Several different factors may cause scarring of kidney tissue. Kidney scarring is also known as glomerulosclerosis, which refers to the glomeruli, the clusters of miniscule blood vessels inside the kidney that filter wastes out of the blood for excretion in urine. The factors that can lead to kidney scarring include high blood pressure, diabetes, drug use, kidney infection and several diseases such as lupus, an autoimmune disorder resulting in hardening of body tissues. Whatever the cause, kidney scarring results in several effects that may require medical treatment.
Proteinuria
Kidney scarring often results in excessive amounts of protein excreted in the urine, a condition known as proteinuria. As the blood vessels in the kidneys become damaged from scarring, the walls of the blood vessels begin to leak protein from the bloodstream into the urine. The excess protein may cause urine to take on a foamy or frothy appearance. Proteinuria is one of the first signs of kidney scarring, and many tests for kidney scarring involve testing for high levels of protein in the urine.
Hypoproteinemia
As excess protein leaks from the blood into urine, protein levels in the blood can drop to low levels, which is known as hypoproteinemia. These low levels of protein can cause additional complications.
Hematuria
Another effect of kidney scarring is the presence of blood in the urine, also called hematuria. Similar to the effect of protein, as the walls of the blood vessels in the kidneys harden, red blood cells can leak into the urine. This blood in the urine may cause urine to appear pink or light brown in color. If only small numbers of red blood cells are leaking into the urine, the color may be unaffected, so the hematuria can only be detected by medical tests.
Progressive Renal Failure
Kidney scarring reduces the ability of kidneys to filter wastes out of the bloodstream, resulting in progressive renal failure. If kidney scarring is left untreated, renal failure may progress to total kidney failure, a life-threatening medical condition. If the kidneys completely fail, kidney transplant or kidney dialysis, a complicated procedure that uses a machine to filter blood, is necessary in order for a patient to survive.
Swelling
As kidney function is reduced, a common effect is fluid retention leading to swelling, also known as edema. Swelling is most common in the hands, feet and ankles at the end of the day. Swelling may also occur around the eyes, leading to puffy eyes, in the morning. Fluid may also accumulate and cause swelling in the abdomen.
High Blood Pressure
Kidney function is closely linked to blood pressure. As a result, kidney scarring may cause high blood pressure. This high blood pressure may then worsen the damage to the kidneys and increase kidney scarring.
