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Homeopathy, the best way to retrace the chronic disease Clinical Case: Brain tumour in canine by Carolina Gómez, Argentina
Brain tumours in Dogs and Cats
Cancer that affects different tissues that make up the brain, is under-diagnosed in elderly dogs and cats. A relative tendency for brain tumours has been found in young animals (Boston Terrier and Boxer breeds). The development of a brain tumour usually has serious consequences in patients, generating powerlessness in the majority of guardians. However, these tumours vary widely in their level of malignancy and some can be treated effectively. Unfortunately there are many things that are still not known about the development and evolution of the different types of brain tumours in dogs and cats.
• Thetermbraintumourmeanssimplyamass of cells in the brain. Brain tumours are classified as primary or secondary according to the origin of the tumour cells.
• Primary brain tumours: this category includes meningiomas, gliomas, papillomas of choroid plexus, adenomas, and pituitary adenocarcinomas, among others.
1 Meningiomas are primary brain tumours of most common presentation in dogs, cats and humans. These tumours are originated in the membrane arachnoid meninges. Meningiomas should not be considered as brain tumours in the strict sense, but they are classified together, because of their location within the cranial cavity and action invading and compressing the nervous tissue. These tumours occur more frequently in dolichocephalic breeds such as the Golden Retriever. Meningiomas tend to grow relatively slowly and are susceptible to be treated (although malignant forms can be found).
2 Gliomas: these tumours originate in the glial cells and include ependymomas, astrocytomas, oligodendrogliomas and glioblastomas multiforme. They are common in certain brachycephalic breeds, such as the Boxer, the Boston terrier and the Bulldog French and English.
3 Papilloma of the choroid plexus: choroid plexus tumours are relatively common in dogs. Due to the location of their cell of origin, they tend to arise within the ventricular system, and can block the drainage of cerebrospinal fluid; therefore, a small tumour can cause very severe neurological signs.
4 Adenoma or pituitary adenocarcinoma: the pituitary gland lies beneath the forebrain and is attached by a stalk to the hypothalamus. Pituitary adenomas are common in dogs causing hyperadreno- corticism (central origin Cushing’s disease).
5 Others: There are other forms of brain
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tumours, whose discovery is exceptional. Secondary brain tumours: these tumours spread to the brain tissue from a tumour present in another part of the body. Tumours that commonly secondarily affect the brain are: hemangiosarcomas, mammary carcinomas and melanomas. The prognosis in these situations is usually very poor, since they have already spread through the body. Whenever you suspect or confirm a diagnosis of brain tumour, routine practice should be to take chest x-rays and even carry out ultrasound of abdomen to check that there is no evidence of tumours in other parts of the body.
Signs caused by brain tumours
Symptoms and signs caused by brain tumours are due to the mechanical compression or invasion of surrounding tissues. The resulting signals are directly related to the area of the brain affected and are not tumour-specific, since any disease that affects the area of the brain will produce similar symptoms.
The forebrain
The forebrain is responsible for thoughts, behaviour and the final integration of sensory information. Therefore, the tumours in the tissues of the forebrain, can cause:
• Abnormalities in behavior, such as loss of learned behaviour, depression, etc.
• Increase or decrease in appetite and thirst • Constant movement or walking in circles
• Sometimes, affected animals behave as if
they suffered pain
• Onset of seizures is the most common sign
in animals with affections of the forebrain. These seizures can occur along with any of the other signs listed above, or present themselves as sole anomaly. Wherever a dog or a cat older than five or six years of age has a seizure, it is important to take into account the possibility of a brain tumour. (Note: the case of ‘Micky’ is within the preceding description).
Brain stem
The brain stem plays various vital functions, including the regulation of motor function, the level of wakefulness, respiratory and cardio- vascular systems. The sense of balance also arises in the brain stem. The nerve paths that control movements and the sensitivity of the face, eyes, throat, larynx, tongue and the muscles of mastication originate in this portion of the brain. Tumours in this region can be rapidly fatal if, for example, they affect the control of respiration. Usually the first manifestations of disorders of the brain stem are the vestibular signs and weakness in one side of the body. There are a wide variety of
additional signs, such as difficulty swallowing, change in phonation and involuntary movements of the eyes. The progression of symptoms can lead to paralysis, coma, and death.
The cerebellum
The cerebellum controls coordination of movements and interacts closely with the vestibular system for balance and posture control.
Diagnosis
It should be suspected that there might be a brain tumour, when there have been neuro- logical signs in an animal of more than 5 years old. It is important to understand that, with rare exceptions, brain tumours are tumours of soft tissue so don’t become manifest in x-rays of the scull. Magnetic Resonance Imaging (MRI) or Computerized Tomography (CT) is used with excellent diagnostic methodologies.
The following consecutive steps are recommended to arrive at a diagnostic presumption before an MRI or a CT:
• Full general objective examination and
neurologic examination, particularly in order to identify other health problems and locate neurological signs in a particular area of the brain.
• Blood routine to rule out a systemic problem and step count to assess anaesthetic risks.
• Chest x-rays to check that there is no evidence that the cancer has spread to the lungs (a common site of metastases).
Treatment
Conventional brain tumours treatment options include surgical removal, radiotherapy, chemo- therapy and palliative treatment of the symptoms. • Surgery: in the case of tumours located in
the forebrain, they can be extracted along with the tumour, some surrounding tissue without causing undesirable effects in the long run. Meningiomas tend to be housed in surface areas and therefore are the best candidates for surgical removal. Gliomas are more difficult to remove, since they are deeply imbedded within the cerebral network.
• Radiation therapy: since nervous tissue cannot tolerate large doses of radiation, the total applied dose is limited and must be done under general anaesthesia. If the animal is affected by a very large tumour mass, it is preferable to remove it surgically if possible in order to initially decompress and then perform chemotherapy sessions.
• Chemotherapy: the brain is protected by the blood-brain barrier from various potentially harmful molecules that circulate