What are the 4 Stages of Diabetic Nephropathy

Diabetic nephropathy is renal damages caused by long term high blood sugar level in the blood. In the early stage of diabetic nephropathy there are no obvious symptoms and it is often neglected and in the later stage it will cause a series of symptoms and signs such as swelling, foamy urine, poor appetite, nausea, fatigue, headache, itching, etc.

According to the symptoms and severity of kidney damages, diabetic nephropathy can be divided into 4 stages and each has different symptoms and prognosis.

Stage I

Glomerular filtration rate (GFR) increases and the kidneys are enlarged. There is also increase of blood flow, glomerular capillary perfusion pressure and internal pressure. The glomerular basement membrane and mesangial area is normal. In this stage the renal damages can be recovered with proper treatments.

Stage II

It is called period of normal albuminuria. GFR is normal or increased and UAER (urinary albumin excretion rate) is normal (less than 30mg/24h). its excretion will increase after exercises and stress and it can be recovered if the cause is removed. The glomerular basement membrane is thickened and there is increase of mesangial matrix. Blood pressure is usually normal.

Stage III

It is called early diabetic nephropathy. GFR is roughly normal and there is persistent increase of UAER. There is obvious thickening of the basement membrane and mesangial matrix and some glomeruli become necrotic. There is slight increase of blood pressure and lowering blood pressure can help reduce the excretion of albumin.

Stage IV

It is the stage of clinical diabetic nephropathy. There is large amount of albumin leakage in urine and urinary quantitative is more than 0.5g/24h. In some severe conditions, the proteinuria can be more than 3.5g/24h and patients will have symptoms of hypoalbuminemia, edema and hypertension with various degrees of nitrogen retention and diabetes fundus lesions. The thickening of basement membrane and mesangial matrix becomes even worse.

Stage V

It is the end stage renal failure. The excretion of albumin decreases. This is not due to the improve of illness condition but because most glomeruli being involved and the GFR is less than 10ml/min. Patients will have a series of symptoms as mentioned before---hypertension, edema, increase of creatinine and urea nitrogen, loss of appetite, nausea, vomiting, anemia, metabolic acidosis, low blood calcium, high potassium or even uremia neuropathy and cardiomyopathy.