The first period is renal reserve compensatory stage. Because kidney has a good reserve and compensatory ability, though its function was decreased in clinic, it can meet the common demand to discharge waste material and regulate water-electrolyte. In this period, there is no symptom, and the result of kidney function tests is in the normal range or a little higher.
The second is renal insufficiency stage. In this period, more glomerulus (about 65% to 70%) were damaged. And the kidney has some obstacles in discharging waste material. Creatinine urea nitrogen can be higher or beyond the normal standard. Patients may have anemia, lassitude, weight losing, absent mindedness. But these symptoms are usually neglected. Once patient has dehydration, infection, haemorrhage or other situations, it will show obvious symptoms quickly.
The third period is renal failure stage. In this period, the kidney function is damaged seriously (about 75% to 95%), and it cannot maintain the body's internal environment stable. And their symptoms like fatiguability, lacking instrength, attention-deficit disorder are exacerbated. Their anemia are more obvious, and nocturnal enuresis becomes more. Their serum creatinine and urea nitrogen rose sharply, which is usually together with acidosis. So this period is also called azotemia stage.
The fourth period is uremia period or renal insufficiency end-stage. At this time, glomeruluses were damage more than 95%. There are obvious symptoms like intense nausea and vomit, oliguria, dropsy, malignant hypertension, serious anemia, cutaneous pruritus, urine flavor in mouth.
