Hypertonic urine

Introduction The normal human plasma permeation rate is 280-310 mOsm/kg·H20, and the normal urine permeability/plasma infiltration ratio is (3-4.5): 1, which is also used to evaluate the concentrated dilution function of the kidney. When the urinary permeation amount is 300mOsm/kg·H20, it is called isotonic urine. Above the plasma permeation amount, the urine has been concentrated, which can be called hypertonic urine.

Cause

Pathogenesis:

The collecting tube is parallel to the medullary ridge and is in an osmotic pressure gradient. When the tubule fluid flows toward the distal end and the collecting tube through the proximal end of the distal convoluted tubule, the permeability of the two parts to water is regulated by ADH, and when the ADH increases, the permeability of the epithelial cells to the water of the tube wall Increase, because the interstitial fluid of the corresponding parts is in a hypertonic state, water infiltrates into the interstitial space from the lumen, so that the urine is gradually concentrated, forming hypertonic urine.

Found in high fever, dehydration, cardiac insufficiency, poor peripheral circulation, renal congestion and so on.

an examination

Related inspection

Urine sediment urine osmotic pressure uric acid urine sediment 12 hours count uric acid

1. In the medical history, pay attention to whether there is severe burn shock, serious infection, excessive infusion and too fast, whether there is severe inhalation injury and respiratory failure after burn, and whether or not vasoconstrictor drugs are misused.

2. Due to the complex burn condition, chest eschar, affecting the accuracy of chest examination, its symptoms are often confused with the performance of burn itself, shock and infection. For severely burned patients, especially in shock, the monitoring of the heart should be strengthened to avoid Missed or misdiagnosed.

Differential diagnosis

Identification: urinary exudation is called isotonic urine at 300mOsm/kg?H20, higher than plasma permeation means urine has been concentrated, it can be called hypertonic urine at this time; below the plasma permeation means urine has been diluted At this time, 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 pyelonephritis, polycystic kidney and other renal interstitial lesions; acute tubular necrosis, chronic nephritis combined with renal tubular lesions can reduce urine leakage.

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