5 “silent” killers of cats | Dr. Justine Lee

Posted by justinelee in Animal Safety, Blog, Uncategorized

When it comes to caring for your cat, make sure to provide the basics:

• A safe environment (e.g., keeping them indoors if you live on a busy road or city)
• A high quality food (e.g., a meat-based protein)
• Preventative care (e.g., an annual physical examination and the appropriate vaccines as needed)
• Lots of affection and exercise

By doing this, we can help keep our four-legged feline friends healthy for potentially decades! But as cat owners, you should be aware of 5 “silent” killers of cats. By knowing what the most common silent killers are, we can know what clinical signs to look for. With most of these diseases, the sooner the clinical signs are recognized, the sooner we veterinarians can treat it.

1. Chronic kidney failure

One of the top silent killers of cats is chronic kidney failure [This is sometimes called chronic renal failure (CRF) or chronic kidney injury (CKI)]. These terms are all semantically the same, and basically mean that 75% of both the kidneys are ineffective and not working. Clinical signs of CRF include excessive drinking and urinating, larger clumps in the litter box, weight loss, bad breath (due to kidney poisons building up in the blood and causing ulcers in the mouth, esophagus, and stomach), lethargy, and hiding. Thankfully, with appropriate management, cats can live with CRF for years (unlike dogs). Chronic management may include a low-protein diet, frequent blood work, increasing water intake (e.g., with a water fountain or by feeding a grueled canned food), medications, and even fluids under the skin (which many pet owners do at home, once properly trained).

2. Hyperthyroidism

Hyperthyroidism is an endocrine disease where the thyroid gland produces too much thyroid hormone. This is seen in middle-aged to geriatric cats, and can result in very similar clinical signs to chronic kidney failure, including excessive thirst and urination and weight loss. However, as hyperthyroidism increases the metabolism of cats, it causes one classic clinical sign: a ravenous appetite despite weight loss. It can also result in a racing heart rate, severe hypertension (resulting in acute blood loss, neurologic signs, or even a clot or stroke), and secondary organ injury (e.g., including a heart murmur or changes to the kidney). Thankfully, treatment for hyperthyroidism is very effective and includes either a medication called methimazole, surgical removal of the thyroid glands – less commonly done), or I131 radioiodine therapy. With hyperthyroidism, the sooner you treat it, the less potential side effects or organ damage will occur to your cat.

3. Diabetes mellitus

Another costly, silent killer that affects cats is diabetes mellitus (DM). As many of our cats are often overweight to obese, they are more at risk for DM. With diabetes, the pancreas fails to secrete adequate amounts of insulin, a nature hormone that drives sugar (e.g., blood glucose) into the cells. As a result of the cells starving for glucose, the body makes more and more glucose, causing hyperglycemia (e.g., a high blood sugar) and many of the clinical signs seen with DM. Common clinical signs for DM are similar to those of CRF and hyperthyroidism and include:

• Excessive urination and thirst
• Larger clumps in the litter box
• An overweight or obese body condition with muscle wasting (especially over the spine or back)
• A decreased or ravenous appetite
• Lethargy or weakness
• Vomiting
• Abnormal breath (e.g., acetone breath)
• Walking abnormally (e.g., lower to the ground)

Treatment for DM can be costly, as it requires twice-a-day insulin injections that you have to give under the skin. It also requires changes in diet (to a high protein, low carbohydrate diet), frequent blood glucose monitoring, and frequent veterinary visits. With supportive care and chronic management, cats can do reasonably well; however, once diabetic complications develop (e.g., diabetic ketoacidosis; hyperosmolar, hyperglycemic syndrome), DM can be life threatening.

4. Cardiac disease

Heart disease is very frustrating for both cat owners and veterinarians. That’s because why dogs almost always have a loud heart murmur (e.g., one we can hear with our stethoscope) indicative of heart disease, cats often don’t have a heart murmur present. In fact, it’s estimated that 50% of cats with heart disease have no auscultable heart murmur. Clinical signs of heart disease include:

• A heart murmur
• An abnormal heart arrhythmia (e.g., an abnormal beat and rhythm)
• A racing heart rate
• Collapse
• Passing out (e.g., syncope)
• Increased respiratory rate
• Difficulty breathing
• Blue-tinged gums
• Open mouth breathing
• Acute, sudden paralysis (e.g., typically of the hind limbs)
• Cold, painful hind limbs
• Sudden pain
• Sudden lameness
• Sudden death

Once cardiac disease is diagnosed (typically based on physical exam, chest x-rays, and an ultrasound of the heart called an “echocardiogram”), treatment may include emergency care for oxygen therapy, diuretics, blood pressure support, and heart medications. Long-term prognosis is poor, as the heart medication does not cure the heart disease; it prevents cardiac disease from getting worse. The exception? Cardiac disease caused by hyperthyroidism, which gets better once the hyperthyroidism is treated!

5. Cancer

As dogs and cats live longer, we as veterinarians are seeing more die of cancer. Cancer can affect any tissue or organ, and result in subacute or chronic death. The most common type of cancer in cats is gastrointestinal cancer, often due to lymphosarcoma. Clinical signs of cancer include weight loss, not eating, vomiting, diarrhea, weight loss, difficulty breathing, abdominal distension or bloating, weakness, lethargy, hiding, fever, and generalized malaise. Once diagnosed, the prognosis for cancer is poor. For this reason, the sooner you notice clinical signs, the sooner diagnosis and treatment may be initiated.

When it comes to your cat’s health, make sure to be aware of these common silent killers. The sooner you notice the signs, the sooner we can do blood work and diagnose the medical problem. The sooner we diagnose the problem, the sooner we can treat it!