Elderly acute renal failure

　　Acute renal failure (ARF) can occur in the process of various diseases, with diverse etiologies, which are usually divided into three major categories: acute renal failure due to acute decrease in renal blood flow (prerenal ARF), various renal diseases (intrinsic ARF), and urinary tract obstruction (postrenal ARF). The most common type of ARF in clinical practice is acute tubular necrosis (ATN) caused by renal ischemia and/or nephrotoxic damage. Sometimes, different types may coexist. Common drugs that can cause nephrotoxic ATN include...

　　This disease often complicates hypertension, anemia, heart failure, pericarditis, cardiomyopathy, electrolyte and acid-base imbalance, renal osteopathy, fractures, infection, and so on. In addition to the above systemic complications, chronic renal failure patients with long-term dialysis may also have the following complications:

　　1. Aluminum poisoning

　　End-stage renal disease patients undergoing routine dialysis treatment are prone to develop aluminum poisoning.

　　2. Dialysis-related amyloidosis

　　Dialysis-related amyloidosis (DRA) is a bone and joint disease seen in long-term dialysis patients, and its clinical symptoms and incidence are closely related to the duration of dialysis.

　　The initial symptoms of acute renal failure patients are related to their etiology. Most patients have an acute onset, and may be accompanied by varying degrees of uremic manifestations, including early onset of decreased appetite, nausea and vomiting, abdominal distension, diarrhea, or upper gastrointestinal bleeding in the digestive system. Severe cases are often accompanied by hypertension, heart failure, and arrhythmia, and even can appear drowsiness, somnolence, or consciousness disorders. Some patients may also develop anemia due to trauma, hemorrhage, hemolysis, or severe infection.

　　It is still not possible to confidently prevent the occurrence of acute renal failure, but taking preventive measures in susceptible populations may be of great significance in preventing its occurrence. The main measures include: actively controlling the primary disease or pathogenic factors (such as ischemia, trauma, and infection), rationally applying various drugs and contrast agents in susceptible populations, and timely resolving vascular lesions. Close monitoring of the changes in renal function, urine volume, and urine enzymes in susceptible populations, early diagnosis of acute tubular injury, and timely treatment can help prevent the occurrence of this disease.

　　The main manifestations of elderly acute renal failure are water, electrolyte, and acid-base imbalance. This disease generally requires the following examinations for diagnosis.

　　1. Blood count examination

　　Blood count examination is used to understand the presence and severity of anemia, and combined with red blood cell morphology, reticulocytes, etc., it can assist in the differentiation and etiological diagnosis of acute and chronic renal failure.

　　2. Urine examination

　　Urine examination is extremely important for diagnosis, differential diagnosis, and clinical typing, and it requires comprehensive clinical analysis. In addition to routine checks, urine diagnostic index is often used to differentiate prerenal azotemia from ATN, with sodium excretion fraction being the most sensitive, with a positive rate as high as 98%; the positive rate of urine sodium excretion can also reach above 90%. The accuracy of these indicators may be affected by diuretics or hypertonic drugs, so detection should be performed before taking medication.

　　3. Renal function and biochemical indicators examination

　　Changes in blood creatinine, blood urea nitrogen, serum potassium, and blood HCO3 can be used to judge the severity of ARF and distinguish whether there is a hypermetabolic state. In addition, low blood sodium, low blood calcium, or increased blood phosphorus can be found, and blood gas analysis can help determine metabolic acidosis or alkalosis.

　　To help elderly patients with acute renal failure recover better, it is recommended that patients pay attention to the following dietary principles:

　　First, suitable for eating

　　1. Staple foods and beans mainly include: oatmeal, sorghum, red bean, corn flour, wheat starch, rice, millet, etc.

　　2. Meat, eggs, and milk mainly include: chicken, white duck meat, wild duck meat, perch, grass carp, crucian carp, crucian carp, black carp, toad, milk, eggs, etc.

　　3. Vegetables mainly include: mustard, lettuce, green pepper, bitter melon, cabbage, winter melon, cucumber, eggplant, bamboo shoots, chrysanthemum flower, seaweed, enoki mushroom, etc.

　　4. Fruits mainly include: persimmon, apple, tangerine, strawberry, watermelon, kiwi, grape, pineapple, water chestnut, peach, etc.

　　Second, avoid eating

　　1. Strictly control salt intake. Depending on the condition, salt should be avoided or reduced, and preserved vegetables and cured products should be avoided.

　　2. Avoid spicy and irritating foods. Foods such as pepper, chili, curry, spices, and mustard that have a stimulating effect on the kidneys should be avoided.

　　3. Avoid high-fat foods. It is not advisable to consume high-fat and high-cholesterol foods such as lard, egg yolks, and animal livers.

　　4. Avoid dietary soy protein. Do not eat soybeans, soy milk, tofu, and other foods.

　　5. Avoid eating pork head, sardines, and other foods.

　　According to the different stages of onset, different treatment methods are required for this disease. The specific treatment methods are as follows:

　　First, treatment for oliguria: Treatment for oliguria

　　The focus of this period of treatment is to regulate water, electrolyte, and acid-base balance, control azotemia, provide nutritional support, treat the primary disease, and prevent and treat complications.

　　1. Treat the primary underlying cause.

　　2. Nutritional therapy: Try to supplement nutrition through the gastrointestinal tract. In the early stage, protein intake should be strictly controlled at 0.6g/(kg·d) of high-quality protein. Moderately supplement amino acids or glucose solution to ensure that the daily caloric intake per kilogram of body weight is between 126 to 188kJ (35 to 45kcal). For patients with hypermetabolic states, strengthen nutritional support, and increase protein intake to 1.0g/(kg·d), and consider gastrointestinal, intravenous, or total parenteral nutrition administration.

　　3. Maintain water and sodium balance: Strictly calculate the 24-hour fluid intake and output. Follow the principle of 'input equal to output' when administering fluids. Patients undergoing dialysis treatment can have a slightly increased fluid intake. During oliguria, closely monitor the patient's weight, blood sodium, and central venous pressure. If the weight decreases by 0.3 to 0.5 kg per day and blood sodium and central venous pressure are normal, it can be considered that the fluid intake is appropriate; excessive fluid restriction or insufficient fluid administration may worsen renal ischemic injury, while excessive fluid administration may lead to complications such as acute pulmonary edema or brain edema.

　　4. Treatment for hyperkalemia: The most effective therapy is hemodialysis or peritoneal dialysis. Since it can be a high-risk factor for acute death, it should be given emergency treatment before dialysis is prepared.

　　5. Correction of metabolic acidosis: In general, metabolic acidosis is not severe as long as sufficient calories are provided and the diet is appropriate. In the state of high metabolism, metabolic acidosis is more severe and can worsen hyperkalemia, so it needs to be treated in a timely manner.

　　6. Active control of infection and other complications: Common complications include infections in the lungs, urinary tract, and biliary tract, etc. Antibiotics with no nephrotoxicity should be selected for treatment based on bacterial culture and drug sensitivity tests. Active treatment should be given to other complications such as upper gastrointestinal bleeding and arrhythmia.

　　7. Dialysis Therapy: Dialysis therapy is the most effective measure for rescuing acute renal failure. Early dialysis can help patients through the oliguria period, reduce complications, and mortality. It has a significant effect on correcting azotemia, hyperkalemia, pulmonary edema, brain edema, and hypertension caused by water intoxication, correcting acidosis, and improving symptoms. The indications for dialysis treatment.

　　Second, Treatment During the Polyuria Period

　　The focus of this period of treatment is still to maintain water, electrolyte, and acid-base balance, control azotemia, treat the primary disease, and prevent and treat complications. The amount of fluid supplementation is generally controlled to be less than 500 to 1000 ml less than the output, and it is as possible as possible to replenish fluids through the gastrointestinal tract. This is conducive to shortening the polyuria period. Electrolyte imbalances should be monitored and corrected in a timely manner, and bedridden patients should pay attention to the prevention and treatment of infection. For patients undergoing dialysis treatment, dialysis should continue at the beginning of the polyuria period to maintain blood urea nitrogen levels.

　　Third, Treatment During the Recovery Period

　　Generally, no special treatment is needed during the recovery period, and it should be avoided to use drugs that damage the kidneys. Renal function should be re-examined every 1 to 2 months until it is completely restored.

　　In recent years, research on the prevention and treatment of tubular injury by using drugs such as adenine nucleotides, oxygen free radical scavengers, calcium channel blockers, and endothelin receptor antagonists, and promoting cell injury repair by various growth factors has made significant progress, but its exact effects still need to be confirmed by clinical evidence-based medicine.