It was 2018 when my husband and I moved into our house and received the most unexpected housewarming gift. Hearing a short, chirpy meow, I stopped what I was doing and saw a tiny black cat in the backyard. I learned that Sophia had lived in the woods behind our house long before we did. It was only fitting she stayed at her home. I’m a cat lover, and she was a darling. It was no problem feeding her. It was warm out, and other neighborhood cats visited us that summer. The running joke among the neighbors is that their dogs and cats would live here, too, if they could.

When winter came and the temperature dropped, I worried about Sophia freezing. I purchased wet cat food along with the dry kibble she ate. She was initially timid, but before I knew it, this cat, scared of her shadow, was in my lap, letting me rub her chin. Not long after, my husband caught her and brought her indoors.

Being an outdoor cat for years, she wasn’t thrilled to be stuck indoors. She would meow at the door to go out in the weeks following. I often felt like a horrible, selfish pet parent, hearing her cries to go outdoors. This tiny cat had lived in the woods for years. She knew how to survive, but what if she refused to come indoors when the temperature dropped? What if she never came back? I felt like I was punishing a child who had done nothing wrong, but I’d heard of coyotes in the area. I had to make the best decision for Sophia.

She adjusted to life indoors eventually. Most nights, she sleeps at my side. She’s made a friend with our other cat named Kid. He climbs into bed with Sophia, so I’ve nicknamed them the married couple.

We suspect Sophia is older than Kid. Our veterinarian estimates she is over 15 years old based on the haze in her eyes and other factors. She’s fragile, weighing just over 6 pounds. She’s as light as a newborn and cries as much. At first, I thought the other cats were stealing her food. Sophia takes her meals under our bed. It’s the only place she’ll eat. Growing up in the woods, she probably hid from predators that would eat her kill or, worse, make her their meal.

Sophia’s senior blood work results were excellent on earlier visits to the veterinarian. The vet estimated her to be much younger than she was on those visits. Her old blood work coming up didn’t concern me.

What frightened me was the cyst that had developed on her neck. Was it a reaction to the topical flea medicine I had applied, or could our sweet girl have cancer? She’d also lost weight, primarily muscle.

Her picky eating habits didn’t help. The staff at the local Petco have come to know me. Every other day, I would stop in after work and pick up cans of cat food in different flavors and brands, hoping that Sophia might select one and stick with it. Why couldn’t she return to eating her old favorite, chicken in gravy?

I would do whatever it took to see that my tiny girl lived her best life. I booked a last-minute appointment at the veterinarian for Sophia and our Bully Maze, who already had an annual appointment scheduled at that time. I would bring up Sophia’s weight loss and her picky eating habits while they examined the cyst. I prayed Sophia would be alright.

I dismissed Sophia’s extra vocalizations that day as her being uncomfortable at the vet. She’s always chatting, answering questions, asking for food, and commanding attention with her meows. I teased that the vet techs couldn’t wait to get us out of the waiting room when they heard Sophia coming. They showed us to a room a half hour earlier than our appointment time.

Maze, our usual patient Bully, tolerated the noise far less than we did. She shook all over, doing the crocodile roll when the veterinarian tried to examine her. To avoid stressing Maze out, the vet examined Sophia first. My husband took her home, allowing Maze time to calm down.

Sophia’s cyst was innocuous. Her senior blood work revealed an elevated level of thyroid hormone. Sophia’s diagnosis was hyperthyroidism.

Please note the disclaimer before I go into detail about my research on the topic.

DISCLAIMER

I am not a veterinarian, vet tech, or medical professional. I’m sharing a personal experience and the research I’ve done regarding hyperthyroidism and chronic kidney disease in cats.

If you suspect your cat has either of these or an illness that needs medical attention, bring them to a veterinarian.

What is Hyperthyroidism?

According to the Feline Hyperthyroidism Treatment Center website, “Hyperthyroidism is a wasting disease caused by increased thyroid hormones, resulting from one or more benign tumors (adenomas) of the thyroid gland.” https://www.felinehtc.com/hyperthyroidism

Sophia’s thyroid hormone levels were raised, but not as high as they could be. The constant meowing or crying was because Sophia was hungry. The thyroid gland manufactures the thyroid hormone, and the hormone manages the body’s use of energy. Thyroid hormones impact the body’s cells and organs. Sophia’s body was using up energy faster than she could make it, which meant her organs had to work harder to keep up.

Cats have two thyroid glands in their neck. If the thyroid glands produce insufficient hormones, the body’s energy use will slow down. Slow heart rate, fatigue, and weight gain are a few examples of inadequate thyroid hormones.

Conversely, a hormone surplus will expedite the body’s energy consumption. Elevated blood pressure, increased heart rate, and higher metabolism are symptoms of hyperthyroidism. Cats primarily consume animal protein. When they burn protein instead of fat, they lose muscle. Found at https://www.felinehtc.com/hyperthyroidism

Hyperthyroidism is prevalent in older cats. Many cats will develop hyperthyroidism. Diseases of the kidney and liver can influence thyroid hormone levels. Nutrition and certain medications can also disrupt hormone levels.

It’s important to note that hyperthyroidism progresses slowly. Signs may be subtle, and you may not notice them.

Information found https://www.vet.cornell.edu/animal-health-diagnostic-center/testing/protocols/feline-thyroid

Signs of Hyperthyroidism Include

Weight loss, despite increased appetite

Vomiting

Diarrhea

Drinking and urinating more than usual

Hyperactivity

Unkempt coat

Signs of more advanced Hypothyroidism

High Blood pressure

Heart disease

Retinal detachment or blindness

Found Signs at https://www.fda.gov/animal-veterinary/animal-health-literacy/hyperthyroidism-cats-theres-fda-approved-drug-treat-it#hyperthyroidism

Sophia became a picky eater; she was very vocal, and when she ate, she wanted me by her side. Cats with hyperthyroidism exhibit behavior changes. They may purloin food off the table, become fussy eaters, or vocalize their hunger.

Hyperthyroidism that isn’t treated can result in heart failure, diseases of the kidneys and liver, and ultimately death.

Treatment for Feline Hyperthyroidism

Radioactive iodine therapy is performed in specialty clinics. A shot of radioactive iodine is given to the cat. The bloodstream sponges up the iodine. The radiation destroys the benign tumor on the thyroid gland without compromising other tissues. The cat would remain at the treatment facility briefly and return home, where he would need to be isolated due to the radioactive component of the therapy. The outlook after treatment is good, but the overall cost is expensive, and treatment is only available in some places.

Anti-thyroid medication is usually given twice daily for the rest of the cat’s life to reduce thyroid hormone production. Topical anti-thyroid gels are also an option. Side effects include “vomiting, fever, low energy, weight loss, and facial itching.” The cost for the pill form of the medication is relatively low. https://www.webmd.com/pets/cats/cat-hyperthyroidism

Sophia is currently on the medication Methamozle to reduce the amount of thyroid hormone production in her body. She is taking the pill. Methamozole comes in an oral liquid form or a topical gel applied to a hairless part of the cat’s body, often the ear.

According to the VCA website, “Pregnant and nursing women, or women who may become pregnant, should wear gloves when handling the medication, cat litter, or body fluids from treated pets. Anyone applying the transdermal gel should wear gloves during administration.” Found at https://vcahospitals.com/know-your-pet/methimazole

Sophia has not been diagnosed with Chronic kidney disease (CKD), but it is important to note that CKD can occur with hyperthyroidism.

Hyperthyroidism and Chronic Kidney disease (CKD)

Hyperthyroidism and Chronic Kidney disease (CKD) are common diseases in older cats. Hyperthyroidism and CKD can occur at the same time, but they also “mask” each other. In other words, the signs are similar, and one disease could mimic the other or be the cause of another. The Royal Veterinary College of London’s website states, “The effect of hyperthyroidism leading to an increase in glomerular filtration rate (GFR)…”https://www.rvc.ac.uk/clinical-connections/concurrent-chronic-kidney-disease-and-hyperthyroidism

To better understand how these concurrent diseases work, I researched Chronic Kidney disease and how the kidneys work.

The kidneys have numerous functions. Their primary functions are eliminating waste from the bloodstream, managing vital minerals such as potassium and sodium, conserving water, and producing urine. Found at https://vcahospitals.com/know-your-pet/kidney-failure-chronic-in-cats

In other words, they rid the body of toxins that, over time, could build up and poison the bloodstream and cause other illnesses.

Healthy kidneys can filter a large volume of fluid. Blood flows into the renal artery, a large blood vessel in your kidney, and then it travels through smaller branches of blood vessels until it reaches the nephrons. Each nephron has a filter called a glomerulus and a tubule. The glomerulus filters your blood, and the tubule returns the necessary substances to your blood and removes the waste. https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work

The preliminary signs of CKD, changes in the cat’s coat and weight loss, are often overlooked as part of natural aging.

Chronic Kidney disease isn’t evident “clinically” until the kidneys are at a point of no return and they haven’t functioned well for a while. According to the VcA Animal Hospital website, that point of no return is when “ two-thirds” or “67-70 %” of the kidneys are not functioning as they should. By then, the disease has done substantial damage. The cat has suffered for months or years. Treatment may slow the disease progression, so bringing the cat to a veterinarian is essential. Found at https://vcahospitals.com/know-your-pet/kidney-failure-chronic-in-cats

Signs of CKD

Weight loss

Poor hair condition

Bad breath

Appetite changes that could stem from mouth ulcers

Lack of energy

Sadness

Excess drinking and urinating

Vomiting and diarrhea

Anemia

Treatment for Chronic Kidney Disease

Treatment for chronic kidney disease in cats involves lowering blood pressure, reducing protein loss in urine, and treating anemia. Oral medication is used to lower blood pressure, and angiotensin-converting enzyme (ACE) inhibitors are used to reduce protein loss. Replacement erythropoietin, a glycoprotein hormone produced naturally in the kidneys, can be used to stimulate the production of red blood cells. Blood transfusions are another treatment option for anemia.

Other therapies such as "phosphate binders, potassium supplements, antioxidants, intravenous administered subcutaneous fluids, and alkalinization therapy to ease nausea and vomiting caused by chronic acidosis may be used to treat chronic kidney disease in cats.” https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/chronic-kidney-disease.

Bring your cat to a vet if you have reason to believe your cat has CKD or hyperthyroidism. Treatment may benefit your feline and improve your feline’s quality of life.

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Sources

Cornell University (n.d.). Feline Thyroid Tests. College of Veterinary Medicine. Retrieved January 11, 2024, from https://www.vet.cornell.edu/animal-health-diagnostic-center/testing/protocols/feline-thyroid

Cornell University (n.d.). Chronic kidney disease. College of Veterinary Medicine. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/chronic-kidney-diseased

Farmer, V. (2023, January 16). Cat Hyperthyroidism (Overactive Thyroid) Symptoms and Treatments. WebMD. Retrieved January 11, 2024, from https://www.webmd.com/pets/cats/cat-hyperthyroidism

FDA US Food and Drug Administration (17, December 3). Hyperthyroidism in Cats—There’s an FDA-Approved Drug to Treat It. US Food and Drug Administration. Retrieved January 11, 2024, from https://www.fda.gov/animal-veterinary/animal-health-literacy/hyperthyroidism-cats-theres-fda-approved-drug-treat-it#hyperthyroidism

Feline Hyperthyroidism Treatment Center (n.d.). What Is Feline Hyperthyroidism? Feline Hyperthyroid Treatment Center. Retrieved January 11, 2024, from https://www.felinehtc.com/hyperthyroidism

Royal Veterinary College of London (n.d.). Concurrent chronic kidney disease and hyperthyroidism. Retrieved January 10, 2024, from https://www.rvc.ac.uk/clinical-connections/concurrent-chronic-kidney-disease-and-hyperthyroidism

U.S. Department of Health and Human Services (n.d.). Your Kidneys & How They Work. National Institute of Health. Retrieved January 10, 2024, from https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work

VCA animal hospitals (n.d.). Chronic Kidney Diseases in Cats. Retrieved January 10, 2024, from https://vcahospitals.com/know-your-pet/kidney-failure-chronic-in-cats