Several conditions can cause protein in your kidneys. According to the National Institute of Diabetes and Digestive and Kidney Diseases, or NIDDK, when blood passes through healthy kidneys, the kidneys filter out waste products and leave things that your body needs, such as proteins, in your blood. Most proteins are too large to pass through your kidneys' filters and into your urine. However, certain diseases, called glomerular diseases, can attack the tiny blood vessels, or glomeruli, in your kidneys, causing protein to accumulate in your kidneys and, eventually, your urine.
Membranous Nephropathy
Membranous nephropathy can cause protein to leak out of your blood and into your kidneys and urine. According to the University of Maryland Medical Center, membranous nephropathy, also known as membranous glomerulonephritis, is a kidney disorder that involves inflammation and alteration of the structures within your kidney that help filter waste and fluids. Membranous nephropathy-related inflammation leads to problems with kidney function. The most common cause of membranous nephropathy is a thickening of the glomerular basement membrane -- a portion of your kidneys that helps filter waste and excess fluid from your blood. Common signs and symptoms associated with membranous nephropathy include protein in your kidney and urine, swelling throughout your body, foamy-appearing urine, weight gain, loss of appetite, excessive urination at night, elevated blood pressure and fatigue.
IgA Nephropathy
IgA nephropathy can cause protein in your kidneys and urine. The NIDDK states IgA nephropathy, also known as Berger's disease, is a kidney disorder that develops when IgA -- a protein that helps your body ward off infections -- settles in your kidneys. Over time, the IgA deposits can cause your kidneys to leak blood and protein into your urine. IgA nephropathy can occur at any age, reports the NIDDK, even in childhood. Men are more commonly affected than women, and IgA nephropathy is more likely to occur in caucasians and Asians. Along with kidney problems caused by diabetes and elevated blood pressure, IgA nephropathy is one of the most common kidney diseases. According to MayoClinic.com, common signs and symptoms associated with IgA nephropathy include protein in your kidneys and urine, cola- or tea-colored urine, flank pain, foamy-appearing urine, swelling in your hands and feet, high blood pressure and low-grade fever.
Focal Segmental Glomerulosclerosis
Focal segmental glomerulosclerosis can cause protein to accumulate in your kidneys and urine. According to the University of North Carolina Kidney Center, focal segmental glomerulosclerosis is a relatively common type of kidney disease, especially among Americans. Although there are several risk factors that may contribute to this condition, the cause of focal segmental glomerulsclerosis in most people is unknown. Focal segmental glomerulosclerosis is scar tissue that develops in your glomeruli, or tiny blood vessels in your kidneys that filter out harmful substances. The MedlinePlus website states common signs and symptoms associated with focal segmental glomerulosclerosis include protein in your kidneys and urine, foamy-appearing urine, loss of appetite, generalized swelling of your body and weight gain. Possible risk factors associated with this condition include congenital kidney defects, obesity, obstructive sleep apnea and certain viruses, such as HIV.
References
- National Institute of Diabetes and Digestive and Kidney Diseases: Proteinuria
- University of Maryland Medical Center: Membranous Nephropathy
- National Institute of Diabetes and Digestive and Kidney Diseases: IgA Nephropathy
- Mayo Clinic: IgA Nephropathy
- University of North Carolina Kidney Center: Focal Segmental Glomerulosclerosis
- Medline Plus: Focal Segmental Glomerulosclerosis
