By Dr Ananya Mandal, MD
Diabetic nephropathy is the damage caused to kidneys due to diabetes mellitus. Usually, the condition develops after a diabetes duration of about 10 years. Around one fourth of all people who have had diabetes for more than 10 years are at risk of diabetic nephropathy.
Diabetic nephropathy is not typically characterized by symptom onset, meaning that most individuals who develop it are unaware of the condition until it has already caused considerable damage. Screening diabetic patients for kidney damage is therefore important in reducing the risk of long-term kidney damage and its associated problems.
Some of the features of diabetic kidney disease that may eventually manifest include:
Edema or swelling of the ankles, feet, lower legs or hands due to water retention.
Urine that is foamy or frothy in appearance due to excessive protein being excreted in the urine. This is most commonly seen in the first urine of the day.
Weight gain due to fluid retention and edema
Nausea and vomiting
Loss of appetite
Feeling unwell and tired
High blood pressure
Stages of development of diabetic nephropathy
During stage 1, the rate of kidney filtration is increased. The glomerular filtration rate (GFR) in the kidney is increased and the organ may increase in size. However, urine albumin levels and blood pressure may be only mildly raised or normal. At this early stage of nephropathy, there is no pathological damage and the condition is usually reversible.
During stage 2, there is structural damage of the glomeruli and microalbuminuria starts to occur. The GFR is higher than normal.
Stage 3 disease is termed early stage renal disease. The albumin excretion rate is continuously raised and may exceed 200 μg/min. Blood levels of creatinine are raised and blood pressure may also be high.
This stage of disease is termed clinical diabetic nephropathy, an irreversible stage of disease. There is a decline in GFR of 1 ml/min every month, large amounts of protein pass into the urine and blood pressure is almost always raised.
Stage 5 kidney disease is kidney failure or end stage renal disease. The GFR is less than 10 ml/min. Increases in serum creatinine and blood urea nitrogen are accompanied by severe edema, hypertension and hypoproteinemia. This stage of disease necessitates dialysis and even kidney transplant.
Reviewed by Sally Robertson, BSc