What is CKD,
an "incurable disease" ?
A chronic kidney disease is a status of kidney which function declines under 30% or less than normal.
This disease is incurable and suffers many cats.
Functions of Kidneys
Then, what are the "normal functions" of kidneys?
Kidneys of cats are bean-shaped organs that on both left and right back sides of cats' body.
Their main 3 roles are "excretion, adjustment, and production".
Role of Excretion
It is to excrete concentrated unnecessary things in a body as urine, by filtering blood.
As the concentrating capacity of kidney declines, body wastes will be accumulated, and necessary water and nutritions will be lost at the same time.
Role of Adjustment
It is to remains body pH(acid and alkali) stable.
If the pH balance is lost, a whole body and its organs will be damaged.
In general, pH balance would be inclined to whether alkali or acid after having a meal or working out, however its stable balance is remained by the adjustment functions of kidney.
Kidney also adjusts blood pressures. In order to remain stable blood flow, it highers blood pressure by making vessels to be constricted.
Role of Production
It is to help the productions of red blood cells and bones.
Kidney secretes necessary hormones to produce red blood cells (erythropoietin) and activates necessary vitamin to produce bones (vitamin D).
When this production function declines, anemia or a lack of calcium (osteoporosis) occurs.
Classifications of Kidney Disease
Kidney disease is a status which the functions of kidneys become dysfunctional for some reason.
It can be classified into "acute" and "chronic" depending on the kidney functions decline rates.
(Acute Kidney Disease)
Kidney functions decline rapidly (in a few hours or a few days).
The causes would be dehydration, diarrhea, bleeding, low cardiac output, medicine poisoning, urinary obstruction, bladder inflammation, urinary tract dysfunction etc.
For example, heatstroke by being in a hot places such as a car or a room in summer season, or medicine poisoning can be a cause of AKD.
Food which can be dangerous for cats are; leeks, chives, onions, garlics, mashrooms, cow milk, alcohol, chocolates, cocoa powder, avocados, nuts, shellfishes, squids, octopuses etc.
(Chronic Kidney Disease)
Kidney functions decline gradually in a few months to years.
It is an incurable disease which develops to the last-stage CKD in the end.
The causes of most CKD cases are unknown, and only available treatment is to delay or suppress the progression of CKD.
Those treatments aim to improve patient cats' QOL (Quality of Life) and prolong their lives.
30% of Senior Cats Suffer
In case of cats, almost 30% (1 out of 3) of senior cats over 15 years old suffer from CKD.
It is one of the top causes of cats' death.
Compares to CKD of dogs, it is almost 2 or 3 times more than dogs.
There are rarely hereditary or congenital type of CKD to be found.
For Siamese, Maine Coon, Abyssinian, Burmese, and Russian Blue cats are familial nephropathy, which kidney functions decline with age.
Why is CKD Common in Cats?
Why many cats are likely to suffer from CKD?
It is deeply related to an environment cats have used to live.
Libyan wildcats that used to live in ancient Egypt are told to be the direct ancestors of current cats.
For the cats lived in desert, losing body water for urinary excretion was a serious matter.
Therefore, the cat's body is structured to consentrate urine efficiently and not to excrete body water as much as possible.
However, this structure needs more energy and kidney functions become exhausted much faster.
Also, the cat is a carnivore animal which needs more protein than other animals, however high protein food makes kidney exhausted.
Due to those reasons, CKD is very common in senior cats.
Live Longer by Early Detection
Although CKD is incurable disease, there are many cases that the cats can liver longer by early detection and appropriate treatment.
However, the problem for the CKD cases of cats is that symptoms are often latescent.
Over 70% of kidney functions of cats are lost when symptoms of CKD become apparent or the result of blood test shows abnormal status.
What is an Early-Stage?
CKD is classified into stage 1 (early-stage) to stage 4 (last-stage) depends on the progression level.
However, it is hard to notice the symptoms of CKD at the early-stage.
For many cases, detection is too late and it is already the last-stage when the owner takes the cat to the hospital.

Stage 1

According to IRIS Staging of CKD(*1) which is used to classify stages of CKD, it is very difficult to detect CKD at stage 1, as there is no clear clinical condition can be seen at this stage.

Stage 2

At stage2, there are some slight clinical conditions such as drinking more water than before (polydipsia) and the number or volume of urine increases (pollakiuria, polyuria) can be seen.
Those symptoms can be noticed if the owner carefully observes cat's daily status regularly.

Stage 3

At stage 3, there are clinical conditions on whole body such as drinking more water than before (polydipsia), the number or volume of urine increases (pollakiuria, polyuria), constipation, dull fur, less appetite (anorexia), losing weight, and vomitting can be seen.

Stage 4

At stage 4, there are many failures occur to many organs other than kidney as well.
Abnormality becomes apparent on whole body, and most of them are very serious.
*1 IRIS Staging of CKD is classified by IRIS (International Renal Interest Society) based on blood creatinine concentration (*2).

*2 Creatinine is one of the body waste products. Kidney filters creatinine in the blood and excretes it as urine. Creatinine is excreted only as urine, and there is a possibility of kidney function to be bad if the creatinine level in the blood becomes higher. When the creatinine blood test resulted to be higher, 75% of kidney function is already lost.
Early Treatment
The treatment of CKD is to delay the progression of disease by fluid therapy and dietary therapy.
For CKD, no definitive treatment to eliminate the cause of disease can be done, but only symptomatic treatment by relieving symptoms caused by the disease can be done.
At the last-stage, renal transplantation or renal dialysis would be needed.
On the other hand, it is possible to have a treatment to suppress the progression of CKD if it is detected at the early-stage.
There was a report that the medicine called "RAPROS" launched by Toray in 2017 is effective for the cats suffering from stage 2 and stage 3 of CKD.
There are also some reports saying that cats can live 3 years longer if they can have treatment at the early-stage of CKD. Also in 2016, Professor Miyazaki at Tokyo University and his fellows have figured out the cause of cats' CKD and presented their studies which leads to the improvement of CKD treatment and preventive measures to avoid chronicity of CKD.
AIM (apoptosis inhibitor of macrophage) is a protein in the blood which becomes active when kidney functions decline and it contributes to the recovery of kidney functions, however AIM is not functioning enough for the cats.
Prof. Miyazaki and his fellows have reported that it is possible to promote the improvement of CKD and avoid chronicity by the administration of AIM.
Including these new possibilities in CKD treatments, we can save longer lives of cats by detecting initial symptoms as early as possible and have appropriate treatments for them.
Early detection and early treatment enable to improve cats' QOL and make their lives longer.

A Point of Early Detection
A point to detect the signs of cats' CKD is for the owners to sense the symptoms of early-stage.
To do this, the owner's knowledge and careful observation would be a great help.
The difficult part of detecting CKD is that there is no outstanding symptom, and even if there is any, most of them tend to be missed.
The only symptoms that can be seen at the early-stage are losing weight, less appetite, polydipsia and polyuria. However in general, it is often considered that many of the senior cats tend to lose weight or appetite with age, and it results in the late detection of disease.
Therefore, getting to know the cats' daily health conditions regularly is very important to enable early detections.

Then, what kind of daily health checks will be needed to detect CKD at early stage?
Daily check points are "appetite, body weight, water intake, and urine output".
Also, these points are preferred to be recorded regularly.
If the cat starts to suffer from CKD, waste products accumulate in the cat's body and it leads to less appetite.
This symptom may be gradually seen over the months.
It is important not to miss the signs of cats such as leaving their food or vomitting after eating.
The average number of cats' meals is 3 times in a day for kittens and 2 times in a day for adult cats.
Cats' appetite often fluctuates, however the owners should watch out if there are cases such as the cat does not eat at all or eats too much.
Body Weight
When the cat loses appetite, nutritions cannot be intaken from food and the cat inevitably loses weight.
In order not to miss this sign, it is better scaling the cat's weight at least once a month.
It is very important to record how the body weight changed compared to the last time.
As the difference of 0.1 kg (3.5 oz.) is a huge for the cats, it is better to use digital scale which can scale in detail if possible.
When scaling the cat's body weight, it is better to have a knowledge of healthy body weight of your cat.
To know the healthy body weight of your cat, refer to cat's Body Condition Score (BCS) (*4).
It's an index to evaluate the obesity rate of the cat. Scores of the current body can be judged by actually watching and touching the part of rib and lower back of the cat.
The desirable score is BCS=3, and thus the body weight at this time would be estimated as between 95% and 106% of the desirable body weight.
Water Intake
The body water is being lost when the cat is suffering from CKD, due to decline of kidney functions.
The cats usually do not intake much water, however the cat suffer from CKD tends to drink more water than usual to make up for the lost water.
The CKD is already developing when the owner notices that the cat drinks more water than usual.
Therefore, checking the volume of daily water intake is very inportant.
At a normal state, the average volume of cat's daily water intake is less than 50 ml (1.7 fl oz.) per body weight of 1kg (35 oz.).
If the volume of water intake exceeds this average, it can be considered as polydipsia.
Measument of the volume of water intake is better to be done every morning and night.
Put about 200 ml to 300 ml (6.8 oz. to 10 oz.) water to the usual dish and substract the remaining volume from the first volume. For the cat eating wet food, it should be calculated as the volume ofwater intake.
Also, evaporated water volume of the wet food which was left over a long time should be also added for the calculation.
In order to calculate the evaporated water volume, prepare the same amount of water in the same dish as the one for drinking water and put a net cover on it.
As the original volume of cat's water intake is very small, these kind of tricks for calculation is needed.
When the cat is suffering from CKD, the cat excretes a lot of weak urines as urines cannot be consentrated.
Furthermore, if the cat drinks more water, the volume of urine increases. For normal cats, the average volume of urine per day is less than 50 ml (1.7 fl oz.) per body weight of 1kg (35 oz.).
If the volume of urine exceeds this average, it can be considered as polyuria.
To measure the volume of urine, substract the weight of pet sheet after urination from the weight of original pet sheet.
In case of using litter sand, check the lump of litter sand after urination.
As a guide, a lump of 50 ml (1.7 fl oz.) of litter sand would be about 7 cm (2.8 in.). In addition to that, it is recommended to check the number of cat's urination. As a guide, a number of urination per day is about 1 to 3 times. If the cat urinates over 5 times a day, it is too much and should watch out.
Also, it is good to check color or smell of urines.
Preventive Measures against CKD
CKD can be considered as a fate of senior cats, however its prognosis will greately change if the owners take care of their cats regularly at home.
For that, the dedicated support of the owner is very important.
Try to think about 3 points of "water, food, and careful observation" when taking care of the cat at home and having preventive measures against CKD.
1. Point of Water Supply
It is recommended to keep drinking water fresh and available always.
It is better to have a several water-drinking spots for the cats to drink whenever they want.
Also, it is good to feed not only dry food, but also wet food for hydration.
2. Point of Dietary Management
A high-protein food (however if feeding low-protein food to the normal cats may lead to loss of muscle volume and lose weight) and excessive intake of phosphorus wosen the conditions of CKD.
In general, high-protein food is basic for cats as they are carnivorous animal, however unnecessary intake should be avoided.
The minimum neecessary intake volume of protein for cats is about 20% of each cat food, and 3 g to 5 g (0.1 oz. to 0.17 oz.)/kg (35 oz.) per day.
However, there are some cat foods which include over 40% of protein in the current market.
Also, animal protein (such as chicken, turkey, pork, salmon, tuna, bonito, egg etc.) are preferred to as protein source, however there are many cheaper cat foods include vegetable protein (such as soy beans, wheat, corn etc.).
Furthermore, the problem for carnivorous cats is an excessive intake of phosphorus (main essential minerals).
A life such as feeding cat food and chicken snacks regularly may cause excessive intake of phosphorus.
It is important for the owners to check and control it.
Also, n-3 fatty acid such as DHA included in fish has a function of smoothing the blood flow.
It may be a good choice to choose cat food which includes them.
3. Point of Careful Observation
Other than anything, the owners' careful observation of their cats will decide the lives of cats.
CKD develps gradually and slowly.
It enables the owners to notice the change of their cats' status at once if they carefully observe their cats in addition to the regular check-ups at animal hospitals.
Small changes and signs of cats that the owners can notice at home are; not climbing to the higher places, stopped grooming, drinking a lot of water, volume of urine increased, losing weight, not playing, the body became stiffer etc.
It may be the best help for the cats if the owners notice their silent voice.
For anyone who wants to protect your cats from CKD
Toletta enables early detections of CKD.
Let's take good care of your cats' health condition by using toletta, and live much "longer and happier" with your cats!