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Hyperthyroidism in cats – what you need to know

While having only been identified in the past 30 years or so, hyperthyroidism has become the most common endocrine disease diagnosed in cats.

The disease is the result of a benign growth on the thyroid glands that produces an excessive amount of thyroid hormone (or T4). In a small percentage of cats, this growth is cancerous.

Thyroid hormone is responsible for the metabolic rate in the body. No breeds are particularly affected, with many of the cats diagnosed being the common Domestic Short-Haired mixed breed cats.

The cause of this condition has yet to be identified. Iodine levels in the diet have been thought to play a role, cats eating diets of mostly fish based canned food, soy proteins in food, and environmental factors such as being exposed to polybrominated diphenyl ethers (PBDE) chemicals used to fire-protect materials and products.

The proportion of hyperthyroid claims in metro areas is 5% higher than all cat claims in metro areas. The disease affects older cats, with most cats being diagnosed with the condition at around 13 years of age or over (15% of cats, rising to 30% of cats at aged 17 and above).

Due to the advanced age of the cats, the pets usually suffer other health problems as well as hyperthyroidism.

According to PetSure data, the top five disorders that usually co-exist with hyperthyroidism are:

  • Renal (kidney) disorder
  • Arthritis
  • Hypertension (abnormally high blood pressure)
  • Inflammatory bowel disease (IBD)
  • Hepatopathy (liver disorder).

Common signs of hyperthyroidism in cats include:

  • Weight loss, despite the cat having an excellent appetite
  • Increased intake of water
  • On/off vomiting and diarrhoea
  • Possible behavioural changes, including hyperactivity and signs of more aggressiveness.

Treatment options for this condition include medical therapy, surgery or radioactive iodine therapy. PetSure has seen an increase in the use of radioactive therapy however most cats are treated medically with anti-thyroid drugs. Treatment of comorbidities including heart disease and kidney disease is required.

Any advice is general only and may not be right for you. Cover is subject to the policy terms and conditions. You should consider the relevant Product Disclosure Statement or policy wording available from the relevant provider to decide if a product is right for you. Insurance products are issued by The Hollard Insurance Company (ABN 78 090 584 473; AFSL 241436) and administered by PetSure (Australia) Pty Ltd (ABN 95 075 949 923; AFSL 420183) through our Authorised Representatives and our distribution partners.

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