A high specific gravity of urine in a child is the cause. Causes of increased and decreased urine density in adults and children. Leukocytes in urine
The relative density of urine is considered to be quite an important diagnostic indicator, especially in nephrology. In certain pathological conditions, the specific gravity of urine is increased or decreased.
Low urine density - what does it mean?
Sometimes, to determine the degree of performance of the renal structures, it becomes necessary to conduct such specific studies as the Zimnitsky test, Nechiporenko, etc. ...
Usually, such a detailed study of urine is prescribed if there is a suspicion of pathology of the kidneys or other structures of the genitourinary system. And even with somatic disorders, urine studies are indispensable, because the specific gravity of urine is one of the main functional indicators of renal activity.
In addition, the determination of this value helps to reveal the filtration capacity of the kidneys. Why is that? The point is in the mechanisms of urine formation.
Urine is formed in several stages:
- First, primary urine is formed in the renal glomeruli. Under pressure, the blood is filtered, clearing it of various toxins and other waste products.
- Then the primary biomaterial is reabsorbed through the nephron tubules, and the beneficial substances from it are returned to the body, while the remaining liquid containing ammonia and urea, uric acid components and sulfates, chlorine and sodium, forms secondary urine. It is sent to the urinary structures, from where it is then excreted.
The determination of the specific gravity of urine is carried out using a special device - a hydrometer (or urometer). The development of hypostenuria is said if in all portions of urine during the Zimnitsky test the specific gravity is below 1.010.
The values
The value of urinary density is determined by the content of salts and urea in it. As a rule, this indicator is not constant and throughout the day it constantly changes, which depends on the food and drink consumed, on the loss of fluid with sweat, etc.
- For adults, the norm is 1.015-1.025.
- In newborns, these values are 1.002-1.020.
- In the future, the level of urine density gradually increases and by the age of 5 it normally reaches 1.012-1.020;
- Starting from the age of 12, this indicator is the same as that of an adult, i.e. 1.011-1.025.
So, the following indicators are considered normal:
Causes
Decreased urine density or hypostenuria is diagnosed if the urinary density level drops to 1.005-1.010. Such a decrease may indicate a low concentration renal function, which is regulated by antidiuretic hormonal substances. If such hormones are present in abundance, then water in the body is absorbed much more actively, so little urine is concentrated. If there is no antidiuretic hormone or too little of it, then a lot of urine is formed, and its specific gravity decreases. There are many reasons for the decrease in the specific gravity.
In pregnant women
In women in the normal position, the specific gravity of urine is 1.010-1.025.
Hypostenuria in pregnant women is usually detected due to:
- Renal pathologies;
- Hormonal disorders;
- With excessive urination;
- With toxicosis of pregnant women.
In children
In newborns, a decrease in specific gravity is usually recorded immediately after birth, but soon all indicators return to normal. On average, for newborns in the first weeks of life, the characteristic maximum density values are 1.016-1.018. Relative hypostenuria is considered the norm even in a healthy child in the first year of life.
If the relative density of urine is lowered for a longer period, then they talk about disorders in renal activity associated with organ failure.
In adults
In the adult population, pathological causes of decreased urine density are caused by conditions such as:
- Chronic kidney failure;
- Diabetes insipidus type (nephrogenic, central, or idiopathic);
- Chronic pyelonephritis;
- Chronic nephritis;
- Resorption of edematous zones and infiltrates of inflammatory origin, which is usually observed during the recovery period after any inflammation;
- The degeneration of healthy renal cells into connective tissue structures, characteristic of nephrosclerosis;
- Nutritional dystrophy due to lack of nutrients and starvation;
- Glomerulonephritis;
- Acute tubular lesions;
- Lack of antidiuretic pituitary hormone, in which there is no proper absorption of water, as a result of which the urine is diluted with a low density;
- Involuntary polydipsia, characteristic of persons prone to various kinds of neurotic disorders and having an unstable psyche (mainly in women);
- Abundant drinking regimen or taking diuretic drugs, etc.
Physiological decrease in the specific gravity of urine occurs against the background of alcohol abuse, but soon, if the patient stops drinking, the indicators return to normal.
In parallel with a decrease in density, patients may observe signs of kidney failure such as:
- Hyperthermia all over the body;
- Chronic tiredness;
- Soreness in the lower abdomen and lumbar region;
- Changes in the color characteristics of urine (darkening or bloody impurities);
- Decreased total urine output.
If the reason that the urine density is below normal is diabetes, when blood sugar rises, then patients involuntarily begin to drink more fluids and urinate more often.
Regardless of the reasons that provoked the density of urine is less than normal, the appearance of pathological signs requires a medical examination. In the absence of treatment, each of the factors can cause complications, therefore, it needs compulsory treatment.
Diagnosis of each disease begins with laboratory tests. One of the most informative indicators of the study is the relative density of urine. When the specific gravity of urine is significantly lower than normal, doctors insist on further diagnosis using modern examination methods. The reasons for this condition must be established, because many of them threaten health and even human life.
What is low urine specific gravity
Relative density is a parameter by which the functional activity of the kidneys is assessed by the concentration and dilution of urine. The amount of fluid circulating through the body is variable. Its volumes go down and up depending on many factors:
- ambient temperature;
- the amount of fluid in the diet;
- time of day;
- eating salty or spicy foods;
- with profuse sweating during sports.
Normally functioning kidneys cope with the function of filtration and excretion regardless of the volume of fluid - metabolic products should not accumulate in the human blood. If there is an insignificant amount of water in the body, then the secondary urine turns out to be concentrated, compacted, of a rich dark color. In medicine, this condition is called hypersthenuria, or increased relative density of urine.
With an increase in the amount of fluid in the body, an additional burden falls on the kidneys. The primary task is to filter the blood from accumulated harmful decomposition products:
- Urea and its chemical compounds.
- Chlorides, sulfates, ammonia.
- Creatinine.
At the next stage of urination, the kidneys remove a large volume of water from the body in order to reduce the stress on the cardiovascular system and internal organs. The resulting urine is practically colorless, because the concentration of the dry residue in it is extremely low. This condition is called hypostenuria, or decreased relative density of urine.
If hypostenuria is caused by natural causes (drinking fluids in heat), then there is no cause for concern. But there are diseases in which a low specific gravity of urine is regularly detected according to the results of the study.
You can read more about the specific gravity of urine.
Using a urometer, the specific gravity of urine is determined
Why does the specific gravity of urine decrease?
Primary urine is formed during the filtration of blood by single-layer capillary cells under a pressure of 70 mm Hg. Art. In the renal tubules, nutrients from the primary urine are reabsorbed back into the blood flowing through the capillaries. The reabsorption process occurs due to the functional activity of the epithelial cells of the renal tubules. In just one day, about two liters of secondary urine are formed from 150 liters of primary urine.
The main reason for the decrease in the relative density of urine is a violation of the production of vasopressin, a peptide hormone of the hypothalamus. For example, in some types of diabetes insipidus, the daily volume of urine excreted by a person reaches 20 liters at a rate of 1.5 liters. This is due to the almost complete absence of vasopressin in the body.
Antidiuretic hormone (ADH) accumulates in the pituitary gland and then enters the bloodstream. Its main functions are:
- narrowing of the lumen of veins and arteries;
- preservation of fluid in the human body.
Antidiuretic hormone increases the reabsorption of fluid, increases the concentration of urine, and reduces its volume. By regulating the amount of water in the human body, vasopressin increases the permeability of fluid in the kidney tubules.
The content of solids in urine is a variable value, which is in direct proportion to the composition of blood plasma. This process is regulated by nervous and humoral mechanisms. With an increase in the salt content, the production of vasopressin increases, which enters the kidneys with the blood and increases the reabsorption of fluid from the primary urine. The concentration of secondary urine increases, along with it all harmful substances are removed from the body, and only a small amount of fluid.
If the blood contains a large amount of fluid, then the concentration of antidiuretic hormone decreases, as well as reabsorption. Secondary urine consists of a small amount of solids dissolved in a large volume of water.
How is low urine specific gravity determined?
The fact that a person has a reduced relative density of urine is often revealed when diagnosing diseases that have nothing to do with the urinary system. The determination of the specific gravity occurs as a result of a general analysis of urine, along with the content of leukocytes and products of protein metabolism. But the informative value of the indicator is difficult to overestimate - with its help, doctors detect severe pathologies that require urgent treatment.
As a rule, a low specific gravity of urine is determined during functional tests:
- Folgart's test.
Taking such measurements helps to obtain more accurate results of relative density and even approximately determine the cause of hypostenuria. For example, with a decrease in the indicator to 0.01, we can talk about isostenuria, which occurs when the kidney is wrinkled. Isotenuria is diagnosed in a person whose kidneys have completely lost the ability to concentrate and remove urine from the body.
The main tool for functional tests is the urometer.
The research is carried out in several stages:
- The urine sample is placed in a cylinder. If a small amount of foam appears, then dispose of it with filter paper.
- With a little effort, the urometer is immersed in urine. The device should not come into contact with the cylinder walls - this will distort the research results.
- After the disappearance of the oscillations of the urometer, the relative density is measured along the border of the lower meniscus.
To obtain a more accurate result, it is important to take into account the ambient temperature, taking as a basis the average indicator of 15 ° C.
By the way, today you can successfully measure the specific gravity of urine at home using multi-indicator test strips. If a person has diabetes insipidus, frequent determination of urine density is required to monitor the course of therapy. Test strips make the patient's life much easier, because the state of health does not always allow him to leave the house.
Reasons for a decrease in the relative density of urine
The specific gravity of urine is lowered when the density level drops to 1.01. This condition signals a decrease in the functional activity of the kidneys. The ability to filter out harmful substances is significantly reduced, which can lead to slagging of the body, the emergence of numerous complications.
But such an indicator is sometimes taken as the norm. For example, in pregnant women, hypostenuria often develops with toxicosis. In this state, women sometimes experience disturbances in the work of the gastrointestinal tract, which cause fluid retention in the body. Expectant mothers suffer from urination disorders - urine is excreted often, but in small portions.
A decrease in the relative density of urine in pregnant women also happens for the following reasons:
- Disorders of the kidneys. When carrying a child, many factors arise, under the influence of which the ability of the kidney to function actively decreases. It is a growing uterus that squeezes the pelvic organs. The circulatory system also expands, which puts more stress on the kidneys.
- Change in hormonal levels. Increased production of female sex hormones causes a certain imbalance in other biologically active substances.
Immediately after the baby is born, the first urine sample is taken from him to assess kidney function and general health. As a rule, the specific gravity of a newborn's urine does not exceed 1.015-1.017. Such indicators persist during the first month of life, and then begin to increase with a change in diet. Hypostenuria in infants is considered normal and does not require medical attention.
Read more about the decrease in the specific gravity of urine in children.
Hypostenuria is observed in healthy people who have consumed significant amounts of fluids or foods with a diuretic effect (watermelon, melon). In adherents of a monotonous diet, a decrease in urine density is diagnosed - a lack of protein products in the diet is formed. The use of diuretics in the treatment of various diseases also leads to hypostenuria, but usually this condition is corrected by changing diuretics or reducing their dosage. The concentration of solids in the secondary urine decreases with the resorption of edema or increased sweat separation in case of colds.
It is extremely important to distinguish between physiological and pathological reasons for a decrease in the specific gravity of urine. Kidney pathologies lead to impaired filtration of chemical compounds, therefore, a decrease in urine density does not develop due to a large volume of fluid consumed, but as a result of the resulting diseases of the urinary system.
If, during functional tests, a monotonic relative density of urine is recorded during the day, then the doctor will definitely prescribe further studies.
Diseases in which the specific gravity of urine decreases
There are three main types of pathologies in which the production of vasopressin decreases and fluid reabsorption does not occur. With each urination, a large volume of urine is excreted with a low concentration of urea and its salts. Such diseases include:
- involuntary polydipsia;
- neurogenic diabetes insipidus;
- nephrogenic diabetes insipidus.
When diagnosing a low urine density, doctors suspect the development of these particular diseases, especially when the patient complains of the following symptoms:
- The occurrence of edema of various localization.
- Pain in the abdomen and lower back.
- The urine has acquired a darker color, impurities of blood have appeared in it.
- Decreased urine volume with each urination.
- Drowsiness, insomnia, weakness, and apathy often occur.
The addition of a bacterial infection of the bladder leads to an expansion of symptoms: pain appears during urination, the temperature rises, and disruptions in the functioning of the gastrointestinal tract occur.
Polydipsia causes a decrease in urine specific gravity
Polydipsia
Polydipsia is a condition that causes intense thirst. To quench it, a person drinks a huge amount of liquid, far exceeding the physiological need. The kidneys filter out the increased volumes of blood, resulting in the formation of unconcentrated urine.
Involuntary polydipsia is diagnosed in people whose mental state is extremely unstable. To determine the disease, it is usually enough to interview the patient and the results of the relative density of urine.
Neurogenic diabetes insipidus
The main symptoms of neurogenic diabetes insipidus are constant thirst and frequent urination. The disease develops with insufficient production of vasopressin by the hypothalamus. What factors may cause pathology:
- head trauma;
- infectious diseases;
- malignant and benign neoplasms;
- the consequences of surgical operations;
- congenital pathologies.
Lack of antidiuretic hormone results in fluid loss when highly diluted urine is produced. A person seeks to make up for the loss by drinking large volumes of fluid, but the absence of vasopressin in the body leads to a vicious circle.
Disruption of the hypothalamus leads to a decrease in the specific gravity of urine
Nephrogenic diabetes insipidus
The disease develops when the kidney is unable to respond to vasopressin. The reason for this may be the use of certain medications, as well as:
- Chronic renal failure.
- Urolithiasis disease.
- Sickle cell anemia.
- Congenital kidney disease.
If the cause of diabetes has not been diagnosed, then idiopathic diabetes insipidus is determined.
With a decrease in the specific gravity of urine, further careful examination is required. This means that there is a latent pathology in the body, and it requires urgent medical or surgical treatment.
They can fluctuate within fairly wide limits, and these fluctuations can be physiological or pathological. Physiological fluctuations are a variant of the norm, and pathological ones reflect any disease.
An increase or decrease in relation to the norm of any indicator cannot be assessed unambiguously, and it is impossible to draw a conclusion about the presence of a disease. The test results can help to find out the possible cause of the disorders, which can be only at the stage of the syndrome, and not the formed disease. Therefore, the timely detection of abnormalities in the analyzes will help start treatment and prevent the progression of the disease. Also, test indicators can be used to monitor the effectiveness of treatment.
Consider the probable causes of changes in various indicators of the general urine analysis.
Causes of urine discoloration
In the presence of pathology, urine can change its color, which indicates a certain syndrome and disease.The correspondence of urine colors to various pathological conditions of the body is reflected in the table:
| Pathological color urine | Potential disease (cause of urine discoloration) |
| Brown, black |
|
| Red (the color of meat slops) |
|
| Dark brown frothy (urine colored beer) |
|
| Orange, rose red |
|
| Brown (strong color tea) |
|
| Colorless or white-yellow |
|
| Milky (color of milk, cream) |
|
These color variations will help you navigate, but for an accurate diagnosis, you should take into account data from other examination methods and clinical symptoms.
Causes of the appearance of turbidity in the urine
Violation of the transparency of urine is the appearance of turbidity of varying severity. Turbidity in urine can be represented by large amounts of salts, epithelial cells, pus, bacterial agents, or mucus. The degree of turbidity depends on the concentration of the above impurities.From time to time, every person has cloudy urine, which is formed by salts. If you can't donate this urine for analysis in the laboratory, you can conduct a test to find out the nature of the turbidity.
To distinguish salt in urine from other turbidity options at home, you can slightly warm the liquid. If the haze is formed by salts, then it can either increase or decrease until it disappears. The turbidity formed by epithelial cells, pus, bacterial agents or mucus does not change its concentration at all when the urine is heated.
The reasons for the change in the smell of urine
The smell of fresh urine is normal - not harsh or irritating.Most often, the following pathological urine odors are noted:
1.
The smell of ammonia in urine is characteristic of the development of inflammation of the mucous membrane of the urinary tract (cystitis, pyelitis, nephritis).
2.
The smell of fruits (apples) in the urine develops in the presence of ketone bodies in people with type 1 or type 2 diabetes.
Reasons for changing the acidity of urine
The acidity of urine (pH) can change to an alkaline and acidic region, depending on the type of pathological process.The reasons for the formation of acidic and alkaline urine are reflected in the table:
Causes of changes in urine density
The relative density of urine depends on the function of the kidneys, therefore, a violation of this indicator develops in various diseases of this organ.Today, the following options for changing the density of urine are distinguished:
1.
Hypersthenuria - high-density urine, more than 1030-1035.
2.
Hypostenuria - urine with a low density, in the range 1007-1015.
3.
Isotenuria - low density of primary urine, 1010 or less.
A single excretion of urine with high or low density does not provide grounds for detecting hypostenuria syndrome or hypersthenuria. These syndromes are characterized by prolonged excretion of urine during the day and night, with high or low density.
Pathological conditions causing disturbances in urine density are shown in the table:
| Hypersthenuria | Hypostenuria | Isostenuria |
| Diabetes mellitus type 1 or 2 (urine density can reach 1040 and higher) | Diabetes insipidus | Chronic renal failure severe degree |
| Acute glomerulonephritis | Resorption of edema and inflammatory infiltrates (period after the inflammatory process) | Subacute and chronic jade severe |
| Congestive kidney | Alimentary dystrophy (partial starvation, nutritional deficiencies, etc.) | Nephrosclerosis |
| Nephrotic syndrome | Chronic pyelonephritis | |
| Edema formation | Chronic nephritis | |
| Convergence of edema | Chronic renal failure | |
| Diarrhea | Nephrosclerosis (renal degeneration tissue into the connective) | |
| Glomerulonephritis | ||
| Interstitial nephritis |
Determination of chemicals in urine for various diseases
As we can see, the physical properties of urine in the presence of any disease can change quite significantly. In addition to changes in physical properties, various chemicals appear in the urine, which are normally absent or present in trace amounts. Consider in which diseases there is an increase in concentration, or the appearance in the urine of the following substances: - protein;
- bile acids (pigments);
- indican;
- ketone bodies.
Causes of protein in urine (proteinuria)
The appearance of protein in urine can be caused by various reasons, which are classified into several groups, depending on the origin. An abnormal increase in the concentration of protein in the urine above 0.03 g is called proteinuria. Depending on the protein concentration, moderate, moderate and severe proteinuria are distinguished. Moderate proteinuria is characterized by a loss of protein up to 1 g / day, average - 1-3 g / day, pronounced - more than 3 g / day.Types of proteinuria
Depending on the origin, the following types of proteinuria are distinguished:- renal (renal);
- stagnant;
- toxic;
- feverish;
- extrarenal (extrarenal);
- neurogenic.
| Proteinuria type | The reasons for the development of proteinuria |
| Renal (renal) |
|
| Stagnant |
|
| Toxic | The use of the following medicines in very high doses: salicylates, isoniazid, pain relievers and gold compounds |
| Feverish | A severe increase in body temperature caused by any disease |
| Extrarenal (extrarenal) |
|
| Neurogenic |
|
Causes of the appearance of glucose (sugar) in the urine
The appearance of glucose in the urine is called glucosuria. The most common cause of glucosuria is diabetes mellitus, but there are other pathologies that lead to this symptom. So, glucosuria is divided into the following types:
1.
Pancreatic.
2.
Renal.
3.
Hepatic.
4.
Symptomatic.
Pancreatic glucosuria develops against the background of diabetes mellitus. Renal glucosuria is a reflection of metabolic pathology, and it occurs from an early age. Hepatic glucosuria can develop with hepatitis, traumatic organ damage, or as a result of poisoning with toxic substances.
Symptomatic glucosuria is caused by the following pathological conditions:
- concussion of the brain;
- hyperthyroidism (increased concentration of thyroid hormones in the blood);
- acromegaly;
- Itsenko-Cushing's syndrome;
- pheochromocytoma (tumor of the adrenal gland).
Causes of the appearance of bilirubin in urine
Bilirubin in urine appears with parenchymal or obstructive jaundice. Parenchymal jaundice includes acute hepatitis and cirrhosis. Obstructive jaundice includes various options for blocking the bile ducts with an obstacle to the normal outflow of bile (for example, cholelithiasis, calculous cholecystitis).Causes of the appearance of urobilinogen in urine
Urobilinogen at a concentration exceeding 10 μmol / day is determined in urine with the following pathologies:- infectious hepatitis;
- chronic hepatitis;
- cirrhosis of the liver ;
- tumors or metastases to the liver;
- hemoglobinuria (hemoglobin or blood in the urine);
- hemolytic jaundice (hemolytic disease of the newborn, hemolytic anemia);
- infectious diseases (malaria, scarlet fever);
- fever of any cause;
- the process of resorption of foci of hemorrhage;
- volvulus;
- bile acids (pigments);
- indican.
Causes of the appearance of bile acids and indican in urine
Bile acids (pigments) appear in urine when the concentration of direct bilirubin in the blood rises above 17-34 mmol / l.The reasons for the appearance of bile acids in urine:
- Botkin's disease;
- hepatitis;
- obstructive jaundice (calculous cholecystitis, gallstone disease);
- cirrhosis of the liver.
Causes of the appearance of ketone bodies in urine
Ketone bodies include acetone, hydroxybutyric and acetoacetic acids.The reasons for the appearance of ketone bodies in urine:
- diabetes mellitus of moderate and high severity;
- fever;
- severe vomiting;
- therapy with large doses of insulin for a long period of time;
- eclampsia of pregnant women;
- cerebral hemorrhage;
- traumatic brain injury;
- poisoning with lead, carbon monoxide, atropine, etc.
Decoding microscopy of urinary sediment
One of the most informative fragments of a general urine analysis is sediment microscopy, in which the number of different elements in one field of view is counted.Leukocytes, pus in the urine - possible causes of the appearance
An increase in the number of leukocytes more than 5 in the field of view indicates a pathological process of an inflammatory nature. An excess of white blood cells is called pyuria - pus in the urine. The reasons causing the appearance of leukocytes in the urine:
- acute pyelonephritis;
- acute pyelitis;
- acute pyelocystitis;
- acute glomerulonephritis;
- treatment with aspirin, ampicillin;
- heroin use.
Sometimes, to clarify the diagnosis, urine is stained: the presence of neutrophilic leukocytes is characteristic of pyelonephritis, and lymphocytes - for glomerulonephritis.
Red blood cells, blood in the urine - possible causes of the appearance
Erythrocytes in urine can be present in varying amounts, and when their concentration is high, they speak of blood in the urine. By the number of erythrocytes in the urinary sediment, one can judge the development of the disease and the effectiveness of the treatment used.The reasons for the appearance of red blood cells in the urine:
- glomerulonephritis (acute and chronic);
- pyelitis;
- pyelocystitis;
- chronic renal failure;
- injury (bruise, rupture) of the kidneys, urethra or bladder;
- tuberculosis of the kidney and urinary tract;
- tumors;
- taking certain medications (sulfa drugs, urotropin, anticoagulants).
Cylinders in urine - possible causes of the appearance
Among all types of cylinders, the appearance of hyaline is most often noted in the urinary sediment. All other types of cylinders (granular, waxy, epithelial, etc.) appear much less frequently.The reasons for the detection of various types of cylinders in urine are presented in the table:
| Type of cylinders urinary sediment | Causes of the appearance of cylinders in the urine |
| Hyaline |
|
| Grainy |
|
| Waxy |
|
| Erythrocyte |
|
| Epithelial |
|
Epithelial cells in the urine - possible causes of the appearance
Epithelial cells are not only counted, but divided into three types - squamous epithelium, transitional and renal.Squamous epithelial cells in the urinary sediment are detected in various inflammatory pathologies of the urethra - urethritis. In women, a slight increase in squamous epithelial cells in the urine may not be a sign of pathology. The appearance of squamous epithelial cells in the urine of men undoubtedly indicates the presence of urethritis.
Transitional epithelial cells in the urinary sediment are detected in cystitis, pyelitis or pyelonephritis. Distinctive signs of pyelonephritis in this situation is the appearance of transitional epithelial cells in the urine, in combination with protein and a shift in the reaction towards the acidic side.
Renal epithelial cells appear in urine with serious and deep organ damage. So, most often, cells of the renal epithelium are detected in nephritis, amyloid or lipoid nephrosis or poisoning.
Pathologies leading to the excretion of salts in the urine
Crystals of various salts can appear in the urine and normally, for example, due to the peculiarities of the diet. However, in some diseases, the excretion of salts in the urine is also noted.Various diseases that cause the appearance of salts in the urine are presented in the table:
The table shows the most common salts that are of diagnostic value.
Mucus and bacteria in urine are possible causes of
Mucus in the urine is determined with urolithiasis or long-term chronic inflammation of the urinary tract (cystitis, urethritis, etc.). In men, mucus can appear in the urine with prostatic hyperplasia. The appearance of bacteria in the urine is called bacteriuria. It is caused by an acute infectious and inflammatory process occurring in the organs of the urinary system (for example, pyelonephritis, cystitis, urethritis, etc.).
The general analysis of urine provides a fairly large amount of information that can be used to make an accurate diagnosis in combination with other techniques. However, remember that even the most accurate analysis does not allow diagnosing any disease, since for this it is necessary to take into account clinical symptoms and data from objective examinations.
1. Amount of urine
Diuresis is the volume of urine generated over a certain period of time (daily or minute urine output).
The amount of urine delivered for a general analysis (usually 150-200 ml) does not allow any conclusions to be drawn about violations of daily urine output. The amount of urine delivered for general analysis affects only the ability to determine the specific gravity of urine(relative density).
For example, to determine the specific gravity of urine using a urometer, at least 100 ml of urine is required. When determining the specific gravity using test strips, you can do with a smaller amount of urine, but not less than 15 ml.
2. Color of urine
Normal urine is yellow.
The saturation of the yellow color of urine depends on the concentration of substances dissolved in it. With polyuria, the dilution is greater, therefore the urine has a lighter color, with a decrease in urine output it acquires a rich yellow tint.
The color changes when taking medications (salicylates, etc.) or eating certain foods (beets, blueberries).
Pathologically altered urine coloration occurs with hematuria (a type of meat slop), bilirubinemia (the color of beer), with hemoglobinuria or myoglobinuria (black), with leukocyturia (milky white).
3. Clarity of urine
Normally, freshly released urine is completely clear..
Turbidity of urine is due to the presence in it of a large number of cell formations, salts, mucus, bacteria, fat.
Cloudy urine can also indicate microhematuria, but in most cases it is a sign of infection (i.e. bacteriuria). Note: Urinalysis can be used as a preliminary test for urinary tract infection in asymptomatic patients. In the course of the studies carried out, it turned out that the sensitivity of visual examination of urine samples for the diagnosis of bacteriuria is 73%.
4. Smell of urine
Normal urine odor is mild, nonspecific.
When urine is decomposed by bacteria in the air or inside the bladder, for example, in the case of cystitis, an ammonia odor appears.
When urine that contains protein, blood, or pus decays, such as in bladder cancer, the urine smells like rotten meat.
In the presence of ketone bodies in the urine, the urine has a fruity odor, reminiscent of the smell of rotting apples.
5. Urine reaction
Normal urine reaction is acidic.
Fluctuations in urine pH are due to the composition of the diet: a meat diet causes an acidic reaction of urine, a vegetable diet - an alkaline one. With a mixed diet, mainly acidic metabolic products are formed, therefore it is believed that the normal reaction of urine is acidic.
It is necessary to store urine before the general analysis in a cold room and no more than 1.5 hours. With prolonged standing in a warm room, urine decomposes, ammonia is released and the pH shifts to the alkaline side. An alkaline reaction underestimates the relative density of urine. In addition, leukocytes are rapidly destroyed in alkaline urine.
An alkaline urine reaction is characteristic of a chronic urinary tract infection, and is also noted with diarrhea, vomiting.
The acidity of urine increases with febrile conditions, diabetes mellitus, tuberculosis of the kidneys or bladder, renal failure.
6. Specific gravity of urine (relative density of urine)
Normally, the morning urine portion should have a specific gravity in the range of 1.018-1.024.
The relative density of urine (the density of urine is compared with the density of water) reflects the functional ability of the kidneys to concentrate and dilute and can be used as a screening test for mass examinations of the population.
Figures for the relative density of morning urine equal to or exceeding 1.018 indicate the normal concentration ability of the kidneys and exclude the need for its study using special methods. High or low figures of the specific gravity (density) of morning urine necessarily require clarification of the reasons for these changes.
Analysis decoding
High specific gravity of urine
The relative density of urine depends on the molecular weight of the particles dissolved in it. Protein and glucose increase urine specific gravity. For example, diabetes mellitus can be suspected only by one general urine test with relative gravity numbers from 1.030 and above against the background of polyuria.
Low specific gravity of urine
The formation of urine is regulated by the concentration mechanism of the kidneys and the antidiuretic hormone (ADH) produced by the pituitary gland. In the presence of antidiuretic hormone, more water is absorbed and as a result, a small amount of concentrated urine is produced. Accordingly, in the absence of antidiuretic hormone, water absorption does not occur and large volumes of diluted urine are excreted.
There are three main groups of reasons for a decrease in the specific gravity in the general analysis of urine:
- excess water intake
- neurogenic diabetes insipidus
- nephrogenic diabetes insipidus
1. Excess water intake (polydipsia) causes a decrease in the concentration of blood plasma salts. To protect itself, the body secretes large volumes of diluted urine. There is a disease called involuntary polydipsia, which usually affects women with an unstable psyche. The leading signs of involuntary polydipsia are polyuria and polydipsia, low relative density in the general urine analysis.
2. Neurogenic diabetes insipidus- insufficient secretion of an adequate amount of antidiuretic hormone. The mechanism of the disease is the inability of the kidneys to retain water through the concentration of urine. If the patient is deprived of water, the urine output is almost not reduced and dehydration develops. The relative density of urine may drop below 1.005.
The main causes of neurogenic diabetes insipidus are:
Hypopituitarism - insufficiency of the function of the pituitary gland or hypothalamus with a decrease or cessation of the production of tropic hormones of the anterior pituitary gland and antidiuretic hormone.
- The most common reason for a decrease in the specific gravity of urine is idiopathic neurogenic diabetes insipidus... Idiopathic neurogenic diabetes insipidus is most often found in young adults. Most of the underlying disorders leading to neurogenic diabetes insipidus can be identified by concomitant neurological or endocrinological symptoms (including cephalalgia and visual field disturbances or hypopituitarism).
- Another common cause of a decrease in the specific gravity of urine is damage to the hypothalamic-pituitary region due to head trauma, neurosurgical intervention in the pituitary gland or hypothalamus. Or damage as a result of a brain tumor, thrombosis, leukemia, amyloidosis, sarcoidosis, encephalitis after an acute infection, etc.
- The intake of ethyl alcohol is accompanied by a reversible suppression of ADH secretion and short-term polyuria. Diuresis occurs 30-60 minutes after drinking 25 g of alcohol. The volume of urine depends on the amount of alcohol taken in a single dose. Continuous use does not lead to persistent urination, despite the existence of a constant concentration of alcohol in the blood.
3. Nephrogenic diabetes insipidus- a decrease in the concentration of the kidneys, despite the normal content of antidiuretic hormone in the blood.
The main causes of nephrogenic diabetes insipidus are:
- The most numerous subgroup among patients with nephrogenic diabetes insipidus is made up of persons with parenchymal kidney disease (pyelonephritis, various types of nephropathies, tubulointerstitial nephritis, glomerulonephritis) and chronic renal failure.
- Metabolic Disorders:
- Connes syndrome- combination of polyuria with arterial hypertension, muscle weakness and hypokalemia. The relative gravity of urine can range from 1003 to 1012).
- Hyperparathyroidism- polyuria, muscle weakness, hypercalcemia and nephrocalcinosis, osteoporosis. The relative density of urine decreases to 1002. Urine, due to the significant content of calcium salts, often has a white color.
- Rare cases of congenital nephrogenic diabetes insipidus. The relative density of urine may drop below 1.005.
The specific gravity of urine is one of the key parameters of the general analysis. WHO has established standards for the results of studies of the specific gravity in various categories of citizens: children, men, pregnant women, etc.
The indicator of the relative density of urine can change quite quickly under the influence of the following factors:
- Diet;
- Drinking regime;
- The intensity of physical activity;
- Sweating intensity.
Any process of elimination and accumulation of fluid in the body able to influence on the specific gravity of urine.
How is it defined?
Laboratory research is carried out using a special device - urometer (hydrometer)... Measuring scales allow you to determine the specific gravity of urine in the range from 1,000 to 1,060 g / l.
50-100 ml of urine is carefully collected in a cylinder, taking care to avoid foaming. If the foam does come out, it is removed with filter paper. The device is immersed in urine so that its top remains above the liquid level.
When the urometer stops self-immersion, you need to nudge it slightly with your fingers, as it does not fully submerge. Hand movement creates slight vibrations. It is appropriate to determine the relative density of urine only after the complete cessation of fluctuations.
The urometer should not come into contact with the walls of the container, therefore, choose a cylinder with a diameter larger than the widest part of the device.
When a small amount of urine (20-50 ml) is provided for analysis, it is diluted with distilled water to the required volumes and carry out the measurement in the prescribed manner. The last two digits of the set value are multiplied by the dilution rate.
It is possible to determine the parameters of the specific gravity of urine, even if only a few drops were collected for analysis. In this case, the liquid mixture method is used.
A mixture of benzene with chloroform is poured into a cylindrical container and the collected urine is introduced with a pipette. If the drops of urine sink, then its relative density is higher than the parameters of the mixture; if the drops fall on top, then the density is lower.
By adding small amounts of chloroform or benzene to the mixture, the mixture is adjusted until the drop of the test urine is exactly in the middle of the container... "Averaging" the drop means that the specific gravity of the urine is equal to the specific gravity of the solution, which is easy to determine in laboratory conditions.
When starting laboratory tests, you should observe rules for its conduct:
- Ambient temperature = 15 degrees Celsius (a deviation of 3 degrees is permissible);
- Lack of protein or glucose in the material;
- , smell, clarity and acidity of urine.
Some urometers are calibrated to measure at 20 or 22 degrees. It is necessary to pay attention to the instructions on the body of the device.
Functional tests
When abnormalities are detected by OAM, as a rule, additional functional tests are prescribed. and a concentration test allow you to assess the general condition of the kidneys, their ability to concentrate and excrete with salts.
According to Zimnitsky
Laboratory test evaluates the functional capacity of the kidneys in a patient without the use of a drinking diet... A person collects 8 servings of urine, urinating every 3 hours within one day.
Urometer examines the relative density of each portion of urine and the resulting volume. The result of the study shows an objective difference between day and night, while the nighttime urine output should be about 1/3 of the daytime.
How to correctly collect a urine test according to Zimnitsky, read our article.
Concentration
Preparing the patient for the analysis consists of in one day exception from his diet the use of liquids in any form. Urine is collected every 4 hours. Each portion is examined using a urometer and the results obtained are analyzed.
If the specific gravity fits in the range of 1.015-1.017 g / l, this means that the patient's kidneys cannot cope with the main function and do not concentrate urine in the required volume. This state is called isostenuria.
What are the intervals for the specific gravity of urine?
During the day, the relative density of urine fluctuates and deviates from the norm within 0.001-0.005 g / l. Average values for people of various categories:
- Newborn up to 5 days - 1.008-1.018;
- From 5 days to 2 years - 1.002-1.004;
- Child 2-3 years old - 1010-1.017;
- Child 4-5 years old - 1.012-1.020;
- Child 6-17 years old - 1,011-1030;
- Adult - 1,010-1,025;
- Pregnant woman - 1.003-1.035.
Most informative there will be an analysis of night or first morning urine, since in a dream a person's breathing slows down, the intensity of sweating is reduced and the liquid does not come from the outside.
Deviation from the norm: causes and effects
High and low urine density in medical terminology is called hypersthenuria and hypostenuria, respectively.
Both conditions indicate a violation of the normal water-salt metabolism in the body and often make it possible to identify functional diseases and pathologies in the human body.
Hypersthenuria
Increased specific gravity of urine usually accompanied by quite obvious swelling. This symptom may indicate the development of glomerulonephritis or.
In addition, hyperstenuria is characteristic of various endocrinological diseases, when violation of hormonal functions reduces the level of fluid in the human body.
Causes of hypersthenuria:
- Physiological processes associated with significant loss of fluid (profuse vomiting and diarrhea, increased sweating, bleeding, large area burns, etc.).
- Injuries to the abdomen, back, intestinal obstruction.
- Toxicosis in women during pregnancy.
- Chronic diseases of the urinary system.
- Taking antibiotics in high dosage.
- Endocrine diseases with disruption of natural metabolism.
Physiological hyperstenuria does not require medical intervention. The specific gravity of urine will return to normal levels as soon as the body replenishes the fluid loss.
Symptoms of hypersthenuria:
- Decrease in the volume of excreted urine.
- urine.
- Increased odor of urine.
- Puffiness.
- Weakness, drowsiness and fatigue.
- Girdle pain in the abdomen and back.
As noted above, an increase in urine weight loss may occur due to the presence of glucose or protein in urine... If one of these components is found in the urine, additional functional studies are prescribed.
Hypostenuria
The concentration of dry residue in urine is below normal, decrease in its relative density occurs due to an increase in fluid intake or the development of pathological processes inside the body.
Hypostenuria reasons:
- - acute inflammatory process in the kidneys.
- Chronic diseases of the urinary system.
- Non-diabetes mellitus of a different nature (neurogenic, nephrogenic, during pregnancy, etc.).
- Increased fluid intake.
Symptoms of hypostenuria:
- An increase in the volume of urine excreted.
- Light color of urine.
- Pallor of the skin.
Often hypostenuria asymptomatic and deviations from the norm can only be detected by conducting a general urine test.
How to normalize urine specific gravity?
When abnormalities in the specific gravity of urine are caused by physiological reasons, then normalization occurs without medical intervention... As soon as the body replenishes the fluid loss or removes excess fluid, the relative density indicator will return to normal.
If hyperstenuria or hypostenuria are manifested against the background of diseases, then the indicators of the specific gravity of urine can be normalized only through therapeutic intervention or elimination of the pathological cause.
What is encrypted in the forms of the clinical analysis of urine, see the video: