Diabetic nephropathy can be divided into 5 stages: Stage I: Increased glomerular filtration rate, increased renal volume, increased renal blood flow, glomerular capillary perfusion pressure and internal pressure. The glomerular basement membrane and thylakoid membrane are normal. It can be recovered with appropriate treatment. Stage II: i.e. normal albuminuria stage. Glomerular filtration rate is normal or increased, urinary albumin excretion rate is normal (less than 20 micrograms/min or 30 mg/24 hours), excretion increases after exercise or stress, and returns to normal after removal of the trigger. The glomerular basement membrane is thickened and the thylakoid matrix is increased. Blood pressure is mostly normal. Stage III: Early diabetic nephropathy. Glomerular filtration rate is approximately normal, urinary albumin excretion rate is consistently higher than normal, and blood pressure is mildly elevated. The glomerular basement membrane is thickened and the thylakoid matrix is significantly increased. Glomerular nodular and diffuse lesions and small arterial vitelliform lesions are present and glomerular wasting has begun to occur. Patients in this stage have mildly elevated blood pressure, and lowering blood pressure can partially reduce urinary microalbumin excretion. Stage IV: Clinical diabetic nephropathy. Large amounts of albumin, urine protein quantification consistently greater than 0.5 grams per 24 hours for non-selective proteinuria, and in severe cases greater than 3.5 grams per 24 hours for urine protein, hypoalbuminemia, edema and hypertension, often with varying degrees of nitrogen retention and diabetic fundopathy. The glomerular basement membrane is further thickened, the thylakoid matrix is further increased, and the glomerulus is deserted. Stage V: i.e. end-stage renal failure. Urinary protein excretion is reduced due to glomerular wasting, glomerular filtration rate is less than 10 ml/min, with hypertension, hypoalbuminemia, edema, elevated blood creatinine and urea nitrogen, loss of appetite, nausea and vomiting, anemia, metabolic acidosis, hypocalcemia and hyperkalemia, and may be followed by uremic neuropathy and cardiomyopathy.