Isotonic urine

Introduction Isotonic urine (reduced urinary concentration and dilution function): CRF (chronic renal failure) early renal function is reduced and the dilution function is normal. As the condition worsens, the kidney dilution function is also impeded, so that the final urinary osmotic pressure is close to plasma, and the urine specific gravity is often fixed. At 1.008-1.012, it is called isotonic urine.

Cause

Acute renal failure (ARF) causes a rapid decrease in renal urinary function in a short period of time, causing a syndrome of water, electrolytes, acid-base balance disorders and metabolic waste accumulation.

The normal human plasma permeation rate is 280-310 mosm/kg·h20, and the normal urine permeability/plasma permeability ratio is (3-4.5): 1, which is also used to evaluate the concentrated dilution function of the kidney. The urinary exudation is called isotonic urine at 300 mosm/kg·h20. The higher than the plasma osmotic amount indicates that the urine has been concentrated. At this time, it can be called hypertonic urine. Below the plasma osmosis, the urine has been diluted. The urine is called hypotonic urine.

1. After 12 hours of drinking water, the urine permeability should be greater than 850mosm/kg·h20. If it is lower than this value, the kidney concentration function is not good. Under the same conditions, the ratio of urinary permeation/plasma permeability should be greater than 3:1, and the ratio of renal enrichment and dilution function may be reduced to 1:1 or lower.

2. Chronic renal pelvis, polycystic kidney and other renal interstitial changes, acute tubular necrosis, chronic nephritis with renal tubular lesions can reduce urine leakage.

an examination

Related inspection

Urine routine renal blood flow kidney CT examination glomerular filtration fraction glomerular filtration fraction (GFF)

The osmotic pressure of urine is measured by the freezing point reduction method to reflect the concentration of solute in the urine. The osmotic pressure of isotonic urine is 250-400 mOsm/L.

1, urine color: normal urine is light yellow to yellow brown. Often affected by diet, sweating, etc. In addition, color urine such as soy sauce, red wine, dark brown, etc. can be seen. After the influence of drugs, it is recommended to go to the hospital for further examination.

2, urine volume: under normal circumstances, normal adults for a day and night (24 hours) urinary O. 8 ~ 2.0 liters. However, drinking water, exercise, sweating, and temperature can all affect urine output.

3. Specific gravity: The proportion of 24-hour urine in normal people is around 1.015, often fluctuating between 1.010 and 1.025, due to diet, exercise, sweating and so on. The random urine specific gravity fluctuates from 1.005 to 1.030.

4, transparency: fresh urine is clear and transparent without precipitation. After standing for a while, flocculation can occur, especially in female urine. When the urine is discharged, it is turbid, often caused by white blood cells, epithelial cells, mucus, microorganisms, and the like.

Differential diagnosis

Under normal circumstances, the normal urine specific gravity is passive at 1.015~1.025. When the body is dehydrated and the kidney function is normal, the specific gravity of the urine can be as high as 1.030 or more: otherwise, the specific gravity of the urine can be as low as 1.003 or less: if the specific gravity of the urine is fixed between 1.010 and 1.012, the kidney concentration function is impaired.

Isotonic urine: In chronic renal failure, due to renal dysfunction and dilution dysfunction, urine solute is close to serum concentration, urine specific gravity is fixed at 1.008 ~ 1.012, called isotonic urine. Since the molecular weights of various urinary solutes are inconsistent, the same 1 gram concentration and different solute have different effects on the specific gravity of urine. Therefore, it is preferable to measure the osmotic pressure of urine by the freezing point reduction method to reflect the concentration of solute in urine. The osmotic pressure of isotonic urine is 250-400 mOsm/L.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.