Page 972 - Problem-Based Feline Medicine

964 PART 11 CAT WITH AN ABNORMAL GAIT

Differential diagnosis Histologic lesions were most severe in the ventral
spinal gray matter, consisting of neuronal cell loss and
Clinical signs may be similar to other diseases that
gliosis. No effective treatment is known.
affect the lower motor neuron including motorneuro-
pathies, myopathies and some diseases of the neuro-
muscular junction. Differential diagnosis
Hypokalemic myopathy (low plasma potassium),
Treatment chronic organophosphate toxicity (history of exposure),
No effective treatment is known. myasthenia gravis (tensilon test, anti-acetylcholine
receptor antibodies, decreased serum cholinesterase
Clinical signs usually progress until euthanasia or death activity).
occurs months to years after initial onset of signs.
In rare instances, clinical signs may stabilize or even Treatment
improve.
No effective treatment is known.
Prognosis Clinical signs progress until euthanasia or death occurs
Many of these diseases are progressive, and treatments months to years after initial onset of signs.
either have not been attempted or have not been benefi-
cial. DEGENERATIVE MYOPATHIES (X-LINKED
MUSCULAR DYSTROPHY, HEREDITARY
DEGENERATIVE MOTORNEUROPATHIES MYOPATHY, NEMALINE ROD MYOPATHY)

Classical signs
Classical signs
● Signs begin 2–24 months of age.
● Progressive weakness and muscle atrophy
● Weakness and reduced activity.
in adult cats.
● Stiff, choppy gait.
● Decreased to absent spinal reflexes.
● Increased muscle mass and hypertrophy of
● Tremor, especially of the head and tongue.
the tongue (X-linked muscular dystrophy).
● Cervical ventroflexion.
● Ventral flexion of neck and dorsal
● Dysphagia.
protrusion of scapula (hereditary myopathy
of Devon Rex).
See main reference on page 903 for details (The Cat
● Any breed may be affected; inherited
With Neck Ventroflexion).
myopathy occurs in the Devon Rex.
Clinical signs
Degeneration of the lower motor neuron cell bodies in Pathogenesis
the ventral horn of the spinal cord and occasionally the
cranial nerve nuclei leads to chronic progressive signs. An X-linked muscular dystrophy similar to
Duchenne’s and Golden Retriever myopathy has been
All cats were adults.
described in male cats. A membrane-associated protein
Clinical signs included progressive weakness and (dystrophin) is deficient or absent.
muscle atrophy, tremor, especially of the head and
Cardiac muscle may also be affected.
tongue, ventroflexion of the neck and dysphagia.
A specific cause of the other myopathies has not been
Diagnosis completely established.

Mild to moderate fibrillation potentials, consistent Clinical signs
with denervation, were found in the appendicular
(limb) and paraspinal muscles with electromyography. X-linked muscular dystrophy: