Overactive thyroid gland

Unfortunately, cats suffering from hyperthyroidism are often brought to the veterinarian only in a critically ill condition. With their anxious facial expression typical of the disease and the shaggy coat, the affected animals offer a pitiful image. Even overweight animals are emaciated, although they eat with cravings. However, the affected velvet paws vomit frequently and suffer from persistent diarrhea. They drink more than they used to and urinate a lot. Remarkable is the change in nature: originally balanced, benign cats become agile, nervous and aggressive creatures.

Benign tumor as a cause - early detection important

Hyperthyroidism is caused by a benign tumor that produces extra thyroid hormone. The tumor usually consists of two nodes - rarely there are many nodes and sometimes only one. The nodes can often be felt already during the scanning of the thyroid gland. To represent the altered thyroid tissue also graphically, one uses the method of scintigraphy. For this purpose radioactive pertechnetium is injected intravenously. This accumulates in the tumor and you can see how many nodes the tumor consists of. The scintigraphy is performed under general anesthesia and subsequently the four-legged patients must remain in the radiation protection area for twelve to forty-eight hours at the clinic. The amount of thyroid hormone, the so-called total thyroxine T4, can be determined by means of a blood test. If it is elevated, this is a sure indication of an overactive thyroid. Since thyroid hyperfunction is the most common hormone disorder in older cats and it is important to start treatment as soon as possible, all T4 levels should be determined at least once a year in all cats from the age of eight years onward - even with completely healthy appearing velvet paws. Because experience has shown that in over 18% of clinically normal cats the T4 value in the blood is increased.

Why too much thyroid hormone makes you ill

Too much thyroxine (the name of the thyroid hormone) fuels metabolism, leading to gastrointestinal problems with chronic diarrhea. Increased liver function, respiratory problems and palpitations are also a symptom of hyperthyroidism. The fueled metabolism massively increases the blood circulation. However, just like the old man's blood vessels are no longer elastic in the old cat, but rigid and therefore can not give in to the increased blood rush, which is why the blood pressure increases. It comes to dangerous hypertension, which in turn damages the heart and kidneys. As high blood pressure damages the retina of the eye, it can lead to sudden blindness. Affected cats scream in panic and have wide-open pupils. It is therefore particularly important in cats with hyperthyroidism, the blood pressure regularly checked by the veterinarian. Another indication of hyperthyroidism is heat intolerance, tremors and muscle weakness. The onset of muscle weakness is favored by vomiting and diarrhea, as these lead to potassium deficiency. Cats with muscle weakness often show a typically downturned neck.

Uncomplicated therapy with only one tablet daily

Recently, the treatment of hyperthyroidism in cats for pet owners has become much easier, since there are now tablets for this disease, which need only be administered more than once daily. The tablets are well tolerated and completely tasteless, so they are easily absorbed by delicate cats with the food. This modern medicine normalizes the elevated blood level of the thyroid hormone T4 and thus quickly and safely eliminates the signs of hyperthyroidism. At the beginning of treatment, regular checks at intervals of two to three weeks at the veterinarian are necessary to adjust the cat to the optimal dosage for her. A lifelong treatment is required because the drug does not cure hyperthyroidism, but only regulates hormone levels. It is a reversible therapy in which the drug is stored in the thyroid gland and blocks the formation of other thyroid hormones. When the tablets are discontinued, the thyroid gland begins to revert to hormone production. In the event that a typical symptom of hyperthyroidism recurs during treatment with the tablet, the veterinarian must be consulted immediately so that the dosage of the tablets can be adapted to the particular condition of the cat.

Radioiodine therapy only in special cases

It is an internal radiation therapy in which the injected radioactive iodine enters the tumor through the bloodstream and destroys it. Radioiodine therapy, however, has several disadvantages: the cats treated with it must stay at the clinic for five to six days for reasons of radiation protection, and five to thirty percent of these cats cause hypofunction of the thyroid, which in turn requires its own therapy. Therefore, the irreversible radioiodine therapy is especially in such cats in question, in which a regular tablet entry is not possible because they either come home only irregularly or refuse to take the tablet vehemently.

How to maintain renal insufficiency and hyperthyroidism in balance

Often, older cats suffer from both hyperthyroidism and chronic renal insufficiency. Interestingly, these two conditions affect each other positively and keep their balance. In other words, they delay the progression of the other disease. This means that, on the one hand, kidney values ​​are kept lower due to hyperthyroidism and, on the other hand, kidney disease does not increase thyroid T4. This circumstance must be taken into account in the treatment of hyperthyroidism, otherwise the kidney values ​​could explode. If thyroid therapy does not diminish as kidney levels rise, kidney failure occurs. Therefore, in cats, which also suffer from kidney disease in addition to the hyperthyroidism, the reversible therapy with tablets over the radioiodine therapy to give preference because tablets have the ability to react with the dosage on a change in renal values. Regular blood tests are indispensable for this reason as well.