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Brn tumor in cats
A brn tumor is a mass or abnormal growth of tissue in the brn that can lead to neurological signs and symptoms such as seizures, blindness, or paralysis. The most common type of brn tumor in cats is a neoplastic glial tumor of astrocytic cell origin. These tumors are generally categorized as primary or secondary, which refers to whether or not they originate from a site outside of the central nervous system (CNS). Primary brn tumors arise within the brn parenchyma, usually between 1 and 6 ,cm from the surface of the brn. Secondary brn tumors are derived from outside the CNS, including tumors from the brn, spinal cord, eyes, and meninges.
Primary brn tumors account for 80 to 85% of all brn tumors in cats. Secondary brn tumors include tumors that arise from the meninges, eyes, spinal cord, cerebrospinal fluid, and other CNS tissues. The most common types of secondary tumors in cats include:
Schwannoma — Tumors that arise from the sheath (Schwann cells) of sensory nerves.
Medulloepithelioma — Tumors that arise from cells that form the epithelium of the inner ear (i.e., sensory receptor cells).
Lipoma — Tumors that arise from the fatty pads of the brn (cerebellar lipoma).
Other types include neurofibroma, granular cell tumor, and hemangioma.
The prognosis for most cats with a brn tumor is guarded. Cats diagnosed with a brn tumor are likely to succumb to the disease within six months to a year of diagnosis. The prognosis for specific types of brn tumors varies depending on the type and site of the tumor, age and size, and whether the tumor was primary or secondary. However, a few of these brn tumors can be cured. Most of these cats can be successfully treated with surgery alone.
Tumors that grow in the brn and are detected in the early stages may be surgically resected. Therefore, the first step in making an accurate diagnosis is to perform a complete neurological examination. The cat's brn is carefully examined by a veterinarian with experience in neuroanatomy and by taking a full neurological examination. The cat's head is stabilized in a head ring, and the brn is examined using either a direct or indirect binocular ophthalmoscope. A complete neurological examination is essential to diagnose or rule out any other conditions, such as stroke. For example, a head ring with a stabilizer may be used to make a diagnosis of a brn stem lesion. Cats that have a neurologic problem should be hospitalized and should have an MRI or CT scan of the head performed.
Blood samples may be taken to perform a complete blood count (CBC), and the concentration of serum sodium, potassium, and blood urea nitrogen (BUN) is measured. An analysis of the cerebrospinal fluid (CSF) is performed to detect the presence of abnormal proteins. If the cat is unable to stand or walk, a diagnosis may not be possible. A CT scan of the head is the primary method of diagnosing most tumors in the brn. This scan is important to rule out other causes of seizures before proceeding with more invasive diagnostic tests. These tests include a CT scan of the head and an MRI of the brn, which are both needed to accurately diagnose brn tumors.
Magnetic resonance imaging
An MRI or CT scan can be used to make a diagnosis of a brn tumor. However, an MRI may not be avlable in every hospital, and a CT scan can be more cost effective. The procedure is performed under general anesthesia in a specialized radiology suite. The MRI machine is large, so only large animals may be placed in the machine. Anesthesia is administered via a vein or a combination of intravenous and inhaled anesthetic. The cat is placed in a custom designed head ring that immobilizes the head. The head ring is fitted with a bite block and is secured to the MRI machine. The bite block is used to immobilize the cat's mouth so that a bite guard can be fitted.
A specialized cat MRI machine is required to obtn an MRI of the brn and cervical spine. Cats that are sedated can be placed on the MRI machine, but are unable to move due to the bite block in place. If the cat is unable to lie down, the head ring may need to be adjusted to place the cat in an upright position. A special imaging coil is wrapped around the head of the cat and attached to a computer system. A special radio frequency (RF) pulsing device is connected to the MRI machine to generate an RF pulse, which excites hydrogen atoms in the body. This causes the atoms to change spin states, which creates a magnetic field that can be used to visualize the structure of the brn. This sequence can be repeated multiple times to create a series of images of the brn.
In some cases, a CAT scan may be performed on cats who have an MRI of the brn or MRI of the head. This procedure is more invasive than an MRI and is performed under general anesthesia. The cat is placed on the scanning table. A thin plastic tube called a nasal endotracheal tube is inserted into the cat's mouth and into the nasal passages, which is used for inhalation of anesthetic. The cat is then intubated into the endotracheal tube, which is connected to a reservoir for anesthetic. Anesthesia is administered to the cat via the endotracheal tube. The cat is then placed in the MRI machine for the CAT scan.
MRI is considered the gold standard of diagnostic imaging. It can be useful in determining the extent of the tumor, whether the tumor is invasive, and whether the tumor has spread outside of the brn. However, there are two major limitations with MRI. First, it is not used for diagnosis due to the inability to differentiate between brn tumors and lesions, such as abscesses and metastatic tumors. Second, there are no specific clinical signs associated with many types of brn tumors, making it more difficult to make a clinical diagnosis.