Hyperthyroidism in Cats

What is hyperthyroidism?

Hyperthyroidism is a hormone disease in which the thyroid gland, found in the neck, makes too much thyroid hormone (T4). It is common in middle-aged and older cats. It is usually caused by a non-cancerous growth of the thyroid gland.

Thyroid hormone controls how fast the body works. Too much of it speeds everything up, so the cat burns energy quickly and loses weight. Over time it can strain the heart and raise blood pressure. It can also hide kidney disease, because it increases blood flow through the kidneys.

Signs to watch for

Common signs include:

• Weight loss with a good or bigger appetite
• Drinking more and passing more urine
• Restlessness or loud crying, often at night
• Vomiting or diarrhoea
• An untidy or matted coat
• A fast heartbeat

The signs come on slowly, so they are easy to mistake for normal ageing.

Which lab tests help

The usual first test is T4, Total, which measures the main thyroid hormone in the blood. A raised result in a cat with typical signs supports the diagnosis. In early or mild cases, or when the cat has another illness, total T4 can sit within the reference range shown on the lab report. Your vet may then repeat it or add T4 Free (FT4). Free T4 is more sensitive, but it can also be raised in some sick cats without thyroid disease, so it is read together with total T4. Feline T4 (fT4) is a cat-specific T4 test; the lab confirms the method when you book.

Kidney checks are important. A Kidney Function Test (KFT), SDMA (Symmetric Dimethylarginine) and Urine Routine show how well the kidneys are working. Because an overactive thyroid can hide kidney disease, vets usually check kidney values at the start and again later.

A Liver Function Test (LFT) is also useful, because liver enzymes are often raised in cats with hyperthyroidism. For a wider check of an older cat, the Pro Panel includes free T4 with blood count, liver, kidney and sugar tests. Your vet may also measure blood pressure and check the heart.

A registered veterinarian interprets every result together with your cat's signs and history.

When to see your vet

See your vet promptly if your older cat is losing weight while eating well, drinking more, or becoming restless or noisy. Go the same day if your cat has breathing trouble or collapses.

Testing in Bhopal

Pashupatinath Vet Lab in Shahpura, Bhopal provides free sample collection anywhere in Bhopal, so an older cat does not need to travel for a blood sample. From other districts, samples can be sent through your local vet, by courier or by bus parcel; the lab coordinates by phone or WhatsApp on +91 88175 01118. The lab confirms sample needs and reporting time when you book. Reports come on WhatsApp, by email and in My Reports.