Relative density of urine is considered a rather important diagnostic index, especially in nephrology. In certain pathological conditions, the specific gravity of urine is increased or decreased.
Low density of urine - what does it mean?
Sometimes, to determine the degree of efficiency of the kidney structures, it becomes necessary to carry out specific studies such as the Zimnitsky, Nechiporenko and other tests. It is during the laboratory urine test that hypostenuria or reduced urine density is detected, which is determined by the concentration of the substances( urea and various salts present in it).
In addition, the determination of this value helps to reveal the filtration ability of the kidneys. Why is that? The point is in the mechanisms of urine formation.
Urine is formed in several stages:
- First, in the renal glomeruli, primary urine is formed. Under pressure, the blood is filtered, cleared of various toxins and other products of vital activity.
- Then the primary biomaterial through the nephron tubules is reabsorbed, and the beneficial substances from it return to the body again, while the remaining liquid containing ammonia impurities and urea, uric acid components and sulfates, chlorine and sodium forms secondary type urine. It is sent to the vesicular structures, from which it is then taken out.
Determination of the specific gravity of urine is carried out with the help of a special device - hydrometer( or meter).The development of hypostenuria is said, if in all the portions of urine in the Zimnitsky trial, the specific gravity is below 1.010.
The values of
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 is constantly changing, which depends on the drink and food consumed, on fluid loss with sweat and so on.
- 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 is normally as high as 1.012-1.020;
- Since the age of 12 this indicator is the same as in an adult, that is, 1,011-1,025.
So, the following parameters are considered normal:
| Age | Density |
|---|---|
| 1 day life | 1,008-1,018 |
| First six months of life | 1,002-1,004 |
| From 6 months to year | 1,006-1,016 |
| 1-5 years | 1,010-1,020 |
| 6-8 years | 1,012-1,020 |
| 9-12 years | 1,012-1,025 |
| Adults | 1,010-1,025 |
Causes of
A decreased urine density or hypostenuria is diagnosed if the urinary density falls 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 the water in the body is absorbed much more actively, so the urine is concentrated little. If there is no antidiuretic hormone or it is too low, then urine is formed a lot, and its specific gravity is reduced. There are a lot of reasons for reducing the specific gravity.
In pregnant women
In women in the normal position, the specific density of urine is 1.010-1.025.
Hyposthenuria in pregnant women is usually detected due to:
- Kidney pathologies;
- Hormonal disorders;
- With excessive urination;
- In case of toxicosis of pregnant women.
In children,
In newborns, the decrease in specific gravity is usually recorded immediately after birth, but soon all the parameters are normalized. On average, for the newborns of the first weeks of life, the characteristic maximum density indices are 1.016-1.018.Relative hyposthenia 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 it is said of violations in renal activity related to organ failure.
In adults,
In adults, the pathological causes of decreased urine density are caused by conditions such as:
- Chronic kidney failure;
- Diabetes of a non-sugar type( nephrogenic, central or idiopathic);
- Pyelonephritis of chronic form;
- Chronic nephritis;
- Degradation of edematous zones and infiltrates of inflammatory origin, which is usually observed during the recovery period after any inflammation;
- Degeneration of healthy renal cells into connective tissue structures, characteristic of nephrosclerosis;
- Interstitial type of jade;
- Food 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, resulting in the urine is diluted with low density;
- Involuntary polydipsia, characteristic of persons prone to various neurotic disorders and having an unstable psyche( predominantly in women);
- Plentiful drinking regimen or intake of diuretics, 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 are normalized.
In parallel with a decrease in density, patients can observe signs of kidney failure, such as:
- Hyperevelopment on the whole body;
- Chronic fatigue;
- Soreness in the abdomen and lumbar region;
- Changes in color characteristics of urine( darkening or appearance of bloody impurities);
- Reduction in total urine output.
Regardless of the reasons that provoked urine density is less than normal, the appearance of pathological signs requires a medical examination. Each of the factors in the absence of treatment can cause complications, and therefore requires compulsory treatment.