Cat's thyroid is overactive

My 12-year-old cat suddenly seemed hungry, but lost weight. My vet found a lump in his neck and high blood pressure. Bloods are being checked for a suspected overactive thyroid, for which there are treatment options. Is this common?

- DR DAVID GRANT

Hyperthyroidism, (overactive thyroid glands), in cats is a common problem. Intriguingly it was reported for the first time in the 1970s in the US and not long after in the UK and elsewhere. Suddenly vets were seeing many cases, suggesting something new in the environment.

There have been many theories since, but nothing conclusive. Meanwhile the condition continues to be diagnosed regularly.

Excessive hunger, weight loss and an elevated blood pressure are suggestive signs. Often it is possible to palpate one or more thyroid lobes in the neck. Another feature is that cats can become quite irritable, a complete change in personality.

I am sure I hadn't seen anything like this prior to the 1970s, but I have seen many cases since.