SCD & You

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Understanding Sickle Cell Disease

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Learning about the science behind sickle cell disease (SCD) is important. When you understand what’s happening in your body, you can be more comfortable talking about it. Plus, you may be able to make changes to your routine that can help you better manage your condition.

Helpful tips for living with sickle cell disease

Managing your sickle cell disease may feel overwhelming. Remember that small steps may make a difference. Consider the following tips to help manage sickle cell disease:


Talk to your doctor regularly about how you are managing your sickle cell disease. You can use the Doctor Locator to find a doctor in your area who has experience treating sickle cell disease.


Stay healthy by taking care of yourself. Remember that you’re not alone. Consider reaching out to your medical care team, family, friends, or other sources of support. They may be able to help you handle the emotional and social challenges of sickle cell disease.


Wash your hands, eat safely prepared food, and get vaccines to avoid getting sick.


Try to avoid very hot or very cold temperatures.


Drink 8 to 10 glasses of water a day and eat healthy foods.


Get plenty of rest and work with your doctor to develop an exercise plan that works for you.


Consider joining a support group and share tips about living with sickle cell disease.


The genetics of sickle cell disease

Sickle cell disease is an inherited disorder. That means if someone has sickle cell disease, it was passed down from both their birth parents. Specifically, it is a protein in your red blood cells known as the hemoglobin (Hb) gene passed down by each parent that can cause a child to have sickle cell disease, carry the sickle cell trait, or not carry the trait at all. The hemoglobin gene that you inherit is very important because hemoglobin helps your blood stay healthy and carry oxygen all through your body. An abnormal hemoglobin gene causes the red blood cells to become rigid and sickle-shaped, which affects how healthy your blood can be.

The figure below shows how each parent's hemoglobin gene can be passed down to their child. In this example, both parents are sickle cell trait carriers. They have one normal hemoglobin gene (HbA) and one sickle hemoglobin gene (HbS). 


It is important to understand that these chances remain the same each time the two sickle cell trait carriers have a child. If the couple’s first child has sickle cell disease, their second child is just as likely to have sickle cell disease. If a person wants to know whether he or she carries a sickle hemoglobin gene, a doctor can order a blood test to find out.

If you are living with sickle cell disease, the type of the disease that you have depends on the hemoglobin genes you inherited. HbSS is the most common type of sickle cell disease. As the figure above showed you, HbSS comes from each parent passing on an abnormal sickle cell hemoglobin gene.

HbS, however, is not the only abnormal hemoglobin gene that a parent can pass on to their child. There are other abnormal hemoglobin genes, like HbC and Hbβ thalassemia. Any combination of the abnormal sickle cell hemoglobin gene with another abnormal hemoglobin gene can result in a child being born with sickle cell disease. The figure below shows the different types of sickle cell disease that are possible.


Sickle cell disease occurs in about 1 of every 365 African American births, but the trait presents in about 1 of every 13 African American births.

Those who carry the sickle cell trait face few, if any, potential health challenges directly related to having the HbS gene. However, sickle cell trait carriers, relative to the general population, are at increased risk for certain complications, including:

  • Cysts or other lesions on the kidney
  • A blood clot in the lungs
  • Tissue damage to the spleen, typically due to lack of oxygen at high altitudes
  • Heat stroke

How sickle cell disease can impact your health


Normal red blood cells look like discs. They do what healthy red blood cells are supposed to do. They carry oxygen through your body. However, if you have sickle cell disease some of your red blood cells are not healthy-looking discs. Instead, they have a sickle shape. Sickled red blood cells are not stable. While a red blood cell that is disc-shaped can live in your bloodstream for up to 4 months, a sickled red blood cell can break apart in fewer than 3 weeks.

The breaking apart of red blood cells is called hemolysis. While hemolysis is normal (everyone’s red blood cells break apart in time), it happens more quickly and more often in people who have sickle cell disease. Your body will try to make new red blood cells to replace the ones that broke apart. Unfortunately, it is hard for your body to produce the new blood cells it needs fast enough. That creates a problem called anemia, which can make you feel weak and tired. If the anemia is severe you will have to receive blood transfusions.



Pain Crises

The symptom you probably think of most when you think of sickle cell disease is sudden, intense pain. Such painful episodes are also known as pain crises. What is important to know is that it is not just your sickled red blood cells that lead to pain crises. Other blood cells, such as white blood cells and platelets, are affected too. So your blood vessels are in a chronic state of inflammation.

Look over the figures below, and read the descriptions. They'll help you see why pain crises are the result of how sickle cell disease affects your whole blood system, not just red blood cells.


Damaged blood vessels in sickle cell disease


Your blood vessels can become damaged, which causes blood cells and blood vessels to become "sticky."


Clusters form in bloodstream in sickle cell disease


The stickiness of the blood cells makes them more likely to get stuck to one another. When blood cells stick to each other, they form clusters in the bloodstream.


Blocked blood and oxygen flow caused by clusters in sickle cell disease


The clusters can reduce or block blood and oxygen flow.


Vaso-occlusive crisis in sickle cell disease


When blood cell clusters get big enough, they can lead to a pain crisis without warning. The pain during a pain crisis can be severe and require medical intervention.

In addition to causing severe pain, when the flow of blood gets blocked during a crisis there can be longer-term health risks. For example, your organs that rely on oxygen from your blood may become damaged.

You may hear a doctor refer to pain crises as vaso-occlusive crises. Vaso is a Latin term that refers to blood vessles. Occlusion is just another way of saying blockage.

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