Proteinuria

Introduction to proteinuria Due to the filtration of glomerular filtration membrane and the reabsorption of renal tubules, the amount of protein in the urine of healthy people (multiple molecular weight proteins) is very small (less than 150 mg per day), when qualitative protein examination , a negative reaction. When the protein content in the urine increases, regular urine examination can be measured, called proteinuria. If the urine protein content is 3.5g / 24h, it is called a large amount of proteinuria. Common in febrile diseases, more common in the early stage of the disease, urinary protein disappears with hypothermia, only lasts for a few days, in addition to protein in the urine, there are also a few white blood cells and epithelial cells. Adhere to the treatment of primary diseases such as kidney disease, strict control of diet, and reasonable intake of high-quality protein. Nephrologists recommend that patients with kidney disease do not consume a high-salt diet and an excessively high-protein diet during treatment. This is conducive to disease treatment and physical health, so patients with kidney disease must strictly follow the doctor's advice to arrange three meals a day, to avoid the many troubles caused by improper diet. basic knowledge The proportion of illness: 0.005%-0.01% Susceptible people: no special people Mode of infection: non-infectious Complications: glomerulonephritis nephritis rapid progressive nephritis

Cause of proteinuria

Acute glomerulonephritis (30%):

Acute glomerulonephritis, referred to as acute nephritis (AGN), is a group of diseases with acute nephritis syndrome as the main clinical manifestation. Acute nephritis is more common in children than men. Usually, one to three weeks after the pre-infection (about 10 days on average), the incubation period is equivalent to the time required to induce the body to produce an immune complex after the primary immunization of the pathogenic antigen. The incubation period of the respiratory infection is shorter than that of the skin infected person. It is characterized by acute onset, hematuria, proteinuria, edema and hypertension, and may be associated with transient azotemia. More common in streptococcal infections, but other bacterial, viral and parasitic infections can also be caused.

Nephrotic syndrome (32%):

Nephrotic syndrome (NS) can be caused by a variety of causes, with increased glomerular basement membrane permeability, manifested as a group of clinical syndromes with large amounts of proteinuria, hypoproteinemia, high edema, and hyperlipidemia.

Urinary system infection (25%):

Urinary tract infection: The main manifestation of cystitis in adult women is urinary tract irritation, that is, frequent urination, urgency, dysuria, white blood cell urine, occasionally hematuria, and even gross hematuria, bladder area may have discomfort. Generally no obvious symptoms of systemic infection, but a small number of patients may have low back pain, low fever (generally no more than 38 ° C), white blood cell count is often not increased. About 30% of cystitis is self-limiting and can heal itself within 7 to 10 days.

Proteinuria prevention

To prevent proteinuria episodes, you should pay attention to:

1. Nephrologists recommend that patients with kidney disease do not consume a high-salt diet and excessive high-protein diet during treatment. This is conducive to disease treatment and physical health, so patients with kidney disease must strictly follow the doctor's advice to arrange three meals a day, to avoid the many troubles caused by improper diet.

2. Pay attention to prevent the occurrence of recurrence causes (such as cold, fatigue, diarrhea, etc.), adhere to treatment, avoid the use of nephrotoxic drugs.

Proteinuria complications Complications glomerulonephritis nephritis rapid progressive nephritis

(1) Mesangial toxicity of proteinuria:

In the renal failure model, the accumulation of serum proteins in the mesangial membrane can be observed. The accumulation of these macromolecular substances in the mesangial area can cause damage to the mesangial cells and increase the synthesis of mesangial matrix, resulting in small kidneys. The ball hardens. In the proteinuria nephropathy model, aggregation of apolipoprotein B with low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) and apolipoprotein A deposition in the glomeruli eventually leads to glomerular sclerosis.

(2) Toxic effects of proteinuria on proximal convoluted tubule cells:

When proteinuria occurs, the amount of protein that enters the renal tubular epithelial cells increases, increasing lysosomal activity, suggesting that the protein causes lysosomes to spill into the tubular cytoplasm, and subsequent cell damage can stimulate inflammation and scar formation.

(3) Biological changes in tubule cells caused by proteinuria:

Many kidney diseases with proteinuria have excessive cell proliferation, which represents a non-adaptive reaction leading to renal failure. A growing body of evidence suggests that proteins can directly modulate tubule cell function, altering their growth characteristics and expression of cytokines and matrix protein phenotypes, which can lead to the release of PDGF, FN and MCP-1 from the basal side of the tubule and induce fibrosis.

(4) Proteinuria causes tubulointerstitial hypoxia:

Re-absorption of white urine requires additional energy to digest large amounts of protein, which can cause hypoxia in the tubule cells, causing damage to the tubule cells.

Proteinuria symptoms common symptoms proteinuria edema with proteinuria hematuria with proteinuria late pregnancy edema

Common in febrile diseases, more common in the early stage of the disease, urinary protein disappears with hypothermia, only lasts for a few days, in addition to protein in the urine, there are also a few white blood cells and epithelial cells.

Proteinuria examination

Physical examination

Pay attention to edema and serous effusion, bone and joint examination, degree of anemia and examination of heart, liver and kidney signs.

Fundus examination, normal nephritis, normal or mild vasospasm, chronic nephritis, fundus arteriosclerosis, hemorrhage, exudation, etc. Diabetic nephropathy often has diabetic fundus.

2. Laboratory examination

Urine protein examination can be divided into qualitative, quantitative and special examinations.

1). Qualitative inspection

It is best to have morning urine, the morning urine is the strongest, and the orthostatic proteinuria can be ruled out. Qualitative examination is only a screening test, not as an accurate indicator of urine protein content.

2). Quantitative examination of urine protein

3). Urine protein special inspection

Commonly used urine protein electrophoresis examination can distinguish between selective proteinuria and non-selective proteinuria.

Proteinuria diagnosis

diagnosis

(1) medical history

Such as history of edema, occurrence of hypertension, history of diabetes, history of allergic purpura, history of drug use in damaged kidneys, history of heavy metal salt poisoning, history of connective tissue disease, history of metabolic diseases and gout attacks.

(2) Physical examination

(3) Laboratory inspection

Differential diagnosis

1, acute glomerulonephritis: after streptococcal infection, edema, hypertension, hematuria, proteinuria and tubular urine.

2, chronic glomerulonephritis: edema from the lower extremity, spread from the bottom up, long course of disease, easy to relapse, late stage often have renal dysfunction, the first appearance of hypertension.

3, pyelonephritis: systemic infection symptoms, low back pain, bladder irritation, laboratory tests for pyuria urine is its characteristics.

4, systemic lupus erythematosus: belonging to autoimmune diseases, hair loss, facial butterfly erythema, oral ulcers, migratory arthritis, photoallergies, Raynaud's phenomenon, multiple organ damage, especially heart and kidney, especially kidney Loss first. Its proteinuria is generally more, and some patients appear in the form of nephrotic syndrome.

5, multiple myeloma: elderly men with good hair, anemia and is not commensurate with kidney damage. The disease progresses rapidly and is easy to damage kidney function, bone destruction, bone pain, and pathological fracture. Its urine protein is spilled proteinuria.

6, other: severe exercise, microalbuminuria, fever, proteinuria, heart failure, renal congestion caused by proteinuria, drug poisoning caused by proteinuria, due to a clear history and corresponding physical examination, the general diagnosis is not difficult.

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