Page 836 - Problem-Based Feline Medicine

828 PART 10 CAT WITH SIGNS OF NEUROLOGICAL DISEASE

There are no pathognomonic clinical signs for acquired Pathogenesis
hydrocephalus in adult animals.
Feline ischemic encephalopathy is an ischemic necro-
Correlation of degree of ventricular enlargement and sis of the cerebral hemisphere of cats.
clinical signs is poor.
The distribution of the vascular change is usually in the
area supplied by the middle cerebral artery.
Treatment
Vascular lesions, however, are infrequently found at
Medical treatment may include general supportive care, necropsy.
and medications to limit CSF production and reduce
Some authors have speculated that this disease is the
intracranial pressure.
result of a Cuterebra migration.
Glucocorticoids are used to decrease CSF produc-
One 7-year-old Siamese cat has been reported with an
tion, thereby, limiting intracranial pressure and further
intravascular malignant T-cell lymphoma occluding the
neurologic injury. Prednisone at 0.25–0.5 mg/kg is
middle cerebral artery.
given orally twice daily. The dose is gradually reduced
at weekly intervals to 0.1 mg/kg every other day. This
dose is continued for at least one month. Then the med-
Clinical signs
ication is discontinued if possible.
Clinical signs begin acutely.
Alternatively, dexamethasone may be given orally at
0.25 mg/kg every 6–8 hours. The dose can be gradually Signs often reflect a unilateral cerebrocortical abnor-
reduced over 2–4 weeks. mality.
Some animals can be adequately managed with long- Signs include seizures, circling, blindness, behavior
term glucocorticoid administration at low doses. changes and may progress to stupor and coma.
If no clinical benefits are observed within 2 weeks, or
if side effects develop, other forms of therapy should be
Diagnosis
tried.
Routine laboratory evaluations are normal.
Surgical procedures where a shunt is placed in the
ventricle are designed to provide controlled CSF flow Cerebrospinal fluid often contains elevations in pro-
from the ventricles of the brain to the peritoneal cavity. tein content but this finding is not pathognomonic for
Commercial pediatric ventriculoperitoneal shunts are this disease.
available for thus purpose.
CSF may contain mild increases in nucleated cells
Prognosis (usually < 10 cells/μl). Neurophils, macrophages and
mononuclear cells are possible.
Generally poor unless definitive surgical correction is
Diagnosis of a structural intracranial abnormality in the
successful. In some cats, clinical signs can be managed
cerebral hemisphere is most readily accomplished with
on a long-term basis with medication therapy alone.
magnetic resonance imaging of the brain. Minimal
changes, however, may be seen on MR studies with this
FELINE ISCHEMIC ENCEPHALOPATHY*
disease.
Classical signs Cerebral angiography would theoretically aid in the
diagnosis of this disease, but is rarely performed.
● Signs occur acutely and reflect a unilateral
cerebrocortical abnormality.
● Signs include seizures, circling, blindness, Differential diagnosis
behavior changes and may progress
rapidly to stupor and coma. Rule out brain tumor, encephalitis, head trauma and
hydrocephalus.