Which of the following is a common clinical sign of feline hyperthyroidism?

Feline hyperthyroidism is a condition commonly seen in older cats and is characterized by an excess production of thyroid hormone primarily due to a benign tumor of the thyroid gland. One of the hallmark clinical signs of this condition is weight loss, despite an increased appetite. This occurs because the elevated levels of thyroid hormones boost the cat's metabolism significantly, leading to catabolism of body tissues, including fat and muscle.

Other common clinical signs of feline hyperthyroidism can include increased thirst and urination, hyperactivity, vomiting, and changes in coat quality. However, weight loss remains a key indicator that veterinarians look for when diagnosing this condition, making it essential for recognizing hyperthyroidism in affected cats.

In contrast, diarrhea, urinary incontinence, and ascites are not typical signs directly associated with feline hyperthyroidism. Diarrhea may occur in various feline gastrointestinal conditions, urinary incontinence can stem from different urinary or neurological issues, and ascites generally relates to conditions involving fluid build-up in the abdominal cavity, which are not typical manifestations of hyperthyroidism. Thus, focusing on weight loss is crucial in understanding the presentation and diagnosis of feline hyperthyroidism.