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Kidney and Urinary Tract Diseases


Why are kidneys important?

The main function of the kidneys is to produce urine. Urine consists of mostly water, small amounts of ions, and waste products. Thus, the kidneys have a very important job in regulating body fluids and removing the wastes and poisons from the body. When the kidneys don't work properly, these waste products accumulate in the bloodstream, which is life-threatening if not treated.

What are the signs of a kidney or urinary tract problem?

Pay attention to the urination habits of your pet. If you notice any abnormalities, you should get your pet to the veterinarian. Signs to look for are increased volume of urination, increased thirst, urinating more frequently and in small amounts, straining to urinate, painful urination, urinating in unusual or inappropriate places, uncontrollable urination or dribbling, foul urine odor and blood in the urine.

What will the veterinarian do?

After the physical examination, we will need to collect a urine sample. The preferred method of collection is by cystocentesis, a procedure in which a sterile urine sample is extracted by needle and syringe. If your pet has an empty bladder, we will try the procedure again in a couple of hours or until the bladder is palpable. A sterile urine sample is ideal because it is free of the debris and secretions that could cloud the results of urinalysis and also because it could be used for a urine culture, which confirms a bladder infection. The veterinarian might also do bloodwork to check kidney function and radiographs to evaluate kidney size and shape and to look for kidney or bladder stones.

The following are some common problems of the kidneys and urinary system:

Kidney Failure

The failure of the kidneys to maintain their normal excretory function is called renal failure. Bloodwork will show elevated levels of BUN and Creatinine, which are waste products in the bloodstream that need to be excreted by the kidneys. Also, results of the urinalysis will show a below normal urine concentration. Renal failure may be chronic or acute.

Chronic renal failure persists for months to years and is irreversible because of permanent kidney damage. Unfortunately, it is a common condition in geriatric dogs and cats. Pets with chronic renal failure are prone to increased urination, increased thirst, dehydration, hypertension, vomiting, diarrhea, loss of appetite, weight loss and lethargy. Pets with chronic renal failure can live a good quality life with proper management and care. Management consists of fluid therapy (intravenously and/or subcutaneously), periodic blood and urine rechecks, dietary therapy of low protein/phosphorus/sodium diet, and possibly drugs as needed.

Acute renal failure is the rapid onset of dysfunctional kidneys over hours to days. It may be reversible or irreversible depending on the severity of the kidney damage. Signs to look for are increased urination, no urination for more than a day, loss of appetite, vomiting, diarrhea, lethargy, and extreme depression or coma. Acute renal failure may be caused by ingestion of harmful drugs or poisons, such as ibuprofen, lead and antifreeze. It can also occur when the pet is in shock and the blood pressure gets too low, which decreases the supply of blood to the kidneys. The treatment and management of acute renal failure consists of aggressive intravenous fluid therapy and extensive monitoring of blood pressure, blood chemistries, and urine output. back to top

Urinary Tract Infection

Urinary tract infection is the most common cause of problems associated with urination. Sometimes it is called "UTI" for short or "bladder infection" or "cystitis." It occurs when bacteria colonize the urinary tract.

The first signs of a urinary tract infection are increased frequency of urination, straining to urinate, and inappropriate urination. Dogs and cats with bladder infections often urinate uncontrollably in the house and seem uncomfortable because they have a need to urinate so often. Further symptoms to look for are foul urine odor and blood in the urine.

The veterinarian will do a urinalysis and urine culture to find out whether the urine contains any bacteria. If bacteria is found, the culture is sent to a diagnostic laboratory where the bacteria is identified and the veterinarian can prescribe the appropriate antibiotic treatment. The pet will be on antibiotics for at least 14 days, after which another urinalysis and urine culture will confirm whether or not the infection is gone.

Urine Crystals and Bladder Stones

Another common cause of urinary problems in pets is urolithiasis or bladder stones. Bladder stones are formed by the accumulation of urine crystals. Such factors as urine pH, diet, and water intake influence the formation of urine crystals. When urine crystals show up in a urinalysis, it does not necessarily mean that the pet has bladder stones, but that the pet is predisposed to stone formation. Sometimes bladder stones show up on radiographs and ultrasounds. In order to dissolve certain kinds of bladder stones and urine crystals and prevent further recurrence, the veterinarian will recommend a specially formulated diet to fit the pet's needs. However, some types of bladder stones have to be taken out surgically because they can create a urinary tract obstruction if they are not removed.

Feline Urological Syndrome

(FUS) The cause of feline urological syndrome is unknown, but it is a very common urinary problem in cats. When urine crystals combine with mucus along the urinary tract, they can form a plug which blocks the flow of urine. This occurs more often in male cats than females because males have longer and narrower tracts. The symptoms are straining to urinate with little or no urine coming out, crying, blood in the urine, and inappropriate urination. Inadequate water intake, lethargy, poor nutrition, obesity, stress, and viral or bacterial infection may all be involved in causing FUS. Cats with FUS often have recurrent urinary tract blockage which is life-threatening if it is not relieved. Treatment may involve corrective surgery, urinary catheterization, IV fluid therapy, medication, and special diet. Frequent urine checks are necessary to ensure that crystals do not build up again. To avoid FUS, provide your cat with plenty of fresh water, a balanced diet, lots of exercise, and a clean litter box.

Urinary Tract Obstruction

Urinary tract obstruction is an emergency! If you see your pet straining to urinate, having difficulty passing urine, and trying to urinate more frequently and in unusual places, then call the veterinarian immediately because this could be a life-threatening situation. Cats with urinary tract obstruction might also sit in the litterbox meowing and crying in pain. An animal that is unable to pass urine can die within a day or two.

Bladder stones in dogs and crystal/mucus plugs in cats are usually the causes of urinary tract obstruction. The blockage occurs along the urethra, the tract that carries urine out of the body from the bladder. Males have longer and narrower urethras, thus they are more prone to obstructions than are females. When the urethra is blocked, urine builds up in the bladder and prevents the kidneys from removing wastes from the body. Unless the blockage is removed, the animal will suffer in pain until death occurs.

In order to relieve pressure from the full bladder, the veterinarian will apply manual pressure or remove urine directly with a needle and syringe. If the obstruction remains, the animal will need to be anesthetized and a catheter placed into the urethra. The catheter is attached to a collection system so that urine flow and production can be monitored. Intravenous fluid therapy might be necessary to maintain normal hydration and blood chemistry levels. The pet will remain hospitalized for 2-4 days and must be able to urinate normally for at least 12 hours before it can be discharged. Cats with recurrent urethral obstructions will need corrective surgery. To prevent any further recurrence of urinary tract obstruction, the veterinarian will recommend a prescription diet for your pet that is formulated to discourage urine crystal formation. Also, make sure your pet drinks plenty of fresh water, gets lots of exercise, and urinates normally throughout each day.

Urinary Incontinence

Urinary incontinence is the failure of an animal to control urination normally. It is more commonly seen in dogs than cats. The signs to look for are urine dribbling or dripping when the dog is not trying to urinate, urine soaked fur around the tail or hind leg area, and spots of urine wherever the dog has been lying down. Sometimes the dog will suddenly get up after urinating while asleep. Urinary incontinence could be caused by a weakening of the muscle that controls the flow of urine, birth defect, urinary tract infection, or neurologic disease. The veterinarian will run a urinalysis and urine culture to rule out urinary tract infection and then dispense the proper treatment. In most cases, urinary incontinence can be controlled by long term drug therapy.