Neonatal acute renal failure

　　: Various pathogenic factors before, during, and after neonatal birth can cause acute renal failure. According to the nature and location of renal injury, the etiology can be divided into three major categories: pre-renal, renal, and post-renal.

　　One, pre-renal

　　: Any clinical factor that can reduce cardiac output or reduce blood volume during the neonatal period may cause decreased renal blood perfusion, leading to pre-renal renal failure. Insufficient renal blood perfusion in neonates most commonly occurs within 48 hours after birth in various pathological conditions, such as asphyxia and hypoxia, respiratory distress syndrome, heart failure, hypotension, severe dehydration, massive hemorrhage, sepsis, hypothermia, and so on.

　　Two, renal

　　Caused by renal parenchymal damage, also known as true renal failure. The main causes are as follows.

　　10, renal hypoxia: Severe asphyxia with hypoxia or prolonged duration can cause varying degrees of renal damage, mainly seen in perinatal hypoxia.

　　8, renal ischemia: Renal vascular lesions such as massive hemorrhage, thrombosis and embolism of renal arteries (or renal arterioles), stenosis, necrosis of renal cortex or medulla, renal infarction, renal vein thrombosis (severe dehydration, poor circulation, diabetic mother's baby) can all reduce renal blood flow and insufficient blood supply to renal tubules.

　　6, renal toxicity: Pathogenic factors include nephrotoxic antibiotics such as aminoglycoside antibiotics, polymyxin, amphotericin, and drugs that are prone to cause renal damage, such as indomethacin, tolazoline, and so on.

　　4, other renal diseases: Congenital renal developmental abnormalities, such as bilateral renal agenesis, bilateral renal cystic disease, neonatal polycystic kidney disease, congenital syphilis, toxoplasmosis, congenital nephrotic syndrome, and pyelonephritis, and so on.

　　Three, posterior renal

　　Posterior renal renal failure is mainly caused by urinary tract obstruction, which can be seen in various congenital urinary tract malformations, such as posterior urethral valves, urethral diverticula, phimosis, urethral stricture, ureteral hernia, neurogenic bladder, and so on. It can also occur due to urethral stricture caused by extrarenal tumors compressing the urethra or iatrogenic surgical catheterization injury.

　　Neonatal acute renal failure often complicates with hyperkalemia, hyponatremia, hypocalcemia, hyperphosphatemia, metabolic acidosis, hypertension, heart failure, pulmonary edema, and arrhythmia, etc.

　　The clinical manifestations of this disease mainly include the following aspects:

　　1. Non-specific symptoms

　　Children may have symptoms such as anorexia, vomiting, pallor, and weak pulse.

　　2. Main symptoms

　　Children may have oliguria or anuria. Excessive fluid administration (edema, weight gain) can lead to hypertension, heart failure, pulmonary edema, cerebral edema, and convulsions.

　　3. Signs

　　Children may experience edema, ascites, and other symptoms.

　　In terms of prevention, it is first necessary to maintain fluid volume balance, provide expansion therapy to correct hypovolemia, and treat cardiac insufficiency to maintain renal perfusion blood volume. Infection shock is also one of the main causes of renal failure, so it is necessary to actively control infection and take various measures to maintain blood pressure stability. For children with pre-existing renal damage, it is necessary to use contrast agents and other nephrotoxic drugs with caution. It is currently believed that actively treating the primary disease, maintaining volume balance (expansion when necessary), and stabilizing blood pressure are still the most important measures to prevent renal failure.

　　In the diagnosis of neonatal acute renal failure, in addition to relying on clinical manifestations, chemical tests are also needed. The main examination methods for this disease are as follows:

　　1. Urine examination

　　Neonatal urine

　　2. Blood biochemistry tests

　　Blood biochemistry tests show increased levels of potassium, magnesium, and phosphorus, while sodium, calcium, and chloride levels decrease, and the carbon dioxide combining power decreases.

　　3. Renal ultrasound examination

　　Renal ultrasound examination can accurately describe the size, shape, hydronephrosis, calcification, and changes in the bladder, and this examination should be performed for those suspected of having renal vein thrombosis or unexplained progressive azotemia.

　　4. Radionuclide renal scanning

　　Radionuclide scanning can understand the renal blood perfusion situation and make comparative judgments on glomerular filtration rate.

　　5. CT and MRI

　　CT and magnetic resonance imaging are helpful in determining posterior urethral obstruction.

　　In terms of diet, attention should be paid to the following three aspects in children with the disease:

　　1. Caloric intake

　　Children with the disease should choose sugar as the main source of calories, and an appropriate amount of fat and minerals should be provided.

　　2. Protein

　　High-quality protein should be selected, and the amount should be adjusted appropriately during the treatment process according to the condition of renal function. In the case of acute renal insufficiency, it generally should not exceed 30g per day.

　　3. Electrolytes and vitamins

　　The intake of sodium should be determined according to the kidney's ability to retain and excrete sodium, as well as the presence of hypertension, cardiac insufficiency, edema, and other conditions, and an increase in vitamin intake should be considered.

　　The treatment methods for this disease mainly include the following.

　　Chapter 1: Early Prevention and Treatment

　　The focus of early prevention and treatment is to remove the cause and treat symptoms. For example, correct hypoxemia, shock, hypothermia, and prevent infection, etc. Renal pre-renal renal failure should be supplemented with volume and improved renal perfusion. Renal post-renal renal failure should focus on relieving obstruction.

　　Chapter 2: Treatment During the Oliguric or Anuric Phase

　　1. Correction of Electrolyte Imbalance

　　(1) Hyperkalemia: All sources of potassium intake should be discontinued. If there are no changes in the electrocardiogram, mild hyperkalemia (6-7 mmol/L) can be treated with sodium polystyrene sulfonate 1g/kg; if there are changes in the electrocardiogram and serum potassium is greater than 7 mmol/L, calcium gluconate should be administered to antagonize the toxicity of potassium to the myocardium, and sodium bicarbonate should be administered concurrently. If hypernatremia and heart failure occur concurrently, sodium bicarbonate should be prohibited.

　　(2) Hyponatremia: Mild hyponatremia (serum sodium 120-125 mmol/L) can be corrected by restricting fluid volume, making the extracellular fluid normal, and gradually correcting acidosis. If serum sodium is less than 120 mmol/L and symptoms are present, 3% sodium chloride should be supplemented.

　　(3) Hyperphosphatemia and Hypocalcemia: Reduce the intake of phosphorus and supplement calcium.

　　2. Correction of Metabolic Acidosis: 5ml/kg of sodium bicarbonate intravenous drip can correct metabolic acidosis.

　　3. Treatment of Hypertension: Hypertension mainly occurs due to water retention, and the intake of water and sodium should be restricted, and diuretics and antihypertensive drugs should be administered.

　　4. Nutrient Supply: Adequate nutrition can reduce the decomposition of tissue protein and the formation of ketone bodies, while appropriate calorie intake and the supply of exogenous essential amino acids can promote protein synthesis and the growth of new cells.

　　5. Control of Infection: Control of infection should be selected with drugs sensitive to bacteria and nontoxic to the kidneys.

　　6. Peritoneal Dialysis: If the above measures are ineffective in treating neonatal ARF, and severe hyperkalemia, heart failure, and pulmonary edema occur, dialysis can be provided.

　　Chapter 3: Treatment During the Diuresis Phase

　　The principle of treatment during the diuresis phase is to properly supplement water and electrolytes (mainly potassium, sodium, and calcium) and avoid infection.

　　Chapter 4: Treatment During the Recovery Period

　　Anemia can be treated with a small amount of blood transfusion and various vitamins.