Protein appearing in urine is called proteinuria, that is, urinary protein. Normal urine contains a small amount of small molecular protein, which can not be detected by routine urine examination. When the protein in urine increases, routine urine examination can detect proteinuria. Proteinuria is a common manifestation of kidney disease, and proteinuria can also occur in systemic diseases.
Etiology: There are many reasons for proteinuria, including functional proteinuria, postural proteinuria or pathological proteinuria. Common ones are: after strenuous exercise, at the peak of fever, eating a high-protein diet; Nutcracker phenomenon; Various kidney diseases and renal vascular diseases.
Clinical manifestations: The clinical manifestations of low back pain caused by different causes are also different, such as:
1. Functional proteinuria
Functional proteinuria is a mild and temporary proteinuria (24-hour proteinuria is generally less than 0.5 ~1g), and the proteinuria disappears quickly after removal. It often occurs in young adults and can be seen after mental stress, severe cold or heat, long-distance marching, strong physical labor, congestive heart failure and eating a high-protein diet.
2. Postural proteinuria
There is no proteinuria in the urine in the morning, and proteinuria gradually appears after getting up. When standing, walking or strengthening the lordosis posture for a long time, the proteinuria content increases, and it decreases or disappears after lying down 1 hour, which mostly occurs in slender young people or adults. Repeated postural proteinuria should be paid attention to except nephropathy, such as nutcracker phenomenon (also known as left renal vein compression syndrome, which is caused by the compression of left renal vein by aorta and superior mesenteric artery).
3. Pathological proteinuria
Proteinuria persists, and the protein content in urine is high. Routine urine examination is often complicated with hematuria, leukocytosis and tubular urine. It may be accompanied by other renal diseases, such as hypertension and edema. Pathological proteinuria is mainly found in various glomerular, tubulointerstitial diseases, hereditary nephropathy, renal vascular diseases and other kidney diseases. Common such as:
(1) Primary glomerular disease ① Nephritis can be occult, acute, rapid or chronic. Often complicated with hematuria, hypertension and edema. ② The 24-hour urine protein quantification of nephrotic syndrome is greater than or equal to 3.5g, accompanied by hypoalbuminemia, edema and hyperlipidemia. ③ Renal insufficiency can be divided into acute and chronic renal insufficiency. Proteinuria is the manifestation of renal damage.
(2) Secondary glomerular diseases ① Lupus nephritis is the manifestation of systemic lupus erythematosus involving the kidney. Women of childbearing age are more common. According to the severity of kidney involvement, the amount of urine protein can be small to large. ② Henoch-Schonlein purpura nephritis is the manifestation of renal involvement in Henoch-Schonlein purpura. The main manifestations are hematuria and proteinuria, which are common in children and can also occur in adults. Proteinuria mostly occurs 2 ~ 4 weeks after purpura appears. (3) Diabetic nephropathy is a common complication of diabetes, with early kidney involvement, but urine protein can be negative by routine urine examination, and then microalbuminuria gradually appears, and then develops to massive proteinuria, and even end-stage renal disease, that is, renal failure needs dialysis and other treatments. ④ The abnormal urine test of gouty nephropathy appeared later and slightly, with only mild proteinuria and a small amount of red blood cells. Late stage can progress to chronic renal failure. ⑤ Hypertensive Nephropathy After 5 ~10 years of primary hypertension, kidney damage often occurs. Proteinuria caused by benign hypertension is generally mild to moderate proteinuria (24-hour proteinuria is generally less than1.5 ~ 2g), and a large amount of proteinuria rarely occurs. Some of them are combined with microscopic hematuria, and often have hypertension, left ventricular hypertrophy, cerebral artery and retinal arteriosclerosis. Another kind of proteinuria caused by malignant hypertension is often sudden, and the 24-hour urinary protein can be quantified from less to more, most of which are accompanied by hematuria and leukocytosis, and the renal function deteriorates sharply.
(3) In tubulointerstitial diseases, such as pyelonephritis and interstitial nephritis, the urine protein is mostly+to++,and the 24-hour urine protein is more quantitative <: 2 grams.
(4) Hereditary nephropathy such as Alport syndrome, Fabry's disease, thin basement membrane nephropathy, congenital nephrotic syndrome, etc., due to genetic abnormalities, lead to renal structural defects, resulting in different degrees of proteinuria.
(5) Others, such as high altitude proteinuria, can be seen in people who enter the plateau from the plain, and the urine protein is positive, quantitative >; 400 mg /24 hours, no proteinuria before going to the plateau, onset after entering the plateau, oxygen inhalation can improve, return to the plain and return to normal.
What should I do if there is "+"in urine protein?
Don't be nervous if there is a plus sign in urine protein. At this time, you need to check the 24-hour urine protein quantification to see the loss of protein. If the protein content in urine reaches more than 0. 15g/24h, it is necessary to see a doctor in time.
Is "+"in urine protein a kidney disease?
1. In some cases, urine protein will appear "+".For example, if you have an examination after strenuous exercise, you are too tired recently, or you eat a lot of high-protein food, it will cause short-term urine protein to appear "+".At this time, you should pay attention to rest, light diet, adjust it, and then go for an examination. If you still have urine protein "+"after another examination, you should pay attention to it.
2. However, sometimes urinary protein "+"appears after repeated examinations, which may also be caused by urinary tract infection. If urinary tract infection occurs, it should be treated in time, otherwise it may also cause kidney inflammation.
3. If there is only a small amount of proteinuria, but there is no hematuria, and whether there are any other conditions in the body, such as edema, hypertension or abnormal renal function, the nephropathy in this case is not very serious. As long as you actively cooperate with the doctor for treatment, I believe that urinary protein will disappear soon.
Although an increase in urinary protein indicates that the kidney is seriously ill and a decrease in urinary protein indicates that the condition is getting better, sometimes a decrease in urinary protein may also be a sign of the deterioration of the condition, because sometimes urinary protein may not fully reflect the pathological degree of the kidney. For example, when most of the glomeruli are fibrotic, protein in the body cannot be well filtered, which means that the urinary protein will decrease during the examination, but in fact this is caused by the deterioration of the condition.
Therefore, we can't judge the severity of the disease simply by whether there is "+"in urine protein, or whether there is nephropathy. We have to go through other series of examinations before we can finally diagnose nephropathy.