Elderly nephrotic syndrome

　　The incidence of secondary nephrotic syndrome in senile nephrotic syndrome is high, among which renal amyloidosis is the highest, accounting for about 15% of all nephrotic syndrome in elderly patients. The next is various tumors, which often cause secondary nephrotic syndrome in the elderly, such as gastrointestinal tumors, lymphoma leukemia, lung cancer with an incidence of 11%. There are also other diseases, such as diabetic nephropathy in elderly diabetes, hepatitis B, certain drugs (non-specific anti-inflammatory drugs, gold preparations, penicillamine), vasculitis, cryoglobulinemia, macroglobulinemia, etc. In primary nephrotic syndrome, the pathological type is the most common in membranous nephropathy. According to the analysis of foreign data in the 1980s: membranous nephropathy accounts for 36.5%, minimal change accounts for 19.4%, various proliferative nephritis accounts for 15.3%, focal glomerulosclerosis accounts for 7.7%, and other types are rare.

　　This disease often manifests as edema. If not treated in time, it may lead to the following complications:

　　1. Infection

　　In elderly patients with nephrotic syndrome, due to the significant decrease in immune function under the action of hormones, infections are more likely to occur, and the onset of infection is insidious, with atypical clinical manifestations. This syndrome is also prone to cause urinary tract infection, but when nucleated cells appear in the urine, do not easily diagnose urinary tract infection. Urine culture should be performed to distinguish whether it is a bacterial infection.

　　2. Thrombosis, embolism

　　This is one of the severe and fatal complications of this syndrome, which is recognized. In nephrotic syndrome, there is a hypercoagulable state, which is related to the changes in coagulation, anticoagulation, and fibrinolysis of this syndrome. Added to this is the blood thickening caused by low protein and hyperlipidemia, which makes the tendency for coagulation and thrombosis in this syndrome more serious.

　　3. Renal function damage

　　This disease can be complicated by renal failure, so patients should receive timely treatment and pay attention to the treatment of complications to reduce the damage of this disease.

　　This disease often occurs after infection (tonsillitis, pharyngitis, or general upper respiratory tract infection), after catching a cold, or after fatigue. The onset can be acute or chronic, and sometimes insidious. The main manifestations include:

　　1. Edema

　　The patient presents with systemic, edematous, and collapsible edema, which is most commonly seen in the ankle area in the early stage. In the morning, there may be edema of the eyelids and face. As the course of the disease progresses, edema can spread throughout the body and lead to pleural effusion, peritoneal effusion, and even pericardial effusion. In elderly patients, severe edema can lead to heart failure.

　　2. Large amounts of proteinuria

　　The urine protein of patients is >3.5g/24h, and severe cases can reach several grams, showing selective or non-selective proteinuria.

　　3. Hypoproteinemia

　　The total protein in plasma decreases, mainly due to the decrease in plasma albumin, usually between 10～30g/L (1～3g/dl), occasionally decreased to 5.8g/L (0.58g/dl).

　　4. Hyperlipidemia

　　Most patients have an increase in blood cholesterol, phospholipids, and triglycerides.

　　Rational prevention is the key to reducing the incidence of the disease. Next, I will bring you the prevention measures for this disease, and introduce them in detail as follows:

　　First-level prevention

　　1. Appropriate exercise, stable emotions, to increase the body's immunity and disease resistance.

　　2. Avoid catching a cold, dampness, or overfatigue.

　　3. Prevent colds to avoid triggering the disease.

　　4. Avoid using drugs harmful to the kidneys.

　　5. Regularly carry out re-examination of relevant items.

　　Second-level prevention

　　1. Treat colds promptly with medication.

　　2. Timely treat infections in various parts of the body. Pay attention to drug allergies when taking medication to avoid triggering and aggravating the disease.

　　3. If proteinuria appears in the urine, it should be timely investigated and treated. Regular re-examination should be carried out when the condition is stable, including urine routine, blood lipids, plasma protein, and blood pressure.

　　4. Try to use as few drugs excreted by the kidney as possible during the period of renal function decline to avoid drug accumulation, resulting in drug poisoning and aggravating kidney damage.

　　Third-level prevention

　　The main treatment is to actively treat the primary disease with treatment methods to reduce the damage to the kidneys caused by the disease.

　　The incidence of secondary nephrotic syndrome in elderly nephrotic syndrome is high, among which renal amyloidosis is the highest. The diagnosis of this disease generally requires the following examinations:

　　1. Urinalysis and renal function examination

　　Urine routine examination shows a large amount of proteinuria, only 15% to 20% of patients have microscopic hematuria, and gross hematuria is rare. At the beginning of the disease, about 30% of patients have a slight increase in serum creatinine, and elderly patients have a significant increase in serum creatinine. Albumin in plasma protein

　　2. Serum protein electrophoresis

　　Serum protein electrophoresis mainly shows a decrease in albumin, an increase in α2 and β2 globulins, and a normal lower limit or decrease in γ-globulin.

　　3. Determination of urinary C3

　　An increase in the content of C3 in urine is mainly seen in proliferative and sclerotic cases and has reference value in the differential diagnosis of nephrotic syndrome.

　　4. Determination of urinary fibrinogen degradation products (FDP)

　　This examination can help determine the type of nephrotic syndrome and select treatment plans. When there are minor changes, the urine FDP is 1.2 μg/ml. If the urine FDP is >3 μg/ml and does not decrease continuously, it suggests that the activity of the lesion is strong.

　　5. Renal biopsy

　　This examination can provide morphological diagnosis for determining the pathological type of nephrotic syndrome and has guiding significance for the determination of treatment plans and the estimation of prognosis.

　　Improper diet can greatly reduce the efficacy of disease recovery, therefore, during the treatment of this disease, patients must pay attention to not eating the following kinds of food:

　　1. Spinach

　　Spinach is sweet and cool in taste, and some regions believe it belongs to 'inducing' food. Clinical observations in modern medicine show that after some patients with nephritis eat spinach, an increase in urinary casts or salt crystals can be seen, and the urine color becomes turbid. Therefore, patients with kidney disease should avoid eating spinach or eat it cautiously.

　　2. Bamboo shoots

　　Bamboo shoots are fresh and sweet in taste, and can clear heat and promote diuresis. However, according to modern research, due to the high content of insoluble calcium oxalate in bamboo shoots, this is not conducive to chronic nephritis and renal insufficiency, so they should be avoided.

　　3. Ginger

　　Ginger is warm and spicy in nature and taste. The gingerol in ginger can stimulate the mucous membranes of the bladder and other urinary systems, thereby aggravating the inflammatory reaction of the urinary system infection. Therefore, for patients with urinary system infection, whether it is cystitis or urethritis, ginger should not be eaten in large quantities.

　　3. Pepper

　　Urological infections are considered to be caused by dampness and heat descending into the bladder, known as 'heat stranguria', in traditional Chinese medicine. Pepper is very spicy and hot, which is easy to enhance heat and inflammation. Therefore, patients with urinary tract infections with heat in the bladder should not eat too much pepper, otherwise the condition will certainly worsen.

　　4. Legumes

　　Legume products are the first choice for many patients with diseases, but for patients with reduced renal function, a large amount of protein diet can increase the excretion of urinary protein and worsen renal function damage, so it is best to avoid eating them.

　　This disease often occurs after infection (tonsillitis, pharyngitis, or general upper respiratory tract infection), or after catching a cold or being overworked. The general treatment methods for this disease are as follows:

　　First, general treatment

　　1. During nephrotic syndrome, bed rest should be the main treatment, as bed rest can increase renal blood flow and urine output, and prevent cross-infection. However, appropriate bedside activities should also be performed to avoid limb thrombosis. After symptoms improve, activities can be appropriately increased. This is conducive to reducing blood lipids and reducing complications. However, if there is an increase in urinary protein, activity should be reduced.

　　2. Diet therapy should consume easily digestible and absorbable light semi-liquid diet. Because nephrotic syndrome patients often have digestive tract mucosal edema during edema, which affects digestion, attention should be paid to the composition of diet.

　　Second, symptomatic treatment

　　1. Treatment of edema: In addition to limiting sodium intake and bed rest, appropriate diuretics can be used.

　　(1) Osmotic diuresis: intravenous injection of hypertonic glucose and fructose or intravenous infusion of exogenous substances that cannot be reabsorbed by the renal tubules, such as low molecular weight dextran and mannitol. The mechanism is to bring more solutes and water to the renal tubules, raising the osmotic pressure within the renal tubules to increase urine output. However, caution should be exercised when the urine output is less than 400ml/d to avoid osmotic nephropathy and acute renal failure.

　　(2) Inhibition of reabsorption of electrolytes: mainly the inhibition of sodium and potassium ions in the renal tubules. For example, thiazide diuretics, such as hydrochlorothiazide (dihydrochlorothiazide) 25-50mg, 2-3 times/d, have diuretic effects on most patients. Furosemide (Lasix) and other potent diuretics, when taken orally, intramuscularly, or intravenously, have better diuretic effects. Attention should be paid to hypotension when using such drugs.

　　(3) Anti-mineralocorticoid drugs: Increased aldosterone is a factor in nephrotic edema. Therefore, spironolactone (Aldactone) can be used to inhibit aldosterone diuresis.

　　(4) Plasma Products: In patients with severe hypoproteinemia, who have refractory edema and oliguria due to orthostatic hypotension and hypovolemia, the use of human albumin or plasma can temporarily increase blood volume and osmotic pressure, and has a good diuretic effect. Especially when given diuretics like furosemide (Lasix) at the end of infusion, it can enhance the diuretic effect. It is worth noting that plasma products should not be used as nutritional supplements or diuretics, as they are completely excreted by urine within 24-48 hours after administration. Moreover, they increase the burden on the kidneys and reduce the efficacy of steroids. Excessive administration of human serum albumin can also cause damage to renal tubular epithelial cells leading to 'protein overload nephropathy'. Especially in the elderly or those with heart failure, rapid and excessive administration of human serum albumin may pose a potential risk of left heart failure.

　　2. Treatment of Hyperlipidemia: In the past, there was insufficient emphasis on lipid-lowering treatment. In recent years, it has been recognized that hyperlipidemia increases blood viscosity, making it easier to form thrombi and accelerate the occurrence of coronary heart disease. At the same time, hyperlipidemia can stimulate the proliferation of mesangial cells in the glomeruli, promoting glomerulosclerosis. Therefore, in addition to dietary attention, lipid-lowering drugs are of great significance. The following drugs are used in lipid-lowering treatment:

　　(1) Hydroxymethylglutaryl-CoA Reductase Inhibitors: These primarily block the liver's synthesis of cholesterol. This class of drugs includes lovastatin, 20-80mg/day. When combined with dietary treatment, it can enhance the efficacy of the drug. According to the application results of the past 6 years, these drugs are considered to be a reasonable and safe class of drugs. These drugs can be used in combination with bile acid binders. However, they should not be used with bile acid sequestrants, as this can cause severe rhabdomyolysis.

　　(2) Bile Acid Binding Resins: They lower cholesterol but are ineffective in lowering triglycerides. They are generally not used alone, such as cholestyramine (Colestipol).

　　(3) Double-filtered plasma exchange to remove high blood lipids from the plasma is helpful in treating 'hormone-resistant' nephrotic syndrome and reducing protein levels.