hearing aids are available for animals, but most will not tolerate something in ear canal • Client info • Hearing loss is permanent • If hereditary, do not breed • Animals can be taught to hand signals rather than words • Animals should not be off leash when outside • Hearing aids are available for dogs but are usually not tolerated; would only be appropriate for hearing impaired

15. Laryngeal Paralysis • 3 types—always be cautious of laryngeal paralysis because of the chance of rabies • Hereditary—seen in Bouvier des Flandres and Siberian Huskies • Seen at 4-6 mo of age • Acquired—can occur from lead poisoning, rabies, trauma, inflammation of vagus nerve • 1.5 to 13 yr of age • Idiopathic—seen in middle-age to old large- and giant-breed dogs; castrated dogs and cats have a higher incidence than female and non-neutered males

16. Laryngeal Paralysis • Signs— • Inspiratory stridor • Resp distress • Loss of endurance • Voice change • Dyspnea/cyanosis/complete resp collapse • Dx—laryngoscopy will show laryngeal abductor m. (away from midline) dysfunction • Rx—surgical intervention including: • Arytenoidectomy • Removal of vocal folds • Client info—prognosis is guarded to good; do not breed if hereditary

17. Laryngeal Paralysis

18. Megaesophagus • Causes-lack of esophageal peristalsis (3 types): • Hereditary—a gene for the disease is identified in wire-haired fox terriers and min schnauzers • Congenital—G Danes, G Shepherd, I Set, Newfound, Shar-Peis, greyhounds (no gene ID’ed) • evident about weaning time when solid food is introduced • Due to incomplete nerve development in esophagus • Acquired—may be seen at any age; Pb tox; may be associated with neuropathies (e.g., myasthenia gravis, tick paralysis) • Signs • Regurgitation of undigested food • Respiratory problems (aspiration pneumonia) • Lack of growth

19. Megaesophagus Dx—barium swallow Esophagus is 3 times normal diameter

20. Megaesophagus • Rx— • Elevated feeding (on platform, stairs) • Liquid or soft diet high in calories • Give several small feedings daily • Gastrostomy tube (long term) is an option • Client info • Prognosis—guarded to poor • Treatment aim is to reduce clinical signs and prevent aspiration pneumonia • There is no cure

21. Tick Paralysis • Cause—female tick (Dermacenter variablis, D. andersoni) → salivary neurotoxin • Neurotoxin interfered with Ach at neuromuscular jct • Not seen in cats; humans are affected • Signs— • Gradual onset of voice changes and hind-limb ataxia (motor deficit) progressing to a flaccid, ascending paralysis (1-3 d) • Sensation is intact • Ticks on the dog • Rx • Remove ticks (manually or with dip) • Usually resolves in 1-3 d • Supportive care until dog recovers • Ventilation required for resp paralysis

22. Tick Paralysis

23. Coonhound Paralysis (Polyradiculoneuritis ) -thought to be an immune response to an unknown etiologic factor in raccoon saliva -some dogs will get it 1-2 wk after exposure, others exposed to same raccoon will not • Signs—(similar to tick paralysis and rabies) • Weakness begins in hind limbs with paralysis progressing rapidly to a flaccid tetraplegia • Alert, afebrile animal • Loss of spinal reflexes (patella tap, etc) • Loss of voice; labored breathing; inability to lift head • May die of resp failure • May last for 2-3 mo (usually good Px) • Rx—supportive nursing care • Client info— • Dogs can be affected without exposure to raccoon • May require long-term nursing care • Some animals will regain total function, while more severely affected animals may not

24. Idiopathic Facial Nerve Paralysis • Etiology—unknown • Occurrence • C Span, Corgis, Boxers, E Set, DLH cats • Signs— • Older dogs (>5 y) • Ear droop • Lip paralysis • Sialosis (drooling) • Deviation of nose • Collection of food in paralyzed side of mouth • Absence of menace and palpebral reflex

25. Idiopathic Facial Nerve Paralysis • Rx—efficacy of corticosteroids unknown • Artificial tears to prevent corneal ulcers • Keep oral cavity clear of food • Client info— • Cause is unknown • Complete recovery does not usually occur • May develop keratoconjunctivitis sicca (dry eye) • Animals may require life-long maintenance