What is the reason for high creatinine urea nitrogen?

The level of blood urea nitrogen (BUN) is an important indicator of changes in renal function. Patients with kidney disease often have high creatinine. If a normal person is tested positive for high creatinine and urea nitrogen, further examination should be done to see if there is any problem with the kidneys. So, what is the reason for high urea nitrogen?

1. Normal value of urea nitrogen:

The normal fasting urea nitrogen of adults is 3.2-7.1 mmol/L (9-20 mg/d1). Once it exceeds this range, our urea nitrogen is too high.

2. Reasons for high urea nitrogen:

Pathological factors

High urea nitrogen indicates kidney damage or renal dysfunction. Clinically, high urea nitrogen can be seen in the following three situations:

1. High renal level is seen in renal dysfunction caused by acute nephritis, chronic nephritis, toxic nephritis, severe pyelonephritis, renal tuberculosis, renal vascular sclerosis, congenital polycystic kidney and renal tumors. It is especially valuable for the diagnosis of uremia. The degree of increase is proportional to the severity of the disease. For example, BUN exceeds 9mmol/L in the azotemia stage and may exceed 20mmol/L in the uremia stage, which helps to estimate the condition.

2. Prerenal hyperactivity is seen in congestive heart failure, severe burns, shock, massive gastrointestinal bleeding, dehydration, severe infection, diabetic acidosis, adrenal cortex insufficiency, hepatorenal syndrome, etc.

3. Postrenal high level is seen when urinary tract obstruction increases renal tissue pressure and reduces glomerular filtration pressure, such as prostate hypertrophy, urethral obstruction caused by tumor compression, or bilateral ureteral stones.

4. Blood urea nitrogen is easily affected by urine volume and nitrogen load. Upper gastrointestinal bleeding, certain serious liver diseases, severe infections, the use of corticosteroids and excessive protein in the diet may cause a temporary increase in blood urea nitrogen.

5. In the early stages of renal insufficiency, blood urea nitrogen does not necessarily increase. Only when the glomerular filtration rate drops below 50% of normal will blood urea nitrogen show abnormalities.

Physiological factors

A simple increase in urea nitrogen can be caused by consuming too much protein in the diet. By changing the dietary structure and balancing the combination of protein, sugary foods and vegetables, the level can quickly return to normal.