White sediment in male urine

Urine has a certain health indicator significance for the human body, which is one of the reasons why there is a urine test in clinical medicine. Many men have white precipitates in their urine, which is probably a manifestation of proteinuria. There are many reasons for proteinuria. Below, we will introduce the classification and common causes of proteinuria!

1. Physiological proteinuria

There is no organic lesion, which is common in the following two situations:

1. Functional proteinuria is transient proteinuria caused by stressful conditions such as strenuous exercise, fever, and tension. It is more common in adolescents. The urine protein in qualitative tests usually does not exceed (+).

2. Postural proteinuria is common in adolescents during puberty. Proteinuria occurs in the upright and lordotic postures and disappears in the supine position. The general protein excretion is <1g/d.

2. Glomerular proteinuria

Proteinuria is caused by damage to the glomerular filtration membrane, increased permeability, and plasma protein filtration that exceeds the reabsorption capacity of the renal tubules. The most common clinical proteinuria is often seen in primary or secondary glomerular diseases, such as acute nephritis, rapidly progressive nephritis, chronic nephritis, IgA nephropathy, nephrotic syndrome, lupus nephritis, purpuric nephritis, diabetic nephropathy, hypertensive nephropathy, tumor nephropathy, renal amyloidosis, toxic nephropathy, and kidney damage caused by infection. It is also seen in congenital nephritis, renal circulatory disorders, renal hypoxia, and accelerated renal blood flow.

3. Renal tubular proteinuria

When the structure or function of the renal tubules is damaged, the renal tubules are unable to reabsorb the normally filtered small molecular weight proteins, resulting in protein excretion in the urine, which is called tubular proteinuria. It is common in tubular-interstitial diseases caused by various reasons, such as pyelonephritis, interstitial nephritis, reflux nephropathy, uric acid nephropathy, renal tubular acidosis, heavy metal poisoning, Fanconi syndrome, hypokalemic nephropathy, renal medullary cystic changes, radiation nephritis, analgesic nephropathy, and rejection reaction after kidney transplantation.

4. Overflow proteinuria

The abnormal increase of small molecular weight proteins in the blood, such as light chain proteins, hemoglobin, and myoglobin in multiple myeloma, is filtered out from the glomeruli and exceeds the reabsorption threshold of the renal tubules, causing proteinuria. All of them can be reabsorbed by the renal tubules. Bence Jones protein is more common in multiple myeloma, but also in macroglobulinemia, heavy chain disease, light chain disease, amyloidosis, and occasionally in monocytic leukemia; hemoglobin or myoglobin is seen in a large amount of muscle tissue damage, excessive hemolysis, etc.; rejection of transplanted kidneys and diffuse intravascular coagulation. Increased FDP in urine is also overflow proteinuria.