What is Hemolytic Anemia?

Hemolytic anemia is anemia that occurs due to an increased rate of red blood cell destruction (shortened life) that exceeds the compensatory capacity of bone marrow hematopoiesis. Bone marrow has 6 to 8 times the red blood line hematopoietic compensation potential. If the red blood cell destruction rate is within the compensation range of the bone marrow, there is hemolysis, but no anemia occurs, which is called a hemolytic disorder, or a hemolytic state. The life span of normal red blood cells is about 120 days, and anemia occurs only when the life span of red blood cells is shortened to 15-20 days.

Basic Information

nickname: Hemolytic disease
English name: hemolytic anemia
Visiting department: Hematology

Common causes: Caused by internal defects of red blood cells and abnormal external factors of red blood cells
Common symptoms: Chills, fever, anemia, jaundice, hemoglobinuria, etc.
Contagious: no

Causes and pathogenesis of hemolytic anemia

The underlying cause of hemolytic anemia is shortened red blood cell life. The causes of the accelerated destruction of red blood cells can be broadly divided into internal defects of red blood cells themselves and abnormalities of external factors of red blood cells. The former is mostly hereditary hemolysis, and the latter causes acquired hemolysis.

Inherent red blood cell defect

Including red blood cell membrane defects (such as hereditary red blood cell membrane structure and functional defects, acquired red blood cell membrane anchor chain membrane protein abnormalities), red blood cell enzyme defects (such as hereditary red blood cell enzyme deficiency), globin abnormalities (such as hereditary hemoglobin disease), etc. .

2. External factors of red blood cells are abnormal

Including immune factors, non-immune factors.

(1) Immune factors

Autoimmune hemolytic anemia (AIHA), neonatal hemolysis, incompatible blood transfusion, drug-induced anemia, etc.

(2) Non-immune factors

Physical and mechanical factors: artificial heart valve, heart valve calcification stenosis, disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), marching hemoglobinuria, large area burn, etc

Chemical factors: snake venom, phenylhydrazine, etc .;

Infectious factors: malaria, mycoplasma pneumonia, infectious mononucleosis and so on.

3. Place where hemolysis occurs

Red blood cell destruction can occur in the blood circulation or the monocyte-macrophage system, which is called intravascular hemolysis and extravascular hemolysis, respectively. The clinical manifestations of intravascular hemolysis are often obvious, accompanied by hemoglobinemia, hemoglobinuria, and hemosiderin. Extravascular hemolysis mainly occurs in the spleen, and clinical manifestations are generally mild. There may be a slight increase in serum free heme and no hemoglobinuria. In situ hemolysis may occur in certain diseases. For example, in diseases such as megaloblastic anemia and myelodysplastic syndrome (MDS), the young red blood cells in the bone marrow are destroyed in the bone marrow before being released into peripheral blood. In situ hemolysis or ineffective erythropoiesis, it also belongs to extravascular hemolysis and may also have jaundice.

Classification of hemolytic anemia

There are several clinical classification methods for hemolytic anemia. According to the incidence and disease can be divided into acute and chronic hemolysis. According to the hemolytic site can be divided into intravascular hemolysis and extravascular hemolysis. The more clinically significant is the classification by etiology and pathogenesis.

Clinical manifestations of hemolytic anemia

Although there are many diseases of hemolytic anemia, they share certain characteristics. The clinical manifestations of hemolytic anemia are mainly related to the duration of the hemolytic process and the severity of hemolysis.

Chronic hemolysis is mostly extravascular hemolysis, and the onset is slow, showing three characteristics of anemia, jaundice and splenomegaly. Due to the long course of disease, patients' respiratory and circulatory systems often have good compensation for anemia, and their symptoms are mild. Because long-term hyperbilirubinemia can affect liver function, patients may be complicated by gallstone disease and liver damage. In the process of chronic hemolysis, some causes such as viral infections, patients may develop temporary erythropoietic stagnation for about a week, which is called aplastic crisis.

Acute onset of acute hemolysis, short-term massive hemolysis caused chills, fever, headache, vomiting, lower back pain and abdominal pain in limbs, followed by hemoglobinuria. In severe cases, acute renal failure, peripheral circulation failure, or shock may occur. Later, symptoms and signs of jaundice, paleness, and other severe anemia appeared.

Hemolytic anemia test

Laboratory tests for hemolytic anemia can traditionally be divided into three categories:

1. Increased red blood cell destruction

Check for hemoglobinemia, hyperbilirubinemia (indirect bilirubin), and decreased serum globin; urinalysis shows increased hemoglobinuria, hemosiderin-containing urine, and urobilinogen excretion; faecocholidinia Excretion increases.

2. Red blood hematopoietic compensatory hyperplasia

Check whether there is an increase in reticulocytes, usually above 5%, sometimes up to 50%; young red blood cells appear in the surrounding blood, mainly late red, and sometimes there are late young bone marrow young red cell proliferation, and the proportion of young red blood cells in the bone marrow is obvious The increase is mainly middle and late red with normal morphology.

3.Special examination for various hemolytic anemia

Such as whether the red blood cell morphology changes (spherical, oval, mouth-shaped, spinous, target-shaped, fragmented, sickle-shaped), phagocytosis of red blood cells and autoagglutination, Heinz bodies, erythrocyte osmotic fragility, red blood cell life check For differential diagnosis.

Diagnosis of hemolytic anemia

Chronic hemolysis has clinical manifestations of anemia, jaundice, and splenomegaly. Laboratory tests have evidence of increased red blood cell destruction and erythropoiesis compensatory hyperplasia. Hemoglobinuria strongly suggests acute intravascular hemolysis. The diagnosis of hemolytic anemia can be considered. According to the preliminary diagnosis, special examinations for various hemolytic anemias are selected to determine the nature and type of hemolysis.

Differential diagnosis of hemolytic anemia

Diseases with anemia accompanied by strong bone marrow erythropoiesis and reticulocyte hyperplasia or anemia with jaundice can be confused with hemolytic anemia.

Hemolytic Anemia Treatment

Hemolytic anemia is a group of heterogeneous diseases whose treatment should vary from disease to disease. Correct diagnosis of the cause is a prerequisite for effective treatment. The following are principles for the treatment of certain hemolytic anemias.

Remove the cause

Acquired hemolytic anemia, if the cause is found, is expected to be cured after removing the cause. After drug-induced hemolytic anemia is discontinued, the condition may soon recover. Hemolytic anemia caused by infection can be terminated after the infection is controlled. Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency should avoid eating fava beans or taking oxidative drugs; cold set syndrome should pay attention to cold protection and warmth; drug-induced anemia should be discontinued immediately; suspected hemolytic transfusion reaction, Blood transfusion should be stopped immediately, and the cause should be further identified; infection can also cause hemolysis or aggravate the original hemolytic defect, attention should be paid to prevention and treatment

2. Glucocorticoids and other immunosuppressants

Mainly used for certain immune hemolytic anemia. Glucocorticoids have a good effect on warm antibody autoimmune hemolytic anemia and can also be applied to PNH. Cyclosporine and cyclophosphamide are effective against a small number of immunolytic anemias, such as warm antibody autoimmune hemolytic anemia or cold antibody autoimmune hemolytic anemia, which are ineffective for certain glucocorticoid treatments.

3. Blood transfusion or component transfusion

Blood transfusion can quickly improve the symptoms of anemia, but blood transfusion can cause serious reactions in some hemolytic anemia, so its indications should be strictly controlled. Paroxysmal nocturnal hemoglobinuria (PNH) transfusion may cause an acute hemolytic attack. Autoimmune hemolytic anemia with high concentrations of autoantibodies can cause difficulty in matching. In addition, hemolysis may be exacerbated after transfusion. Therefore, transfusion of hemolytic anemia should be considered as a support or life-saving measure. If necessary, use red blood cell suspension or wash red blood cells.

4. Splenectomy

It is suitable for hemolytic anemia that mainly occurs in the spleen, such as hereditary spherocytosis (absolute indication), autoimmune hemolytic anemia that does not respond to glucocorticoids, and those who require a larger dose of glucocorticoid maintenance therapy In some hemoglobin diseases (pyruvase deficiency and thalassemia), although the disease cannot be cured after spleen incision, it can reduce the destruction of red blood cells and relieve the disease to varying degrees.

5. Other treatments

Severe acute intravascular hemolysis can cause fatal complications such as acute renal failure, shock, and electrolyte disorders, and should be actively addressed. Folic acid consumption is increased in some chronic hemolytic anemia, and appropriate supplementation of folic acid is appropriate. Chronic intravascular hemolysis increases iron loss, and it can be treated with iron after confirming iron deficiency. Patients with severe anemia of severe globin production that has long relied on blood transfusion can cause hemochromatosis and can be treated with iron chelator flooding.