A. What diseases can lead to nephrotic syndrome? Nephrotic syndrome is caused by glomerular diseases, which can be divided into three major categories according to their causes: 1. Secondary nephrotic syndrome: glomerular diseases caused by other diseases (such as allergic purpura, systemic lupus erythematosus, diabetes, etc.) affecting the kidneys. 2.Primary nephrotic syndrome: caused by glomerular self lesions, which can be diagnosed clinically only after secondary nephrotic syndrome is excluded. 3, congenital nephrotic syndrome: glomerular disease related to genetic factors. The common etiology varies according to age. The most common secondary nephrotic syndromes in children, adolescents and middle-aged and elderly are allergic purpura nephritis, hepatitis B virus-associated nephritis (mostly systemic lupus erythematosus nephritis in women) and diabetic nephropathy and tumor-associated nephropathy, respectively. Second, what are the symptoms of nephrotic syndrome patients? The most common and prominent symptom – edema. At first it is mostly seen in the face, gradually spread to both lower limbs and the whole body, in severe cases patients will have a high degree of eyelid swelling, so that they can not open their eyes; the skin of the limbs is tight, thin and translucent, lancing or skin breaks where water seepage; male patients scrotum can be swollen like a ball; even the appearance of thoracic fluid and ascites, resulting in abdominal distension, poor appetite, chest tightness and shortness of breath, breathing difficulties and other symptoms. The degree of edema is usually consistent with the degree of decrease in serum albumin, and most of them are accompanied by a decrease in urine output. Patients with secondary nephrotic syndrome will also have different symptoms depending on the characteristics of their primary disease, let’s briefly understand it. 1, allergic purpura nephritis First, what is purpura – hemorrhagic rash. The rash varies in size and is pinpoint to soybean size, and can fuse into patches when there are many. The rash is mainly distributed in the extremities, the extensor side of the calf is most common. The rash is initially red, and then gradually darkens, does not fade when pressed, occasionally itchy, and often appears in batches. Secondly, what is allergic purpura – a disease caused by the body’s allergy to a substance (such as infection, drugs, food, vaccines, etc.). Some substances attack small blood vessels throughout the body and cause inflammation of blood vessels. As a result, in addition to purpura, redness, swelling and heat in the joints, abdominal pain, blood in the stool and kidney damage can occur. About 1/3 of patients develop renal damage, i.e., allergic purpura nephritis, mostly in children and adolescents. It often develops within 4 weeks after the appearance of purpura, and the clinical manifestations may include hematuria (deformed red blood cell hematuria), proteinuria, edema, hypertension and even abnormal renal function (elevated creatinine). 2. Systemic lupus erythematosus nephritis First of all, what is systemic lupus erythematosus – an autoimmune disease. The attack of multiple autoantibodies (such as anti-nuclear antibodies, anti-ds-DNA antibodies, anti-Sm antibodies, etc.) causes damage to multiple organs throughout the body. Clinical manifestations include skin damage (facial rash, butterfly erythema), fever, oral ulcers, hair loss, vasculitis and internal organ damage (damage to kidneys, hematological system, heart, nervous system, etc.). Secondly, what is lupus nephritis – SLE invades the kidneys. The rate of invasion is almost 100%. It is mostly seen in young and middle-aged women, with a male to female ratio of 1:9. According to its six pathological types (I-VI) from mild to severe manifestations of varying degrees of proteinuria, edema, hypertension and even abnormal kidney function. 3, diabetic nephropathy First, what is diabetes – a chronic systemic metabolic disease. The incidence is extremely high, with elevated blood sugar as the main manifestation, divided into two types: type 1 and type 2. Second, what is diabetic nephropathy – diabetes if poorly controlled over a long period of time, the kidney complications caused by diabetic nephropathy. About 1/4 of diabetic patients have complications of kidney damage, which is common in middle-aged and elderly people, ranging from mild to severe manifestations of microproteinuria, massive proteinuria, edema, hypertension, abnormal kidney function, and finally progressing to uremia.