Bellevue Veterinary Hospital, Parksville

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Feline Hyperthyroidism

Black cat on HalloweenBLACK CATS AND HALLOWEEN

Even though Halloween has already passed, a lot of black cats are still coming in for their annual checkups here at Bellevue Veterinary Hospital. And speaking of kitty cats (black or otherwise), hyperthyroidism is a very common ailment in the older ones.

In fact, hyperthyroidism is the most common endocrinopathy (hormonal disease) of cats.

Hyperthyroidism is a sustained high metabolic state caused by thyroid nodules secreting too much thyroid hormone. 98% of these nodules are benign.

Hyperthyroidism typically affects middle age to older cats.

The most typical scenario is a cat that is losing weight despite good appetite. Another common finding on physical exam is the presence of a heart murmur. Other signs may include intermittent vomiting, increased drinking, diarrhea, behaviour change and poor hair coat.

Diagnosis is made via a blood test which shows elevated thyroid level.

The 3 most common ways that we treat hyperthyroidism here at Bellevue Veterinary Hospital include:

  1. Methimazole - a medication which blocks the pathway that leads to the formation of thyroid hormone. This medication comes in the form of a tablet or a transdermal gel that is applied to the inner part of the ear.
  2. Y/D Diet - is a special diet from Hill’s. It is an ultra-low iodine deficient diet that is effective in lowering T4 values. This diet is only suitable for indoor cats.
  3. Radioactive Iodine Injection - this is a potential cure for hyperthyroid cats but does require a 1 week stay at a referral clinic in Victoria. The radioactive iodine is absorbed into and destroys the problematic thyroid tissue. It is curative in 98 - 99% of cats.

Tags: Medications, Geriatrics, Thyroid