Chronic Renal Disease,Diabetic Cat Care

The information contained in this sticky is provided for educational purposes only and is not intended to replace veterinary advice. The intention of this sticky is to open doors to understanding about the specific medical condition or topic, allowing for educated and on-going discussion with your vet.

Diabetic Cat
Care

Chronic
Renal Disease 101

What is CRD?

CRD (Chronic Renal Disease, also known as CRF, Chronic Renal Failure) is the slow and non-reversible decline of kidney function.

The role of the kidneys is vital: they control and regulate numerous important levels in the body through filtering or by secreting hormones that control or effect:
· Fluid levels
· Waste products and toxins
· Various electrolyte and mineral levels
· pH of the bloodstream by regulating hydrogen ions and bicarbonate uptake
· Red blood cell production through the secretion of Erythropoietin or EPO
· Blood pressure through the secretion of the enzyme Renin which controls the sodium-potassium balance, fluid volume and blood pressure
· The metabolism of Vitamin D to its active form
· Stomach acid levels via the secretion of the hormone gastrin, which stimulates gastric acid

The kidneys are composed of thousands of nephrons, tiny filtering tubes that keep back what is good (and needed by the body), and send the waste products and toxins out in urine. When kidney function is normal, not all nephrons work at once, some are held back to work if necessary.

In CRD, more and more nephrons die off and are replaced with scar tissue. The remaining nephrons become bigger to try and handle the additional work load, but are increasing unable to cope as they become fewer.

Waste products build up in the body. The body responds by increasing thirst – so fluid intake. While that does help flush out some of the increasingly high levels of waste, important electrolytes and protein are also lost, leading to weight loss and weakness.

Stomach and intestinal ulcers can develop as waste products build up, altering the blood pH. Vomiting and loss of appetite can result. Mouth ulcers and gingivitis can occur as bacteria in the mouth turn excess urea into ammonia.

Hormonal imbalances lead to excess sodium, which can create hypertension. Phosphorous and calcium levels also build.

As the disease continues, the hormone that stimulates the creation of red blood cells, EPO, is no longer secreted in sufficient quantities, and anemia is common.

The disease is categorized into 4 stages based on Creatine levels.

Reasons why CRD occurs are not always clear; in most cases it is simply age, but toxins, and various diseases such as FeLV or FIP, cancer etc. can be implicated.

Left untreated, CRD is a fatal disease….but with correct treatment and care, you can give your cat several more years of good quality life.

Symptoms

A multitude of symptoms can occur with CRD. Many are non-specific, and CRD is often only turned up through routine lab tests.

Symptoms include:
· Weight loss
· Excessive drinking and urination
· Vomiting
· Decreased appetite
· Fatigue
· Poor, unkempt coat
· Anemia

By the time symptoms occur and tests are made, normally 66-70% of kidney function has already been lost. Cats can function on limited levels – many will continue to do relatively well with appropriate support therapy with only 10% kidney function or even less.

Diagnosing CRD

In order to diagnose CRD, the following lab results are necessary:

1) BUN (or Urea) - values are higher than normal range
2) Creatine – values are higher than normal range
3) USG -values are lower than normal range
4) Phosphorous - values are higher than normal range

A number of reasons can exist for one or two of the above, and is why diagnosis needs to take into consideration all of the above lab values.

BUN (Blood Urea Nitrogen)

BUN measures the level of urea – a by-product of protein metabolism by the liver which is excreted by the kidneys.

Normal BUN values for our high protein fed cats can be up to 20% higher than lab “normal” ranges: these ranges were established with cats on a more usual high carb/lower protein diet.

BUN levels can be elevated due to, amongst other things, dehydration (a common cause), stress, gastro-intestinal bleeding or certain medications (some abx, anti-inflammatories…).

Creatine
Creatine is a waste product of muscle metabolism.

Reasons for elevated Creatine levels other than CRD include kidney infection, inflammation, hypertension or possibly other health issues. Heavily muscled cats will also have higher levels.

USG (Urine Specific Gravity)
USG measures how concentrated the urine is: the lower the value, the more diluted. Levels tend be lower in wet fed cats due to their increased intake of water vs. dry fed cats. Unregulated FD cats that are drinking a lot will also have more dilute urine.

Liver disease, hyperthyroidism and use of corticosteroids can also lead to more dilute urine.

IRIS Staging of Feline Renal Disease WSAVA

Food and the CRD Cat

Many vets are stuck in old thinking that a cat with CRD requires a reduced protein diet (usually recommending a switch to a prescription wet food loaded with high carb fillers or a switch to dry food). A reduced protein diet is NOT recommended!!!

Dr. H, DVM, July 2006

“Please understand that the whole concept of protein restriction for CRD cats is a fallacy, or at the very least a completely unproven hypothesis. at most, the problem with high protein diets is NOT the protein but the phosphorous, which can be controlled without removing the protein. It is my view, supported by dozens of successfully managed cats with CRD on high protein diets, that it is protein restriction that is the most direct cause of the deterioration and death of CRD cats in most cases, not excessive dietary protein.”

Dr. H, DVM, September 2006

“Please be aware than many sites with general information about managing CRD in cats still recommend low-protein diets for cats. This "dogma" has become controversial at this time, and has no true science behind it. I do NOT put my CRD cats on protein restricted diets. While this approach may be appropriate for dogs (omnivores) it is not appropriate for cats with their ongoing high protein requirements. It is best to feed low carb, high protein diets with as low phosphorus as possible and/or a phosphorus binder to reduce the amount of this mineral in the CRD cat's diet.”

Your cat should remain on the species appropriate high protein/low carb diet that it is intended to eat. If you are giving canned food, it is recommended to select one with the lowest amount of phosphorous.

Cooked egg whites are an excellent source of low-phosphorous high quality protein, as is full fat cottage cheese; adding some to a CRD cat’s food is recommended to help reduce phosphorous levels.

Adding extra water to your cat’s food is also highly recommended to help flush toxins from the kidneys and kept them well hydrated.

From Tracie Hotchner's Cat Chat Dr. H on feline kidney disease

http://www.radiopetlady.com/shows/cat-chat/feline-kidney-disease/

Treatment

Treatment for CRD cats consists of treating the side effects of CRD and includes in priority:

1) ACE inhibitors
2) Fluid therapy (Sub-Q fluids)
3) Vitamin B Complex
4) Antacids/anti-nausea medication
5) Phosphorous binders if those levels are elevated

Depending on what side effects your cat may be suffering from, treatment may also be given for
1) Constipation
2) Anemia
3) Hypertension
4) Potassium imbalances
5) Metabolic Acidosis

ACE Inhibitors
Benazepril (brand names Lotensin in the US or Fortekor in Europe) is an ACE inhibitor. It inhibits a hormone that constricts arteries and veins, relaxing them and helping to increase blood flow through the kidneys. Benazepril also reduces protein loss through urine.

Fortekor is very commonly prescribed in Europe for CRD cats. Its use is rarer in the US, and some insistence may be needed to get your vet to agree to prescribing it. It can make a real difference for your cat and is highly recommended.

Fluid therapy

Fluid therapy is a cornerstone of CRD treatment. Administrating fluids corrects the dehydration suffered by most cats, increases urine production, thus decreasing the high levels of waste products.

It is better to give sub Q fluids in smaller more frequent amounts that one big amount. A common amount to give in earlier stages would be 50ml once a day. If 100ml is recommended, it is better to split this into 50 ml BID.

You will need the bag of fluids, a venoset (the tubing that is attached to that) and needles. 18 gauge needles are commonly used, though some people find the slower flow on the smaller gauge needles make the fluids easier to administer.

Lactated Ringers are usually given in the early stages of CRD. If a cat develops problems with high calcium levels, Normosol may be recommended.

Sub Q fluids should be room temperature or warmed to blood temperature for minimal discomfort for your cat. Placing the bag in a bowl of warm water is one method of doing that. They should be administered high in the shoulder. A “lump” of fluid will forum under the skin, which will slowly be absorbed over the next hours.

It is not uncommon when pulling the needle out after Sub Q administration, fluids (sometimes mixed with blood) can trickle back out through the hole left in the skin. If this happens, apply pressure to the skin until the seepage stops.

How to Administer Sub Q fluids:
http://www.youtube.com/watch?v=qyYiE6jlOVQ
http://www.youtube.com/watch?v=-4Ta537YEOU

Vitamin B 12
This is an essential nutrient for cats, but even more so for cats with CRD, for more detailed information about the benefits (and concerns) about Vitamin B12, please click here.

Vitamin B Complex
Vitamin B is water soluble. Both the additional water in food and the Sub Q fluids may result in low B vitamin levels for your cat. Giving Vitamin B Complex is therefore recommended.

Antacids/Anti-vomiting Medications

CRD cats often have elevated levels of gastric acid and may have stomach or intestinal ulcers, leading to excess acid, stomach pain and vomiting.

Slippery Elm Bark is natural remedy recommended to help with gastric upset. It coats the stomach, mucus membranes and intestines. Slippery Elm Barb should be given 2 hours before or after any other medication. Slippery Elm Bark is increasingly difficult to find in Europe today as it has been outlawed due to EU regulations. It can be ordered from US sites.

PepsidAC (1/4 tab of 10mg tablet) administered BID can help. PepsidAC is the brand name for famotidine. It may be possible to find it in its generic form; however, it is usually in 20mg tablets. PepsidAC can be used as well if Slippery Elm alone is not providing enough relief, but the two should not be given at the same time.

Phosphorous Binders

Phosphorous binders are indicated if your cat’s level of Phosphorous is over 6 (US) or 1.9 (International).

High Phosphorous levels will quicken the progression of CRD, and can result in a number of very unpleasant side effects for your cat: lack of coordination, nausea, loss of appetite and weight, tremors for example.

There are 3 types of Phosphorous binders: Calcium based, aluminum based, and “others”

Aluminum based binders in the form of Aluminum Hydroxide tend to be used the most. Note that you should not administer Aluminum Magnesium Hydroxide as Magnesium can be harmful to cats and, in particular, to CRD sufferers. There are, however, concerns about long term ingestion of aluminum and its potential toxicity to cats. Aluminum has been shown to potentially cause neurological problems and to be toxic to kidneys in humans. Some research has also shown neurological effects on dogs.

Calcium based binders may therefore be preferable, particularly for lower levels of increased phosphorous (they may not be as effective as aluminum hydroxide for very high levels.).

Epakitin (US & Canada)/Ipakitine (elsewhere) is a natural binder derived from crab and shrimp shells and seems not to have raised calcium levels in studies (one point of concern with calcium based binders). It also contains an element that binds to toxins, and some people have seen improved BUN and Creatine levels with its use. Dr. Hodgkins recommends Epakitin (and recommends against use of aluminum binders).

There are also some relatively new binders on the market, however there is to date, limited information concerning their results; Lanthanan Carbonate Binders (Renalzin/Fosrenal ) and Sevelamer Hydrochloride (Renagel/Renvela).

Additional treatments that may be needed:

- Constipation can be helped with Slippery Elm or Miralax (Restoralax in Canada)
- Vitamin B complex and iron supplements are used to help with Anemia.
- Hypertension can be better controlled with amlodipine (brand names include Norvasc or Istin).
- Potassium imbalances are treated with potassium supplements or potassium may be added to Sub Q fluids if levels are low; high levels are difficult to treat, and traditional recommended treatments seem to have somewhat limited success
- Metabolic Acidosis is treated via fluid therapy, Bicarbonate of Soda, and often Potassium Citrate if potassium levels are low.

Additional Resources

“Tanya’s Comprehensive Guide to Chronic Renal Disease” is an excellent and more than comprehensive site concerning CRD. The information regarding food is not recommended based on TR (or what we know about species appropriate diets for cats), but the provided tables can help you in determining lower phosphorous canned food choices for your cat. The information at Tanya’s site is extremely in-depth and very helpful.

For more information, Feline CRF Information Centre

Why Do So Many Domestic Cats Have Chronic Kidney Failure? Dr. Karen Becker

Please post on the Head to Tail forum if you have questions or need additional help dealing with CRD.