Urinary Symptoms in Dogs
Most urinary tract disorders cause some disturbance in the normal pattern of voiding. There are a number of signs to look for.
Dysuria (Painful Urination)
Signs of dysuria are obvious distress during urination with straining, dribbling, licking at the penis or vulva, crying out in pain, voiding frequently in small amounts, squatting but not passing urine after many tries, and/or passing mucus, blood clots, or bloody urine. These signs indicate a disorder of the bladder, urethra, or prostate.
Pain and swelling in the lower abdomen suggest an overdistended bladder. A dog who does not pass urine after prolonged squatting or lifting of the leg is obstructed. This is usually caused by a stone, but could also be due to a tumor obstructing the urine flow.
Hematuria (Blood in the Urine)
Blood in the first portion of urine that clears with voiding indicates a problem in the urethra, penis, prostate, uterus, or vagina. Blood that appears at the end of voiding suggests a disease of the bladder or prostate. A uniformly bloody urine is seen with diseases of the kidneys, ureters, and bladder.
Bleeding without pain suggests kidney disease. Vaginal bleeding may give a false impression of hematuria. Microscopic hematuria means finding red blood cells on microscopic examination of urine that appears normal to the naked eye.
Polyuria (Excessive Urination)
Frequently passing large volumes of urine suggests kidney disease. The dog compensates by drinking large amounts of water. You may notice the increased thirst (polydipsia) first.
Other common causes of polyuria include diabetes mellitus, Cushing's syndrome, a pituitary tumor, hyperparathyroidism, and some types of poisoning. Polyuria should be distinguished from dysuria and urinary incontinence.
Incontinent dogs void inappropriately, in many cases because they have lost voluntary control. Characteristic signs are wetting the bedding or floor where the dog has been sleeping, dribbling, sometimes frequent voiding, and voiding urine when excited or stressed. Incontinence is discussed on page 416.
Diagnosing Urinary Tract Diseases
Because of overlapping symptoms and the fact that more than one organ may be involved, it is difficult to make an exact diagnosis based on the symptoms alone. Laboratory tests can be of considerable help. Routine tests are urinalysis, which tells your veterinarian whether your dog has a urinary tract infection, and blood chemistries, which provide information about the function of the kidneys. Blood chemistries may include a BUN (blood urea nitrogen, which measure the efficiency of the kidney's filtering mechanisms. However, this value can be influenced by diet and other factors. Creatinine is another kidney function test.
Your veterinarian may ask you to bring in a urine specimen, which you can easily obtain by collecting a sample midstream in a plastic specimen container as the dog voids. These “free catch” samples may have some contamination from the dog's hair and penis or vulva. Sterile urine specimens are obtained by aspirating urine from the bladder with a sterile needle and syringe, called cystocentesis, or by passing a sterile catheter into the bladder through the urethra. This will be done by your veterinarian when it is important to culture the urine. A valuable urine test, called the UPC ratio, determines the urine protein:creatinine ratio-again showing the efficiency of the kidneys. The proportion of protein may also reflect inflammation or disease elsewhere in the body.
X-ray films of the abdomen are particularly useful in diagnosing stones. Abdominal ultrasonography is an excellent, noninvasive test that provides images of the kidneys, ureters, and bladder. An intravenous pyelogram (IVP) is an X-ray examination in which a dye is injected into a vein. The dye is excreted by the kidneys and outlines the renal pelvis and ureters. Other selective studies include CT scan and surgical exploration and biopsy of the kidneys or the bladder.
This article is excerpted from “Dog Owner’s Home Veterinary Handbook” with permission from Wiley Publishing, Inc.
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