Diagnosing Renal Dysplasia in Dogs
Dogs born with abnormal kidneys can develop a number of nonspecific clinical signs. Alternatively, they may never show symptoms at all. It is not particularly difficult for veterinarians to detect renal abnormalities. However, it is important to pinpoint the reason for the renal dysfunction, so that appropriate treatment or management protocols can be established.
When a veterinarian sees a dog that just “ain’t doing right” (called “ADR” in veterinary circles), he will give that dog a thorough physical examination and will take a complete history from the owner of the dog’s health, diet, living conditions, immunization status and other pertinent subjects. The dog may be lethargic, tired and skinny and may be drinking much more water – and “peeing” much more urine – than it normally does. The attending veterinarian will probably recommend an initial database that includes drawing blood samples for a complete blood count (CBC) and serum biochemistry profile. These routine tests are very valuable to assess a dog’s overall systemic health. The veterinarian also likely will suggest taking a urine sample for assessment of kidney function. The urine sample may be submitted for culture and sensitivity, to determine whether a bacterial urinary tract infection is present and, if it is, which antibiotics would be best to treat the condition. Most dogs with renal dysplasia will have abnormal results on these tests.
Abdominal radiographs (X-rays of the abdomen, or “belly”) may be taken. In affected dogs, they may reflect small, underdeveloped kidneys and possibly other renal abnormalities. Ultrasound of the abdomen is also useful to identify irregularly small kidneys and abnormal kidney structures and tissues.
Ultimately, the only way to confirm and definitively diagnose renal dysplasia is to take tissue biopsies from both of the dog’s kidneys and submit them to a veterinary pathology laboratory. The laboratory will assess the biopsy samples through a process called histopathology. Histopathology (also called histology) is an area of anatomy that deals with the microscopic structure, composition and function of tissues and organs. Highly trained veterinary pathologists can look at tissue samples under a microscope and determine whether they are normal or abnormal. Usually, if the samples are abnormal, skilled pathologists can determine and tell the treating veterinarian why that is so. Dogs over 2 to 3 months of age should have normal kidney tissue and structures when examined microscopically. If the biopsy samples show poorly developed, immature and/or disorganized kidney tissues that are inappropriate for the animal’s age, renal dysplasia is the likely culprit.
Genetic tests are available to identify the genetic mutations that cause renal dysplasia in Lhasa Apsos, Shih Tzus and Soft Coated Wheaten Terriers. Over time, such tests probably will become available for many additional breeds.
Kidney abnormalities are not especially difficult to diagnose. Unfortunately, they can be quite difficult, if not impossible, to successfully treat.