Acute renal failure is secondary to shock, trauma, severe infection, hemolysis and poisoning and other causes of acute renal parenchymal damage in general, it is a syndrome. Its main pathological changes are tubular necrosis, clinical oliguria or urine closed, accompanied by severe water, electrolytes and metabolic disorders and uremia in vivo. In recent years there is another acute renal failure with normal or more urine output, which is characterized by normal urine or more, but the increase in azotemia and uremia day by day, known as non-oliguric acute renal function Failure.
Acute renal failure (acuterenalfailure, ARF) referred to as acute renal failure, is a clinical critically ill. The disease is an acute renal damage caused by a variety of reasons, in a few hours to several days to make a significant decline in renal function adjustment function, so that can not maintain body fluid electrolyte balance and excretion of metabolites, and lead to hyperkalemia, metabolic acid Poisoning and acute uremic syndrome, this syndrome clinical called acute renal failure. Acute renal failure in the narrow sense refers to acute tubular necrosis. Generalized ARF according to the cause can be pided into three kinds: prerenal, renal posterior, renal parenchymal acute renal failure. ). According to clinical manifestations ARF can be pided into oliguria and non-oliguric type and high decomposition type. Inpatients with acute renal failure incidence of about 5%, so far the mortality rate is still as high as 50%.
【Causes of acute renal failure 】
Acute renal failure is caused a lot of reasons, according to the cause of acute renal failure is pided into the following five clinical types.
(A) shock type acute renal failure: a variety of causes of shock can lead to acute renal failure. Common causes of bleeding, water and electrolyte imbalance, heart failure and so on.
(B) the infection type of acute renal failure: bacteria, viruses, fungal infection can be complicated by acute renal failure. Predilection acute renal failure virus infection is mainly viral pneumonia, encephalitis, hepatitis and epidemic hemorrhagic fever. Bacterial infections, especially Gram-negative infections, are likely to cause acute renal failure.
(C) Extensive acute renal failure: is caused by severe crush injury. Its pathogenic factors and clinical process is extremely complex. It is a common and important type of clinic.
(D) hemolytic acute renal failure: blood group does not match the blood transfusion, a large number of lost old blood, mechanical hemolysis can be complicated by acute renal failure. The main pathogenesis is diffuse intravascular coagulation.
(E) poisoning acute renal failure: acute renal failure caused by a lot of toxic species, can be summarized into the following four categories: ① heavy metal compounds such as mercury. ② organic compounds such as DDT, dichlorvos and so on. ③ biological poison such as snake venom and mushroom and so on. ④ nephrotoxic drugs such as nephrotoxic antibiotics.
Acute renal failure, renal microcirculation, renal ischemia and disseminated intravascular coagulation is the three central links of the process. As follows:
(A) renal microcirculation disorder
1. The role of catecholamines in the pathogenesis: Some people in the rescue of epidemic cerebrospinal meningitis, bacterial pneumonia, toxic dysentery and drug allergy shock process, observed in the fundus microvascular spasm and intrauterine children's amine value increased. Therefore, the microcirculation disorder causes functional oliguria to be achieved by catecholamines which is positive.
Acute renal failure
2. Feritin, the effect of Renin-angiotensin system in the pathogenesis: renal ischemia or toxins can cause renal tubular injury, the proximal renal tubular sodium reabsorption decreased, dense spot sodium concentration increased, causing kidney release and blood vessels Increased angiotensin Ⅱ, so that glomerular anterior artery contraction, decreased renal blood flow, glomerular filtration rate decreased, causing acute renal failure.
Acute renal failure
(2) renal ischemia
1. Renal ischemia caused by renal vasoconstriction: normal kidney blood supply is very rich, kidney blood flow accounted for 20% to 25% of the output. Shock caused by a variety of reasons, the body in order to ensure that the heart, brain and other vital organs of the blood supply, peripheral arteries, including renal artery line contraction, and thus reduced renal blood flow and renal ischemia.
2. Kidney ischemia caused by short circuiting: kidney blood circulation has two circular pathways. One by the renal artery, arcuate artery, interlobular artery, into the ball artery, and then pooled to nourish the renal artery, and then into the renal vein system. The other is the blood flow into the interlobular artery after the ball into the straight vessel without direct into the venous system short circuit cycle. Under normal circumstances 90% of the blood through the first cycle, only 10% of the blood through the short circuit. When the body by a variety of strong irritation, such as trauma, shock, infection, the body to renal vasoconstriction as the body's protective measures, so that the renal blood circulation abnormal short circuit phenomenon that more than 90% of the blood by short circuit, leading to renal cortex and renal tubular blood supply greatly reduced, causing acute renal failure.
(3) the effect of diffuse intravascular coagulation in the pathogenesis
Decreased blood pressure while shock caused by various reasons , tissue blood flow reduction, slow blood flow within the capillaries, cell hypoxia, the release of thromboplastin and lactic acid accumulation, the blood was hypercoagulable state, with trauma, bacteria and other biological toxins , acidosis, hypoxia and other vascular endothelial cell damage caused by the accumulation of platelets and red blood cells and destruction, the release of coagulation substances, activation of coagulation system, resulting in microvascular blood clotting and thrombosis. Renal microvascular coagulation and thrombosis will inevitably increase the renal ischemia and eventually lead to acute renal failure.
Surgery, trauma, shock, bleeding and other causes based on the occurrence of oliguria and anuria is the clue of diagnosis of acute renal failure. If the urine output per hour less than 17 ml or 24 hours less than 400 ml of urine; or hypotension by anti-shock treatment, make up blood volume of 3 hours or more, urine output is still 17 ml per hour, or even 24 hours Urine less than 100 ml, can be considered acute renal failure, should be further examination, to identify and confirm the diagnosis.
(A) the beginning of the period
1. Blood deficiency diagnosis: ① blood loss, shock, dehydration and other medical history. ② low blood pressure or normal, pulse pressure is small, pulse faster. ③ less urine, but the proportion of more than 1.020, normal urine routine examination. ④ central venous pressure less than 6 cm water column. ⑤ after the liquid supplement test increased urine output.
2. Diagnosis of renal vasospasm: ① to correct the lack of blood volume, dehydration and shock signs disappeared, but still less urine. ② urine specific gravity of 1.020 or more, normal urine routine, or the emergence of a small number of glass-like and fine-tube type. ③ No response to liquid replenishment test. ④ intravenous infusion of diuretic mixture, due to the lifting of renal vasospasm, urine output can be increased. The composition of the diuretic mixture is as follows:
Procaine 1 gram
Aminophylline 0.25-0.5 g
Sodium benzoate caffeine 0.25-0.5 g
Vitamin C 1-3 grams
Papaverine 30 mg
10% to 25% glucose 200-500 ml
First, urine examination: urine less urine ≤ 17ml / h or <400ml / d, urine specific gravity is low, <1.014 or even fixed at 1.010 or so, urine is acidic, urine protein qualitative + ~ +++.
Second, azotemia: blood urea nitrogen and creatinine increased.
Third, blood tests: red blood cells and hemoglobin are decreased, white blood cells increased, thrombocytopenia. Blood potassium, magnesium, phosphorus increased, normal or slightly lower serum sodium, decreased serum calcium, carbon dioxide binding capacity is also reduced.
Four, urinary sodium quantitative> 30mmol / L.
5, pure water clearance rate determination: this method is helpful for early diagnosis.
(A) the beginning of the treatment
1. Etiology of treatment: the cause of acute renal failure due to numerous, it can only choose to explain.
(1) active prevention and treatment of shock, to correct the lack of blood capacity: a variety of causes of shock should take all measures to add blood volume as soon as possible, so that blood pressure rise to ensure kidney blood flow. In the anti-shock treatment process, the use of antihypertensive drugs must pay more attention to those who cause strong renal vasoconstrictive drugs, especially norepinephrine, should be avoided.
(2) hemolytic acute renal failure should take the following measures: ① intravenous infusion of sodium bicarbonate solution to alkalize the urine, to prevent methemoglobin blocking the renal tubular and correct metabolic acidosis. ② intravenous mannitol to penetrate diuretic. ③ application of hydrocortisone to alleviate the antigen-antibody reaction, reduce hemolytic symptoms, increase renal blood flow. ④ If necessary, consider transfusion therapy.
(3) drug poisoning should be promptly excluded from the gastrointestinal tract, and use antagonists. Such as oral activated carbon, milk, protein water and dimercapto propanol.
2. Elimination of renal vasospasm, improve renal blood circulation
(1) 654-2 application: 654-2 can relieve microvascular spasm, while anti-platelet aggregation, contribute to the improvement of microcirculation, so high-dose application of 654-2 on the prevention and treatment of acute renal failure has a significant role.
(2) the application of vascular dilatation: such as aminophylline, opium poppy, procaine, sodium benzoate caffeine, phenoxybenzene, phentolamine and so on.
3. Diuretics applications: a permeable diuretics such as mannitol and sorbitol. Strong diuretics beneficial uric acid and furosemide.
(B) the treatment of oliguria
1. Diet control: Give high carbohydrate low protein diet. Requiring protein intake to be low, 0.3 to 0.4 grams per kilogram per day, the intake of protein quality is high, with the necessary amino acids, and must supply enough heat 1000 ~ 2000 calorie / day.
2. Liquid control: the amount of liquid should grasp the "rather slightly less than the number of" principle. The daily highs can be calculated according to the following methods:
(1) Daily requirements equal to explicit water loss plus non-dominant water loss minus endogenous water. The average adult water content of 400 ml, non-dominant water loss of 800 ml, so the actual application can use 400 milliliters as the base plus the previous day's urine output and other discharge.
(2) by weight: If the daily weight loss of 0.2 to 0.5 kg, no significant changes in serum sodium, indicating that appropriate rehydration.
3. Correct electrolyte imbalance: hyperkalemia prevention and treatment: this period of patients prone to hyperkalemia, often no obvious symptoms at early stage, severe sudden death, it should be closely observed, active prevention and treatment.
(1) calcium application: calcium can not make potassium decreased, but can be against the inhibition of potassium ions on the heart to strengthen the role of myocardial contraction. Can be 10% calcium gluconate 50 to 100 ml or 5% calcium chloride 50 ml fraction intravenous or intravenous infusion. Note that the amount of use is not too much, pay attention to the speed not too fast.
(2) sodium solution application: sodium is potassium antagonist. General application of sodium lactate or sodium bicarbonate solution, because in addition to its role against potassium ions, but also to correct metabolic acidosis, is conducive to the treatment of hyperkalemia.
(3) the application of hypertonic glucose and insulin: the use of hypertonic glucose and insulin can be extracellular potassium ions into the cell to reduce hyperkalemia. The general ratio is 3 units of glucose plus 1 unit of insulin.
(4) sodium type / Sulfonated polystyrene resin enema: per gram of resin can exchange 3 milliequivalents of potassium. With 20 to 60 grams of resin added to 150 to 400 ml of water to retain enema can be potassium 60 to 180 milliequivalents.
(5) dialysis therapy
Treatment of hyponatremia is mainly to limit the water, generally not treated.
Hypocalcemia caused convulsions should take calcium supplementation. Generally available 10% sour calcium calcium intravenous injection.
Hypermagnesemia symptoms can take magnesium antagonist calcium treatment.
Metabolic acidosis is very harmful, should be corrected if serious. General application of sodium bicarbonate solution or sodium lactate solution.
4. Prevention and treatment of azotemia and uremia
(1) supply enough calories: more than 2000 calories a day, of which glucose should be more than 150 grams. Control the intake of protein.
(2) the use of drugs to promote protein metabolism: such as testosterone propionate and phenylpropionate dragon and so on.
(3) Chinese medicine enema: 30 grams of raw Guizhi, rhubarb 30 grams, 3
Acute renal failure prevention is mainly to actively prevent the primary disease, to avoid and eliminate the predisposing factors is the fundamental prevention. Therefore, pay attention to the following three points:
First, the regulation of five internal organs: normal living, diet, pay attention to health, to avoid the invasion of exogenous pathogens, especially in the epidemic season and the region should strengthen the precautionary measures; don’t eat food which is spicy, so as not to produce hot and humid; maintain a happy spirit, so that blood and avoid the qi stagnation; strengthen physical exercise, improve the body defense ability.
Second, to prevent poisoning: the data show that 20% to 50% of acute renal failure is caused by drugs, and some caused by exposure to harmful substances. Therefore, try to avoid the use and exposure to drugs or toxic substances that are toxic to the kidneys. If accidentally taken or exposed to timely detection and early treatment.
Third, the prevention and treatment in a timely manner: once induced acute renal failure occurred in the primary disease, should be treated early, pay attention to expand blood volume, correct water and electrolyte imbalance and acid-base imbalance, recovery cycle function. If the disease is to occur, should take early measures to add blood volume, increase cardiac output, restore renal perfusion and glomerular filtration rate, excluding renal tubular obstruction, prevention and treatment, to prevent DIC, renal ischemia causing damage to the renal parenchyma. At the same time take the application of blood circulation drugs, the prevention of the disease have a positive effect.
5. Control of infection: acute renal failure generally without sulfa drugs. Antibiotics like the tetracycline family, streptomycin, kanamycin, polymyxin and so on are excreted from the kidneys, can lead to accumulation of poison in the short term, should try not to use. Generally use ampicillin, carbenicillin, chloramphenicol, erythromycin, penicillin and so on.
6. Other treatments
(1) physical therapy: kidney area hot compress
(2) closed therapy: perineal capsule fat capsule closed therapy
(3) coenzyme A and adenosine triphosphate application to promote renal repair and recovery function have a certain effect.
(C) the treatment of polyuria
When the 24-hour urine output is more than 400 ml means that enter the polyuria, indicates the renal parenchyma began to repair. Polyuria is pided into two stages, that is, from 24 hours urine output more than 400 ml to non-protein nitrogen began to decline to polyuria early. This period due to poor recovery of renal function, the discharge of solute less water back to the absorption is also less, so the blood chemistry changes not only did not improve, and sometimes the concentration of non-protein nitrogen increased, so the treatment and oliguria is basically the same The Then from the non-protein nitrogen began to drop to the normal value for the late polyuria. This stage of patients began to gradually improve the situation, increased appetite, but because of the large loss of water and electrolytes, if not added in time will bring a series of complications. So, the treatment of this stage mainly includes:
1. maintain the balance of water: patients in the oliguria stage mostly in the state of different degree of too much water, so with the arrival of polyuria, make the patients’ excessive excess of water to achieve a new balance. Liquid supplement should be 1/3 ~ 2/3 of the amount of urine can be, if the amount of urine supplement, will extend the polyuria.
2. Maintain the electrolyte balance: With the discharge of water, there must be a large number of electrolyte loss, it must be added in time. Generally every liter of urine need to replenish 500 ml of saline, 24 hours urine output more than 1500 ml should be added when appropriate potassium salt.
3. Prevention and treatment of infection: this stage of patients are often very weak, very low resistance, prone to infection, must be actively to control.
4. Strengthen the nutrition: gradually increase the intake of high-quality protein, anemia can be a serious blood transfusion.
(D) the treatment of rehabilitation
Because of the negative balance of protein is very serious after acute renal failure, so this stage the main treatment is to actively add nutrition, given high protein, high sugar, high vitamin diet. In addition, we should gradually increase the amount of activity to promote the recovery of various organs of the body. The recovery of renal function often takes more than a year.
|item||Acute renal failure||dehydration|
|1.history||shock, poisoning, trauma, surgery||loss of body fluids，inadequate intake of fluids|
|2.specific gravity of urine||low fixed at 1.010||above and below 1.020|
protein +, red blood cell and granule tube type
|4.urinary sodium||higher than 40 milli / liter, at least no less than 30 g / liter||more than 15 milli g / liter|
|5.hematocrit||normal or decreased||rise|
|6.plasma protein||normal or decreased||rise|
|8.blood potassium||rise faster||slightly rise or fall|
|9.the blood stasis||obviously||mild|
|10.central venous pressure||normal or high||below normal|
|11.urinary and plasma urea ratio||<5||>5|
|12. liquid supplement test||urine volume does not increase||urine volume increases|
(二) identification of anuria and acute renal failure after kidney transplantation
1. History: post renal anuria without shock, trauma, hemolysis, dehydration and other history. If the operation history, often for gynecological surgery or pelvic surgery, and acute renal failure is different. In addition to post renal anuria often happens suddenly, the 24 hour urine volume in 50 ml, or even no urine.
2.symptom: post renal anuria occurred often in before or after the onset of anuria appeared pain with unilateral or bilateral renal area, the children sometimes palpable and inferior pole of kidney, tenderness and percussion pain. If the above signs are confined to one side, after the diagnosis of renal anuria more.
3. laboratory tests and other tests: post renal anuria such as urine for inspection, the proportion of the general were normal, no urinary tube inside. If it is stone, tuberculosis, there can be red blood cell and pus cell inside the urine. Post renal anuria such as cystoscopy and ureteral intubation, while a ureteral catheter can be blocked, sometimes over the obstruction to the renal pelvis, a large number of urine derived. In acute renal failure, the catheter is not inserted into the renal pelvis, and large amounts of urine can not be derived. Post renal anuria on X-ray kub, obstructed kidney shadow can increase, sometimes can be found in the primary disease such as renal tuberculosis clues, calcification, stone positive shadow etc.. Nephrogram, post renal anuria visible excretory segments increased in obstructive renal map. Acute renal failure is characterized by abnormal parenchymal phase.
Figure 1 Identification of an isotope renal map
(三) differential diagnosis of functional acute renal failure (oliguria) and organic acute renal failure (oliguria)
1. urinary sediment examination: function of acute renal failure often appears transparent and fine particles of tube, and the organic acute renal failure is the epithelial cell type, cell degeneration and a large number of coarse granular cell type tube tube type, also can appear a lot of free renal tubular epithelial cells.
2. the ratio of urine plasma osmotic pressure: function of acute renal failure when urine osmotic pressure is normal or high (greater than 600 mOsm / L), urine, plasma osmotic pressure ratio is greater than 2:1, acute renal failure and the organic urine osmotic pressure close to the plasma osmotic pressure (300 mOsm / L), the ratio between the two less than 1:1.
3. urine sodium concentration: in functional acute renal failure, the reabsorption function of urinary sodium is not destroyed, thus sodium is retained, and the urinary sodium concentration is less than 20 milli / liter. In organic acute renal failure, sodium reabsorption decreases and urinary sodium rises by more than 40 milli g / liter.
4. urine plasma creatinine ratio: the urinary concentration function of functional acute renal failure has not been destroyed, so the ratio of urine to plasma creatinine is often greater than 40:1. Renal tubular degeneration and necrosis in organic acute renal failure. The urine concentration function is disrupted and the urine plasma creatinine ratio is often less than 10:1.
5. blood urea nitrogen creatinine ratio: function of acute renal failure in the renal tubules velocity decreased and urea on the filtration of renal tubular reabsorption increased, while creatinine excretion remains constant, therefore, blood urea nitrogen, creatinine ratio greater than 20:1. In organic acute renal failure, the ratio is often 10:1.
6. hour excretion test: phenolsulfonphthalein test by conventional methods, but only one hour to collect urine samples, the error with saline rinse bladder to reduce residual urine caused by. The excretion of phenol red secretion need adequate renal blood flow and renal tubular excretion, so very often said organic acute renal failure, such as phenol red excretion in more than 5%, there may be a function of acute renal failure, renal tubular function is not fully damaged.
Table two diagnostic criteria of functional and organic acute renal failure
|functional||Part of organic||fully organic|
|1.urine plasma osmotic pressure ratio||>2：1||1.9：1～1.1:1||<1.1:1|
|2.urinary sodium concentration||<20equivalent / liter||20～40 milli g / L||>40 milli g / L|
|3.creatinine ratio of urine to plasma||>40：1||40：1～10：1||<10：1|
|4.blood urea nitrogen creatinine ratio||>20:1||40: 1～10：1||<10：1|
5.one hour phenolsulfonphthalein excretion rate trace