Reasons Why Older Cats Prone to Hyperthyroidism Explain

What is Hyperthyroidism in Cats?

Hyperthyroidism, also known as hyperthyroidism syndrome, is a common endocrine disorder in cats, particularly in those over the age of eight.

The thyroid is a butterflyshaped gland located at the base of the throat. When this gland produces an excess of thyroid hormones, it leads to hyperthyroidism. The surplus thyroid hormones can affect all organ systems in cats, stimulating each system and causing reactions such as changes in behavior, weight loss, increased or decreased appetite, hyperactivity or lethargy, fever, rapid heartbeat, and/or arrhythmias, increased thirst and urination, diarrhea, and osteoporosis. Feline hyperthyroidism is relatively easy to treat, and the prognosis is generally good if detected early.

Symptoms of Hyperthyroidism

The typical clinical symptoms of hyperthyroidism in cats include weight loss (which can progress to cachexia), increased appetite, and restlessness or overexcitement. Other symptoms may include changes in the cat's coat (patchy hair loss, dull coat, matted fur, lack of or excessive grooming), polyuria, polydipsia, vomiting, and diarrhea. Some affected cats may exhibit aggressive behavior, which can be resolved after successful treatment for hyperthyroidism. In some cases, drowsiness, weakness, and anorexia are the main clinical features, in addition to weight loss. Due to the impact of hyperthyroidism on multiple systems, the symptoms can be similar to those of other diseases, so when older cats (over 10 years old) have internal medical conditions, it is advisable to suspect hyperthyroidism.

How to Treat Hyperthyroidism

There are four common treatment options: medication, surgery, radioactive iodine therapy, and dietary management. Each option has its own advantages and disadvantages, and the veterinarian will determine the best course of action based on the cat's condition, the hospital's overall medical level, and the pet owner's financial capabilities.

Medication therapy (methimazole) and dietary management (iodinefree prescription food and water) are relatively simple to implement, but there is a 100% recurrence rate once treatment is stopped, and medication therapy can also cause various side effects.

Surgical removal of the thyroid gland carries risks both during and after the procedure, as well as the possibility of iatrogenic hypocalcemia. However, the cure is quick, and the surgery is not complex.

Radioactive iodine is the most effective treatment method, but it requires a high level of medical expertise.

The prognosis for cats with hyperthyroidism usually depends on whether appropriate treatment is used; in general, the prognosis is good as long as an appropriate treatment plan is adopted. In some cases, complications involving other organs can also worsen the prognosis.