Transcript Signs - Dr. Roberta Dev Anand

ATLANTOAXIAL
INSTABILITY
Atlantoaxial Joint
Atlanto-Axial Joint
Atlantoaxial Instability (Subluxation)
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Signs
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Toy and miniature breeds
Reluctance to be patted on head
Neck pain
May have tetraparesis (weakness in all 4 limbs) or tetraplegia
(paralysis in all 4 legs)
Sudden death due to respiratory paralysis
Diagnosis—
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Radiographs: lateral x-ray of neck in slight ventroflexion
• avoid further spinal cord damage with positioning
Atlantoaxial Instability (Subluxation)
Normal toy breed dog
CT scan:
dens is
marked
by *
Toy breed dog with atlantoaxial subluxation
Narrowed spinal canal
X-rays of same dogs; note separation of C1 and C2 when dog’s neck is flexed in B
Atlantoaxial Instability (Subluxation)
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Treatment—
Medical
• splint neck in extension with cage confinement x 6 w
• treat like other spinal cord trauma
– Surgical (if unresponsive to medical Rx)
• stabilize/decompress
• attach dorsal process of axis to arch of atlas
• fuse atlas and axis joint with pins and bone graft
• hemilaminectomy to relieve spinal cord compression
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Client info—
prognosis is fair to good for animals with mild signs
animals should not be used for breeding; may be
hereditary
Atlantoaxial Instability: Surgical Correction
Stabilization using trans-articular
screws
Stabilization using screws and bone cement
Cervical Spondylomyelopathy: Wobbler
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Cervical spinal cord compression as a result of
caudal vertebral malformation or misarticulation.
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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
Cervical Spondylomyelopathy: Wobbler
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Dx
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Radiographs to show malalignment and narrowing
of spinal canal
Myelogram is essential to locate the region of
compression
CT and MRI if available
Cervical Spondylomyelopathy: Wobbler
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Rx—without treatment, prognosis is poor
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Medical
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Anti-inflammatory doses of corticosteroids
Neck brace
Cage confinement
Surgical
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Decompression of spinal cord by laminectomy
Stabilize vertebral column
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screws and wire dorsally
spinal fusion ventrally
Cervical Spondylomyelopathy: Wobbler
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Client info
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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
Degenerative Myelopathy
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Etiology—unclear
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May be autoimmune response to antigen in nerv sys
Degeneration of white matter in ascending and descending tracts
Signs
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Mainly in G Shep and Shep mixes (>5 yr)
Progressive ataxia and paresis of hind limbs
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
Degenerative Myelopathy
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Dx—
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Neurologic Exam
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↓ 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—
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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
Degenerative Myelopathy
Deafness: Causes
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damage to auditory pathway
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damage to auditory nerve
hereditary or congenital
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bull terriers, Dobes, Rotts, Pointers, blue-eyed white cats, Dalmations, Aust
Heelers, Aust shepherds, Eng setters, Catahoula
related to drug therapy
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chronic otitis
rupture of tympanic membrane
damage to middle ear (ossicles)
aminoglycosides (gentamicin, streptomycin, kanamycin
topical polymyxin B
Chloramphenicol
Chlorhexidine w/ centrimide
normal old age—usually due to atrophy of nerve ganglia or cochlear hair
cells
Deafness
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Dx
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Inability to rouse sleeping animal with loud noise (e,g,. blast from air
horn) is diagnostic
Rx: No treatment is available in most cases
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Hearing aids are available for animals, but most will not tolerate
something in ear canal
Client info
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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
Laryngeal Paralysis
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3 types (always be cautious of laryngeal paralysis because of the chance of
rabies)
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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 giantbreed dogs; castrated dogs and cats have a higher
incidence than female and non-neutered males
Laryngeal Paralysis
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Signs:
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Dx: laryngoscopy will show laryngeal abductor m. dysfunction
Rx: surgical intervention including:
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Inspiratory stridor
Resp distress
Loss of endurance
Voice change
Dyspnea/cyanosis/complete resp collapse
Arytenoidectomy
Removal of vocal folds
Client info: prognosis is guarded to good; do not breed if
hereditary
Laryngeal Paralysis
Megaesophagus
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Causes-lack of esophageal peristalsis (3 types):
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Hereditary—a gene for the disease is identified in wire-haired fox
terriers and min schnauzers
Congenital—Great Danes, German Shepherd, Irish Setters, Newfies,
Sharpeis, Greyhounds (no gene ID’ed)
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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
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Regurgitation of undigested food
Respiratory problems (aspiration pneumonia)
Lack of growth
Megaesophagus
Dx—barium swallow
Esophagus is 3 times normal diameter
Megaesophagus
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Rx
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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
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Prognosis—guarded to poor
Treatment aim is to reduce clinical signs and prevent
aspiration pneumonia
There is no cure
Tick Paralysis
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Cause—female tick (Dermacenter variablis, D. andersoni) →
salivary neurotoxin
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Neurotoxin interfered with Ach at neuromuscular jct
Not seen in cats; humans are affected
Signs—
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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
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Rx
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Remove ticks (manually or with dip)
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Usually resolves in 1-3 d
Supportive care until dog recovers
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Ventilation required for resp paralysis
Tick Paralysis
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
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Signs: similar to tick paralysis and rabies
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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 respiratory failure
May last for 2-3 mo (usually good Px)
Rx: supportive nursing care
Client info
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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
Idiopathic Facial Nerve Paralysis
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Etiology—unknown
Occurrence
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Cocker Spaniels, Corgis, Boxers, Eng Setter, DLH cats
Signs—
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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
Idiopathic Facial Nerve Paralysis
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Rx—efficacy of corticosteroids unknown
– Artificial tears to prevent corneal ulcers
– Keep oral cavity clear of food
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Client info—
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Cause is unknown
Complete recovery does not usually occur
May develop keratoconjunctivitis sicca (dry eye)
Animals may require life-long maintenance