Reading cat tests. Detailed explanation of the biochemical analysis of urine in a cat

It is widely accepted that the pH of a cat's urine can be directly related to the health of its urinary tract. Is your cat at risk for crystals in the bladder? How does feeding a cat affect the pH of its urine? Let's demystify the normal pH range of cat urine and how these numbers may correlate with feline urinary tract health.

What is urine pH and why is it important to your cat's health?

pH- a measure of acid or alkali in any liquid.

The pH level in urine - whether human or cat - reflects the difference between health and disease.

Cats are especially susceptible to problems with pH changes. When the pH is too high or low, conditions are favorable for the formation of salt crystals in the bladder and urethra. This causes irritation, local swelling, capillary bleeding, infection, and possibly obstruction (blockage) of the urinary tube. The condition of blockage and obstruction of the urethra in cats in English is called by the abbreviation FLUTD. Complete obstruction of the urethra can lead to the death of the animal within 72 hours if the problem is not corrected in time.

Normal urine pH in cats

For cats' urinary tract health, their urine must be acidic. The normal pH range is 6.0 to 6.5. A pH higher than this can lead to the formation of struvite (magnesium ammonium phosphate crystals). A pH below 6.0 may cause calcium oxalate crystals to form. In my veterinary practice, “alkalinization” of urine is more common than “acidification.” And, for example, among cat owners, the process is reversed, that is, their blood has a more acidic pH. You can find out what this is connected with and how to normalize urine pH. You can also measure this important indicator there.

Other Factors Affecting Cat Urinary Tract Health

• Excessive concentrations of minerals in the urine, which are thought to come from poor quality and unbalanced feeding. For many years, the total ash content of cat food was considered an indicator influencing the occurrence and development of “feline urolithiasis” (as it was then called), in fact, ash is the amount of dry residue from the combustion of food, which in no way determines either share, nor the quality of what it consists of. For this reason, in developed countries of old Europe, it is legally prohibited to indicate such inscriptions as “low ash” on cat food labels. There are recommended standard indicators for the content of various minerals, nutrients and biologically active substances in food for cats and kittens, but we will write about this in one of the following articles.
• Excess magnesium and phosphorus. Magnesium and phosphorus have recently been implicated as potential culprits in FLUTD. The source of magnesium is also important. Veterinarians believe that magnesium oxide causes an increase in the pH of urine, and magnesium chloride, on the contrary, leads to its “acidification.” The recommended ratio of phosphorus and calcium is also taken into account in the recommendations of organizations that control feed production in developed countries of the world.
• Water consumption and water regime. For normal functioning of the kidneys and urinary tract system, the blood requires sufficient fluid. That is, the saline solution of minerals in the liquid part of the blood must be of such a concentration that it does not provoke the formation of crystals in the urine. A cat that consumes a normal amount of drinking water will urinate quite frequently. This will also make your urine less concentrated, which will help prevent crystals from forming.

The connection between a cat's diet and the health of your pet's urinary tract

This connection is so important that many of the best cat food manufacturers publish urine pH ranges for their various cat food recipes on packaging. This information is much more important than the label on the ash content of the feed.

If the company that provides you with their cat food does not disclose this information on their packaging, or there is no mention of pH at all, then we recommend that you refrain from purchasing such food for your cat.

The phenomenon of increased protein in a cat's urine is called proteinuria. Protein particles are small, they easily pass through the glomeruli and are therefore excreted along with the urine. If the urine contains protein in small quantities, then this is normal and a physiological process. When protein levels are elevated, this indicates health problems in the cat. In such a situation, it is important to identify the cause of the problem and provide quality treatment.

There are quite a lot of factors for the occurrence of a disorder, and only a veterinarian, after carrying out the necessary tests, will be able to determine why a cat’s urine contains increased protein. The disorder also occurs in dogs.

Reasons

The appearance of changes in the composition of urine, in which increased protein secretion occurs, is caused by various problems and further worsens the condition of the sick cat. Protein, washed out of the body along with urine, is present in the blood. Violation of its secretion is an indicator of a serious problem. The main reasons for the occurrence of pathology are as follows::

• systemic diseases, such as systemic lupus erythematosus, which also affects the kidney;
• chronic bacterial lesions of the body, especially the urinary and circulatory systems;
• infectious pathologies such as Lyme disease or ehrlichiosis;
• diabetes mellitus – older cats are most often affected;
• pathologies of the pituitary gland, including Cushing's disease;
• persistent increase in blood pressure - hypertension occurs not only in humans, but also in cats, most often over the age of 10 years;
• hereditary predisposition to the appearance of disorders in the process of urine production;
• inflammatory pathologies of the kidneys, including urolithiasis;
• inflammatory pathologies of the circulatory system are a fairly common reason that urine contains protein above normal;
• persistent disturbances in the metabolism of proteins and carbohydrates, against the background of which excessive deposition of amyloid occurs in the internal organs.

The older the pet, the higher the likelihood that he will develop disorders in which the urine contains excess protein.

Diagnostics

If it is suspected that a cat has proteinurinia, a full examination of the animal is carried out, which includes:

• urine test for carotene in cats;
• urine test for protein - interpretation of a cat's urine test is carried out by a veterinarian. The amount of substance and its density are determined;
• pressure measurement;
• general blood test - shows the main physical parameters of the animal’s condition. Decoding is carried out in a laboratory or by a veterinarian;
• biochemical blood test.

If necessary, other diagnostic measures are also carried out, such as ultrasound and general urine examination. They detect the presence of stones. The list of necessary tests and studies is determined by the veterinarian who is treating the cat. When the amount of protein in the urine is even the upper permissible limit, there is no talk of pathology.

Symptoms

The manifestation that the urine has increased protein is similar in symptoms to the signs of many pathologies, which makes it impossible to make an accurate diagnosis based on them alone. Symptoms that suggest that a cat has proteinuria are:

• lack of appetite;
• frequent vomiting;
• rapid weight loss;
• severe weakness;
• apathy and lethargy.

As soon as the first causes of a disorder in the cat’s body have been identified, it is necessary to urgently visit a veterinarian for a diagnosis and quality treatment before it is too late. In some cases, when the urine contains protein in particularly large quantities, and the pet’s condition is very serious, and therapy will definitely not produce results, the question of euthanizing the cat may be raised to stop its suffering. The presence of excessive protein in the urine is a serious phenomenon for a cat.

Treatment of pathology

Treatment is carried out after the reason why the urine contains protein in high concentrations has been established. It is important to accurately determine whether proteinuria is cancerous. If the disorder is caused by an oncological process in the kidneys, treatment can only be carried out in the early stages of the disease, and therefore, if the process is already far advanced, only maintenance therapy is possible, as well as the prescription of medications to relieve pain.

If it is discovered that the cat suffers from high blood pressure, then he is prescribed a course of medications to normalize the animal’s blood pressure. The cat is also transferred to special feeding, which reduces salt and fat to a minimum. At the same time, to improve the condition of blood vessels and kidneys, products with omega-3 fatty acids are prescribed. They must be given every day.

It is important that the owner carefully monitors the cat’s condition during therapy and follows all veterinary recommendations; this normalizes the pet’s condition, including the protein that urine contains. Swelling may develop as a side effect of therapy. In such a situation, the cat should be shown to a veterinarian. The specialist, having established how much protein the urine contains, will adjust the treatment and prescribe means to remove excess fluid from the body. With timely treatment, a cat can live with the disorder for many years.

We recently completed studies that showed that the pH level of cat urine is not a favorable predictor of calcium oxalate oversaturation. And, although metabolic acidosis is accompanied by a decrease in urinary calcium concentration, it is possible to formulate a cat diet to maintain a urine pH of 5.8-6.2, thereby maintaining a low urinary RSS of calcium oxalate. This helps prevent the formation of struvite and calcium oxalate crystals.

In some cases of persistent calcium oxalate crystalluria or recurrent forms of this type of urolithiasis, it is recommended to resort to auxiliary drug treatment. For this purpose, potassium, thiazide diuretics and vitamin B6 can be used. Potassium citrate is widely used to prevent relapses of calcium oxalate urolithiasis in humans, since this salt, reacting with calcium, forms soluble salts that can lead to a deficiency of these elements in the body of animals. Special studies of the effectiveness of hydrochlorothiazide for calcium oxalate urolithiasis and the safety of its use in cats have not been conducted. Therefore, this drug cannot yet be recommended for their treatment.

The effectiveness of treatment for urolithiasis should be monitored through urine tests of patients, which should be carried out initially at intervals of two, then four weeks, and subsequently every three to six months. Since not all cats suffering from calcium oxalate stone disease excrete calcium oxalate crystals in their urine, patients should be examined radiographically every three to six months. This makes it possible to timely diagnose relapses of urolithiasis. Detection of uroliths at a stage when they are still quite small in size allows them to be removed by flushing the cat's urinary tract with water under pressure.

Treatment approaches for localization of urinary stones in the kidneys and ureters

Literature data regarding the most effective method of treating cats with uroliths localized in the kidneys and ureters is contradictory. Kyles et al reported that 92% of cats with ureteral uroliths were found to be azotemic at initial evaluation. In 67% of cases, several uroliths are found in the ureter, and in 63% of cats with this pathology, stones are localized in both ureters. Nephrectomy is rarely used for this pathology due to the high probability of urolith formation in both ureters simultaneously, the increased severity of renal failure accompanying this form of urolithiasis, and the high incidence of relapses of the latter. Removing urinary stones from the kidneys surgically entails the inevitable loss of nephrons. Therefore, this method of treatment is not recommended until it becomes clear that the uroliths located in the kidney are indeed causing serious illness in the animal. The indication for dissection of the ureter in order to remove uroliths from it is the progressive development of hydrocele of the renal pelvis. The operation is performed only if there is indisputable evidence that urinary stones are localized in the ureter. After such surgery, cats may experience complications such as urine accumulation in the abdominal cavity and ureteral stricture. An alternative to surgical treatment is conservative therapy. The palliative method of treatment in 30% of cases ensures displacement of the urolith from the ureter to the bladder. Lithotripsy is widely used in humans, but this approach has not yet become a routine method for removing kidney and ureteral stones in veterinary medicine.

Calcium phosphate uroliths

Identifying and eliminating conditions that contribute to the formation of calcium phosphate uroliths is the first and most important step in the prevention of this type of urolithiasis. The cat should be evaluated for primary parathyroidism, hypercalcemia, high concentrations of calcium and/or phosphate in the urine, and alkaline urine. Analysis of medical history data can provide information about whether dietary therapy for another type of urolithiasis has been previously carried out and whether urine alkalizing agents have been used for this purpose. If it was not possible to diagnose the patient’s primary disease against which calcium phosphate urolithiasis developed, then they resort to the same treatment strategy that is used for calcium oxalate urolithiasis. However, necessary precautions should be taken to prevent excessive increases in urine pH, which often occurs when a cat receives special foods intended for the treatment of calcium oxalate urolithiasis.

Urate uroliths

The frequency of detection of urate uroliths in cats is lower than struvite and calcium oxalate uroliths - less than 6% of cases of urate urolithiasis are recorded in Siamese cats, and 9 out of 321 - in Egyptian Mau.

Urate uroliths can form in cats with portosystemic anastomosis and in various forms of severe liver dysfunction. This may be due to a decrease in the conversion of ammonium to urea, which leads to hyperammonemia. Urate uroliths in cats with portosystemic anastomosis usually contain struvite. Urate uroliths also occur in the following cases:

For urinary tract infections accompanied by an increase in the concentration of ammonia in the urine;

With metabolic acidosis and highly alkaline urine;

When cats are fed foods rich in purines, such as those made from liver or other internal organs,

In most cases, the pathogenesis of this type of urolithiasis remains unknown.

Theoretically, the urate type of urolithiasis can be corrected with the help of nutritional therapy. However, there is no published clinical trial data on the effectiveness of special diets in treating this disease in cats.

The feeding strategy for cats diagnosed with urate stone disease should be aimed at reducing the purine content of the diet. As with other types of urolithiasis, sick animals should be encouraged to consume large amounts of water, as well as increase the moisture content of the feed. This approach helps to reduce the concentration of urine and its saturation with compounds from which uroliths are formed.

Alkalinization of urine

Alkaline urine contains little ionized ammonia, so increasing urine pH is considered an effective way to reduce the risk of ammonium urate stones. Low-protein, plant-based diets induce alkalinization of the urine, but may require the addition of potassium citrate to enhance this effect. Its dosage is selected for each patient individually, based on the results of determining urine pH, which should be maintained at 6.8-7.2. Increasing this indicator above 7.5 should be avoided. since highly alkaline urine can create favorable conditions for the crystallization of calcium phosphate. If a cat receives plant-based food, it must be balanced in all nutrients and meet the individual needs of the animal.

Xanthine oxidase inhibitors

Allopurinol is an inhibitor of xanthine oxidase, the enzyme responsible for the catalytic conversion of xanthine and hypoxanthine to uric acid. It is used to treat animals of other species to increase the excretion of urate in the urine. Although one publication reported that allopurinol was administered orally to cats at a dose of 9 mg/kg body weight per day, its effectiveness and potential toxicity in cats is unclear. Therefore, this drug cannot yet be recommended for the treatment of cats.

During the dissolution of uroliths, it is necessary to monitor changes in their size. To do this, a survey and double-contrast X-ray examination, as well as an ultrasound scan, are performed every 4-6 weeks. After complete dissolution of the uroliths, it is recommended to confirm this fact using ultrasound or double contrast cystography. In the future, it is advisable to repeat such examinations at least every two months for a year, since the risk of recurrence of the formation of cystine urinary stones is extremely high. The effectiveness of treatment is also confirmed through urine tests, which are carried out at intervals of 3-6 months.

Cystine uroliths

Drug treatment aimed at dissolving cystine uroliths in cats has not yet been developed. Small cystine uroliths can be removed from the urinary tract by flushing it with high pressure water. Large urinary stones must be removed surgically.

If an attempt is made to dissolve cystine uroliths, then all efforts should be directed at reducing the concentration of cystine in the urine and increasing its solubility. This goal is usually achieved by reducing the content of methionine and cystine in the diet while using drugs containing thiol.

These drugs interact with cystine by exchanging thiol disulfide radicals. As a result of this interaction, a complex is formed in the urine, which differs from cystine in being more soluble. N-2-mercaptopropionyl-glycine is recommended to be given to cats at a dose of 12-20 mc/kg body weight with an interval of 12 hours.

Alkalinization of urine

The solubility of cystine depends on the urine pH level in cats, and it increases in alkaline urine. You can increase the pH of urine by using a diet containing potassium citrate or by giving animals this drug orally.

During the process of dissolving urinary stones, it is necessary to monitor changes in their size. To do this, cats regularly undergo plain and double-contrast X-ray examinations, as well as ultrasound scans at intervals of 4-6 weeks. After complete dissolution of the uroliths, it is recommended to confirm this fact using ultrasound or double contrast cystography. In the future, it is advisable to repeat such examinations at least every two months for a year, since the risk of recurrence of the formation of cystine urinary stones is extremely high. The effectiveness of treatment is also confirmed through urine tests, which are carried out at intervals of 2-3 months.

In dogs with chronic kidney disease, a baseline urinary protein-to-creatinine (UPC) ratio of >1.0 is associated with a threefold increased risk of uremic crisis and death.

The relative risk of adverse outcomes increases by 1.5 times for every 1 increase in UPC.

In another study in dogs, proteinuria was correlated with the degree of functional impairment as measured by glomerular filtration rate; life expectancy of dogs with UPC< 1,0 в среднем была в 2,7 раза выше, чем у собак с UPC > 1,0.

In a prospective long-term study in cats without signs of azotemia, proteinuria was found to be significantly associated with the development of azotemia over 12 months. Both proteinuria and serum creatinine have been associated with decreased survival in cats with chronic kidney disease. This pattern persisted in cats even at UPCs as low as 0.2–0.4.

Chronic proteinuria has been shown to lead to interstitial fibrosis, degeneration and atrophy of renal tubules. There is evidence that resorbed proteins and lipids have a direct toxic effect on renal tubular epithelial cells, causing inflammation and apoptosis. In addition, excessive breakdown of proteins by lysosomes leads to lysosome rupture and intracellular release of cytotoxic enzymes. Proteinuria can lead to an excessive increase in the load on the epithelial cells of the renal tubules. The protein casts cause blockage of the tubules, which leads to further cell damage. Damage to the glomerular filter leads to decreased perfusion of the tubular interstitium, which causes cellular hypoxia. The increased selective permeability of the glomerular filtration increases the filtration of other substances, such as transferrin, further damaging the tubules.

Because proteinuria is associated with adverse outcomes, a thorough understanding of the optimal treatment of proteinuria in cats and dogs with chronic kidney disease is critical for the veterinarian.

Clinical assessment of proteinuria
Accurate assessment of proteinuria involves 3 key components: persistence, location, and intensity. Persistent proteinuria is proteinuria that is detected 3 or more times at intervals of 2 or more weeks. To implement adequate therapy, it is important to identify the causes of proteinuria in a cat or dog. Prerenal proteinuria occurs when there is an increased level of low molecular weight plasma proteins entering the normal glomerulus (examples: hemoglobinuria, myoglobinuria). Postrenal proteinuria occurs when protein enters the urine due to exudation of blood or serum into the lower urinary or reproductive tract (examples: urinary tract infection, urolithiasis, neoplasia). It is important to ensure that proteinuria is not due to prerenal or postrenal causes. Treatment of these pathologies differs significantly from therapy for chronic kidney disease. Renal proteinuria of a glomerular or tubulointerstitial nature is one of the most characteristic forms of proteinuria in the treatment of dogs with chronic kidney disease. Functional proteinuria is rare in dogs and cats, or at least not well documented.

After prerenal and postrenal causes of persistent proteinuria have been excluded, the intensity of the disease determines the glomerular or tubulointerstitial nature of the disease. Intensity is assessed using a quantitative urine protein test (usually UPC, but urine albumin concentration may also be used). After excluding prerenal and postrenal causes, it is recommended that UPC be assessed using a dipstick or sulfosalicylic acid test for any dog ​​with persistent proteinuria. On the other hand, in cats, the target UPC for therapeutic intervention may be no more than 0.2. With such low intensity proteinuria in a cat with chronic kidney disease and dilute urine, dipstick testing may be negative. For this reason, UPC testing is recommended once or twice a year for all cats with chronic kidney disease.

Table 1: Classification of proteinuria in cats and dogs with CKD according to the International Society of Kidney Diseases

The International Renal Society (IRIS) has recommended staging dogs and cats with CKD based on UPC scores (Table 1). Dogs with renal proteinuria and UPC >2.0 usually have glomerular disease, while dogs with UPC< 2,0 может наблюдаться гломерулярная или тубулоинтерстициальная болезнь. У кошек гломерулярная болезнь встречается реже, но ее следует подозревать при UPC >1. Concomitant hypoalbuminuria is additional evidence of the presence of glomerular disease.

Suppression of the RAAS for the treatment of proteinuria
Because the driving force of blood flow influences transglomerular protein transport, altering renal hemodynamics should be an effective way to reduce proteinuria. With this approach, the main target for reducing proteinuria is the renin-angiotensin-aldosterone system (RAAS). Drugs targeting the RAAS include angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor antagonists (ARAs), and aldosterone receptor antagonists (Table 2). All RAAS inhibitors have antihypertensive properties, although most only slightly reduce blood pressure (i.e., 10-15%). In addition to the expected reduction in glomerular capillary blood pressure, these drugs appear to reduce proteinuria through several mechanisms. Likewise, the observed reduction in proteinuria is greater than would be expected based on the antihypertensive properties of these drugs alone.

Table 2: RAAS inhibitors used in dogs and cats with CKD

* Lower initial doses should be used for animals with stage 3 or 4 CKD, as well as in the presence of concomitant diseases that could potentially lead to dehydration or decreased appetite.
**Can be used alone or in combination with an ACE inhibitor.
*** As a rule, combined administration with an ACEI is recommended.
****Recommended only for dogs with glomerular disease, elevated serum or urinary aldosterone and refractory to or intolerant of ACEIs or ARBs.

RAAS suppression is considered the standard of care for dogs and cats with renal proteinuria when UPC levels are >0.5–1 and >0.2–0.4, respectively. RAAS inhibitors reduce proteinuria in animal populations, but the level of effect may vary among individuals. In order to obtain the desired effect on proteinuria, it may be necessary to select drugs or combinations of drugs through trial and error; For some animals the required reduction may not be achievable.

UPC, urinalysis, systemic blood pressure, and serum albumin, creatinine, and potassium concentrations (fasting samples) should be monitored at least quarterly in all animals being treated for kidney disease associated with proteinuria. However, in the case of the introduction of new drugs or changes in the dosage of administered drugs, such monitoring should be carried out more often. UPC, serum creatinine, serum potassium, and systemic blood pressure should be assessed 1 to 2 weeks after initiation or dose changes of ACEIs or ARBs to confirm that recent changes in treatment have not resulted in severe deterioration of renal function (i.e., , an increase in serum creatinine > 30%), an alarming increase in serum potassium concentration, or hypotension (an unlikely occurrence with these drugs).

Diurnal variation in UPC occurs in most dogs with glomerular proteinuria, with greater variability in dogs with UPC > 4. Changes in urinary protein are most accurately measured by assessing changes in UPC over time. Because dogs with UPC > 4 exhibit greater diurnal variability, consideration should be given to either averaging the values ​​obtained from a series of 2-3 UPC assays or measuring UPC from a urine pool from 2-3 samples.

For most dogs and cats with proteinuria, ACE inhibitors are the treatment of choice, with a standard starting dose of 0.5 mg/kg every 24 hours. However, the ARA telmisartan may soon become a reasonable alternative as the drug of choice. For dogs, the ideal goal of therapy is to reduce the UPC to values< 1 без неприемлемого ухудшения почечной функции. Поскольку эта идеальная цель для большинства собак не достигается, часто целью становится снижение UPC на 50% или выше. Степень до-пустимого ухудшения почечной функции будет отчасти зависеть от стадии ХБП у собаки. У собак с ХБП 1-й и 2-й стадии допустимо повышение креатинина сыворотки крови на 30% без изменения курса терапии. Целью лечения для собак с 3-й стадией ХБП является поддержание стабильной почечной функции, допуская лишь 10% повышение креатинина сыворотки крови. Если почечная функция ухудшается сверх этих пределов, могут потребоваться изменения в терапии. Собаки с 4-й стадией ХБП, как правило, не переносят снижение почечной функции, и любое ее ухудшение может повлечь за собой клинические последствия. В то время как для данной категории пациентов могут применяться ингибиторы РААС, начальные дозы и шаг возрастающих доз должны быть очень небольшими, а почечная функция должна внимательно отслеживаться; для поддержания исходно-го уровня почечной функции могут потребоваться изменения в терапии.

If the required reduction in UPC is not achieved, plasma potassium concentration< 6, а любые изменения по-чечной функции находятся в пределах допустимого, дозировка может увеличиваться каждые 4-6 недель. Если целевое снижение UPC не достигнуто при максимальной дозе ИАПФ, следующим шагом будет добавление АРА. Альтернативным вариантом в случаях, когда у собаки наблюдается непереносимость ИАПФ, может быть применение АРА в качестве монотерапии.

Hypertension
Persistent hypertension can cause problems in organs such as the eyes, brain, cardiovascular system, and kidneys. Left untreated, hypertension can cause worsening proteinuria and progressive kidney damage. RAAS inhibitors, as a rule, have a very weak antihypertensive effect, and their use leads to a decrease in blood pressure by only 10-15%. It is advisable to maintain blood pressure at a level< 150 мм рт. ст. Собакам с систолическим давлением крови >160 In addition to the administration of a RAAS inhibitor, additional antihypertensive therapy may be required. The first step in this case will be to increase the dose of the RAAS inhibitor. If this measure is ineffective and after the upper dose limit has been reached, the next step should be an additional calcium channel blocker, usually amlodipine (0.25-0.5 mg/kg every 24 hours). In treated cats and dogs, systolic blood pressure should be maintained at > 120 mmHg. Art.

Diet
In chronic kidney disease in dogs, the intensity of proteinuria can be reduced by changing the diet, in particular by changing the ratio of polyunsaturated fatty acids and protein content. Supplementing the diet with omega-3 polyunsaturated fatty acids or feeding a diet with a reduced omega-6/omega-3 ratio close to 5:1, as in most commercially available foods for animals with kidney disease, is believed to modify the long-term course of kidney disease. and reduces the intensity of proteinuria. It is generally accepted that modified protein feeds for animals with kidney disease reduce intraglomerular pressure as well as proteinuria and the production of uremic toxins.

Aspirin therapy in dogs with proteinuria
Thromboembolism is a common complication of glomerular proteinuria. In this regard, for dogs with UPC > 3, or with an appropriate serum albumin level< 2,5 г/дл часто рекомендуется применять аспирин или клопидогрел. Однако на сегодняшний день существует недостаточно свидетельств безопасности и эффективности этих препаратов для собак с гломерулярными заболеваниями.

Literature
1. Brown S, Elliot J, Francey T, Polzin D, Vaden S. (2013). Consensus recommendations for standard therapy of glomerular disease in dogs. J Vet Intern Med 27:S27–S43.
2. Jacob F, Polzin DJ, Osborne CA, et al. (2005). Evaluation of the association between initial proteinuria and morbidity rate or death in dogs with naturally occurring chronic renal failure. J Amer Vet Med Assoc 226, 393-400.
3. Jepson RE. Brodbelt D, Vallance C, et al. (2009). Evaluation of predictors of the development of azotemia in cats. J Vet Intern Med 23:806–813.
4. King JN, Tasker S, Gunn-Moore DA, et al. (2007). Prognostic factors in cats with chronic kidney disease. J Vet Intern Med 21:906–916.
5. Lees GE, Brown SA, Elliot J, et al. Assessment and management of proteinuria in dogs and cats: 2004 ACVIM forum consensus statement (small animal). J Vet Intern Med 19:377–385.
6. Syme HM, Markwell Pj, Pfeiffer DU, et al. (2006). Survival of cats with naturally occurring chronic renal failure is related to the severity of proteinuria. J Vet Intern Med 20:528–535.
7. Wehner A, Hartmann K, and Hirschberger J. (2008). Associations between proteinuria, systemic hypertension and glomerular filtration rate in dogs with renal and non-renal diseases. Vet Rec 162:141–147.

Shelley L. Vaden,
North Carolina State University College of Veterinary Medicine
Raleigh, North Carolina, USA

To make an accurate diagnosis of a sick cat, it is not enough for a doctor to have high professional skills. Examining the animal, based on external symptoms - poor condition of the coat, watery eyes, fever, etc., he can only say that the cat is unwell.

However, the external signs of many cat diseases are similar, so it is only possible to determine what exactly a pet is sick with through laboratory tests. The more complex the disease, the less common it is, the more tests specialists working in the laboratory will have to do.

One of the main studies that helps establish the diagnosis of the disease is a general urine test. When carrying out a standard analysis, the physical properties of the liquid, its chemical composition and microscopy of the resulting urine sediment are assessed.

Urine color

First of all, the color of urine is assessed, the color of which is influenced by many factors, including the type of diet, medications taken and the presence of pathologies in the animal’s body:

• The normal color of urine is various shades of yellow. It becomes lighter if the cat drinks a lot of water and therefore urinates more frequently.
• The dark color is characteristic of many diseases, during which an increased amount of bilirubin enters the urine, in case of poisoning and hemoglobinuria - the appearance of hemoglobin in the urine, which is absent in a healthy pet. In the latter case, the urine becomes almost black.

Amount of urine excreted

1. In a healthy cat, the amount of urine excreted per day is equal to the volume of liquid it drinks during this time. At home, this amount can only be determined by using a clean tray. Then its contents can be poured into a measuring container and find out whether the volume of urine excreted by the pet corresponds to the norm.
2. Increased urine output is characteristic of diseases such as diabetes, various inflammatory processes, and chronic kidney failure.
3. The release of fluid in a volume lower than normal may be a sign of acute kidney failure, or shock suffered by the pet.

Normally, urine should be clear. Turbidity indicates the presence of microbes in the urine. They are always caused by inflammation of any organs of the urinary system - possible urolithiasis or inflammation of the urinary tract.

Urine density

To assess the functional capacity of the kidneys, urine concentration is determined by determining its relative density. The study is carried out by comparison with the density of water. Normal density values urine is considered to be 1.020 - 1.035. Measurements are made with instruments such as a urometer or a refractometer.

pH value

During a general urine analysis, the pH value is also examined, which reveals the presence of an acidic or alkaline reaction. Basically, these indicators depend on the composition of the cat’s diet. If the main part of her diet consists of meat products, then the urine reaction is acidic. With plant food (a rare occurrence - vegetarian cats), the power reaction becomes alkaline.

Since cats are carnivores by nature, their urine reaction is:

• Normally, it is slightly acidic - the pH value is from 6 to 7. At the same time, more acidic urine indicates the possibility of the cat having diseases such as diabetes, nephritis and congestion in the kidneys.
• an alkaline reaction occurs when bacteria, leukocytes or protein are present in the urine.

You should know that the analysis must be done on fresh urine. During the delivery of the liquid to the laboratory, the urine becomes alkalized, and the pH value changes towards an increase in the amount of alkali. Therefore, for the accuracy of such a check, it is better to use a litmus strip, checking the urine immediately after collecting it for analysis.

Chemical analysis of urine

During a general analysis of urine, a chemical study of its composition is also carried out. At the same time, most of the components in the urine that can indicate the appearance of any diseases in the cat are checked. First of all, urine is examined for the presence of the following substances:

• Protein– it is usually not present in the urine of a healthy animal, although its presence is allowed in amounts up to 0.3 g/liter of liquid. The appearance of more protein accompanies pathogenic processes. An accurate diagnosis can only be made after additional research. The list of possible diseases is long - it could be any infection, pyelonephritis, urolithiasis, urethritis, pyometry, cystitis;
• Glucose– the presence of this carbohydrate is not detected in healthy animals. Its appearance usually indicates that the cat has diabetes. However, it is sometimes also found in renal failure and even in stressful situations. Glucose may appear when there is an excess of carbohydrates in the pet’s diet and treatment with certain medications;
• Ketone (acetone) bodies– this component is absent if the cat is healthy. When detected together with glucose, it marks the cat as having diabetes mellitus. If glucose is absent, then a possible reason for the appearance of ketone bodies may be prolonged fasting, poisoning, severe fever, and even long-term eating of fatty foods;
• Bilirubin- bile pigment. The appearance of bilirubin in the urine indicates problems in the liver or blockage of the bile ducts. May signal hemolytic jaundice;
• Blood and hemoglobin– a signal from the animal’s body about the presence of a serious pathology of internal organs. The appearance of blood in the urine is a sign of injury to the urinary tract or bladder, nephritis, and even the development of a tumor. A change in urine color to coffee indicates the presence of hemoglobin, which is typical for infections, burns and poisoning.

Sediment microscopy

This study is also included in the general urine test. This method more accurately determines the affected area of ​​the urinary system. Particularly accurate information is provided by a urine sample obtained by puncturing the bladder, since in this case the sample excludes the appearance of microbes that have entered the test fluid from the genital tract.

Sediment microscopy involves looking for epithelial cells, which clinicians divide into squamous, transitional, and renal. The diagnosis is influenced by the presence of renal epithelium in the sediment, which indicates the possibility of identifying diseases such as renal failure, nephritis, intoxication, various infections or fever:

• The appearance of transitional epithelium in the sediment indicates the possible presence of diseases such as cystitis, urethritis and a malignant tumor.
• The presence of leukocytes becomes evidence of inflammation of the genitourinary system and infectious processes occurring in the animal’s body.
• The identification of urinary cylinders also indicates kidney disease. These formations consist of cells, salts and protein.
• An increased number of them is not always a sign of disease. Large amounts of salts are sometimes detected after taking certain prescribed medications, and also due to the long period of time between urine collection and analysis. However, some of them can become an opportunity to identify many diseases.
• The presence of mucus in the urine is an accurate sign of pathologies that have appeared in the cat’s body. In healthy cats, mucus is not found in the urine.