7 Hidden Health Issues in Cats and How To Spot Them

Anyone who loves a cat knows how close our bond with them can be; they often follow us around, sit with us while we’re working, and sleep next to us at night.  

Because we become so close with our cats, we may think it should be easy to tell when they aren’t feeling well. However, illness can be difficult to detect because of a cat’s natural instincts to hide their vulnerability from potential threats.  

Although cats are predators to songbirds, rodents, and snakes, they are also small enough to be prey to larger predators such as coyotes, foxes, and hawks. As such, they must be careful when hunting in the wild not to draw too much attention to themselves when they’re sick or injured.   

This instinct has carried over to indoor cats, who might show few to no signs of how they are feeling even to trusted family members, aside from hiding or acting more subdued.  

For this reason, it’s important to have your cat seen by a veterinarian for a wellness exam yearly, even for an otherwise healthy cat. The veterinarian can help detect medical issues that might not be obvious at home.  

Several diseases that can impact cats show only subtle signs in the early stages, so being alert for small changes in your cat’s condition is crucial to getting prompt veterinary care. 

1. Feline Immunodeficiency Virus (FIV)

Feline immunodeficiency virus (FIV) infects a cat’s immune cells, leaving the cat immunocompromised and at risk for developing other infections that could be serious. 

An estimated 5–8% of cats worldwide carry the virus, but not all will develop the full-blown autoimmune disease that can be troublesome for a cat’s health. Any cat can contract FIV, although it seems to be slightly more common in older male cats, in cats who live outdoors and roam freely, and in cats who live in crowded settings with many other cats (such as shelters).  

Signs To Look For

Early symptoms of FIV can be subtle and include low energy, fever, and swollen lymph nodes. 

2. Diabetes

Diabetes, also known more specifically as diabetes mellitus, is a chronic condition in which either:  

• A cat’s pancreas stops producing insulin (Type I), which helps cells take up glucose from the blood for energy 

• A cat’s cells stop being able to respond to insulin (Type II, which is much more common in cats) 

Both types cause increased blood sugar in cats. As a result of a cat’s body being unable to use glucose for fuel, the body will start to break down fat and muscle tissue for energy, with potentially severe consequences.  

As many as 0.5% of all cats will develop diabetes at some point during their life (roughly one in 250), and it’s most common in cats over 6 years of age, obese cats, neutered male cats, and in certain breeds like the Burmese. 

Signs To Look For

The most common symptoms noticed at home in the early stages are increased drinking and urinating, as well as weight loss despite a good appetite. 

3. Cancer

Cancer is a disorder in which a cat’s cells grow at an abnormally fast rate due to changes in the DNA at the molecular level, causing tumors that can sometimes affect the function of a cat’s organs.  

Common types of cancers in cats include: 

• Lymphoma (usually of the GI tract, kidneys, or lymph nodes) 

• Mammary adenocarcinoma (a malignant cancer of the mammary glands in older, unspayed female cats) 

• Squamous cell carcinoma (a type of skin cancer) 

Signs To Look For

Early symptoms of cancer in cats can include:  

• Unexplained weight loss 

• Decreased energy 

• Decreased appetite 

• Vomiting 

• Diarrhea 

Some symptoms may depend on what part of the body is affected. 

4. Dental Disease

Dental disease is a general term for the buildup of plaque and tartar on the teeth. It can progress to the gums, causing inflammation (gingivitis), tooth resorption (bone loss in the teeth), and even bone loss in the jaw.  

As many as 50–90% of cats over 4 years old have some level of dental disease, though it’s most common in:  

• Cats who don’t have their teeth brushed every one to two days with a cat-safe toothpaste and toothbrush 

• Cats with tooth crowding in the mouth from defects present at birth 

• Cats with decreased immune function that prevents them from fighting off bacterial infection (cats with autoimmune diseases like FIV, very old cats, and cats who are sick with other conditions) 

Signs To Look For

Early symptoms of dental disease in cats can include:  

• Decreased eating and subsequent weight loss 

• Preference for soft foods 

• Turning their head while eating 

• Dropping food 

• Bad breath 

5. Kidney Disease

Kidney disease is the progressive loss of kidney function over time. This can lead to many health issues, such as high blood pressure and anemia.  

Approximately 40% of cats 10 years and older have some level of kidney disease, while 80% of cats 16 years and older have kidney disease, making it one of the most common diseases in senior and geriatric cats.  

While age is the most important factor in the development of kidney disease in cats, other factors may play a role, such as breed (Persians, Abyssinians, Siamese, Ragdolls, Burmese, Russian Blues, and Maine Coons may develop kidney disease earlier in life) and lifestyle (cats who drink less water may be at greater risk of kidney disease).  

Signs To Look For

Early symptoms of kidney disease can include urinating more, drinking more, eating less, losing weight, and experiencing low energy.  

6. Arthritis

Arthritis is painful inflammation and progressive degeneration of the joints, usually in older cats. The spine, hips, knees, and elbows are most often affected in cats. 

Approximately 90% of cats 12 years and older have some level of arthritis. It’s most common in older cats and obese cats, and it’s slightly more common in Maine Coon cats due to their stocky bodies and risk of hip dysplasia. 

Signs To Look For

Early signs of arthritis can be subtle, such as: 

• Hiding more 

• Playing less 

• Hesitating to jump on furniture or go upstairs 

• Grooming less 

• Spending more time in warmer areas, such as sunny windows 

7. Hyperthyroidism

Hyperthyroidism is a disorder where the thyroid gland, located in the neck, becomes enlarged and produces too much of the hormones T3 and T4. This leads to an increased metabolism and many other effects.  

Hyperthyroidism is estimated to be present in 10% of senior cats, and it’s most common in middle-aged to older cats.  

Signs To Look For

Early symptoms of hyperthyroidism can include:  

• Weight loss despite a normal or increased appetite 

• Increased drinking and urinating 

• Restlessness