Hyperthyroidism in Cats

Understanding the condition

Hyperthyroidism is a very common disorder of older cats. Cats with hyperthyroidism have an overactive thyroid gland, resulting in excess production of thyroid hormones. This change usually results from a benign (non-cancerous) growth within one or both of the thyroid glands located in the cat's neck. In addition extra thyroid tissue can be located within the cat's chest.

The thyroid hormones are responsible for a number of metabolic functions within the body, including:

• Proper growth of body cells and the development of these cells for specific roles in the body
• Regulation of the metabolism of protein, fat and carbohydrate by these cells
• Regulation of heat production and oxygen consumption, and therefore a wide range of metabolic processes 

Therefore an increase in the levels of these hormones circulating within the body result in a dramatic increase in the body's metabolic rate and hence energy consumption.

The increased energy demands mean the cat has to eat a lot more food to meet its needs, resulting in an increased appetite. Despite this the cat often cannot consume as much energy as it requires from its diet, and must supplement its energy requirements from body reserves of fat and protein, which leads to weight loss.

Diagnosis

Weight loss despite a ravenous appetite is often the first sign noticed by owners. Other signs which may also be noticed are an unkempt coat, diarrhoea +/- vomiting, restlessness or a change in temperament, an increase in thirst and urination, and an increased heart rate. Occasionally cats may present with lethargy or inappetance.

Hyperthyroidism is often suspected from the history and a thorough examination of the cat. However in an older cat there are a number of conditions which can cause similar signs, or may be present in conjunction with hyperthyroidism, so your vet will usually recommend a blood sample is taken to check the liver/kidney function as well as the thyroid hormone level. As hyperthyroidism places a lot of strain on the cat's heart, some degree of heart disease is often present by the time of diagnosis, and further tests may also be recommended to assess heart function.

Treatment

Hyperthyroidism is readily treated and cats tend to respond quickly with appropriate medical management. Treatment is based on tablets which interrupt the synthesis of thyroid hormones and bring the levels of these hormones in the blood back to normal. Initially a three week course of tablets is prescribed to stabilise the cat, and then a re-examination performed to assess the clinical response. A blood sample is usually taken again at this stage to check the response to treatment, and allow any adjustments to the dose to be made appropriately.

Medical treatment controls, but does not cure, hyperthyroidism. If the cat is responding appropriately it may continue on medical treatment for the rest of its life, with regular examinations to ensure correct dosing and monitor weight, as well as monitoring for concurrent health problems as the cat ages. Side effects of medical treatment are uncommon.

Alternatively if your cat has responded well to medical stabilisation, but ongoing tablet treatment will prove difficult, there are surgical options for treatment which may be discussed with your vet.

How to give a tablet to your cat

Unfortunately the tablets used to treat hyperthyroidism are not designed to be crushed or broken up as they have a sugar coating to disguise a bitter taste. Therefore they should be given whole. The thought of giving tablets to cats strikes fear into most cat owners, which is not surprising considering the array of weapons they are born with! Control of teeth and claws is key to successful pill-giving, as well as a bold manner and a reward for the cat afterwards.

1. Firmly grasp the cat's head using your less dominant hand ie your left hand if you are right handed and vice versa. Place your palm over the top of the cat's head, with your thumb and forefinger on the cheek bones either side of the head behind the top jaw. It is useful if an assistant can hold the top of the cat's forelegs (firmly but gently) to prevent it clawing at its mouth while you are giving the pill.
   
2. With the cat's head held in place, gently tilt the head back so that the nose is pointing towards the ceiling.  The mouth should naturally start to open.  If the cat does not open its mouth (perhaps from previous experience!) you can gently squeeze your thumb and forefinger together at the corners of the mouth to force it open.
   
3. Place the tablet between the thumb and forefinger of your dominant hand, or in the pill popper. Use your ring or middle finger to open the cat's mouth further by applying pressure to the middle teeth on the bottom jaw. This pressure, together with tilting the cat's head, will cause the mouth to open. Cats have no strength in the lower jaw in this position and as long as the head is held firmly in vertical they cannot bite. 
   
4. After the mouth is open quickly place the pill as far back in the mouth as possible, aiming for where the tongue meets the roof of the mouth. Keep the cat's head fully back. Once the pill is far enough back it is unlikely the cat will spit it out. If the pill gets under the tongue or to the side of the mouth they can spit it out very deftly!
   
5. Close the cat's mouth and hold it closed. It can help to have a small syringe of water ready to squirt in the back of the mouth while the head is still vertical, this will encourage the cat to swallow. Alternatively, rubbing or blowing on the cat's nose will encourage it to lick its nose, causing it to swallow.
   
6. Let go and watch the cat for a few moments to make sure it doesn't spit out the pill. If it does spit out the pill, throw it away and start again. Watch for lip licking motions which usually indicate that the pill has been swallowed, although some cats are very good at deception so it may be wise to open the mouth again after a few moments to check it has really gone down!
   
7. Don't let your cat make a hasty exit after it has had the tablet. If you encourage it to run 'take-off' you are encouraging it to associate 'flight' with the pill-taking experience. Pet and cuddle it, or reward it with a treat or play with a favourite toy. By pampering your cat, you'll help it to be more prepared and co-operative the next time it is given a pill. 

We do not expect anyone to instantly become expert at giving tablets, and if you are struggling please do let us know so we can talk through alternative options, or help with the first few attempts!