Insufficient Urine Production in Dogs
Oliguria and Anuria in Dogs
A medical condition, known as oliguria, occurs when an abnormally small amount of urine is produced by the body. The amount of urine production may be as low as 0.25 millimeters per kilogram of animal weight per hour. Anuria, on the other hand, is a term for the medical condition in which the body produces practically no urine. The rate of urine production with anuria may be as low as 0.08 millimeters per kilogram of body weight per hour.
There are two types of oliguria. Physiologic oliguria usually occurs when a dog's kidneys limit the loss of renal water as a way to preserve body fluid and electrolyte balance. Pathologic oliguria is a result of a severe impairment of the kidney tissues. Anuria is often, but not always, the result of kidney disease or an obstruction of the urinary flow.
Symptoms and Types
The key symptom of both anuria and oliguria is a definite decreased amount of urine being produced and excreted. The various other symptoms which may occur will depend on the type of anuria or oliguria that is present in the animal.
As an example, physiologic oliguria may include dehydration, a weak, rapid or irregular pulse, a pale mucous membrane, as well as a history of fluid loss through excessive vomiting or diarrhea. Pathologic oliguria, however, will typically include poor appetite, weight loss, and a history of progressive kidney disease.
Anuria is usually discovered by a veterinarian during a physical exam. The main signs of anuria are fluid infiltration into the tissues which surround the urinary tract as well as pain in the abdomen when palpitated.
The different types of oliguria and anuria are caused by various conditions. For example, physiologic oliguria may be a result of renal hypo-perfusion, which is basically a cause of low blood volume or pressure, known as hypertonicity, which is usually indicated by an increased pressure of fluids within the body.
Pathologic oliguria, however, is usually caused by an acute kidney failure or chronic kidney disease. Whereas, anuria can be caused by a complete blockage in the urinary tract, a rupture within the urinary excretory pathway, or from a severe failure of the kidneys.
The main diagnostic procedure for determining if the animal has oliguria or anuria involves the use of a urethrocystope in a procedure called urethrocystoscopy. In this procedure the veterinarian will insert a diagnostic tool into the urinary tract so that he or she may check the tract and bladder wall for evidence of obstruction or rupture.
Other tests that your veterinarian may do may include an electrocardiograph (ECG), abdominal radiography or X-rays, ultrasounds, or urinalysis to help rule out or confirm the presence of a urinary obstruction.
Treatment of Oliguria and Anuria
Both oliguria and anuria are medical emergencies. Immediate medical treatment is requires as both of these conditions will lead to the death of the animal usually within a few hours to a few days. In order for the veterinarian to properly treat these conditions the veterinarian must find the exact underlying cause of the condition.
Often times the animal will also suffer from a renal hypo-perfusion when they have oliguria or anuria. If this is the case the veterinarian will treat the hypo-perfusion by administering a normal saline or similar fluid through an IV (intravenous) drip. Once the hypo-perfusion has been corrected the animal is then put on a diuretic medication, such as Lasix, to help encourage urine production and normal urine flow. However, if there is an obstruction in the urinary tract, such as abnormal tissue growth, or tumor, in the form of a neoplasm, the veterinarian will have to remove the growth before commencing with other treatments.
If the animal has primary oliguria and/or anuria, both of which involve kidney damage, the veterinarian will need to address the underlying symptoms and causes giving the patient a chance to allow its kidneys to make a spontaneous recovery of the kidney functions. Here the veterinarian will try to eliminate any causative factors to either stop, or at least slow down, any further kidney damage before proceeding with other treatments.
Living and Management
If your dog is presently undergoing treatment for oliguria or anuria it is essential that the animal be monitored regularly for signs of progress. This usually involves inserting a urinary catheter so that the veterinarian can accurately determine the urine volume that the dog is currently producing. If the veterinarian charges you with the monitoring of urine production it is extremely important to place and properly clean the catheters properly to avoid any development of a bacterial urinary tract infection. Your veterinarian will instruct you on how to do with this if it is prescribed.
Unfortunately it is impossible to offer any one specific preventive measure as there are many causes for oliguria and anuria. The best advice that can be given to the dog owner is to give the animal as healthy a lifestyle as possible. This usually will involve giving the animal plenty of exercise, the best possible food in the proper proportions for your particular breed, plenty of water, especially on hot days, and plenty of rest between exercise periods.