Identifying the signs of kidney failure in cats can help you make the best choices for your pet. Modern treatments slow the deterioration of kidney disease and keep the cat well for longer, but there is a time when the kidneys shut down and quality of life becomes an issue. This is when truly caring for your cat may mean recognizing it's time to say goodbye.
Understanding Renal Failure in Cats
International Cat Care explains 'renal' or kidney disease is common in cats and a normal part of aging. The kidney has a limited ability to repair itself, and over the course of the pet's life, active kidney tissue is replaced with nonfunctional scar tissue. Various factors hasten this damage such as certain minerals in the diet, infection, high blood pressure, cancer, genetic factors and toxins.
The kidneys' job is to filter naturally occurring toxins out of the blood and get rid of them in urine. In addition, the kidney regulates the body's hydration status and has a role in the production of red blood cells. When the kidney isn't working properly, a number of things happen. Long Beach Animal Hospital outlines the complications which include:
- Rise in toxins levels (most notably creatinine and urea) in the blood, leading to nausea, vomiting and poor appetite
- The cat struggles to concentrate their urine, leading to water loss and dehydration
- Protein leaks through the kidney and is lost, leading to muscle wastage and poor body condition
- Poor production of red blood cells, resulting in anemia
- Hormones that increase blood pressure are retained, leading to hypertension (high blood pressure)
Treatment is aimed at tackling these complications, resting the kidney and slowing deterioration. The sooner the problem is diagnosed and treated, the longer the cat's survival time. Inevitably, deterioration happens to a point where kidney function fails and the cat becomes ill with her final illness. This is known as end stage feline renal disease.
Lab Evidence of End Stage Renal Disease
The International Renal Interest Society divides renal disease into different stages. These range from mild, early disease to end stage. According to these IRIS guidelines a cat is technically in end stage failure when they have less than 10 percent of normal renal function. Markers of kidney function which predict when she has entered end stage include:
- Extremely high blood creatinine levels
- Excessive amounts of protein in the urine
- Very weak urine
- High blood pressure
However, as Prof. Johnathan Elliott advises, test results are only ever a guide to the cat's health and it's important to treat the cat rather than the numbers. For example, some cats have shocking blood results but are relatively well, while others have OK results on paper, but are very sick in reality.
Physical Characteristics of End Stage Renal Disease
A cat in end stage renal disease is poorly and her welfare should be uppermost in the pet parent's mind. VCA Hospitals notes the nature of the illness means the cat is often painfully thin, with little or no muscle mass, and she has a dull, starry coat. In addition:
- High toxin levels in the blood cause her to have bad breath.
- The stomach lining becomes inflamed which causes nausea resulting in a poor appetite and vomiting.
- In an attempt to flush toxins from the blood, the cat is usually very thirsty and produces lots of urine. The end is often close when the cat stops drinking or producing urine.
- Dehydration produces a lack of elasticity in the skin. The classic sign is skin tenting. To detect dehydration lift the skin over the cat's shoulder and let go. The skin should instantly ping back into place, but dehydrated skin takes a second or more to fall back into place, or worse still stays in a peak.
A Cat's Eye View of End Stage Illness
The cat in end stage renal disease feels nauseous and weak. She refuses food and may be very thirsty or stop drinking altogether. She will also be thin and the anemia means she lacks energy even to do simple things like groom. Sadly, a mistake often made by owners is to think a purring cat is happy. A sick cat purrs to comfort herself so the hard decision to say goodbye should not be postponed because the cat is still purring and presumed content.
Therapy Options for End Stage Renal Disease
With less than 10 percent functional kidney tissue left, therapy aims to ease the unpleasant complications of kidney failure. Research on renal disease, published in Waltham Focus, explains it's best to maximize quality of life rather than length of life. Sometimes the best that can be hoped is to make the cat comfortable and ease suffering. If therapy fails to help, an owner faces the unenviable decision to say goodbye and save the cat from distress.
Dehydration makes a cat feel weak and nauseous. The problem is the kidney is so damaged it cannot retain fluid, meaning whatever the cat drinks passes straight through. To correct dehydration, the cat needs to gain more fluid than she loses. It is rarely possible to eliminate dehydration altogether, but boosting the amount of water going into the cat may help her feel better. AAHA guidelines suggest:
- Subcutaneous Fluids: An owner may be taught how to slowly inject depots of sterile saline solution under the skin. Around 60 - 120 mL is injected subcutaneously per day in three to four sites. Unfortunately, in a very sick cat, her circulation is so bad that the body struggles to absorb the fluid.
- Oral Fluids: This involves slowly syringing water into the cat's mouth, giving her plenty of time to swallow each mouthful. On average around 100 - 150 mL is given by this route. Most cats only tolerate around 5 mL at a time, which makes it a huge commitment for the owner.
Rising toxin levels mean the cat has no desire to eat, so the cat becomes progressively weaker. Encouraging the cat to eat can give her vital energy. While prescription renal food is ideal, some food is better than none for a cat that's not eating.
- Vitamin B Injections: Vitamin B stimulates the appetite, but sadly this water-soluble vitamin is lost in urine. Weekly vitamin B injections can help maintain levels, which in turn, supports appetite.
- Anabolic Steroid Injections: This remains controversial because there is little proof that it is effective. However, for decades vets have given weekly or monthly injections of anabolic steroids, which owners anecdotally report improves appetite.
- Appetite Stimulant Tablets: Low doses of appetite stimulants such as Periactin or mirtazapine can help some cats to eat.
- Nursing Care: Providing a favorite food, warming the food and hand feeding may all encourage eating.
Toxin accumulation in the bloodstream makes the cat feel sick. ISFM suggest strategies to reduce nausea make a big difference to quality of life:
- Antacid Medications: Medications which either prevent stomach acid production or neutralize it (for example Omeprazole or Ranitidine) make the cat more comfortable.
- Phosphate binders: Another complication is rising blood phosphate levels, which are also linked to nausea. Adding a phosphate binder such as Ipakitine to food can contribute to lowering blood phosphate levels.
- 'Bandaging' the Stomach: Liquid medications such as Antepsin ease nausea by forming a bandage layer over an inflamed stomach lining.
- Centrally acting anti-sickness medication: Maropitant (Cerenia) acts on the brain to switch off feelings of nausea.
Correcting High Blood Pressure
Cornell University says a probably consequence of renal failure is high blood pressure. This can lead to dizziness or a stroke. It is not always appropriate to give an end stage cat medication to reduce blood pressure, but should your vet decide it is safe for that individual cat, they may prescribe amlodipine.
Severe anemia leads to weakness and poor quality of life. Some veterinary referral centers use injections of erythropoietin to stimulate increased production of red blood cells. However, the American Journal of Veterinary Research suggests this treatment is problematic as many cats become sensitized to the erythropoietin and can develop life-threatening allergic reactions to it.
Correct Secondary Problems
Renal disease may cause problems such as infection or low blood potassium levels. As cat expert Sarah Caney writes in In Practice, correcting secondary problems is important.
- Low Blood Potassium Levels: Low potassium causes extreme muscle weakness, sometimes so severe the cat cannot hold her head up. Correcting this with a potassium supplement may be all that's needed to make a difference.
- Urinary Infections: Weak urine allows bacteria to grow, which can make the cat feel unwell. Culturing the urine to determine an appropriate antibiotic can improve quality of life.
Nursing the End Stage Cat
Nursing is an essential part of caring for a seriously ill cat. You should keep the cat indoors for her own protection. Bed the cat down on a comfortable padded surface, such as Vetbed or a puppy pad on top of blankets. Check the cat regularly in case she has soiled and is lying in urine. If she is not moving around, encourage her to change position when awake to reduce the risk of bedsores. She may feel the cold easily, so ensure the room is warm or provide a heat mat.
The cat will not want to walk far so place a litter box, food, and water within easy reach. Most sick cats feel better for a gentle brush and having their eyes, nose, and mouth wiped clean with damp cotton wool. Let her rest but also provide quiet companionship and fuss when she is awake.
End of Life Decision Making
Sadly, leaving the cat to die naturally may cause suffering. Those high toxin levels often lead to seizures and her last few days are likely to be unpleasant. Instead, before this happens it is kinder to ease her distress by making the humane decision to say goodbye.
Making the ultimate decision is less difficult if you have planned ahead and written down at what stage you consider it unfair to the cat to continue. To aid decision making, it is helpful to think of your cat in her prime and what you would consider unacceptable quality of life back then. For example, if your cat was a greedy eater, then a lack of appetite is a sure sign she is not herself. Weigh up factors such as:
- Dignity - Does she soil herself?
- Lack of pain or discomfort - Is she vomiting regularly?
- Playfulness - Does she now hide away?
These intangible factors often tell you a lot about how sick the cat has become.
The Ultimate Kindness
You love your cat and it breaks your heart to see her so sick. By all means, do everything possible to comfort her, but know sometimes it is kinder to say goodbye than battle on. Euthanasia is hard for an owner, but know you are putting the cat's best interests first and preventing suffering. Ultimately, saying goodbye is a brave decision made from a sense of self-sacrifice. It is not what you want, but what the cat needs, that is of paramount importance in the end.