Hyperthyroidism: Treating My Skittish Cat

Jethro was named after Leroy Jethro Gibbs from NCIS.

If you watch the TV show, you know Gibbs is fearless. However, Jethro is the opposite - a classic scaredy cat - any noise, from a doorbell to a fart, can make this male tiger tabby fearful. He was adopted with Hope, a calico, soon after Splashes, my first cat, died. Two 1-year old kitties were required to fill the huge hole in my heart.

Now, 12 years later, Jethro loves to be petted but is not a fan of being picked up. His only health problem, before his recent diagnosis of Hyperthyroidism, arose after receiving a chin scratch from Izzy resulting in a hard-to-treat infection 3 years ago. Initially, we tried to medicate him with chewable antibiotic pills added to his kibble. Jethro, seeing these scary additions to his food, refused to eat until 12 hours later when we removed them. This infection developed into a deep pyoderma which took months to resolve after various antibiotic injections, pills, and shampoos.

So what did I learn from this experience?

I feared for his quality of life if he ever developed a chronic illness that required daily medication. Jethro loves to snuggle on your legs - in fact, he is on my legs as I type this blog. He sleeps between my legs at night and in the morning switches to my husband’s legs as we drink our morning coffee in bed. All of this stopped when we were treating his pyoderma. In fact, he tried to avoid us, which made feeding or medicating him difficult. Jethro is a smart kitty.

So when he was diagnosed with Hyperthyroidism during the COVID-19 pandemic, my fears were realized. My vet came out to the car and stated she was worried about his weight loss and wanted to do blood work to diagnose a cause. I felt like a bad cat mom as I did not notice this gradual loss. In a few days, the diagnosis of Hyperthyroidism was revealed as his T4 levels were above the normal range. Now the question was how to treat this lovable scaredy cat while maintaining his quality of life.

Let’s briefly examine the importance of Thyroid hormone in regulating cat physiology.

While I teach this topic, I wanted to get input from my cats’ veterinarian - Dr. Susan McConnell from VCA Boonsboro Animal Hospital. My cats love her 😻. In her experience, cats encounter hyperthyroidism almost exclusively, while hypothyroidism is more common in dogs. Often these cats are over 10 yrs and the enlarged thyroid is due to a benign (non-cancerous) adenoma leading to elevated T3 & T4 - the two thyroid hormones.

Thyroid hormones can influence many bodily functions. It is a key regulator of metabolic rate which will influence body weight. Hypothyroidism often presents initially with weight loss, as it did with Jethro, due to the increased metabolic rate. Elevated levels can also have implications for your cat's heart, kidney, intestine, brain, and coat.

Elevated levels of thyroid hormones can cause hypertension. Dr. McConnell stated that the most common concerns she sees with this elevation long-term are kidney damage, heart failure, and detached retinas. It may also change your pet's personality by making them more vocal and anxious. It is important to get complete blood work performed after your cat’s T4 has returned to the normal range as hyperthyroidism may mask kidney problems since elevated blood pressure can increase renal blood flow. So reduce that pressure and the kidneys may function poorly. Thankfully Jethro’s follow-up blood work came back showing no issues after his T4 levels had stabilized. So how are we treating him?

Fortunately, there are many options to treat hyperthyroidism.

The links provided are for information and are not an endorsement. Choose a method based on your individual situation and realize all have potential side effects which should be reviewed with your vet. The first three options involve life-long medical management and only control symptoms while the latter two are surgical management and can be curative. Follow the blood work schedule your vet recommends for all forms of management.

• Methimazole Oral Pills - Administered twice daily and works by inhibiting the enzymes involved in the production of thyroid hormone. This represents the least expensive option and T4 should be reduced in 2-3 weeks. I knew from previous experience that this would be too stressful for Jethro. However this can be effective for many animals, but many may also experience nausea and vomiting.
  

• Methimazole Transdermal Gel - Applied to the inner surface of the ear, twice daily (alternating ears). A compounding pharmacy or online company can formulate a dose tailored to your cat. I choose this route for Jethro as he handles this well with minimal stress. No chasing him to take meds and full snuggle mode at night. The risk for nausea and vomiting is also reduced. Wear a finger cot when applying so the medicine is not absorbed into your system. Clean your animal's ears on a schedule. Some cat owners do it daily. I do it once a week as approved by my vet.

• Special Diet - Dietary therapy limits iodine required for thyroid hormone production and should reduce T4 levels in ~3 weeks. Cats need to eat this exclusively as only a little iodine in their diet is needed for T4 production. Since Jethro is a finicky eater and I have other cats that often share plates - this was not an option. Do not feed these formulations to healthy animals.
  

• Thyroidectomy - An invasive surgical procedure performed under anesthesia to remove abnormal tissue once identified. Caution should be used in cats with underlying health issues. While this was the method I used in my cat Splashes when he was undergoing other surgical procedures, this treatment is the least recommended option.
  

• Radioactive Iodine Therapy - Injection of radioactive iodine is only performed at licensed facilities. It is the treatment of choice especially if your cat is young, but has a large upfront expense. Radioactive iodine is taken up by the abnormal thyroid tissue and destroyed. No anesthesia is required and normal T4 levels are typically restored in 1-2 weeks. In rare cases, it may lead to hypothyroidism if too much tissue is destroyed.

With one of these hyperthyroidism treatments, the prognosis is good for most cats. Jethro's trajectory using the transdermal gel encourages me for his long-term health and well-being. His T4 levels are in the normal range, his weight is stabilized, and he takes his medication without fuss. He is happy and his purr fills my heart with joy.

Next week I will discuss making end-of-life decisions for your beloved fur babies using lessons I have learned from my own cats.