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Cat Killing Conditions That Can Hide Undetected

Many serious illnesses in cats can hide undetected for a while.

When you have a cat in your family, you want to do the best you can to keep him healthy and happy. The best ways to do so are to keep up with his veterinary visits, feed him good quality food, and spend time playing and interacting with him every day.

However, some conditions are common in cats that can hide until they are quite severe. These conditions kill many cats every year, and it's important to know what they are and what symptoms to watch out for.

Kidney Disease

Kidney disease is widespread in cats, especially those over ten years old. The early signs of kidney disease in cats can be easy to miss, and they include:

  • Gradual weight loss
  • Increased water consumption and urination
  • Decreased appetite
  • Mild to moderate lethargy (often mistaken as normal aging)

Many cats show absolutely no signs of kidney disease for a long time. In fact, they generally look and act healthy until at least 75% of their kidney function is gone.

The best way to catch kidney disease early is to have routine blood work done on your cat. A rise in the blood values BUN, creatinine, and potassium can indicate early kidney disease. Changes may be made in diet and fluid intake to help the cat's kidneys maintain function longer if the condition is caught early. You can learn more here: "Kidney Disease in Cats."

Heart Disease

Cardiomyopathy, or an enlarged heart muscle, is common in cats, but it is difficult to diagnose. Many cats have silent heart disease for a long time, which means that they show no signs of illness and often do not even have a heart murmur or anything else that can be detected on the physical exam. In fact, many cats with heart disease don't show signs until they are either in heart failure, when they begin having breathing difficulties and coughing, or until they suffer from a cardiac event like sudden death or thromboembolism.

If your veterinarian does suspect heart disease because he or she notices a heart murmur, racing heart, or pale mucous membranes on physical examination, cardiac ultrasound and other testing may be conducted to diagnose the exact structural problem going on with the heart. Treatment may be possible to help support the heart and prolong the cat's life.

You can learn more about the most common heart condition diagnosed in cats here: "Hypertrophic Cardiomyopathy: HCM in Cats."


Hyperthyroidism is diagnosed quite often in older cats. It is an overactive thyroid gland which produces too much thyroid hormone, and the result is hyperactivity and an overactive metabolism. This disease is not entirely silent because it produces signs such as anxiety, excessive meowing, increased appetite, and weight loss. However, those signs can be gradual and somewhat difficult to detect. People often attribute them to regular age changes.

When hyperthyroidism is suspected, a veterinarian will run blood tests to confirm it, and then treatment consists of one of three choices:

  • Oral medication
  • Radioactive iodine treatment
  • Surgical removal of the thyroid

You can learn more about this condition including its signs, diagnosis, and treatment here: "Hyperthyroidism in Cats."


Cancer in cats is a condition that can hide until it is quite severe. There are many types of cancer, and some of them have vague signs associated with them. For example, a cat with skin cancer might have a change in skin color in a small area masked by fur. It isn't until the area grows and the fur falls out that it's easily noticeable.

Another example of the insidious nature of cancer in some cats is oral squamous cell carcinoma, which can grow as a tumor within the cat's mouth for months before it begins to cause foul breath, drooling, difficulty eating, and weight loss. By the time those signs appear, the tumor is large enough and has been present long enough that it has often invaded underlying bone and metastasized to other sites in the cat's body, like the lungs.

Because cancer can cause so many different signs of illness depending on where it is in the cat's body and what systems it's affecting, it's essential to monitor all aspects of your cat's health and behavior and visit the veterinarian right away if any changes are noticed. You can learn more about what to watch for here: "Warning Signs of Cancer in Cats."

How to Protect Your Cat from These and Other Silent Killers

The best way for you to protect your cat from the conditions listed here as well as many others is to understand that cats often mask illness. They don't usually show signs that they're having a problem until a condition is quite advanced. That means that you have to be a detective and watch for and interpret any early and vague signs of illness appropriately. Here are some things to keep an eye on:

  • The frequency and consistency of your cat's stool
  • Your cat's urinary behavior
  • How much water your cat is drinking and whether it increases or decreases at any time
  • Your cat's behavior, including whether he becomes quieter, starts hiding, has a decrease or increase in energy and activity levels, and how much vocalizing he does
  • Whether your cat moves normally or has any sign of lameness
  • How much food your cat eats and whether that amount ever increases or decreases
  • Your cat's skin, including the appearance of any swellings, lumps, bumps, or discolorations
  • Vomiting
  • Monitor your cat's breathing behavior for signs that it might be labored or faster than normal

In addition to keeping a close eye on things at home, it's crucial that you take your cat in for an exam and any recommended testing at least once a year. That frequency can increase with age and the diagnosis of any medical conditions.

Keep in mind that these are only a few of the many conditions that can affect cats.

You May Also Like These Articles:

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Hypertrophic Cardiomyopathy: HCM in Cats

Saddle Thrombus: Aortic Blood Clots in Cats

Cancer in Cats

Hypothermia and Heatstroke in Cats

Heart Disease in Cats

Anemia in Cats

Heartworm Disease in Cats

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