Juvenile Renal Disease (JRD)

*Please note that our canine geneticists are looking for blood samples for Airedales with renal issues. Please contact airedalehealthfoundation.org to learn how you can help provide a sample and health data on your Airedales.

Kidneys: The kidneys are sophisticated reprocessing machines. Every day, a dog's kidneys process blood to sift out waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.

There are many types of renal issues in canines. When an owner's dog acts poorly and the owner takes the dog into the veterinarian, a blood panel may be run and an outcome of "renal failure" may be determined from the examination and testing results. Renal failure is defined as the inability of the kidneys to remove waste products from the blood. The buildup of toxins produces the signs and symptoms of uremic poisoning. Kidney failure can appear suddenly (acute kidney failure) or come on gradually over months. Most cases are of the gradual onset type and are caused by nephritis and nephrosis. Dogs with kidney failure do not show signs of uremia until 75 percent of functioning kidney tissue is destroyed. Thus, a considerable amount of damage occurs before the signs are noticed.

Signs of Renal Failure: One of the first things you may notice is that your dog drinks and urinates more than usual and indicates her need to go outside to eliminate several times a day. If not allowed to do so, the dog may begin to have housetraining accidents in the house. These signs are due to the failure of the kidneys to concentrate the urine. This results in a large urine output over which the dog has no control, with subsequent dehydration and thirst.

As kidney function declines, the dog retains ammonia, nitrogen, acids, and other chemical wastes in her blood and tissues. This is called uremia. The degree of uremia is determined by measuring serum blood urea nitrogen (BUN), creatinine, and electrolytes.

Signs of uremia are apathy and depression, loss of appetite and weight, a dry haircoat, a brownish discoloration to the surface of the tongue, and an ammonialike odor to the breath. Dogs at this stage may urinate less than normal. Ulcers may arise in the mouth. With the nephrotic syndrome the dog develops ascites and edema. Vomiting, diarrhea, and gastrointestinal bleeding may occur. At the end stages of kidney failure, the dog falls into a coma.

If your dog has any of the symptoms above or you are concerned in general about his health, please see your veterinarian for an examination.

Types of Renal Issues

There are many types of renal issues in canines including Airedales. Congenital (existing at birth) and developmental kidney diseases are a group of diseases in which the kidney may be abnormal in appearance, or may be abnormal in its ability to function normally, or both. These diseases result from inherited or genetic problems or disease processes that affect the development and growth of the kidney before or shortly after birth. Most patients are less than five years of age at time of diagnosis.

Here are some types of renal issues in canines:

RENAL AGENESIS: Failure of kidney formation

RENAL DYSPLASIA (ALSO CALLED JUVENILE RENAL DYSPLASIA): Complete absence of one or both kidneys

PROTEIN-LOSING NEUROPATHY: A loss of proteins from the kidneys

RENAL ECTOPIA: Displacement of one or both kidneys

GLOMERULOPATHY: Disease of the group of small blood vessels in the functional unit of the kidney

TUBULOINTERSTITIAL NEPHROPATHY: Kidney disease involving the tubules and tissue spaces

POLYCYSTIC KIDNEY DISEASE: Formation of multiple, variable-sized cysts throughout the kidney tissue
RENAL TELANGIECTASIA: Dilation of small blood vessels in the kidney, characterized by multiple blood vessel malformations involving the kidneys and other organs
AMYLOIDOSIS of the kidney: A group of conditions of differing causes in which insoluble proteins (amyloids) are deposited outside of cells in various tissues and organs, compromising their normal function
NEPHROBLASTOMA: A congenital kidney tumor

MULTIFOCAL RENAL-CYST ADENOCARCINOMA: A hereditary kidney cancer in dogs
FANCOINI'S SYNDROME: A generalized functional abnormality involving the tubules of the kidney, characterized by impaired reabsorption
PRIMARY RENAL GLUCOSURIA: Presence of glucose in the urine due to primary kidney disease

CYSTINURIA: Excessive excretion of cystine (an amino acid) into the urine
XANTHINURIA: Excessive excretion of xanthine into the urine
HYPERURICURIA: excessive excretion of uric acid, sodium urate, or ammonium urate into the urine
PRIMARY HYPEROXALURIA: A disorder characterized by intermittent high levels of oxalic acid or oxalates in the urine
CONGENTIAL NEPHROGENIC DIABETES: A disorder of kidney concentrating ability, caused by diminished kidney responsiveness to an antidiuretic hormone, such that excessive urine is produced

Because there are a variety of types of renal diseases in dogs, a deeper level of diagnostic information must be obtained if the owner wants to determine exactly what type of renal issue their dog is suffering from. Consulting with the coordinator at the Airedale DNA Bank is especially important in order to get the researchers an exact diagnosis when possible.

From the types of renal issues, this section will focus on two hereditary issues in Airedales that have been occasionally reported and studied in the breed: Renal Dysplasia (RD) and Protein-Losing Neuropathy (PLN).

Renal Dysplasia (RD):

Kidney dysplasia goes by many names, including renal dysplasia, progressive juvenile nephropathy, familial renal disease and most commonly as juvenile renal dysplasia (JRD). (We will refer to this condition below as JRD or juvenile renal dysplasia for ease of communication.) Dogs who are suspected to have kidney dysplasia or kidney failure should be examined by a veterinarian for proper diagnosis and treatment.

Dysplasia is defined as abnormal growth or development of cells or organs. In the case of JRD, the kidney fails to develop properly during embryogenesis in the womb. At birth, immature structures consisting of undifferentiated fetal cells or tissue types are found in the kidney, and are persistent throughout the life of the animal.
JRD can present itself with a wide range of symptoms and pathological findings. Definitive diagnosis of JRD is done by a wedge biopsy which reveals dysplastic lesions, including abnormal ducts, and glomeruli. Individuals with an abnormal biopsy can be asymptomatic, showing no signs of the disease. On the other hand, they may present with classic signs of chronic end stage renal failure, or somewhere between these two extremes. Given this broad spectrum of symptoms, affected individuals often go unnoticed, and remain in the breeding population. This is why development of a genetic test is necessary for the management and elimination of this disease.

Canine geneticists need blood samples from affected Airedales with Juvenile Renal Dysplasia. Please contact us with your information at [email protected] and/or send in your dog's blood sample (How to Send in Your Dog's Blood Sample) to the Airedale DNA Bank. Be sure to mark the condition of your dog and mark that the sample is to be used for research on kidney dysplasia. All information is handled confidentially.Breeds Affected:
JRD is seen in Airedale Terriers, Alaskan Malamutes, Bedlington Terriers, Boxers, Bulldogs, Chow Chows, Doberman Pinschers, Golden Retrievers, Great Danes, Great Pyrenees, Irish Wolfhounds, Keeshonds, King Charles Spaniels, Miniature Schnauzers, Norwegian Elkhounds, Old English Sheepdogs, Portuguese Water Dogs, Samoyeds, Swedish Foxhounds, Shiz TzuAccording to Kenneth C. Bovee, DVM, of the University of Pennsylvania, shih tzus are the most commonly affected dogs, with up to 85 percent of the breed afflicted in the US), Lhasa Apsos, Soft Coated Wheaten Terriers, Standard Poodles, and Yorkshire Terriers. Other types of genetic renal disease are also well known in Rottweilers, Shar Peis, Miniature Poodles, Cairn Terriers, Welsh Corgis,Pekingese, Shetland Sheep Dogs, Collies, Beagles, Basenjis, Bull Terriers and Cocker Spaniels, among others. Similar forms of genetic renal diseases may have different modes of inheritance in different breeds. Other forms of familial and congenital renal diseases seen in the breeds listed above include Glomerulopathy, Amyloidosis, Polycystic kidneys, and Fanconi-like syndrome.

Symptoms

Early symptoms of Juvenile Renal Disease include drinking copious amounts of water, something that might not be readily apparent in a house with more than one dog, frequent urination, and dilute urine which has little color or odor. Some affected puppies leak urine, many do not. Often a puppy owner's earliest complaint is about the difficulty of housebreaking a puppy, only later is discovered to have JRD. The volume of water consumed, and, in some puppies, leakage of urine can make housebreaking a formidable task. As the disease progresses, vomiting, weight loss, anorexia, lethargy, and muscle weakness are seen. There is sometimes a chemical odor to the breath as a result of metabolic waste not being excreted by the kidneys.

In breeds in which juvenile renal diseases are seen, symptoms may be noted as early as a few weeks after birth; and affected puppies are almost without exception symptomatic before two years of age. Some puppies fail to thrive: most grow normally until symptoms appear. Puppies with renal dysplasia may appear clinically normal for extended periods of time before developing signs of chronic renal failure. The rate at which renal dysplasia progresses to overt renal failure depends on the severity of the initial renal lesions. Dogs commonly do not exhibit clinical signs of renal failure until less than 25% of renal function remains. A dog with renal dysplasia affecting only one kidney may be symptom free, and the dog may live a normal lifetime.

If a dog under two years of age is found to have an elevated BUN (blood urea nitrogen) and creatinine, and significant protein in the urine, as indicated by an increased urine protein:creatinine ratio, JRD should be strongly suspected. Abdominal palpation by a veterinarian may reveal small irregularly shaped kidneys. An ultrasound can be a useful diagnostic tool, since the kidneys are often atrophied and underdeveloped. It must be kept in mind, however, that kidneys from affected dogs may be normal size.

The most accurate method for diagnosing JRD is a wedge biopsy from one kidney taken any time after the second month of life, or a histopathologic exam after death. A biopsy or autopsy of a puppy less than two months of age would not be fruitful, since the normally immature kidneys cannot be distinguished from those affected by JRD. The slides should be examined by an experienced pathologist. There are a number of pathologists who have a considerable interest in this disease. It is not reasonable to expect most puppy owners who are not breeders, to agree to a wedge biopsy, since a more accurate diagnosis will not affect the treatment or prognosis, and since the necessary anesthesia is not without risk.

If the reduction in renal function is identified early, when only increased water consumption and urination are evident, medical management can be instituted immediately. Although the renal damage is not reversible, the quality and length of the puppy's life may be improved by early treatment.

Treatment

Treatments for the symptoms of JRD include a low protein and low phosphorus prescription diet, such as Hill's K/D. The predominant effect of the low protein diet is to minimize production of uremic toxins so that the patient feels better. Low protein diets may help extend life in dogs. Phosphorus is more important in this regard, since high phosphorus accelerates renal failure, and restricted phosphorus slows it down. K/D is low in phosphorus, so it remains a good food for dogs in this condition. In addition to diet, IV fluids can be administered to correct disturbances created by the retention of uremic toxins. Epogen can be prescribed to treat the anemia of chronic renal failure, resulting in improving the quality, and probably the length of life. Kidney dialysis for dogs is offered at several veterinary medical sites. The University of California, Davis, Veterinary Medical School is performing kidney transplants, but transplanted kidneys in dogs are commonly rejected, and involve an extraordinary expense and commitment. UC Davis will only do a renal transplant if the red cell cross matching and blood type is a perfect match. and if the tissue typing is also a perfect match. One of four healthy littermates of an affected puppy may offer such a match.