Hemolysis

Introduction Red blood cell rupture, the phenomenon that hemoglobin escapes from the cell. In vitro, hypotonic solution, mechanical strong oscillation, sudden low temperature freezing (-20 ° C ~ -25 ° C) or sudden freezing, peracid or over-alkali, and alcohol, ether, soap, choline salt, etc. can cause hemolysis . Hemolysis in the body, mainly due to the intrinsic defects of red blood cells (such as sickle cell anemia), or due to certain factors in the plasma (such as hemolytic bacteria or some snake venom invasion, antigen-antibody reaction, various mechanical damage, some The role of some drugs, etc., causes red blood cells to be excessively destroyed.

Cause

1. Extravascular hemolysis: abnormal red blood cells can be recognized by macrophages in the spleen and destroyed.

1. Red blood cell surface chemical changes such as autoimmune hemolysis on the surface of red blood cells with antibody IgG, macrophages can recognize and phagocytose such cells.

2. Spherical red blood cells are significantly reduced in proportion to their area and volume, resulting in reduced deformation performance. When they pass through the spleen sinus microcirculation, they are not easy or unable to pass through the spleen sinus microcirculation, which is much smaller than the diameter, and are retained in the spleen. Inside, it is destroyed by macrophages.

3. UHb disease, G6PD deficiency, under the action of oxidants, hemoglobin in red blood cells precipitates, forming denatured globin bodies, making red blood cells become stiff, deformability is poor, the result is blocked in the spleen and by macrophages damage. Similarly, the liver can also remove significant abnormal red blood cells. When a large amount of extravascular hemolysis occurs, the liver cannot combine bilirubin with glucuronic acid in time, so that the indirect bilirubin content in the blood is increased, and jaundice appears.

Second, intravascular hemolysis: Certain chemical substances such as drugs, bacterial toxins, snake venom, plant hemolysin, etc., or transfusion reactions, or certain diseases, etc., cause a certain structure of red blood cells to change, causing hemolysis reaction in the blood vessels.

an examination

Related inspection

Erythrocyte examination plasma free hemoglobin serum binding globin urine routine irregular antibody screening

1. Peripheral blood routine: red blood cell count, hemoglobin content is reduced, broken red blood cells, abnormal red blood cells, etc. can be seen in the blood smear. When typical atypical red blood cells or self-aggregation occur, they provide clues to the cause of hemolysis.

2. Significance of plasma free hemoglobin measurement: normal plasma has only a small amount of free hemoglobin, >40mg/L is an important indicator of hemolysis, especially intravascular hemolysis, such as paroxysmal sleep hemoglobinuria, blood group incompatibility reaction. Extravascular hemolysis, such as hereditary spherocytosis, generally does not increase.

3. Significance of serum haptoglobin assay (Hp)

A, serum haptoglobin reduction is seen in:

(1) Various hemolytic anemias, including intravascular or extravascular hemolysis.

(2) Hepatocyte damage, infectious mononucleosis, congenital non-binding globinemia and the like.

B, serum haptoglobin increased in infection, tissue damage, extrahepatic obstructive jaundice, malignant tumors.

4. The significance of plasma methemoglobin test, this test helps to identify intravascular or extravascular hemolysis, positive for severe intravascular hemolysis, such as paroxysmal nocturnal hemoglobinuria, a high heme albumin band, In the case of spherocytosis, extravascular hemolysis does not have this zone.

5. Urine check

(1) Increased urinary biliary excretion.

(2) The occult blood test is positive because hemoglobinuria occurs when plasma free hemoglobin is significantly increased, exceeding the amount of haptoglobin and tubular reabsorption function.

(3) The urine hemosiderin test is positive, reflecting chronic hemolysis, especially intravascular hemolysis.

Differential diagnosis

(1) The initial treatment of nutritional anemia such as iron deficiency anemia should be followed up and identified.

(2) Ineffective bone marrow hematopoiesis: Reticulocytes are not high, and red blood cells have a short life span.

(3) Hemorrhage in tissue or body cavity: bilirubin (indirect) can also be elevated, and natural recovery after bleeding stops.

(4) high bilirubin, no anemia in Gilbert syndrome or other abnormal bilirubin metabolism, reticulocytes are not high, red blood cell life is normal.

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