What clinical signs are typically exhibited in cases of feline hyperthyroidism?

Feline hyperthyroidism is a common condition in older cats characterized by an overproduction of thyroid hormone, which leads to a range of clinical signs. The correct choice reflects the classic signs typically associated with this disease.

Increased appetite, or polyphagia, is a primary symptom observed in cats with hyperthyroidism due to the body's accelerated metabolism. Despite consuming more food, these cats often experience weight loss, as their bodies are burning through energy at an unusually high rate. Additionally, hyperactivity is another common sign; affected cats may exhibit restless behavior and increased activity levels that were not present before the onset of the disease.

These symptoms arise as a result of the excess thyroid hormone causing increased metabolic rate, appetite stimulation, and changes in energy levels. Therefore, the combination of increased appetite, weight loss, and hyperactivity serves as a hallmark triad for diagnosing feline hyperthyroidism, making this the most accurate choice.