Forebrain disease in older cats: Look for intracranial neoplasia - DVM
  • SEARCH:
News Center
DVM Featuring Information from:

ADVERTISEMENT

Forebrain disease in older cats: Look for intracranial neoplasia


DVM360 MAGAZINE


Successful surgical resection of meningiomas located over the cerebral convexities has been reported. Clinical signs in these cats often improved within several days of surgery, if there was minimal operative brain trauma. Cats with seizures, however, might require continued anticonvulsants. Tumors other than meningiomas might not be amenable to surgery. Some noninvasive gliomas can be resected. In some cats with inoperable tumors, there could be temporary improvement associated with reduction of peritumoral edema subsequent to glucocorticoid therapy. The dosage required for clinical improvement varies. Cats with acutely progressive clinical signs and possible ongoing brain herniation should be given a higher dose (intravenous methylprednisolone at 30 mg/kg) than those with relatively static neurologic involvement (oral prednisone at 0.5 mg/kg every 48 hours and gradually increase until there is improvement). Although clinical signs in some effected cats remit for several months after glucocorticoid therapy, deterioration inevitably occurs. Some tumors also can be, at least partially, responsive to external beam radiation or chemotherapy.

Cerebral ischemic necrosis Cerebral infarction is uncommon in animals due to the relative rarity of atherosclerosis in most species. However, a syndrome of cerebral infarction occurs in cats. There is generally unilateral involvement with the cerebral cortex affected most commonly. The brain stem is affected in some cats, and multiple areas are involved in others. While the changes clearly occur because of ischemia, the nature of the responsible vascular lesion has not been defined in most cats. Cerebrocortical involvement generally occurs in the distribution area of the middle cerebral artery. While an association between this syndrome and cardiomyopathy would seem logical, changes of cardiomyopathy have not been described in effected cats. Multiple causative factors might be involved.

Adult cats of both sexes and several different breeds can be affected. Clinical signs of focal forebrain involvement, and in a small number of cats signs of brain-stem involvement, are seen. These signs do not progress unless there is brain herniation or further infarction or hemorrhage occurs. Most signs resolve completely during a period of several weeks. However, behavioral changes and seizures can persist.

Cerebral ischemic necrosis should be suspected in any cat with acute, nonprogressive forebrain disease. There might be evidence of infarction on CT or MRI, if available. On CSF evaluation, there usually is a mild increase in protein, without inflammation. Increased uptake of radionuclide might be noted in a scintigraphy study.

Methylprednisolone (30 mg/kg intravenously) should be given in severely affected cats to reduce brain edema. While anticoagulants might be helpful in some cases, there is no supportive data. Anticonvulsants are indicated in cats with seizures.

Seizures Seizures can occur in cats with forebrain disease in combination with other signs previously discussed, or they can occur alone. Seizures occur considerably less frequently in cats than in dogs. Most cats with recurrent seizures have structural brain disease. Phenobarbital at 5 mg/kg divided into twice-daily dosing is preferred for long-term seizure control.


ADVERTISEMENT

Source: DVM360 MAGAZINE,
Click here