Your Pet's Health & Urine

In addition to blood tests, an analysis of the urine is a very important way for your veterinarian to monitor your pet's health. A urinalysis can provide clues to medical problems that are not apparent in blood tests. Obtaining a Urine Sample Please note that when bringing your pet to the veterinarian for a urinary problem or for a test to evaluate your pet's urine, please try to prevent your pet from urinating at home or in the hospital yard just before bringing it in for its appointment. It is easier for your veterinarian (and your pet) to have urine in the bladder when a urine sample is needed or an evaluation of the bladder must be done. There are several techniques which may be used to obtain a urine sample from your pet. Cystocentesis The best method for obtaining urine samples when testing for infection is by using a sterile technique to avoid contamination. This is usually done by a technique called cystocentesis (tapping the bladder using a small needle and syringe). This can be done easily and painlessly by placing the animal on its back or side and by palpating (feeling) the bladder and by using ultrasound to guide the tap. Catheterization Another technique for obtaining a urine sample is by catheterization by placing a catheter into the urethra. This is easiest with male dogs which tolerate this procedure well or with anesthetized male cats. It is rarely done on female dogs (only for very precisely measuring urine output or for special contrast studies of the bladder) or almost never on female cats. When done on male dogs and cats, it is usually done not only to obtain a urine sample but as a treatment when small crystals or stones can get lodged in the penis and the animal cannot urinate. These can be pushed back into the bladder where they can be more easily removed with surgery or treated medically. Free catch A "free catch" technique can be used to obtain a urine sample. This usually necessitates the owner slipping a clean container under the pet when s/he urinates. This sample may be used to check for elements and specific gravity of the urine but cannot be used to rule out infection. Urinalysis There are many tests that may be performed on a urine sample to provide important information. Specific gravity This indicates your pet's ability to concentrate urine. A low specific gravity can indicate poor kidney function, some toxicities and dehydration. pH This indicates acidity or alkalinity of the urine. Monitoring the pH is important in preventing some infections as well as preventing various crystals and stones from forming in the urine. Elements These include: glucose (present with diabetes), ketones (present with uncontrolled diabetics), bilirubin (present with some forms of liver disease or anemia), protein (present with some types of kidney problems). Sediment These include: blood (present with infection, inflammation, tumors, trauma), white blood cells (present with infection), casts (present with some toxicities and infection) and crystals (present with certain foods, bladder stones and toxins). Urine culture and sensitivity Urinary tract infections (UTI's) are amongst the most common medical problems that occur in dogs and cats. While most affected animals will show signs of straining to urinate, going small amounts frequently, having accidents in the house, asking to go out more often or making many trips to the litter box, many do not show signs (asymptomatic). Animals especially at risk for UTI's are those in kidney failure, those with crystals and/or bladder stones (which harbor infection) and diabetics (bacteria likes the sugar in the urine). For these individuals, detecting infection is all the more important. An untreated UTI can lead to more serious diseases such as kidney infections (pyelonephritis) or systemic infections (sepsis). To detect infection, there are several techniques. Sometimes, the analysis of the urine itself may reveal the presence of bacteria and/or white blood cells. However, this test alone will not find infections in very dilute urine, nor does it tell the veterinarian what type of bacteria it is and what type of antibiotic is best to treat it. For this information, it is necessary to do a urine culture and sensitivity, usually through an outside laboratory. Even without any obvious signs of infection, geriatric pets and all pets with chronic kidney failure should have a urine culture done every 6-12 months to screen for UTI's since these pets are at high risk for infection. Recommendations for Treatment of UTI's One episode of a UTI: These infections can often be treated with a broad spectrum antibiotic that is most likely to be effective against common bacteria affecting the urinary tract. Recurrent UTI's: A culture and sensitivity is especially important to determine which bacteria are involved and to which antibiotic they are most sensitive. Sometimes, the bacteria can change with each UTI. Ideally, after the initial culture is done, a follow up culture is done about 5-7 days after stopping the antibiotics to make sure that all the bacteria has been eliminated. If recurrent infections have been in your pet's history, it is recommended that urine cultures be done once a month for 3 consecutive months, and every 4-6 months thereafter. Also, it is important to rule out an underlying cause for these recurrent infections such as stones or tumors. Xrays and ultrasound are useful to assess the bladder for these conditions. UTI's that are poorly responsive to antibiotic treatment These animals should have radiographs and/or an ultrasound done to evaluate their bladders and kidneys for the presence of stones, crystals, debris, polyps and tumors, all of which can result in a poor response to antibiotics or recurring infections. After the initial culture is done, a follow-up urine culture should be done about 5-7 days into treatment while on antibiotics and again 5-7 days after stopping a regime of antibiotics (generally given a minimum of 3 weeks). Both of these follow-up cultures should be negative. If the first follow-up culture is positive, the antibiotic should be changed. If the second one is positive, a urine culture should be repeated to determine if there is a change in the bacteria or its sensitivity to antibiotics. A longer course of prescribed antibiotic treatment is indicated. Occasionally, your veterinarian may propose an extended course of antibiotic to be given over several months with urine tests while on the course of treatment. Additional Diagnostics: Radiographs and Ultrasound Radiographs can be used to find some but not all bladder stones. Not all stones are "radio-opaque", that is, not all will appear on a plain radiographs. Sometimes, they can be detected only by using a special dye study (a contrast cystogram) when dye is injected into the bladder to highlight the stones. A dye study is usually needed to see masses of the bladder as well. Ultrasound is often used to rule out causes of recurrent urinary problems, and it allows the veterinarian to see inside the bladder to evaluate for polyps, masses and stones which often not seen on an xray. Incidental findings of a thickened bladder wall, polyps, masses, stones or flocculent material (floating debris) are all reasons for doing a urine culture to rule out an infection that may be present but not yet causing signs. Urinary bladder stones There are several types of bladder and kidney stones. While kidney stones can occur, bladder stones are more common in animals. The most common types of stones, based on composition, are phosphate, urate, cystine and oxalate. Others include: xanthine, sulfanilamide, carbonate and silica. Mixed stones, that is, a combination of these types, can occur as well. Treatment and prevention Most bladder stones require surgical removal. While stones originate in the bladder, they sometimes will move down the urethra and cause straining for female animals and obstruction for male animals. It is important that the stone be analyzed to determine its composition so that preventative measures can be taken since most stones will recur otherwise. This may involve a diet change and/or medications. Each stone, depending on its composition, will require a different treatment regime to change in pH, minimizing certain elements in food such as magnesium or calcium, increasing urine production etc. Some stones, especially struvite stones in dogs, are associated with infection. Depending on their size and the discomfort experienced by the animal, they may necessitate surgical removal or they may be amenable to medical treatment. Only struvite stones can be dissolved with medication and diet change. However, the infection must be treated as well. Even after the stones' surgical removal or dissolution, urine cultures should follow the same protocol as "recurrent UTI's". If you have questions regarding these tests and the treatment protocols, don't hesitate to contact your veterinarian. The above is general veterinary information. Do not begin any course of treatment without consulting your regular veterinarian. All animals should be examined at least once every 12 months.