Page 876 - Problem-Based Feline Medicine

868 PART 10 CAT WITH SIGNS OF NEUROLOGICAL DISEASE

Motor neuronopathies are diseases that affect the cell Differential diagnosis
bodies of the lower motor neuron leading to degener-
Rule out other metabolic, inflammatory, and toxic
ation of the cell in the ventral horn of the spinal cord
causes of tremor.
and occasionally the cranial nerve nuclei. Histologic
lesions are most severe in the ventral spinal gray matter Physiological functions such as shivering from cold or
and consist of neuronal cell loss and gliosis. apprehension should be considered.

Clinical signs Treatment
No treatment is currently helpful or has been attempted
With the encephalomyelopathy of young cats
for affected cats.
reported in the United Kingdom, cats 3–12 months
were affected, however, the disease was seen in cats up
to 3 years of age. Clinical signs usually are progres- Prognosis
sive over weeks to months.
Clinical signs associated with degenerative diseases
Signs include ataxia, paresis, and “head shaking”. progressively worsen.
Ataxia of the pelvic limbs was the initial clinical sign
Animals are commonly euthanized due to the progres-
noted.
sive incapacitation.
Spongiform encephalopathy occurs in older cats, and
clinical signs include muscle tremors, ataxia, dilated Prevention
unresponsive pupils, jaw champing, salivation, and
Do not breed cats affected that have produced kittens
behavior abnormalities. In one additional cat the tremor
with a presumed inherited disease.
was most obvious in the pelvic limbs. Signs progressed
to severe ataxia and hypermetria.
POLIOENCEPHALOMYELITIS
Clinical signs of hypomyelination or dysmyelination
consist of diffuse tremor accompanied by frenzied
Classical signs
behavior and indiscriminate biting. Clinical signs are
worsened with activity. Reported cats were young ● Young to middle-aged cats have been
Siamese < 1 year of age. affected.
● Clinical signs have a slow onset and are
Motor neuronopathies were reported in adult cats and
chronically progressive.
signs included tremor, progressive weakness, cervical
● Signs are variable but include pelvic limb
ventroflexion, dysphagia, and muscle atrophy.
ataxia, seizures, paresis, hypermetria,
intention tremors, decreased pupillary
Diagnosis light reflexes, and hyperesthesia over the
thoracolumbar area.
Antemortem testing for many of these diseases often
results in negative or normal findings.
Pathogenesis
Definitive diagnosis is often rendered only at
necropsy and histopathological examination of the Lesions primarily occur in the spinal cord and include
nervous tissue. severe degeneration and loss of neurons, perivascular
mononuclear cuffing, lymphocytic meningitis, neuron-
In some instances of motor neuronopathies, mild to
phagia and glial nodules.
moderate fibrillation potentials were found in the
appendicular and paraspinal muscles with electromyo- A viral etiology was suggested but not proved.
graphy.
Clinical signs
Cerebrospinal fluid with these degenerative conditions
is normal. Young to middle-aged cats have been affected.