Could Hypothyroidism be causing behavioural problems in dogs?

Could Hypothyroidism be causing behavioural problems in dogs?

Hypothyroidism is when the thyroid gland does not produce enough of the thyroid hormones triiodothyronine, known as T3 and thyroxine, known as T4 and it is quite common in dogs. Cats, on the other hand suffer from an overactive thyroid gland and this is called Hyperthyroidism. I have had cases of Hypothyroidism diagnosed when I have sent my clients to their Vets to get a full thyroid blood test panel done. Sometimes, my clients have called me saying that the Vet will not perform the blood test because their dog is not showing the typical clinical signs of Hypothyroidism. I feel quite sad that some dogs may have had behavioural problems because of Hypothyroidism and ended up being euthanised or put in dog rescues.

You started out with this loving cute pup, and now it is anxious, whines constantly, does not behave properly, can be reactive, nervous, has become intolerant of other dogs and people despite your best efforts with socialisation. Some Vets might just tell you that your dog needs training or that your dog is in canine puberty, and it will not last, but despite all your best efforts, your formerly compliment puppy is out of control. Please before you decide to find your dog another home, thinking the behaviour is your fault or just the breed, have your Vet check for thyroid problems.
Hypothyroidism is often missed in dogs because some dogs do not display the traditional signs of hypothyroidism and only present with behavioural problems, making it easy to miss. A study was conducted on 1,500 dogs with behavioural problems, and it was found that out of those 1,500, 60% of them had a thyroid problem. Fortunately, like people dogs can be treated with thyroid hormones and achieve marked changes in their behaviour.

Traditionally, dogs have only been blood tested for Hypothyroidism when they present with lethargy or other classic thyroid clinical signs such as dry brittle coat, allergies, or flaky skin but aggressive behaviour was not recognised as a clinical sign. Because the clinical signs of Hypothyroidism are so varied and widespread across multiple clinical signs, a single system is often not connected to the thyroid but seen as an isolated problem. Also, because thyroid problems can start in young dogs from 6 months to 1.5 years the clinical signs are often not connected to a potential medical problem but are thought to be due to the temperament of the individual dog.

Many experts now believe that when a dog has changes in behaviour they should be assessed, and blood tested for thyroid problems. While it would make sense that your Vet would test for thyroid problems if there were other symptoms involved, according to at least one study not all dogs with Hypothyroidism and behavioural problems had other symptoms.

One of the primary disruptions that occurs with Hypothyroidism is with norepinephrine and serotonin, which both affect behaviour. For those dogs that have subclinical or a moderate decrease in their thyroid function, behavioural changes are likely to be the first and possibly only symptoms that you will see. For this reason and given the high rate of thyroid problems in dogs with behavioural problems, it may be up to you to advocate for your dog and insist that your Vet does a thyroid panel blood test. Make sure that your Vet does a full thyroid blood panel and not just T3 and T4 because they may miss cases of Hypothyroidism.
Your Vet will also look for the following symptoms as they assess your dog for Hypothyroidism.
Dry itchy skin
Hair grows back slowly after being shaved
Dull coat
Constant shedding
Sad worried facial expressions
Anxiety or hyperactivity

Thankfully, Hypothyroidism can be treated with hormone replacement therapy that can help your dog return to normal behaviour. Dosages may be adjusted as required, as changes in behaviour improve, or regular testing can be done to keep an eye on the thyroid levels. You may need to do your homework to find a Vet that will help you access the cause of your dog’s behavioural symptoms.

Justine Shone

JP Holistic Nutrition


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