What is hyperthyroidism in cats?
Located in the neck, your cat's thyroid glands produce many hormones that help regulate several processes throughout the body and control your cat's metabolic rate. If the thyroid produces too much or too little of these hormones, symptoms of either hypothyroidism (low levels of hormone) or hyperthyroidism (too much hormone) will appear.
Hyperthyroidism can most often be blamed on a non-cancerous tumor located somewhere on the thyroid gland. However, in some rare cases, the tumor may develop into thyroid cancer.
If your cat is suffering from hyperthyroidism, their metabolism will speed up, meaning your kitty will tend to burn energy too quickly, resulting in weight loss even if your four-legged companion is eating significantly more food than they typically would.
What are the symptoms of hyperthyroidism in cats?
While cats of any breed can experience hyperthyroidism, most cats diagnosed with the condition are older—typically between 12 and 13 years old. Male and female cats are equally impacted by the disease.
Symptoms of hyperthyroidism in cats are often subtle in the early days. However, they gradually become more severe over time. Other underlying health issues may also also mask or complicate symptoms of hyperthyroidism, so it's important to see your veterinarian early if your cat shows any symptoms listed below. Cats producing too much thyroid hormone may show one or more of the following symptoms:
- Low tolerance for heat
- Increase in thirst
- Hearty or increased appetite
- Increase in heart rate
- Poor grooming habits
- Mild diarrhea and vomiting
In its more advanced stages, the condition will often cause cats to pant when they are stressed, which is unusual for cats. While many cats suffering from hyperthyroidism have a good appetite and appear restless, others may feel lethargic or weak, or experience a loss of appetite. Left untreated, potential long-term complications of hyperthyroidism include high blood pressure (which is linked to damage to the eyes, heart, brain and kidneys) and heart failure.
If you or your regular vet have noticed any symptoms mentioned above in your cat, you might consider using your favourite search engine to search for 'internal medicine veterinarian near Vancouver' to find reputable and experienced specialists, including our team at Columbia River Veterinary Specialists.
How is hyperthyroidism diagnosed?
It can be somewhat tricky for vets to diagnose hyperthyroidism in older cats. Your kitty will need to have a physical exam, during which your vet will palpate your cat's neck area to look for symptoms of an enlarged thyroid gland. Our veterinary internal medicine specialists use state-of-the-art diagnostic testing to help diagnose your pet's condition and provide advanced care to manage this disease.
What is the best diet for cats with hyperthyroidism?
Hyperthyroidism in cats can often be managed through an iodine-restricted prescription diet from your vet. This may be recommended in conjunction with other treatment options such as surgery to remove the thyroid or antithyroid medication.
Iodine intake is necessary for the production of thyroid hormones, so the goal of an iodine-restricted therapeutic diet is to help reduce the production of thyroid hormones by reducing iodine in your cat's diet.
Iodine levels in foods for cats with hyperthyroidism should be limited to 0.32 parts per million or less. Your vet may prescribe high-quality canned or dry cat food specially made for cats with hyperthyroidism.
Strict adherence to the low-iodine diet is necessary for this treatment to be effective, which can prove challenging for some pet parents and their cats. Along with feeding your cat a prescription food, you will need to avoid giving your cat treats and people food, and prevent your cat from hunting for their own meal while outside. If your cat eats any good other than your prescribed diet, this could sabotage the careful balance of iodine necessary to improve hormone levels.
Diets for Cats with Hyperthyroidism as Part of a Treatment Plan
If diet is one component of your cat's treatment, he or she may benefit from eating grain-free food high in energy and protein, which can help your cat regain weight and muscle mass lost due to their overactive thyroid. Your vet may prescribe specific brands of food depending on your cat's needs.
On the other hand, if your cat's kidney function has been compromised, more moderate protein levels may be required. For cats with kidney disease, eating too much protein can lead to a worsening of symptoms.
The high water content in canned food makes it an ideal choice, as this can counterbalance your cat's tendency to produce too much urine as a result of high levels of thyroid hormones. It's also important that your cat have free access to clean water at all times.
Some studies show that after three weeks of following a prescription hyperthyroidism diet, levels of T4 thyroid hormones begin to decrease, and within a few months, they may even return to normal levels.
Once your cat's thyroid levels have been normalized with methimazole, thyroidectomy or radioactive iodine therapy, and the cat has regained a healthy amount of weight, their diet plan can be adjusted to meet their needs.
Our internal medicine specialists are here to work with you and your primary veterinarian. We can answer your questions, address concerns and offer advice geared to your pet's needs (including food and dietary requirements) at every stage of illness and recovery. We recommend discussing any changes to your cat's diet with your vet first before implementing them.
What is the prognosis for cats with hyperthyroidism?
If the condition is diagnosed and treated early, the prognosis for cats suffering from hyperthyroidism are generally good. In some cases where the condition has become more advanced, complications with other organs can worsen prognosis.