Drooling Cats. A Warning Sign Your Kitty’s Kidneys Are Failing


Chronic kidney disease (CKD) is a common disorder in cats, especially older cats over 10 years old. Studies estimate the prevalence of CKD in cats is around 7.6% in the United States, with higher rates in older cats nearing 12% (Marino et al. 2014). As a cat’s kidneys start to fail, they are unable to properly filter waste products from the blood. This buildup of waste products causes a variety of clinical signs, including increased thirst and urination, weight loss, vomiting, diarrhea, and poor appetite. One symptom that can occur is excessive drooling or hypersalivation. As kidney function declines, toxins accumulate in the body which can cause nausea and oral inflammation or ulcers, leading to increased drooling.

Kidney Anatomy and Function

The kidneys are bean-shaped organs located in the abdomen that play a vital role in filtering waste products from the blood. Cats have two kidneys, with each kidney containing over a million microscopic structures called nephrons that filter the blood. As blood flows through the nephrons, waste products like urea are removed and excreted in the urine while important substances like water and electrolytes are reabsorbed back into the bloodstream (1). This filtration process is critical for maintaining fluid balance, regulating blood pressure, and keeping the blood clean.

Kidney failure or insufficiency occurs when the kidneys can no longer adequately filter blood. This results in a buildup of waste products in the bloodstream along with an imbalance of fluids and electrolytes. As kidney function declines, the kidneys are less able to excrete waste products through urine while also having impaired reabsorption of substances like water. Kidney failure has severe impacts on overall health and can be fatal if left untreated (2).

(1) https://www.merckvetmanual.com/cat-owners/kidney-and-urinary-tract-disorders-of-cats/the-urinary-system-of-cats

(2) https://www.safarivet.com/care-topics/dogs-and-cats/bladder-and-kidneys/

Signs of Kidney Failure

As a cat’s kidneys start to fail, they lose their ability to effectively filter waste products from the blood. This leads to a buildup of toxins in the body that can cause a number of symptoms. Some of the most common signs of kidney failure in cats include:

Increased thirst and urination – One of the earliest signs of kidney disease is increased water consumption and urination. This happens as the kidneys try to flush out the excess toxins and waste products via the urine. Cats may start drinking noticeably more water and urinating larger volumes more frequently.

Weight loss – While kidney disease leads to increased thirst and urination, it also causes appetite loss and weight loss. This is due to the buildup of toxins that make cats feel nauseous, the kidneys’ failure to produce appetite-stimulating hormones, and overall malaise.

Lethargy – The accumulation of waste products in the bloodstream makes cats feel sick and weak. They tend to have less energy and be more lethargic as kidney disease progresses.

Bad breath – Uremia, which is the excess urea and other nitrogenous waste in the blood, causes a characteristic foul, ammonia-like odor to a cat’s breath.

Drooling – Excess saliva production and drooling can occur as kidney failure progresses. The uremic toxins building up in the body irritate the oral cavity and esophagus, leading to increased salivation. Severely uremic cats tend to drool more.

Catching kidney disease early is key, as prompt treatment improves outcomes. Noticing increased thirst/urination, weight loss, lethargy, bad breath, or drooling warrants having a vet examine a cat to check kidney function and look for signs of kidney failure.




Why Kidney Failure Causes Drooling

Kidney failure leads to the buildup of toxins in a cat’s bloodstream. This is because the kidneys are no longer able to adequately filter waste products from the blood. According to the Pet Health Network, “Chronic renal failure (CRF [also known as chronic kidney injury, CKI]) can result in clinical signs of weight loss, increased thirst, increased urination.”1 As toxins accumulate, they can cause painful mouth ulcers and inflammation.

These ulcers make swallowing difficult and painful for the cat. As a result, the cat is unable to swallow saliva normally and ends up drooling. According to SSD Pet Vet, “Chronic drooling can also be a sign of kidney disease or kidney failure in cats.”2 The mouth ulcers and swallowing difficulties caused by kidney failure toxins lead to excessive drooling and salivation problems in cats with chronic kidney disease.

Diagnosing Kidney Failure

There are several tests veterinarians use to diagnose kidney failure in cats:

Blood and urine tests – These lab tests measure levels of waste products like creatinine and BUN (blood urea nitrogen) that build up when the kidneys aren’t functioning properly. Elevated levels indicate reduced kidney function. Urinalysis also checks for protein in the urine, which points to kidney damage.[1]

Imaging tests – X-rays, ultrasound, or MRI scans allow veterinarians to visually examine the kidneys. This reveals abnormalities in kidney size, shape, and structure that signal kidney disease.[1]

In addition to these tests, a veterinarian will evaluate the cat’s symptoms and medical history. Diagnosing kidney failure requires assessing multiple factors.

Early detection is key, as treatment is more effective when kidney disease is caught before the late stages. Annual senior wellness exams help monitor kidney function in aging cats.

[1] https://www.vetinfo.com/diagnosing-kidney-failure-cats.html

Treating Kidney Failure

There are several aspects to treating kidney failure in cats:

Providing fluids is crucial to flush toxins from the body and restore electrolyte balance. Vets often hospitalize cats initially for intravenous fluid therapy. At home, subcutaneous fluids can be given under the skin. Fluids help reduce urea and creatinine levels while supporting kidney function. According to Dutch, flushing the system is step one for treating any stage of kidney disease (https://www.dutch.com/blogs/cats/cat-kidney-failure).

Medications may be prescribed to manage complications of kidney failure: anti-nausea drugs for vomiting, ACE inhibitors for high blood pressure, antacids for ulcers, phosphorus binders for hyperphosphatemia, erythropoietin injections for anemia, potassium supplements for hypokalemia, etc. These medications treat secondary effects and make cats feel better even if the underlying kidney damage can’t be reversed.

Diet is changed to reduce protein, phosphorus, and sodium intake while increasing omega-3 fatty acids, potassium, and antioxidants. Prescription kidney diets aim to reduce workload on the kidneys while providing balanced nutrition. According to Brandywine Veterinary Hospital, homemade or commercial kidney diets serve important therapeutic and preventive roles (https://brandywinevet.com/kidney-failure-in-cats).

Mouth ulcers are common and can make eating painful. Ulcers can be treated with oral rinses, numbing gels, antibiotic creams, steroids, or laser therapy for stubborn ulcers. Ensuring cats eat enough is critical, so treating mouth ulcers helps improve appetite and nutrition intake.

Outlook for Cats with Kidney Failure

Unfortunately, kidney failure is not a curable disease in cats, but the prognosis depends on the severity and how well it can be managed with treatment. According to the Animal Health Foundation, vets may classify kidney disease into 4 stages, from mild dysfunction to end-stage failure, which helps determine prognosis [1]. For cats in early stages, the prognosis can be good with proper management. But in advanced kidney failure, even with intensive therapy, the condition is progressive and will eventually become fatal.

A cat’s prognosis is best when kidney disease is caught early before it advances. With treatment like fluids, medication, and dietary changes, cats can often live with managed kidney disease for months or years. But in end-stage kidney failure, life expectancy is very limited even with aggressive treatment. Euthanasia may be considered to prevent further suffering when a cat has a poor quality of life.

While kidney failure shortens a cat’s life, the goal of treatment is to slow progression of the disease and provide the best quality of life possible. This involves balancing management of clinical signs like poor appetite, dehydration, and wasting against a cat’s daily experience. With dedicated care and monitoring, many owners can provide good quality of life for their cat with kidney disease for some time.

Caring for a Cat with Kidney Disease

There are several important things you can do at home to help care for a cat with kidney disease and support their overall wellbeing:

Encourage Water Intake – Getting enough fluids is crucial for cats with kidney issues. Provide fresh, clean water bowls around the house. Consider getting a cat fountain to entice your cat to drink more. You can also add more moisture to their diet with canned food or by adding water to their meals.

Feed a Kidney-Friendly Diet – Your vet may recommend prescription kidney diets or food designed for renal health. These foods are typically lower in protein, phosphorus, and sodium but higher in calories and omega-3 fatty acids to be easier for the kidneys to process (Source).

Regular Vet Checkups – Take your cat to the vet frequently to monitor kidney values and overall health. Your vet may recommend bloodwork, urinalysis, imaging, and other tests to check kidney function and watch for any changes.

Manage Medications – Your vet may prescribe medications like ACE inhibitors to control blood pressure, antacids for nausea, phosphate binders for phosphorus control, and more. Give medications as directed and monitor your cat for side effects.

Help Control Pain – Kidney disease can be painful. Your vet may prescribe pain medication to keep your cat comfortable. Ensuring your cat rests and avoids stress is also important.

Preventing Kidney Disease

There are several steps cat owners can take to help prevent kidney disease in their feline companions:

Get annual checkups with bloodwork to monitor your cat’s kidney values. Changes in levels like BUN and creatinine can indicate early kidney issues, allowing for early treatment (Blue Pearl Pet Hospital).

Practice good dental care by brushing your cat’s teeth or getting professional cleanings. Dental disease can lead to kidney infections. Keeping your cat’s mouth healthy reduces this risk.

Make sure your cat stays well-hydrated by providing fresh, clean water daily. Cats with kidney issues may benefit from canned food or water fountains to increase fluid intake.

Feed a high quality diet with balanced levels of protein, fat, and carbs. Kidney diets promote kidney health with nutrients like omega-3s and antioxidants (Cheerble).


Key Takeaways on Kidney Failure and Drooling in Cats

In summary, kidney failure is a common condition in older cats that can lead to an increase in saliva production and drooling. As the kidneys lose their ability to filter toxins from the bloodstream, these toxins build up and can cause ulcers in the mouth. The ulcers cause pain and inflammation, which stimulates the salivary glands to produce more saliva. The excess saliva then drips from the mouth as drool.

Drooling is just one of many symptoms associated with kidney disease in cats. Others include increased thirst and urination, weight loss, poor appetite, vomiting, and bad breath. Since the signs are not specific, testing of bloodwork and urinalysis is needed to confirm kidney failure as the cause.

The key takeaway is that drooling in an older cat should not be dismissed as normal aging. It can signal a serious medical condition like kidney disease. So it’s important to have your vet examine any senior cat exhibiting signs of excessive drooling or other abnormalities. With early detection and treatment, kidney disease can often be well managed to improve quality of life.

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