By Dr Ananya Mandal, MD
Diabetic nephropathy describes the damage caused to kidneys due to diabetes mellitus. If left untreated, the condition may eventually result in severe renal disease and renal failure. In the early stages of diabetic nephropathy when the urine levels of albumin are raised, the use of blood pressure medications such as ACE inhibitors can reduce the leakage of protein into urine. In more advanced stages, treatment approaches include blood sugar and blood pressure control along with the correction of other factors that raise the risk of heart disease such as high blood cholesterol.
An outline of treatment for diabetic nephropathy is given below:
Screening for diabetic nephropathy
In the early stages of diabetic nephropathy, individuals may be free of symptom as these tend to only manifest in the later stages of disease when the kidneys are already damaged. Since diabetic nephropathy is fairly common among long-standing diabetic patients, regular screening of these patients for diabetic nephropathy is important. Routine kidney function tests such as urine albumin and blood creatinine assessment are performed to check for the condition while it is still in the early stages. Beginning treatment early prevents or slows down the progression of kidney disease in most diabetics.
Blood sugar control
The basic cause of kidney damage in diabetics is the uncontrolled high blood sugar. Tight blood sugar control using insulin or other antidiabetic medications along with a restricted diet can help prevent or slow the progression of diabetic renal disease.
Blood pressure control
Strict blood pressure control can help protect diabetic individuals against kidney disease, heart disease and other complications of diabetes. Evidence suggests that each 10 mm Hg reduction in systolic blood pressure is associated with a 12% decrease in the risk of developing complications of diabetes such as nephropathy. Ideally, the systolic blood pressure should be maintained below 120 mmHg and diastolic blood pressure below 80 mmHg.
The renin-angiotensin-aldosterone system
A regulatory hormone system called the renin-angiotensin-aldosterone system controls blood pressure and balances the body's fluid content. When blood volume is low, the kidneys secrete renin which converts angiotensinogen into angiotensin I. Angiotensin I is then converted to angiotensin II, a potent vaso-active peptide that stimulates vessel constriction to raise blood pressure.
Angiotensin 2 also triggers the release of aldosterone which causes the kidneys to reabsorb sodium and water in the blood, therefore increasing the volume of bodily fluid and raising blood pressure. The conversion of angiotensin I to angiotensin II is mediated by the angiotensin converting enzyme (ACE). ACE inhibitors such as nalapril and captopril inhibit this conversion and help to maintain a lower blood pressure. The agents can also decrease the risk of kidney damage in individuals with diabetes.
Reviewed by Sally Robertson, BSc