What are the pathological and physiological causes of nephrotic syndrome

Everyone's kidneys are very important. If the kidneys are damaged, not only will your urination be easily affected, but it may also cause many physical problems. Kidney disease has always been one of the diseases that threaten human health, so it should attract more of our attention. Among kidney diseases, nephrotic syndrome is relatively common. So what is the pathophysiology of nephrotic syndrome and how to treat it?

Due to changes in the permeability of the glomerular filtration membrane, protein migration increases, forming a large amount of proteinuria. Changes in the permeability of the glomerular filtration membrane are not only related to pathological changes, but also to changes in the surface charge of the glomerular epithelial cell membrane. There is sialic acid protein on the surface of normal membrane, which is negatively charged, and albumin molecules are negatively charged at pH 7.4. Because like charges repel each other, albumin is not easily filtered. The amount of sialic acid protein decreases in simple nephropathy. This increases protein filtration.

Large amounts of proteinuria lead to hypoproteinemia, especially a decrease in albumin, which reduces plasma colloidal osmotic pressure, causing water and electrolytes to infiltrate the tissue spaces from inside and outside the blood vessels, and secondary increases in aldosterone secretion and antidiuretic hormone secretion. The edema is further aggravated by factors such as the reduction of natriuretic factor.

The occurrence of hypercholesterolemia is mainly due to increased compensatory synthesis in the liver, followed by decreased lipoprotein catabolism.

There are many pathological types of this disease, among which minimal change type is the most common (accounting for about 80%); simple nephropathy mainly belongs to this type, followed by focal segmental glomerulosclerosis and membranous proliferative nephritis. A few cases present with mesangial proliferative type or membranous nephropathy, and such lesions often manifest as nephritic nephropathy.

Nephrotic syndrome is a common disease in nephrology and is often treated with comprehensive treatment based mainly on adrenal cortical hormones. The principles are to control edema, maintain water and electrolyte balance, and prevent and control infections and complications. Adrenal cortical hormones should be used rationally, and immunosuppressive drugs should be used in combination for patients with recurrent kidney disease or hormone resistance. The purpose of treatment is not only to eliminate urine protein, but also to pay attention to protecting renal function.

treat

1. General symptomatic treatment

(1) Rest and activity: When nephrotic syndrome occurs, bed rest should be the main approach until the general condition improves. After the edema has basically subsided, you can do moderate activities in bed or bedside to prevent thrombosis in the limb blood vessels. After the condition has been basically relieved, activities can be gradually increased. Those who have been relieved for half a year without recurrence can consider increasing light indoor work and try to avoid various infections.

(2) Diet: Eat light, easily digestible food, consume 1 to 2 grams of salt per day, avoid pickled foods, and use less MSG and alkali. In the early and critical stages of the disease, a higher intake of high-quality protein should be given, 1 to 1.5 g/kg per day, which can help alleviate hypoproteinemia and the complications caused by it. For chronic non-polar nephrotic syndrome, protein intake should be appropriately limited to 0.8 to 1.0 g/kg per day. The ideal energy supply is 30-35 kcal/kg body weight per day. Patients with severe hyperlipidemia should limit their lipid intake and adopt a low-fat, low-cholesterol diet. At the same time, pay attention to supplementing trace elements such as copper, iron, and zinc. During the application of hormones, appropriately supplement vitamins and calcium supplements.

2. Diuretic and detumescent treatment

(1) Thiazide diuretics: They mainly act on the thick-walled segment of the ascending limb of the loop of Henle and the anterior segment of the distal convoluted tubule, inhibiting the reabsorption of sodium and chloride and increasing potassium excretion to cause diuresis. The commonly used medication is hydrochlorothiazide 25 mg, orally 3 times a day. Long-term use should prevent hypokalemia and hyponatremia.

(2) Potassium-retaining diuretics: They mainly act on the posterior segment of the distal convoluted tubule, excreting sodium and chloride but retaining potassium. They are suitable for patients with hypokalemia. The diuretic effect is not significant when used alone, and it can be used in combination with thiazide diuretics. Commonly used medications include triamterene 50 mg, 3 times a day, or the aldosterone antagonist spironolactone 20 mg, 3 times a day. Hyperkalemia must be prevented during long-term use and it should be used with caution in patients with renal insufficiency.

(3) Loop diuretics: They mainly act on the ascending limb of the loop of Henle and have a strong inhibitory effect on the reabsorption of sodium, chloride and potassium. Commonly used medications include furosemide (Lasix) 20-120 mg/d, or bumetanide (buturetanamine) 1-5 mg/d (40 times more potent than furosemide at the same dose), taken orally or intravenously in divided doses. The effect is better when it is given immediately after the use of osmotic diuretics. When using loop diuretics, caution must be exercised to prevent hyponatremia, hypokalemia, and hypochloremia-induced alkali poisoning.

(4) Osmotic diuretics: By transiently increasing the plasma colloidal osmotic pressure, water in the tissues can be reabsorbed into the blood. At the same time, it creates a hyperosmotic state in the renal tubular fluid, reduces the reabsorption of water and sodium, and causes diuresis. Sodium-free dextran 40 (low molecular weight dextran) or hydroxyethyl starch (706 generation plasma, molecular weight of 25,000 to 45,000 Da) is commonly used, 250 to 500 ml intravenous drip once every other day. Subsequent addition of a loop diuretic can enhance the diuretic effect. However, this type of drug should be used with caution in patients with oliguria (urine volume <400ml/d), because they easily form casts together with Tamm-Horsfall protein secreted by the renal tubules and albumin filtered by the glomeruli, blocking the renal tubules. Their hyperosmotic effect can cause degeneration and necrosis of renal tubular epithelial cells, inducing "osmotic nephropathy" and leading to acute renal failure.

(5) Increase plasma colloid osmotic pressure: Intravenous infusion of plasma or human albumin can increase plasma colloid osmotic pressure, promote water reabsorption in tissues and promote diuresis. If followed by immediate intravenous infusion of 60-120 mg of furosemide (added to glucose solution and slowly infused intravenously for 1 hour), a good diuretic effect can be achieved. Human albumin can also be considered when the patient has severe hypoproteinemia and malnutrition. However, since the transfused plasma and its products will be excreted in the urine within 24 to 48 hours, plasma products should not be transfused excessively or too frequently. Otherwise, glomerular hyperfiltration and tubular hypermetabolism may cause damage to the glomerular visceral and tubular epithelial cells, which may affect the efficacy of glucocorticoids and delay disease remission in mild cases and damage renal function in severe cases. This diuretic method should be used with caution in patients with heart disease to avoid heart failure caused by acute expansion of blood volume.

(6) Others: For patients with severe refractory edema, if the above treatments are ineffective, short-term blood ultrafiltration therapy can be tried. This therapy can rapidly dehydrate the patient. For patients with severe ascites, ascites can be drained under strict aseptic conditions, and then concentrated in vitro and then reinfused into the patient's own veins.

The principle of diuretic treatment for patients with nephrotic syndrome is not to be too fast or too strong, so as to avoid insufficient blood volume, aggravating the tendency of blood hyperviscosity, and inducing thrombosis and embolic complications.

Patients with nephrotic syndrome should pay attention to a light diet. They can eat more high-protein foods and fruits. Moldy and pickled foods should be avoided. Male patients should quit smoking and drinking, which will help in the treatment of the disease. You can choose Imperata Root Soup and Cordyceps and Black Chicken Soup as dietary therapy to assist in treatment, and the effect is very good.