Hyperthyroidism is a disease mostly seen in middle-aged and older cats. The discomfort caused by the increase in the production of thyroid hormones can lead to secondary problems as these hormones affect the whole body.
What Is Hyperthyroidism in Cats?
Hyperthyroidism, also called thyrotoxicosis, is caused by an increase in the production of hormones (known as T3 and T4) secreted by the thyroid gland located in the neck region. The excessive secretion of these hormones, which is of great importance in regulating the metabolic rate of cats, affects many organs, especially the heart.
What Causes Hyperthyroidism in Cats?
Although the reasons for the occurrence of hyperthyroidism in cats are not clearly known, the role of diet in this disease is quite large. The amount of iodine in dietary habits is thought to play an important role in triggering the disease. Chronic exposure to thyroid-disrupting chemicals in food or the environment can also lead to hyperthyroidism in cats.
What Are the Symptoms of Hyperthyroidism in Cats?
Hyperthyroidism; Although it may show different symptoms according to the level of the disease, the age of the cat, its medical history and genetic disposition, the main symptoms can be listed as follows:
- Rapid weight loss despite increased appetite and food consumption
- Constant urination due to frequent water consumption
- Vomiting
- Diarrhea
- Increased amount of stool
- The unkempt appearance of the hairs
- Increased meowing at night
Clinical manifestations of diffuse hyperthyroidism, in which gastrointestinal and cardiovascular findings are common, are as follows:
- Hypertension
- Anorexia
- Tachycardia
- Systolic murmurs
- Dyspnea
- Cardiomegaly
- Congestive heart failure
25% of cats with hyperthyroidism show signs of high blood pressure. Retinal hemorrhages and ruptures may occur due to high blood pressure. If retinal damage is not treated, the process can result in blindness.
How to Diagnose Hyperthyroidism in Cats?
Hyperthyroidism in cats can only be diagnosed with thyroid tests. Cats with hyperthyroidism have a very high level of thyrotoxin (TT4) thyroid hormone. If this hormone level remains normal but symptoms persist, FT4 ED, T3 suppression tests or comprehensive thyroid screening are performed. In cases where the veterinarian deems it necessary, the TT4 test can be repeated after a few weeks.
Treatment of Hyperthyroidism in Cats
Depending on the course of hyperthyroidism in cats, 4 different treatment methods can be followed. These; drug therapy, radioactive iodine therapy, surgery and diet therapy. Each treatment option has different advantages and disadvantages.
In this treatment method, which uses anti-thyroidal drugs, the secretion of thyroid hormones is minimized. Although it is not a definitive treatment method, the progression of the disease and risk formation are largely prevented. With treatment, it may take several weeks for thyroid hormone secretions to return to their normal course. Some cats may experience side effects such as vomiting, anorexia, fatigue, fever, anemia and decreased white cell count in the blood due to drug therapy. It is recommended that cats undergoing drug treatment have regular blood tests every 3 or 6 months.
- Hyperthyroidism Treatment with Surgery
Removing the affected thyroid glands from the body is a method that is frequently used in the treatment of hyperthyroidism with successful results. However, the fact that the disease is generally seen in older cats increases the risk of complications in surgery. Before the operation, it should be noted whether there is ectopic thyroid tissue in the body of the cats with the nuclear scanning method. Ectopic thyroid tissues are thyroid cells located in places where they should not be in the body.
Before surgery, cats need to be treated with various medications.
- Hyperthyroidism Treatment with Radioactive Iodine
It is the process of destroying the abnormal thyroid tissue without damaging the surrounding tissues by radioactive iodine given by injection and rapidly mixing into the blood. Within a few weeks of the end of radioactive iodine treatment, the cat's hormone levels return to normal. The success rate is much higher compared to other treatments.
The treatment processes of cats with hyperthyroidism, which are carried out by reducing the amount of iodine in their food to a minimum, are a matter of debate among physicians. The reason for the disagreements among physicians is the possibility that long-term iodine restrictions may carry hyperthyroidism to further dimensions.
How to Prevent Hyperthyroidism in Cats?
There is no way to prevent the disease, as the exact factors underlying the tumor development that cause feline hyperthyroidism are not known. Regular control and blood screening of older cats minimizes the risk of being affected by the disease.
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