What do you mean by chronic renal failure in dog?
Chronic renal failures of chronic kidney disease which are used interchangeably is defined as kidney disease that has been present for months to year in dog. It is not seen abruptly as chronic kidney (disease) failure develop insidiously , it generally concludes with all sign of uremia (raised level of urea in blood and other nitrogenous waste compound that are normally eliminated by kidney. In chronic renal failure there is an irreversible loss of all the kidney function. It is estimated 1 in 10 dog (10%) of dog will develop kidney disease over a lifetime. As kidney has a function to filter blood and excrete protein waste (urea for example), conserver and balance blood salt and acid and help to maintain normal red blood cell. In CRP there is inability of kidney to efficiently filter the blood and excrete waste produced in body, not the inability to produce urine. Which the dog suffering from CRF produce large quantity of urine but the toxic waste produced in body is not effectively eliminated.
At which age the most cases of CRF occurs?
Unlike liver tissues, kidney tissue cannot be regenerated over deployed. For that reason large amount of spare nephron (filtration unit of kidney) are present in kidney to perform its functions. At least kidney must bet dysfunctional nephrons before any chronicle sign are seen. This means, in most of the cases the dysfunction has been occurring for months to year (long period of time) before the sign of CRF become evident.
In dogs, CRF is associated with ageing means it is more likely to see as the dog get older and there is wearing out of kidney tissue over that time. It is an interesting fact that onset of the condition is related to the size of the dog. For most small breed dog, the early sign of CRF is about 10 to 14 year of age while large breed dog like German shepherd, Labrador, mastiff St. Bernard the sign of failure is seen as early as 7 year of age. That doesn’t mean the small breed dog will not face CRF in early age 7. Sometime acute renal failure develops into CRF.
What are the signs seen in CRF?
When the filtration process of kidney becomes inefficient and ineffective as the dog get older, there is an increased blood flow in kidney to accelerate the filtration process. The body has to maximize the flow of blood in kidney as less and less metabolic waste are removed from the each time and there is accumulation of toxic in body. Their action will lead to production of more urine each time. As there is more excretion of water in the body the dog gets dehydrated and feels thirsty thus drinking more and more water in short period of time? So the early sign of CRF is poly urea (more urine production) and polydipsia (more water) consumption. After approximately more than 2/3 of kidney tissue is damaged, there is rapid rise of waste toxic product in the body and there will be onset of sever disease. There will be sign of uremia and as it progress, the dog loss first body fat and then muscle mass. The coat sheds, loss its sheen and looks unkempt. (The dog seems untidy and messy). The dog generally slows down and has fatigue, increased restlessness, and a loss of interest in the surroundings. mild retchching begin, followed by vomiting froth and meals. The owner can notice body tremor or loss of fine balance & coordination, eventually seizure may (seen) occurs. This point is called end stage kidney failure. Beside these bad breath and ulcer in mouth is also noticeable. Due to elevation of waste product in blood there is sign of general depression. Beside these, less common sign include high blood pressure which can lead to itchy skin from calcium and phosphorous deposition on skin.
How is CRF diagnosed in dog?
Looking at the sign and symptoms of dog, the vet will have thorough physical examination and take detailed history from the owner. The vet may able to feel small shrunken kidney, hear a slight heart murmur with a stethoscope and detect the ureunia smell to the breath. The gum may look drier than normal due to dehydration.
There are basics two test done for kidney function
In urine analysis, there will be noticeable low urine specific gravity. Means the kidney couldn’t concentrate the urine. This is the earliest indication of kidney failure. Similarly, there is a increase in protein in the urine blood chemistry test shows elevated blood urea nitrogen (BUN) and creatinine (CR) as well as raised blood phosphorus level, the dog diagnosed with low urine Sp gravity as well as elevated BUN and CR is said to be azotemia.
However in some cases, there is compensated chronic renal failure in which there will be normal BUN and CR level but low urine Sp. Gravity. So in that condition if the blood test is done the owner may mislead in thinking the dog is OK. So urine Sp. Gravity should be checked. If there is major stress occurred in that dog such as illness or surgery/ anaesthesia, the kidney may feel raising BUN and CR and the dog goes to CRF condition.
How is CRF treated in dogs?
The treatment of CRF depends upon the condition of dog and result of the blood test. The goal is to resolve the specific abnormalities. In some cases, the kidney is damaged beyond repair (80-85%) before diagnosis and the medical treatment for such dog in ineffective however, with early diagnosis and aggressive treatment, many months to years can be added to dog’s life. . A diet for dog with CRF should has following features, relative to standard dog food (normal food is not suitable for CRF faced dog)- a moderate reduced level of highly digestible protein, a good source of non-protein calorie, reduced Phosphorus dietary fiber to trap nitrogenous waste product, vitamin B complex and a good balance of Omega 6 and Omega 3 essential fatty acid to reduce kidney inflammation.
In earlier days very low protein diet is recommended but now-a-days veterinary nutritionist advocate for the use of medium protein and low phosphorus diet.
Similarly, adding antioxidant to the diet scavenge free radical, reducing kidney damage.
Plenty of fresh water is also important and should be provide 24/7. (all the time). Fluid is given intravenously (IV) sometime or in some case under the skin (subcutaneously), high blood pressure is managed by ACE inhibitor such as captoril, rimipril, or with calcium channel blocker such as amlodipine.
In addition to the above mentioned points it is crucial for the owner to avoid the stress to the pet. As when the dog is stressed they may drink and eat less than normal. Reduced water intake is detrimental to diseased kidney. So you have to keep the animal calm and stress free as much as possible in CRF.
What will be the prognosis of dog suffering from CRF?
A lot of owner has a query in their mind about the condition of his dog. Suffering from CRF whether he/she will survive or not. So how long the pet will live or or what will be the pets quality of life depends upon how far the kidney has been damaged. This mean it is completely dependent on the level of toxic produced in the body and the kidney ability to excrete it. Pets will blood creatinine level below 2.5 mg/dl usually so well for a long period of time pets with the level about 2.8mg/dl have also survived for several year. With appropriate treatment but when the CR level exceeds 5, the prognosis becomes poor. In this level 80-90% of kidney has been damaged however it is possible to keep the pet alive for a short span if time but the pet will suffer more day by day. So it would be prudent to put the beloved pet in sleep by euthanizing. For this, you should consult your vet regarding this matter.
Can a kidney disease in dog prevented?
As kidney disease can be inherited, it would be wise to make a responsible breeding of the dog. A diseased dog should not be allowed to breed. Many cases can be prevented by keeping pets safe from toxic substance like rat poison antifreeze and certain food, which the owner may not be aware of , like raise grape and some plants. Beside leptospirosis can cause kidney disease, its vaccination should be given up to date.
A balanced diet us also crucial for the healthy kidney. Consult your vet regarding the the dietary management of your pet. In addition, regular health check up on your dog, blood test should be carried out routinely and looks for the symptoms like drinking too much water and abnormal weight loss. Annually performs the blood test and to see if the kidney is function properly or not. This will help to pinpoint the problem before hand and treatment can be followed soon preventing any setback in future.
Written by:Dr Pratik Man Pradhan,B.V.Sc & A.H
Chief Veterinarian (Mount Everest Kennel Club)