The hyperthyroidism in cats symptoms are not very hard to recognize. You'll notice that your cat is losing weight drastically even though she eats more than usual, or she can even lose the appetite; she will have breathing problems since the heart rate will be high and the blood pressure, as well; she might urinate much often than usual because of kidney dysfunction; and so on. However, some symptoms are harder to notice since they are related to behavioural changes that might be even more dangerous than the physical.
1. Hyperactivity – this is definitely not a good sign, especially because this illness is connected to older cats and they are supposed to be calmed down at that age. You cat is very nervous because of all processes going on in her, and that's the way to manifest it. At some point, your cat may become aggressive, even with you, mostly because she feels helpless and scared. Among all the behavioural hyperthyroidism in cats symptoms, this one happens every time; only the intensity may be different.
2. Yowling and sleepless nights – the cat might begin to produce strange noises that are hard to explain. This doesn't mean that she is in pain, but she feels there is something wrong with her, and her nervous system is disturbed because of hyperthyroidism. Besides, she will probably have the sleeping problems; she'll start wandering around the house or look disoriented. The only good thing is that every owner will note that this is very unusual behaviour and try to find help soon.
3. Lethargy and depression – this behaviour is not very common, but it can get you worried, anyway. Instead of feeling hyperactive and hungry all the time, the cat will lose appetite, or she would only lie in one position for hours. This is not only related to hyperthyroidism in cats symptoms since there are many cats with some other health problems that have practically lost the will to live. For example, one way to find out is your cat suffering, or she is just having a bad day is bringing her favourite things, food and try playing with her, and if that doesn't work, you know what you need to do.
People do making mistakes when they connect behaviour of their cat with a particular disease without talking to the professional. Unfortunately, hyperthyroidism in cats symptoms like in other health problems can be expressed this way, and it's not recommended to find the answer by yourself, or try to treat the cat on your own.