What is diabetic nephropathy?
Diabetic nephropathy is a type of progressive kidney disease that may occur in people who have diabetes. It affects people with type 1 and type 2 diabetes, and risk increases with the duration of the disease and other risk factors like high blood pressure and a family history of kidney disease.
Over 40 percent of cases of kidney failure are caused by diabetes, and it’s estimated that approximately 180,000 people are living with kidney failure caused by complications of diabetes. Diabetes is also the most common cause of end-stage renal disease (ESRD). ESRD is the fifth and final stage of diabetic nephropathy.
Diabetic nephropathy progresses slowly. With early treatment, you can slow or even stop the progression of the disease. Not everyone who develops diabetic nephropathy will progress to kidney failure or ESRD, and having diabetes does not mean you will develop diabetic nephropathy.
What are the symptoms of diabetic nephropathy?
The early stages of kidney damage often do not cause noticeable symptoms. You may not experience any symptoms until you are in the late stages of chronic kidney disease.
Symptoms of ESRD may include:
- general overall unwell feeling
- loss of appetite
- itchy and dry skin
- nausea or vomiting
- swelling of your arms and legs
What causes diabetic nephropathy?
Each of your kidneys has about one million nephrons. Nephrons are small structures that filter waste from your blood. Diabetes can cause the nephrons to thicken and scar, which make them less able to filter waste and remove fluid from the body. This causes them to leak a type of protein called albumin into your urine. Albumin can be measured to help diagnose and determine the progression of diabetic nephropathy.
The exact reason this occurs in people with diabetes is unknown, but high blood sugar levels and high blood pressure are thought to contribute to diabetic nephropathy. Persistently high blood sugar or blood pressure levels are two things that can damage your kidneys, making them unable to filter waste and remove water from your body.
Other factors have been shown to increase your risk of getting diabetic nephropathy, such as:
- being African-American, Hispanic, or American Indian
- having a family history of kidney disease
- developing type 1 diabetes before you are 20 years of age
- being overweight or obese
- having other diabetes complications, such as eye disease or nerve damage
How is diabetic nephropathy diagnosed?
If you have diabetes, your doctor will mostly likely perform yearly blood and urine tests on you to check for early signs of kidney damage. That is because diabetes is a risk factor for kidney damage. Common tests include:
Microalbuminuria urine test
A microalbuminuria urine test checks for albumin in your urine. Normal urine does not contain albumin, so the presence of the protein in your urine is a sign of kidney damage.
BUN blood test
A BUN blood test checks for the presence of urea nitrogen in your blood. Urea nitrogen forms when protein is broken down. Higher than normal levels of urea nitrogen in your blood may be a sign of kidney failure
Serum creatinine blood test
A serum creatinine blood test measures creatinine levels in your blood. Your kidneys remove creatinine from your body by sending creatinine to the bladder, where it is released with urine. If your kidneys are damaged, they cannot remove the creatinine properly from your blood.
High creatinine levels in your blood may mean that your kidneys are not functioning correctly. Your doctor will use your creatinine level to estimate your glomerular filtration rate (eGFR), which helps to determine how well your kidneys are working.
If your doctor suspects that you have diabetic nephropathy, they may order a kidney biopsy. A kidney biopsy is a surgical procedure in which a small sample of one or both of your kidneys is removed, so it can be viewed under a microscope.