Hemolytic Anemia

Overview

Blood is made up of three main types of cells suspended in a liquid medium called blood plasma. The function of red blood cells is to transport oxygen to all the different parts of the body. A substance known as hemoglobin, which also gives RBCs their red color, is responsible for binding to oxygen and enabling its transport.

Red blood cells have a short lifespan. On average, and under normal conditions, RBCs continue to function for a period of about 120 days. Old ones are regularly replaced with fresh ones. Worn out red blood cells are cleared away and broken down into organs like the spleen which then metabolizes the hemoglobin contained in them. New red blood cells are generated and incubated in the bone marrow until they have matured. In order to maintain the total numbers of RBCs in circulation, the process of breakdown must be balanced with the process of production and release of new RBCs.

What Is Haemolytic Anaemia?

‘Anemia’ is any condition involving a significant shortage of red blood cells. However, the shortage of red blood cells leaves the body’s cells and tissues starving of oxygen. Without oxygen, the patient feels weak and short of breath and soon, they start appearing very pale.

‘Hemolysis’ is the process of breakdown of red blood cells, causing them to release their cell contents into the fluid medium (blood plasma) in which they are carried. There can be a range of different causes for hemolysis, including autoimmune activity and even bacterial or parasitic infections. There are two forms of hemolysis, namely, the intravascular and extravascular. The former refers to hemolysis which occurs within blood vessels and the latter label is applicable when hemolysis takes place not in blood vessels but in organs such as the spleen.

‘Hemolytic anemia’ is the name given to the condition where red blood cells are in short supply because something causes them to break down or undergo hemolysis in abnormally large numbers. As we have seen, hemolysis is a normal physiological process. However, if the production of new RBCs in the bone marrow cannot keep pace with the rate of hemolysis and fails to compensate adequately, the patient develops anemia. In other words, hemolytic anemia occurs when the quantity of red blood cells in circulation is heavily depleted because of excessive hemolysis. This can lead to jaundice and other more serious complications. In fact, in severe cases, hemolytic anemia could even be fatal.

What Causes Haemolytic Anaemia?

Today, medical science recognizes a wide range of possible causes for hemolytic anemia. This condition may be caused by intrinsic or extrinsic factors. Examples of intrinsic causes include inherited disorders such as thalassemia. Sometimes, autoimmune activity is also implicated. Extrinsic factors may include drugs that induce higher rates of RBC destruction or even having a defective prosthetic heart valve.

A fuller list of possible causes appears below, grouped under appropriate headings:

• Abnormalities in the membrane of red blood cells: This includes inherited disorders such as hereditary spherocytosis and hereditary elliptocytosis as well as acquired ones like paroxysmal nocturnal hemoglobinuria.
• Hereditary disorders such as sickle cell disease and thalassemia.
• Problems related to metabolism: Examples include G6PD deficiency and pyruvate kinase deficiency.
• Immune-mediated processes: This may include an incompatibility between Rh factors in the blood of a mother and fetus (hemolytic disease of the newborn) or it may involve autoimmune activity as in chronic diseases such as systemic lupus erythematosus and rheumatoid arthritis.
• Cancers such as Hodgkin’s lymphoma and chronic lymphocytic leukemia.
• Certain chemicals or medical drugs: Lead poisoning and snake venom, for instance, can act as causes for hemolytic anemia and certain antiviral drugs are also known to produce this side-effect.
• Having defective prosthetic heart valves.
• Hyperactivity of the spleen: This is known as hypersplenism and it is often related to liver disorders.
• Trauma.
• Vasculitis. This is inflammation of blood vessels.
• Infections: Including those caused by certain bacterial and parasitic agents.
• Therapies such as blood and bone marrow stem cell transplant and hemodialysis
• Blood pressure problems as in preeclampsia and malignant hypertension.

What Are The Symptoms Of Hemolytic Anemia?

Hemolytic anemia presents with the typical characteristics of anemia such as pallor of skin, breathlessness, and fatigue. A more detailed list appears below:

• Fatigue.
• Pale appearance.
• Feeling short of breath.
• Inability to exercise or exert oneself physically.
• Dark colored urine as a result of hemoglobin in the urine. This is known as hemoglobinuria.
• Yellowing of the skin or of the whites of the eyes.

What Are The Different Forms Of Hemolytic Anemia?

There are quite a few different types of hemolytic anemia but broadly speaking, these can be grouped under two main headings. Any case of hemolytic anemia can be described as either inherited or acquired. In other words, the factors responsible for hemolysis are either already present in the body as a result of heredity or else they are acquired later in life due to medications or disease. Alternatively, hemolytic anemia may be classified as either immune-related or non-immune mediated.

What Are Some Complications To Watch Out For?

There is a range of potential complications linked with severe hemolytic anemia. Some possibilities are mentioned in the list below:

• Jaundice.
• Splenomegaly or abnormal enlargement of the spleen.
• Increased risk of developing gallbladder stones.
• Increased risk of pulmonary hypertension.

How Can This Be Diagnosed And Treated?

Outwardly noticeable symptoms may indicate the presence of anemia but in order to correctly pinpoint the nature of the problem, you will need to undergo a variety of blood and urine tests as well as certain other laboratory tests:

• Physical examination.
• Medical history.
• Blood tests.
• Urine tests.
• Liver function tests.
• Bone marrow aspiration or biopsy.

The nature, intensity, and duration of treatment are entirely dependent on the underlying causes responsible for hemolytic anemia and the severity of the condition. Mild cases may not require treatment at all. If the patient is suffering from a hereditary disorder, then treatment may be a lifelong affair. On the other hand, it is possible to permanently resolve hemolytic anemia in instances of acquired causes such as malaria.

The main goal of treatment is to prevent the excessive destruction of RBCs and to bring RBC count back to a normal level. Where autoimmune mechanisms are responsible for hemolysis, the patient may be treated with appropriate medications. For other immune-mediated cases, a procedure known as plasmapheresis may be advised. In instances of blood disorders such as thalassemia or problems related to bone marrow, patients will benefit from blood or bone marrow transfusions.

Prevention

There are no known ways to prevent the onset of inherited hemolytic anemia. If one is born with a deficiency of G6PD (glucose 6 phosphate dehydrogenase), you can reduce the severity of the symptoms by staying away from triggers such as naphthalene balls (moth balls). Genetic counseling and prenatal care can help in detecting Rh incompatibility issues.

A person is said to be suffering from hemolytic anemia when, for a variety of possible reasons, there is an abnormally increased rate of red blood cell destruction in the body such that the rate of replenishment is unable to keep up with it. This problem affects the entire body and all of its organs and tissues since one of the primary functions of blood is to deliver adequate quantities of oxygen to all parts of the body. The condition may be temporary or permanent depending on the nature of the cause. Treatment can help to alleviate the condition to some extent in inherited cases of hemolytic anemia. Whereas, in instances of infection or acquired conditions such as trauma, it is possible to resolve it completely.

References