Feline hyperthyroidism has recently been recognized as the most common endocrine disorder of the cat.
The thyroid is a butterfly shaped gland located on either side of a cat's windpipe.
The thyroid produces hormones that regulate metabolism and organ function. With hyperthyroidism, the thyroid becomes overactive, and produces an excess of thyroid hormone.
The elevated circulating levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) that occur in hyperthyroidism result in a multisystemic disease.
The main way cats develop hyperthyroidism is due to development of a benign tumor, known as an adenoma, in their thyroid gland.
The tumor secretes excess thyroid hormone, creating the condition of hyperthyroidism.
Lateral radiographs of a cat with hyperthyroidism and hyperthyroid heart disease.
Symptoms of Feline hyperthyroidism
The most common clinical signs of hyperthyroidism in cats include
- weight loss,
- increased appetite (although some patients have decreased appetite),
- increased thirst and
- hyperactivity, and
- Weakness (less common, but can be a symptom)
- Labored breathing and panting (less common, but can be a symptom)
- Decreased activity (less common, but can be a symptom)
Diagnosis of feline hyperthyroidism
The diagnosis of feline hyperthyroidism by veterinarians usually requires the combination of a detailed medical history, thorough physical examination, and confirmation of disease via laboratory testing. The medical history should note any changes in activity, behavior, or appearance that are suggestive of hyperthyroidism
What are the treatment options for feline hyperthyroidism
Felines have the same therapeutic choices as human patients:
· Medication to suppress the thyroid gland
· Surgical removal of the tumor
· Radioactive iodine (I-131) injection