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Hemolytic Anemia – Types, Complications and Treatment

Definition

Hemolytic anemia is a medical condition in which the life span of red blood cells is either reduced or prematurely destroyed.The condition of red blood cells being destroyed is called hemolysis. Red blood cells act as a transport medium to carry oxygen to all parts of the body. If there is a lower amount of red blood cells, then the individual is said to be anemic.

Normally, a red blood cell lives for about 120 days. The body gets rid of old red blood cells through a process called hemolysis. It replaces the old ones with new ones through a process called erythropoiesis. In hemolytic anemia, hemolysis happens too early. This shortens the lifespan of red blood cells to less than 120 days.

Hemolytic anemia is due to some intrinsic and extrinsic factors. Intrinsic factors include inadequate hemoglobin production, defective production of erythrocyte cell membranes abnormal red blood cell metabolism. Whereas, extrinsic factors are immune system-mediated causes, hypersplenism, certain infections, poisoning of lead, stibine, and arsine, etc. Treatment of hemolytic anemia includes blood transfusion, steroid therapy, use of immunosuppressants, intravenous antibodies, splenectomy and many more.

Types of Hemolytic Anemia

There are two types of hemolytic anemia:

Types of inherited hemolytic anemia include:

Types of acquired hemolytic anemia include:

Epidemiology

Two databases exist which provide a systematic exclusion of the population of people that are not “normal”: NHANES-III (the third U.S. National Health and Nutrition Examination Survey) database and the Scripps-Kaiser database.  Through these databases, one can see there is no difference in hemoglobin values of men from 20 to 59 or women 20 to 49. This assists in studying patient populations whose values do fall out of the norm from these ranges.

African Americans are found to have a lower limit of normal hemoglobin concentration, lower serum transferrin saturation, higher serum ferritin levels, lower bilirubin levels, and lower leukocyte counts. This is thought to be due to the higher frequency of alpha-thalassemia and G6PD deficiency in the black population. G6PD deficiency is known to affect millions of people worldwide. Although it can be seen worldwide, HE is most predominantly seen in malaria-endemic regions of West Africa. Several forms of anemia are seen in these regions, as it is often thought to be protective against malaria. Overall hemolytic anemias cover a broad range of age groups, races, and both genders as several subcategories can be acquired or inherited.

Pathophysiology

Premature destruction of RBCs can occur intravascularly or extravascularly in the reticuloendothelial system, although the latter is more common. The primary extravascular mechanism is sequestration and phagocytosis due to poor RBC deformability (i.e., the inability to change shape enough to pass through the spleen). Antibody-mediated hemolysis results in phagocytosis or complement-mediated destruction, and can occur intravascularly or extravascularly. The intravascular mechanisms include direct cellular destruction, fragmentation, and oxidation. Direct cellular destruction is caused by toxins, trauma, or lysis. Fragmentation hemolysis occurs when extrinsic factors produce shearing and rupture of RBCs. Oxidative hemolysis occurs when the protective mechanisms of the cells are overwhelmed.

The etiologies of hemolysis are numerous. The hemoglobinopathies lead to splenic destruction and, in the case of sickle cell disease, likely multiple mechanisms of destruction. Inherited protein deficits lead to increased destruction in membranopathies. Enzymopathies result in hemolysis due to overwhelming oxidative stress or decreased energy production. In immune-mediated hemolytic anemia, antibodies bind with the RBCs, resulting in phagocytosis or complement-mediated destruction. The extrinsic nonimmune causes include microangiopathic hemolytic anemia (MAHA), infections, direct trauma, and drug-induced hemolysis, among others.

Causes

Your body makes new red blood cells in the bone marrow, the soft tissue in bones where all blood cells are formed. When you have hemolytic anemia, red blood cells are destroyed through a process called hemolysis.

There are several potential causes for hemolytic anemia, including:1

Symptoms of Hemolytic Anemia

Hemolytic symptoms can be mild or more severe. They also can come on suddenly or develop over time. Typical symptoms include:

Risk factors

Oxidative stress in the setting of G6PD deficiency:

Mechanical damage-related risk factors:

Genetic conditions affecting red blood cells:

Hemolytic Anemia Complications

Complications depend on the cause of the hemolytic anemia and include:

Diagnosis

Your healthcare provider may think you have hemolytic anemia based on your symptoms, your medical history, and a physical exam. Your provider may also order the following tests:

Hemoglobin and haematocrit: This test measures the amount of hemoglobin and red blood cells in the blood.

Complete blood count (CBC): This test checks the red and white blood cells, blood clotting cells (platelets), and sometimes, young red blood cells (reticulocytes). It includes hemoglobin and hematocrit and more details about the red blood cells.

Peripheral smear: A small sample of blood is viewed under a microscope. Blood cells are checked to see if they look normal or not.

Other blood tests: These tests will check for lactate dehydrogenase, bilirubin, and haptoglobin which can causes ongoing hemolysis. Certain tests can find antibodies that cause hemolysis.

Urine tests: These tests can check for hemoglobin from red blood cells breaking down.

Bone marrow aspiration, biopsy, or both: A small amount of bone marrow fluid (aspiration), solid bone marrow tissue (called a core biopsy) often from the hip bones, or both are checked for the number, size, and maturity of blood cells. This test may also look for abnormal cells.

Microscopic view of (a) normal blood cells and (b) hemolytic anemia affected blood cells

What is the treatment for Hemolytic Anemia?

The treatment plan for a person with hemolytic anemia depends on the cause of the disorder. Treatment can also depend on the person’s age, medical history and how severe the anemia is.

Treatment options may include:

In more severe cases, the person may have to stay in the hospital. They may receive the following treatments:

Prevention of Hemolytic Anemia

Some ways to prevent episodes of hemolytic anemia include the following:

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