Decreased plasma albumin

Introduction Plasma albumin is synthesized by hepatocytes and is the most abundant protein in plasma, accounting for 40% to 60% of total protein. The main physiological functions of albumin include: as a source of endogenous amino acid nutrients; it has considerable acid-base buffering capacity; it is also a major carrier in plasma, and many poorly water-soluble substances such as bilirubin, bile salts, prostaglandins, Steroid hormones, metal ions, various drugs, and the like are all transported by binding to albumin. Another function is to maintain blood colloid osmotic pressure; albumin has a small molecular weight, and its concentration in extravascular fluid can be a good indicator of the integrity of various membrane barriers. Plasma albumin reduction: mainly seen in cirrhosis with ascites and other serious liver damage (such as acute liver necrosis, toxic hepatitis, etc.) malnutrition, chronic wasting disease, diabetes, severe hemorrhagic nephrotic syndrome. Ascites is easily produced when it is reduced to less than 25 g/L.

Cause

Causes of decreased plasma albumin

The main reasons for the decrease in plasma protein concentration are:

1 protein loss: a large amount of protein is lost from the urine during nephrotic syndrome; protein is lost in the intestinal lumen and is excreted with feces;

2 synthetic disorders: seen in severe damage to the liver parenchyma (such as cirrhosis) or malnutrition;

3 Dilute the protein when a large amount of sodium water is retained or a large amount of non-colloidal solution is input.

an examination

Related inspection

Plasma protein S assay

Examination of plasma albumin reduction

In addition to the performance of the primary disease, its main clinical manifestations are malnutrition. Negative balance of nitrogen causes significant consumption of subcutaneous fat and skeletal muscle, patients are increasingly thin, and severe cases are dyscrasia. The gastrointestinal mucosa is atrophied, the gastric acid secretion is reduced, the digestive enzyme is reduced, and the appetite is poor. Tiredness and weakness are common symptoms. Patients do not like activities, physical strength declines, reactions become dull, and memory declines. Most have mild to moderate anemia, often dizziness, and may have orthostatic hypotension and bradycardia. The occurrence of edema is associated with a decrease in plasma effective osmotic pressure. The osmotic pressure of body fluid is inversely proportional to the molecular weight of the solute contained therein. The smaller molecular weight of albumin is the main component for maintaining the osmotic pressure of colloid. The total osmotic pressure of plasma and tissue fluid is not much different, but it is impervious to the capillary in the plasma. The wall has more albumin, so the plasma osmotic pressure is higher, so that the water has a tendency to enter the plasma from the tissue fluid. When the plasma albumin is reduced, the effective osmotic pressure is reduced, and excessive water is retained between the tissues, and edema is formed. When the edema is severe, pleural effusion and ascites may occur. In addition, sexual dysfunction, amenorrhea, osteoporosis, and body resistance may occur. Power difference, etc. Those with reduced plasma fibrinogen may have a tendency to bleed.

Differential diagnosis

Symptom identification of plasma albumin reduction

It is necessary to identify the cause of the decrease in plasma albumin.

(1) Decreased synthesis of albumin: common in acute or chronic liver disease, but due to the long half-life of albumin, in some patients with acute liver disease, the decrease in plasma albumin concentration may not be obvious.

(2) Due to malnutrition or malabsorption.

(3) hereditary defects: no albuminemia is a rare metabolic defect, plasma albumin content is often less than 1g / L. However, there may be no symptoms (such as edema), which may be due in part to a compensatory increase in globulin content in the blood vessels.

(4) Increase in albumin catabolism due to tissue damage (surgery or trauma) or inflammation (infectious disease).

(5) abnormal loss of albumin: due to nephrotic syndrome, chronic glomerulonephritis, diabetes, systemic lupus erythematosus, etc., albumin is lost from the urine, sometimes more than 5g of protein can be excreted from the urine every day, more than the liver Compensatory ability. A certain amount of protein can also be lost from the intestinal tract during ulcerative colitis and other intestinal inflammation or tumors. Burns and exudative dermatitis can lose a lot of protein from the skin.

(6) Abnormal distribution of albumin: As the portal vein has a large amount of protein in the ascites, it leaks from the blood vessels into the abdominal cavity.

In addition to the performance of the primary disease, its main clinical manifestations are malnutrition. Negative balance of nitrogen causes significant consumption of subcutaneous fat and skeletal muscle, patients are increasingly thin, and severe cases are dyscrasia. The gastrointestinal mucosa is atrophied, the gastric acid secretion is reduced, the digestive enzyme is reduced, and the appetite is poor. Tiredness and weakness are common symptoms. Patients do not like activities, physical strength declines, reactions become dull, and memory declines. Most have mild to moderate anemia, often dizziness, and may have orthostatic hypotension and bradycardia. The occurrence of edema is associated with a decrease in plasma effective osmotic pressure. The osmotic pressure of body fluid is inversely proportional to the molecular weight of the solute contained therein. The smaller molecular weight of albumin is the main component for maintaining the osmotic pressure of colloid. The total osmotic pressure of plasma and tissue fluid is not much different, but it is impervious to the capillary in the plasma. The wall has more albumin, so the plasma osmotic pressure is higher, so that the water has a tendency to enter the plasma from the tissue fluid. When the plasma albumin is reduced, the effective osmotic pressure is reduced, and excessive water is retained between the tissues, and edema is formed. When the edema is severe, pleural effusion and ascites may occur. In addition, sexual dysfunction, amenorrhea, osteoporosis, and body resistance may occur. Power difference, etc. Those with reduced plasma fibrinogen may have a tendency to bleed.

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