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Symptoms of Hyperthyrodism in Cats

By Robyn Johnson. September 03, 2012 | See Comments

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Symptoms of Hyperthyrodism in Cats

Hyperthyroidism can take effect at a slow pace in the beginning, and be hard to catch. But there are a few warning signs that you can look out for.

Hyperthyroidism causes damage to the body very slowly at first, so it may go undiagnosed for some time. The symptoms are often categorized as normal aging. However, a few symptoms may be more obvious, such as weight loss, increased appetite, and increased thirst and urination. Symptoms may also include diarrhea, vomiting, and hyperactivity. In some cases, the cat will have a visible large moveable or immoveable mass over the trachea and larynx.

Hyperthyroidism symptoms can be categorized into behavioral and physical symptoms.

Behavioral Symptoms of Hyperthyroidism

Behavioral symptoms of hyperthyroidism include polydipsia, polyuria, polyphagia and hyperactivity.

  • Polydipsia is increased or sudden excessive consumption of water. Since it is sometimes difficult to determine if a cat is thirsty or excessively so, there is a formula that may help. Normal daily consumption of water is [140 x (body weight of cat in kg.)0.75]. Any volume above the formulaic solution is likely to be polydipsia.
  • Polyuriais increased or excessive urination, often seemingly uncontrollable. Typically, an adult cat produces between 20-35 milliliters of urine per kilogram of body weight, per day. Urine production in excess of 40 milliliters per kilogram of body weight per day is consistent with polyuria.
  • Polyphagia, an increased or excessive appetite, often manifests itself as trash rooting, food stealing, intensified food guarding, and begging. The ravenous appetite of a cat with hyperthyroidism is often accompanied by weight loss.
  • Hyperactivity is constant quick movement and activity, often when the cat typically would be tired. This is due to the high levels of metabolic hormone, which then creates more energy from fewer calories.

Physical Symptoms of Hyperthyroidism

Physical symptoms of hyperthyroidism may be gradual at first, but eventually they may become obvious and problematic. These symptoms of hyperthyroidism include a visible large mass over trachea and larynx of the cat, dyspnea (difficult breathing), dysphagia (difficulty in swallowing), weight loss, dysphonia (hoarseness.)

  • A visible mass is a commonly associated with hyperthyroidism, and may in fact be the tumor that is causing the thyroid to misfire. It usually covers the trachea and the larynx of the cat.
  • Dyspnea is shortness of breath, and is associated with hyperthyroidism because there is often an overexertion of respiratory function, causing the cat to hunger for air.
  • Dysphagia is a problem with swallowing. Cats with hyperthyroidism often develop a mass on their trachea. This mass may interfere with the swallowing function.
  • Dysphonia is hoarseness of voice, which can be associated with a damaged trachea, often in the case of hyperthyroidism, due to a mass or tumor on the thyroid.
  • Weight loss is a very common symptom of hyperthyroidism, for a couple reasons. The increase in the hormones T4 and T3 increase the metabolic rate of the animal, meaning it burns calories at a higher rate. Also, the increase in activity level burns more calories also.

As some of these symptoms may be difficult to identify as abnormal, it is important to keep track of any behavior or physicality that is inconsistent with your cat previously.

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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