Chronic renal failure can be divided into several stages.

1. Renal compensatory period: In renal compensatory period, the clearance rate of endogenous creatinine exceeds 50%, and the glomerular filtration rate decreases by about 30~60 ml per minute, and the glomerular filtration rate of healthy people is 120 liters per minute. In addition, nephrons will be reduced by 20% at this stage. Although the kidney has lost its reserve function, it can still excrete some metabolites and regulate acid-base balance and water-electrolyte balance. The patient has no special manifestations, even if he goes to the hospital for examination, the blood urea nitrogen or blood muscle enzyme is basically normal or slightly elevated.

2. azotemia stage

In azotemia stage, glomerular filtration rate will be reduced to 25ml per minute, and nephron will be reduced by about 50%. Moreover, the concentration function of the kidney will be impaired, and patients will have polyuria or nocturia. At the same time, with different degrees of anemia, patients will have azotemia, urea nitrogen and serum creatinine will increase significantly. At this stage, patients will have obvious symptoms, such as loss of appetite, general weakness and nausea, mild discomfort and so on. If there is no good protective function, or the extra burden of the kidney will cause diarrhea and vomiting, which will lead to insufficient blood volume. If drugs or infections that are toxic to the heart are used indiscriminately, renal function will decline rapidly, leading to renal failure.

3. Renal failure stage

At the stage of renal failure, glomerular filtration rate decreased by 10~ 15 ml per minute, and nephron decreased by about 70%. The kidney is seriously damaged, which can't maintain the normal balance of water, electrolyte and acid-base, and can't excrete metabolic wastes in the body, which will destroy the internal environment, increase urea nitrogen and serum creatinine, and hinder the concentration and dilution function of urine. Patients will suffer from water and sodium retention, acidosis or hyperkalemia, hyperphosphatemia and liver dysfunction, accompanied by anemia and gastrointestinal symptoms, such as loss of appetite, nausea and vomiting, and some patients will suffer from neuropsychiatric symptoms such as general weakness, listlessness and inattention.

4. Uremic stage: In uremic stage, glomerular filtration rate drops below 10ml per minute, and nephron decreases by more than 90%, so the physical symptoms of patients become extremely obvious, such as nausea and vomiting, inexplicable irritability, inability to lie flat on the bed, anemia, dyspnea, palpitation and convulsion in severe cases, and coma in severe cases. At present, only dialysis can sustain life, and patients may die of brain edema or renal failure.

Extended data:

Etiology of chronic renal failure by stages;

The main causes of chronic renal failure are primary glomerulonephritis, chronic pyelonephritis, hypertensive renal arteriosclerosis, diabetic nephropathy, secondary glomerulonephritis, tubulointerstitial lesions, hereditary renal diseases, long-term use of antipyretic and analgesic drugs and exposure to heavy metals.

Chronic renal failure (CRF) is not an independent disease. It is caused by various reasons and gradually deteriorates. When the end-stage renal function is close to normal 10% ~ 15%, a series of clinical comprehensive symptoms appear.

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