Nephrotic syndrome (nephritic
nephritic syndrome is a group of syndromes with different etiologies and different pathological manifestations, but with similar clinical manifestations. The pathogenesis is caused by the elevated permeability of the glomerular filtration membrane to plasma proteins and the loss of large amounts of plasma proteins from the urine. Clinical manifestations: 1, large amount of proteinuria (>3.5g/d); 2, hypoproteinemia (plasma albumin <30g/L); 3, edema; 4, hyperlipidemia. The first two of them are necessary for the diagnosis. Diagnosis and differential diagnosis: Diagnosis includes three aspects: ① confirm the diagnosis of NS; ② confirm the etiology: secondary etiology and hereditary diseases must be excluded before primary NS can be diagnosed; preferably, a renal biopsy should be performed to make a pathological diagnosis; ③ determine whether there are complications. The secondary causes of Ns that require differential diagnosis mainly include the following diseases: 1. Allergic purpura nephritis occurs in adolescents, with typical skin purpura, which can be accompanied by arthralgia, abdominal pain and black feces, mostly with hematuria and/or proteinuria about l to 4 weeks after the appearance of the rash, and the typical rash helps in differential diagnosis. 2. Systemic lupus erythematosus occurs in adolescents and middle-aged women. Based on the clinical manifestations of multisystem damage and immunological examination, a variety of autoantibodies can be detected, and it is generally not difficult to make a clear diagnosis. 3. Hepatitis B virus (HBV)-associated nephritis
Most commonly seen in children and adolescents, with proteinuria or NS as the main clinical manifestation, the common pathological type is membranous nephropathy, followed by thylakoid capillary glomerulonephritis, etc. The diagnosis in China is based on the following three points: ① positive serum HBV antigen; ② suffering from glomerulonephritis, and can exclude secondary glomerulonephritis such as lupus nephritis; ③ HBV antigen found in kidney biopsy sections. China is a high prevalence area of viral hepatitis B. For patients with viral hepatitis B, children and adolescents with proteinuria or NS, especially membranous. Those with nephropathy should be carefully excluded. 4, diabetic nephropathy occurs in the middle-aged and elderly, NS is common in diabetic patients with a disease duration of lO years or more. Increased urinary microalbumin excretion can be found in the early stage, which gradually develops into massive proteinuria, NSo history of diabetes mellitus and characteristic fundus changes help in the differential diagnosis. 5. Renal amyloidosis
Prevalent in middle-aged and elderly people, renal amyloidosis is part of the systemic multi-organ involvement. Primary amyloidosis mainly involves the heart, kidney, digestive tract (including the tongue), skin and nerves; secondary amyloidosis is often secondary to chronic septic infection, tuberculosis, malignancy and other diseases, mainly involving the kidney, liver and spleen and other organs. Renal amyloidosis often requires renal biopsy to confirm the diagnosis. 6.Myelomeningocele nephropathy
Patients may have characteristic clinical manifestations of multiple myeloma, such as bone pain, increased serum monoclonal immunoglobulin, positive M protein and urine periprotein by protein electrophoresis, and abnormal proliferation of plasma cells (more than 159/5 of nucleated cells) with qualitative changes on bone marrow image. NS can be seen in multiple myeloma with glomerular involvement, and the above-mentioned characteristic features of myeloma are useful for differential diagnosis.