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Diagnostic thinking of nephrotic syndrome

Dec 27, 2016
Nephrotic syndrome (NS) is a clinical syndrome, pided into primary and secondary two categories, caused by glomerular disease. In the diagnosis of primary nephrotic syndrome, we must strictly follow the following three steps: is nephrotic syndrome? Whether primary nephrotic syndrome? What kind of glomerular disease is caused by nephrotic syndrome?
1 diagnosis of nephrotic syndrome
Nephrotic syndrome by clinical manifestations in the following four aspects: the composition of proteinuria (urine protein greater than 3.5g/d); the hypoproteinemia (plasma protein (less than 30g/L); the edema can be light weight, often accompanied by severe effusion); the hyperlipidemia (serum cholesterol or glycerin three greases.). The two is necessary for diagnosis, only the third, the 4 or the fourth place, in order to set up the diagnosis of nephrotic syndrome.
Massive proteinuria is the basis of various manifestations of nephrotic syndrome. The loss of albumin in the urine, and urine albumin in part in the proximal tubule in degradation (daily, up to 10g) that stimulates the liver compensatory increase in protein synthesis, if this compensatory synthesis still can not make up the loss and degradation of protein, namely hypoproteinemia. The plasma colloid osmotic pressure decreased, the water exudation to the subcutaneous edema, and even pleural effusion. Compensatory synthesis of liver protein is not selective, while increasing albumin synthesis, but also increased lipoprotein synthesis. Lipoprotein high molecular weight loss in the urine is not easy to accumulate in the body and a lot of proteinuria of lipoprotein degradation enzyme cofactor for small molecular weight is lost in the urine, the enzyme activity decreased and lipoprotein degradation, these two factors resulted in hyperlipidemia.
Therefore, accurate determination of urinary protein is the premise of diagnosis of nephrotic syndrome, urine protein qualitative or urine protein semi quantitative can not replace urine protein quantitative examination. 2 diagnosis of primary nephrotic syndrome
After the diagnosis of nephrotic syndrome is established, it is necessary to exclude secondary nephrotic syndrome caused by congenital genetic diseases and systemic diseases.
Can cause nephrotic syndrome of hereditary kidney disease is not much. In pediatrics, mainly seen in congenital nephrotic syndrome, including Finland and non Finland type, are autosomal recessive. The disease often in neonatal (Finland type) or infant (non Finland type) onset, showing nephrotic syndrome and progressive renal damage, a few years after the end of renal failure. The incidence of this disease is not high, domestic rare, according to age of onset, clinical pathology and family history to diagnose the disease. In medicine, nephrotic syndrome can cause fewer hereditary kidney disease, only in a handful of patients with Alport syndrome. The genetic mode of Alport syndrome is heterogeneous, mostly autosomal dominant and autosomal dominant. The disease onset before the age of 10, hematuria (100% disease hematuria and proteinuria () is a small amount of protein in the urine, only a few showed heavy proteinuria and nephrotic syndrome), renal dysfunction as the main performance, and often accompanied by nerve deafness and eye diseases (spherical crystals and macular disease). When the chromosomal inheritance of this disease is dominant, the male patients in the family are often more serious than females, and males are more than 30 years old. Kidney tissue electron microscopic examination confirmed that the disease mainly lesions in the glomerular basement membrane thickening and basement membrane and thin, dense in the thickened basement membrane with variable width and longitudinal splitting into a network, so according to the clinical manifestations of disease (kidney, ear, eye lesions) and pathological features (basement membrane lesions) and family history is not difficult to diagnose this disease.
Can be secondary to nephrotic syndrome systemic systemic diseases are many, should be very careful except 11. How to find this kind of secondary nephrotic syndrome? The following tips: the two points can be known in advance in patients with systemic disease, and the disease may be secondary glomerular damage, nephrotic syndrome should be considered as secondary nephrotic syndrome patients in systemic diseases. The advance did not find the presence of systemic disease, only patients with nephrotic syndrome treatment, do not rush to the next primary nephrotic syndrome diagnosis, still must be based on the patient's age, gender characteristics considered may be related to disease system, carefully examined. For example: infantile nephrotic syndrome should be examined carefully for any congenital syphilis, young and middle aged women with nephrotic syndrome carefully check the systemic lupus erythematosus; in nephrotic syndrome in the elderly should carefully check the metabolic diseases (diabetes and amyloidosis) and cancer (multiple myeloma). Very important, often ignored by inexperienced doctors.
Common systemic diseases caused by nephrotic syndrome are mainly:
Henoch Schonlein purpura nephritis in children. A typical skin rash, with joint pain, abdominal pain and melena, often in a rash after 1-4 weeks of hematuria and proteinuria, some patients presented nephrotic syndrome, renal biopsy for mesangial proliferative glomerulonephritis, mesangial IgA and complement C3 showed granular deposition. Typical skin rash can prompt the diagnosis of the disease, renal biopsy pathological examination can further help diagnosis.
Lupus nephritis occurs in young and middle-aged women. Frequent fever, rash (Butterfly erythema and light allergy), oral mucosal ulcers, joint pain, multiple inflammatory and multiple organ system (heart, kidney, blood and nerves, etc.) tired performance. The test of serum complement receptor C3 decreased, a variety of autoantibodies, renal involvement in patients with nephrotic syndrome. Lupus nephritis in clinical nephrotic syndrome is mostly IV type (diffuse proliferative type) or type V (membranous type). Lupus nephritis must rely on renal biopsy pathological typing.
Diabetic nephropathy in middle-aged and elderly. Suffering from diabetes for several years will appear renal damage, the initial presentation of albuminuria, and gradually progressed to a large number of proteinuria, nephrotic syndrome occurs when diabetes has reached more than 10 years. Since then the disease progresses faster, 3-5 into uremia. The typical pathological features of this disease are nodular or diffuse glomerulosclerosis. Because of nephrotic syndrome before the patient has more than 10 years of diabetes history, so the kidney is not easy to misdiagnosis, missed diagnosis.
Renal amyloidosis occurs in middle and old age. Amyloidosis is pided into primary and secondary two kinds, the pathogeny is not clear, mainly involving heart, kidney and digestive tract (including the tongue), skin and nerve; the latter often secondary to chronic suppurative infection and malignant tumors and other diseases, mainly involving kidney and liver and spleen. Renal involvement increased volume, often nephrotic syndrome. Pathological diagnosis requires biopsy (gingival, tongue, rectum, kidney or liver biopsy) pathological examination, pathological changes of Congo red staining positive, electron microscopy showed disorder arranged fine fiber for pathological characteristics.
Myeloma kidney damage in middle-aged and elderly, male more than female. Often has the following performance: bone pain, flat X punched out hole, serum monoclonal immunoglobulin increased, protein electrophoresis increased, M urine protein electrophoresis band, gelsolin positive myeloma can cause a variety of kidney damage, when a large number of light chain protein deposition in glomeruli (light chain nephropathy) or with renal amyloidosis. Clinical often appear in nephrotic syndrome. According to the above typical performance is not difficult to confirm myeloma, myeloma patients once abnormal urine, renal puncture should be done to determine the nature of nephropathy.
3 basic disease diagnosis of primary nephrotic syndrome
After the diagnosis of primary nephrotic syndrome is established, it is necessary to define the basic glomerular disease that causes it, because different basic disease treatment programs and prognosis are different, so renal biopsy must be performed.
The pathological types of primary nephrotic syndrome are the following 5 types:
Small lesions (MCD) occur in young children, especially 2-6 years old children, but the elderly have a peak incidence. More male than female. The disease onset fast, rapid emergence of a large number of proteinuria, and then nearly 100% cases of nephrotic syndrome. Microscopic hematuria incidence was low (15%-20%), no gross hematuria, nor persistent hypertension and renal damage (severe edema can have transient hypertension and hyperlipidemia, after diuretic subsided).
Mesangial proliferative glomerulonephritis (MsPGN) is more common in adolescents than men. Prodromal infection (50%) more acute, can be acute nephritis syndrome (about 20%-30%), otherwise often insidious onset. Nephrotic syndrome incidence of non IgA nephropathy IgA nephropathy (about 30% higher than the former, the latter is about 15%), while the incidence of hematuria in IgA nephropathy than non IgA nephropathy (the former almost 100%, which is about 70%; the occurrence rate of gross hematuria is about 60%, which is about 30%). Renal dysfunction and hypertension were gradually increased with the severity of kidney disease. This type of nephritis is very high in our country, accounting for half of the primary glomerular disease, including IgA nephropathy and non IgA nephropathy each about 1/2, China's primary nephrotic syndrome in about 1/3 cases caused by this type of nephritis.
Mesangial capillary nephritis (MCGN) is also called membranous proliferative glomerulonephritis. Good hair in young adults, male than female. There are prodromal infections (about 60%-70%) more acute onset, can be acute nephritis syndrome (about 20%-30%), otherwise also insidious onset. Often presented with nephrotic syndrome (about 60%), accompanied by significant hematuria (almost hematuria, gross hematuria of 20%), the disease often continues to progress, renal dysfunction, hypertension and anemia appear early in the world, and other symptoms of kidney disease (100%). About 50%-70% serum complement C3 continued to decline, the diagnostic significance of this disease. Membranous nephropathy (MN) occurs in the elderly, male more than female. Insidious onset, high incidence of nephrotic syndrome (80%), some cases have microscopic hematuria (accounting for about 40%), but no gross hematuria. Disease progression is slow, usually in the onset of 5-10 years after the onset of renal damage and hypertension. However, this disease is prone to thromboembolic complications, the literature reported that the incidence of renal venous thrombosis up to 30%-60%.
Focal segmental glomerulosclerosis (FSGS) is more common in adolescents than men. Insidious onset, nephrotic syndrome (50%-75%), high incidence of hematuria (about 75%), visible gross hematuria (about 20%). The diagnosis of kidney dysfunction and hypertension have often been diagnosed. In addition, this disease often appears renal diabetes and other proximal tubular dysfunction.
In the various clinical manifestations of known pathological types of glomerular diseases, can try to infer pathological diagnosis from the clinical manifestations, the following points can be used for reference in the age of onset: the peak age of onset from childhood to old were MCD (children), MsPGN and FSGS (Youth) and MCGN (young), MN (middle aged and elderly). The onset: acute onset, clinical showed simple nephrotic syndrome, mainly for MCD; acute onset after infection and showed acute nephritis syndrome, mainly MsPGN and MCGN; insidious onset is MN and FSGS; and MsPGN and MCGN in the absence of precursor infection cases can be insidious onset. Hematuria: 3 days after the infection, gross hematuria was mostly IgA nephropathy; no gross hematuria, and even those without hematuria were mainly MCD and MN. The renal insufficiency: MCGN renal dysfunction occurs early, rapid progression of renal insufficiency; MN appeared late, slow progress; FSGS and severe MsPGN diagnosed with renal damage; while MCD and mild MsPGN normal renal function. The other: the level of serum IgA IgA in patients with MCGN nephropathy may increase; serum complement often decreases continuously.
The glomerular disease has the following features: a pathological type can present a variety of clinical manifestations, and clinical manifestations can be derived from a variety of pathological types, between the two there is a wide range of cross links, so could not completely correct inference. In general, the highest accuracy of clinicians in inferring pathological types based on clinical performance is only 60%-70%. Therefore, to accurately make the basic diagnosis of primary nephrotic syndrome, renal biopsy must still be carried out pathological examination.

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