Page 813 - Problem-Based Feline Medicine

36 – THE CAT WITH SEIZURES, CIRCLING AND/OR CHANGED BEHAVIOR 805

of large foamy mononuclear cells) that may persist – Mannitol 25% (0.5–2.0 g/kg slow IV over
for several months after the infarction. 20–30 minutes) may be indicated in severe
cases (semi-stupor, pinpoint pupils).
Brain imaging (MRI is optimal) is the only means of
● To control seizures, give anti-epileptic drugs (see
antemortem diagnosis. It typically reveals the lesion in
Likely symptomatic epilepsy, page 802).
the parietal-temporal field of one cerebral hemisphere.
A similar but much milder lesion may be seen in the
other hemisphere. Prognosis

The prognosis is excellent in most cases.
● Persistent personality changes are usually mild,
Differential diagnosis but rarely they may make the animal unsuitable as
The typical form of the disease must be differentiated a pet, for example severe aggression.
from the following: ● Post-ischemic epilepsy is usually well controlled
● Cerebrovascular accidents are rare in cats and with adequate anti-epileptic drug therapy.
older animals are at greater risk. They may be asso- Recurrences of infarction are not reported to occur.
ciated with hypertension due to renal insufficiency,
hyperthyroidism or blood hyperviscosity due to
CONGENITAL AND INHERITED FOREBRAIN
polycythemia vera.
ANOMALIES***
● Head trauma is differentiated by the history and
external signs of trauma to the head and face area.
Classical signs
● Sudden decompensation or hemorrhage associ-
ated with a cerebral tumor is usually seen in older ● Focal or diffuse forebrain signs (mentation
cats with other preceding neurological signs, espe- depression and confusion, central visual
cially mentation and behavioral changes. A pro- deficits with normal pupillary light
gressive rather than a regressive course would be reflexes, proprioceptive positioning and
expected afterwards. hopping deficits).
● Acute and severe encephalitides (infectious and ● Abnormal development and behavior.
non-infectious) are more likely to produce initially ● Occasionally, seizures.
progressive multifocal or diffuse signs.
In cats with the atypical form of ischemic encephalopa-
Pathogenesis
thy with personality changes or seizures as the only
sign, behavioral disorders and other intracranial Congenital hydrocephalus is uncommon and rarely
causes of seizures such as idiopathic epilepsy, active symptomatic in cats. It may be primary (e.g. inherited)
brain diseases must be investigated. or secondary, for example obstructive and/or compen-
satory following fetal encephalitis. Signs are diffuse
and mainly due to a lack of formation or loss of cerebral
Treatment
tissue, although intracranial pressure elevation may
Treatment is symptomatic. sometimes contribute to the signs.
● To reduce cerebral edema and intracranial pressure
Lysosomal storage diseases are inherited, progressive
in the typical form of ischemic encephalopathy,
and lethal multisystemic degenerative disorders that
give:
often involve the CNS of young to adolescent kittens
– Glucocorticosteroids (methylprednisolone
under 1 year of age. Initial signs are often attributable
sodium succinate [SoluMedrol®] 30 mg/kg IV
to cerebellar dysfunction.
or dexamethasone phosphate 0.25 mg/kg IV).
– Furosemide (0.5–2.0 mg/kg IV) may be pre- Lissencephaly-pachygyria is due to an abnormal
ferred to or combined with glucocorticosteroids migration of cerebrocortical neurons. It usually causes
when neurological signs are mild (mental learning disabilities, sometimes with behavioral abnor-
depression/confusion, miotic pupils). malities and seizures.