Causes of urea increase and decrease in blood
Last reviewed: 23.04.2024
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Reduced urea concentration in the blood does not have a special diagnostic value, it is possible after the introduction of glucose, with reduced protein catabolism, increased diuresis, after hemodialysis (eg, poisoning), fasting, liver failure.
There are three groups of causes, leading to an increase in the concentration of urea in the blood: adrenal, renal and adrenal azotemia.
- Adrenal azotemia is also called productive, as it is due to the increased formation of nitrogenous slags in the body. This type of azotemia is observed when consuming a very large amount of protein food, various inflammatory processes with marked increase in protein catabolism, dehydration as a result of vomiting, diarrhea, etc. Under these conditions, excess urea is rapidly removed from the body by the kidneys. A prolonged increase in the urea concentration in the serum above 8.3 mmol / l should be regarded as a manifestation of renal insufficiency.
- Increase in the concentration of urea in the blood most often occurs as a result of a disturbance of the excretory function of the kidneys. Renal (retentional) azotemia can cause the following forms of pathology.
- Acute and chronic glomerulonephritis; with acute glomerulonephritis, an increase in urea concentration occurs rarely and, as a rule, it is short-lived; in chronic glomerulonephritis, the urea content may fluctuate, increasing with an aggravation of the process and decreasing with its attenuation.
- Chronic pyelonephritis; the increase in urea concentration in these patients depends on the severity of nephrosclerosis and the inflammatory process in the kidneys.
- Nephrosclerosis caused by poisoning with salts of mercury, glycols, dichloroethane, other toxic substances.
- Syndrome of prolonged compression (crushing); the concentration of urea in the blood is very high, which is due to the combination of delayed excretion of urea with increased protein breakdown.
- Arterial hypertension with malignant course.
- Hydronephrosis, pronounced polycystosis, tuberculosis of the kidney.
- Amyloid or amyloid-lipoid nephrosis; the increase in urea in the blood in these patients is observed only in the late stages of the disease.
- Acute renal failure (ARF); the concentration of blood urea often reaches very high values - 133.2-149.8 mmol / l. Of great importance is the magnitude of the increase in the level of urea in patients with acute renal failure. Thus, in uncomplicated cases, the urea concentration in the blood increases by 5-10 mmol / l / day, and in the presence of infection or extensive trauma, it rises by 25 mmol / l / day.
- Adrenal azotemia refers to retentional azotemia and occurs when urinary excretion is delayed by any obstructions in the urinary tract (stone, tumor, in particular adenoma or prostate cancer).
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