Wednesday, January 19, 2011


What is Sickle Cell Anemia?

Sickle Cell anemia or Sickle Cell Disease is a blood disorder that occurs due to a genetic alteration that results in the body making sickle–shaped red blood cells instead of the normal disc-shaped red blood cells. Sickle red cells contain abnormal hemoglobin that causes the cells to have a sickle, or crescent, shape. These cells don't move easily through your blood vessels.

In sickle cell anemia, the number of red blood cells is low because sickle cells do not last very long. Sickle cells usually die after only about 10 to 20 days and the bone marrow cannot make new red blood cells fast enough to replace the dying ones.

People who inherit a sickle cell gene from one parent and a normal gene from the other parent have a condition called sickle cell trait.

Sickle cell trait is different from sickle cell anemia. People who have sickle cell trait do not have the disease, but they have one of the genes that cause it. Like people who have sickle cell anemia, people who have sickle cell trait can pass the sickle cell gene on to their children.

What Causes Sickle Cell Anemia?

Sickle cell anemia is an inherited disease. People who have the disease inherit two copies of the sickle cell gene – one from each parent.

The sickle cell gene causes the body to make abnormal hemoglobin. Hemoglobin is an iron-rich protein in red blood cells. It carries oxygen from the lungs to the rest of the body.

In sickle cell anemia, the hemoglobin sticks together after it delivers oxygen to the body's tissues. These clumps of hemoglobin are like liquid fibers. They cause the red blood cells to become stiff and have a sickle, or crescent, shape.

Sickle cells tend to stick together or to blood vessel walls, causing them to get caught in the blood vessels.  

Two copies of the sickle cell gene are needed for the body to make the abnormal hemoglobin found in sickle cell anemia.

Sickle Cell Trait

If you inherit one copy of the sickle cell gene (from one parent), you will not have sickle cell anemia. Instead, you will have sickle cell trait.

People who have sickle cell trait usually have no symptoms and lead normal lives. However, some few people may have medical complications.

People who have sickle cell trait also can pass the sickle cell gene to their children.
A person inherits two copies of the hemoglobin gene—one from each parent. A normal gene will make normal hemoglobin (A). An abnormal (sickle cell) gene will make abnormal hemoglobin (S).

When both parents have a normal gene and an abnormal gene, each child has a 25 percent chance of inheriting two normal genes; a 50 percent chance of inheriting one normal gene and one abnormal gene; and a 25 percent chance of inheriting two abnormal genes.

Who is at risk? 

Sickle cell anemia is most common in people whose families originate from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia.

What are the Signs and Symptoms?

The signs and symptoms of sickle cell anemia vary. Some people have mild symptoms. Others have very severe symptoms and are often hospitalized for treatment.

Sickle cell anemia is present at birth, but many infants do not show any signs until after 4 months of age.

The most common signs and symptoms are linked to anemia and pain. Other signs and symptoms are linked to the disease's complications

Signs and Symptoms Related to Anemia

The most common symptom of anemia is fatigue (feeling tired or weak). Other signs and symptoms of anemia may include:
  • Shortness of breath
  • Dizziness
  • Headaches
  • Coldness in the hands and feet
  • Paler than normal skin or mucous membranes (the tissue that lines your nose, mouth, and other organs and body cavities)

Signs and Symptoms Related to Pain

Sudden pain throughout the body is a common symptom of sickle cell anemia. This pain is called a sickle cell crisis. Sickle cell crises often affect the bones, lungs, abdomen, and joints.

These crises occur when sickle red blood cells form clumps in the bloodstream. (Other cells also may play a role in this clumping process.) These clumps of cells stick to small blood vessels and block blood flow to the limbs and organs. This can cause pain and organ damage.

The pain from sickle cell anemia can be acute or chronic, but acute pain is more common. Acute pain is sudden and can range from mild to very severe. The pain usually lasts from hours to as long as a week or more.

Chronic pain often lasts for weeks or months. Chronic pain can be hard to bear and mentally draining. This pain may limit your daily activities.

Almost all people who have sickle cell anemia have painful crises at some point in their lives. Some have these crises less than once a year. Others may have crises once a month or more.

Many factors can play a role in sickle cell crises. Often, more than one factor is involved and the exact cause is not known.

You can control some factors. For example, the risk of a sickle cell crisis increases if you're dehydrated (your body doesn't have enough fluids). Drinking plenty of fluids can lower the risk of a painful crisis.

You cannot control other factors, such as infections.

Painful crises are the leading cause of outpatient visits and hospital admissions for people who have sickle cell anemia.

Dr. Olukayode Williams

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