Case Study: Progressive Behavior Change in a Cat
February 2, 2018
History:
Chandra, a 14 year old, DSH, was presented for a 5 month history of a slowly progressive behavior change, urinating outside the litter box, withdrawing from client, vocalizing without apparent purpose, and a tendency to walk in circles to the left. Prior to referral, a CBC, serum chemistry panel, urinalysis, serum T4 concentration, and a Cryptococcus titer were obtained which were unremarkable. She was started on prednisone at 0. 5mg/kg BID, and there was initial dramatic improvement. However, the signs would recur whenever the medication was tapered, and now she is not responding as well to the BID dose.
Abnormal Exam Findings:
Iris atrophy, nuclear sclerosis, dental disease, BCS 7/9.
Mentation: Obtunded
Cranial Nerves: absent menace on the right, others normal.
Gait: Ambulatory, tendency to circle to the left.
Conscious Proprioception (CP): unable to assess CPs, but hopping was slower on the right than the left. The remainder of the neurological examination was normal.
Neuroanatomic Localization:
Left Cerebrothalamic.
Differential Diagnosis:
Neoplasia, inflammatory, less likely infectious, other.
Diagnostics:
Three view thoracic radiographs—No gross evidence of metastatic disease
MRI of the brain—uniformly contrast enhancing mass associated with the meninges and compressing the left cerebral hemisphere.
Plan:
Left rostrotentorial craniotomy. The mass was removed and Chandra recovered uneventfully. She was discharged within 3 days of surgery on prednisone 0.5 mg/kg BID x 7 days, then 0.5mg/kg SID until time of recheck. The biopsy was interpreted as a psammomatous meningioma.
She had an inconsistent menace OD and an otherwise normal neurological examination at the two week recheck.
Discussion:
Meningiomas are the most common type of brain tumor in the cat. These tumors do not invade adjacent brain tissue and typically “pop” out easily at the time of surgery. Obviously, attempting to get clean tumor margins is not possible with brain surgery. Surprising to most clients and veterinarians is that follow up radiation and/or chemotherapy is usually not necessary with most feline meningiomas. Since these tumors are so slow growing, and these modalities depend on dividing cells, they do not increase survival time. Generally, these are elderly patients that either die of another disease process prior to regrowth, or the clients can elect to pursue a second surgery in 1-3 years if they become clinical again for their brain tumor. Clients who elect not to pursue a second surgery are usually grateful for the high quality, “bonus” time they have had with their cat. About 15% of feline meningioma patients have more than one meningioma at the time of diagnosis. Not all are surgically accessible, but removing the largest tumor can often afford clients a significant amount of quality time with their cat.
Unlike dogs with brain tumors where seizures are the most common presenting complaint, cats are most commonly presented for behavior changes. Since the clinical signs can be very gradual in onset and can progress slowly over several months, clients will often mistakenly interpret them as old age and don’t bring their pet to the veterinarian until they are significantly affected. The signs may be as subtle as lethargy, withdrawing/hiding, and sleeping a lot, or as severe as blindness, head pressing, and compulsive pacing/circling, with or without seizures. A good response to prednisone may further delay a definitive diagnosis and treatment. Since surgery for meningiomas in cats is often extremely successful, motivated clients should be encouraged to seek a diagnosis. So if presented with an elderly cat patient with behavior changes, meningioma should be on the differential list.
Written by TAMMY STEVENSON, DVM, DACVIM (NEUROLOGY)