Organic proteinuria

Organic proteinuria is associated with nephron damage. Distinguish between selective and non-selective proteinuria.

•In selective selective proteinuria, proteins of no more than 100 kD pass through the glomerular basement membrane, mainly albumin.

•Non-selective proteinuria is accompanied by a loss of protein of different molecular weights, and all plasma proteins are found in the urine.

Prerenal proteinuria

The prerenal mechanism of the appearance of protein in the urine is associated with the accumulation of low molecular weight proteins in the bloodstream: Bens-Jones protein, light chains of immunoglobulins in myeloma, the breakdown products of hemoglobin during transfusion of incompatible blood, and in case of severe muscle tissue injuries – myoglobin.

Renal proteinuria may result from damage to the glomerulus or tubule, or both the tubule and glomerulus, and mixed glomerular tubular proteinuria is more common.

•Glomerular proteinuria is associated with a decrease in the negative charge of the basement membrane, as well as due to damage to the basement membrane by immune complexes (with glomerulonephritis, amyloidosis, diabetic glomerulosclerosis, renal vein thrombosis, myeloma, congestive kidney, hypertension).

•Tubular proteinuria is caused by disruption of the protein reabsorption processes in the proximal region or due to increased secretion of the Tamm-Horsfall glycoprotein (hyaline) (with hereditary or acquired tubular lesion, with acute tubular necrosis, interstitial GN, congenital and acquired tubulopathies,).

•Mixed proteinuria often occurs with severe nephropathy.

Postrenal proteinuria is associated with an infection of the urinary tract, with neoplasms of the bladder, bladder polyposis, with bleeding in the urinary system, with local excretion of immunoglobulins.