Hemolysis Due to Trauma - All You Need to Know

Introduction

Hemolysis is defined as rupturing red blood cells and releasing their contents into the surrounding tissues and fluids such as blood plasma. It is a natural body process. It is the destruction of red blood cells. The dead RBCs (erythrocytes) are replaced by new cells. The normal lifespan of red blood cells is from 110 to 120 days. Sometimes the red blood cells get destroyed soon, which causes a total reduction in the overall red blood cells. After their destruction, they are removed by the spleen. The old red blood cells break down after 110 days and are constantly replaced by new red blood cells. Sometimes the red blood cells are destroyed early, before 100 days, which causes a reduction in the overall count. If this condition persists for many days, it leads to hemolytic anemia (it happens due to low RBCs because of too much hemolysis in the body). The spleen is located in the upper right side of the abdomen, which helps remove the destructed RBCs.

What Are the Characteristics of Red Blood Cells?

Red blood cells comprise cell membranes, proteins associated with the membrane, and hemoglobin. The membrane of RBC is a lipid bilayer. There are some proteins present in the membrane that are integral proteins. These proteins are called peripheral proteins. Other proteins are present in the interior surface of RBC membranes. Hemolysis damages the cytoplasmic membrane of the red blood cell and causes cell death.

What Is the Classification of Hemolysis?

The two main types of hemolysis are:

1. Extravascular Hemolysis - It happens outside the blood vessels. The blood vessels are arteries, veins, and capillaries. When filtered through the spleen, white blood cells remove the destructed RBCs from the blood.

2. Intravascular Hemolysis - It happens within the blood vessel. The destructed parts of the RBCs circulate in the blood.

What Are the Causes of Hemolysis?

Hemolysis is caused due to many reasons, including:

• Some genetic defects cause structural abnormalities that lead to hemolysis. Genetic defects can lead to defective red blood cells.

• Some diseases include sickle cell anemia (an inherited disorder that changes the RBCS into a sickle shape) and thalassemia (an inherited disorder with less hemoglobin and fewer RBCs).

• Autoimmune hemolytic anemia causes hemolysis. It is an autoimmune condition where the immune system destroys its red blood cells. It leads to hemolytic anemia.

• Lymphoma (cancer of the lymphatic system), leukemia (cancer of blood-forming cells and bone marrow), and rheumatoid arthritis (an autoimmune condition that attacks the joints) are the other autoimmune conditions that destroy RBCs.

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• Some bacteria, viruses, and parasites destroy the red blood cells and break them down before the body can create new red blood cells. Malaria involves a parasite that destroys red blood cells.

• Medications can make the immune system attack the red blood cells. It can destroy the red blood cells before they are matured. This condition is called drug-induced hemolytic anemia. Some drugs that cause hemolysis are Acetaminophen, Cephalosporins, Clopidogrel, Dapsone, Heparin, Levofloxacin, Quinidine, Quinine, Rifampin, and Sulfonamides.

• Hypersplenism (a condition where the spleen becomes hyperactive, so it removes too many red blood cells from the blood) can cause hemolysis.

• Pregnancy complications such as eclampsia (eclampsia is a condition in pregnant women characterized by high blood pressure levels, high protein release in the urine (proteinuria), and swelling in the feet, legs, and hands) and preeclampsia (the condition is characterized by elevated blood pressure midway through pregnancy, usually after 20 weeks) can cause hemolysis.

• G6PD (glucose-6-phosphate-dehydrogenase) is an enzyme that protects red blood cells from oxidative stresses. G6PD deficiency causes hemolysis.

• Toxins such as venomous snake bites, infections such as malaria and clostridial sepsis, and blood transfusion damage red blood cells after trauma.

How Does Blood Transfusion After Trauma Cause Hemolysis?

Blood transfusion causes hemolysis through the following mechanism:

• Severe injury due to trauma causes systemic changes leading to organ dysfunction and hemolysis of native and transfused red blood cells.

• A blood transfusion can cause hemolysis due to various reasons. Blood transfusions can cause serious complications.

• The reaction happens when the immune system destroys the red blood cells. Many allergies occur after hemolysis. Not all allergies cause hemolysis. Blood is divided into four groups: O, B, A, and AB.

• Antibodies are produced in the blood if the transfused blood is incompatible with the recipient's blood.

• Antibodies are formed in the receiver’s blood if the donor’s blood is incompatible. Immune response destroys the donor's red blood cells. Mostly the immune reactions do not happen in compatible groups. It happens in non-compatible groups.

• Knowledge about blood type is very important because red blood cells contain antigens and protein markers according to their compatible blood types.

• If a blood bank provides the wrong blood type, the immune system will detect any foreign proteins on the wrong blood type's red blood cells, destroying them. Severe injury due to trauma causes intravascular hemolysis, which may mediate post-injury organ dysfunction.

• The antibodies formed against the donor’s blood destroy them, causing them to burst. The blood types are:

1. A positive.

2. A negative.

3. O positive.

4. O negative.

5. B positive.

6. B negative.

7. AB positive.

8. AB negative.

How Does Transfused Blood Cause Organ Damage?

The transfused blood can damage organs as explained below:

• Transfusion of packed red blood cells can result in intravascular hemolysis. In extravascular hemolysis, the RBCs are killed in the monocyte-macrophage system.

• Hemolysis releases erythrocyte proteins, such as hemoglobin and arginase-1.

• Arginase disturbs the arginine metabolism and limits the production of nitric oxide.

• In addition to native RBCs, transfused RBCs are dead and can exacerbate trauma-induced hemolysis.

• Arginase-1 released from RBCs contributes to the depletion of L-arginine and the subsequent reduction in the nitric oxide necessary to maintain organ perfusion (blood supply).

• Nitric oxide is one of the most potent vasodilators. It is important for vascular homeostasis. It is important in limiting platelet aggregation and ischemia-reperfusion injury, modulating endothelial proliferation, and has anti-inflammatory properties.

• Arginine is the precursor to nitric oxide, catalyzed by a family of enzymes called nitric oxide synthases.

• Nitric oxide causes vasodilation. Increased consumption and decreased nitric oxide and arginine production cause hemolysis and organ dysfunction.

What Are the Diagnostic Tests Done for Hemolysis?

The following diagnostic tests are done to diagnose the red blood cells:

• Complete Blood Count- A complete blood count provides information on all types of blood cells and hemoglobin levels.

• Reticulocyte Count- It is a part of the complete blood count. It provides information on the number of reticulocytes (immature red blood cells). The reticulocyte count increases with hemolysis because the body produces new blood cells in response to destroying old blood cells.

• Peripheral Blood Smear- It shows abnormalities in the blood cells. The abnormalities such as abnormal size or shape. Abnormalities cause the macrophages to destroy red blood cells.

• Lactate Dehydrogenase (LDH)- Lactate dehydrogenase is an enzyme in red blood cells. Increased levels in the blood show that the red blood cells are destroyed at faster-than-normal rates.

• Haptoglobin Test- Haptoglobin binds to hemoglobin. Haptoglobin is a protein. The levels decrease when a huge amount of hemoglobin is released into the blood due to hemolysis.

• Unconjugated Bilirubin- Increased bilirubin in your blood may indicate that large red blood cells are being destroyed.

• Direct Coombs Test- A Coombs test detects antibodies that attach to red blood cells. These antibodies destroy the RBCs prematurely.

• Urine Analysis- Urine analysis checks the signs of bilirubin in the urine, indicating hemolytic anemia.

Conclusion

When hemolytic transfusion occurs, it causes a systemic failure in the hospital. The entire transfusion process must be reviewed, and all the personnel involved, including nurses, physicians, and paramedical staff, should be educated on the protocol for blood transfusion. A blood transfusion should not be carried out without verifying the label, patient name, blood type, and patient ABO group.