Sickle cell disease
We understand how overwhelming a diagnosis of sickle cell disease can be, especially because most children are diagnosed as infants. Right now, you probably have a lot of questions. How dangerous is this condition? Will my child outgrow it? What is the very best treatment? What do we do next?
We’ve tried to provide some answers to those questions, and our experts can explain your child’s condition fully when you meet with us.
What is sickle cell disease?
Sickle cell disease is an inherited blood disorder that occurs when a protein called hemoglobin that helps red blood cells carry oxygen from the lungs to all parts of the body is defective.
What do sickle cells look like?
Normal red blood cells are smooth, round and flexible, like the letter O, enabling them to move easily through your child’s blood vessels. In contrast, sickle cells are stiff, sticky and often shaped like the letter C.
Sickle cells tend to cluster together, making it difficult for them to move through small blood vessels. These clusters can create blockages in your child’s small blood vessels, stopping the movement of healthy, oxygen-carrying blood. This blockage, which can be painful, is what causes the majority of the complications of the disease.
Sickle cells only live for about 14 days, while normal red blood cells can live up to 120 days. This is because the spleen, which helps filter bacterial infections from the blood and act as the recycle center for old red blood cells, tends to destroy the sickle cells. This leads to a lack of oxygen-carrying red cells in the blood, causing chronic anemia. Sickle cells can also damage your child’s spleen, increasing the risk of bacterial infection.
What causes sickle cell disease?
As a parent, you undoubtedly want to know what may have caused your child’s sickle cell disease. Sickle cell disease is an inherited blood disorder, passed from parent to child through a defective hemoglobin S gene (HbS).
What are the different types of sickle cell disease?
There are a number of different types of sickle cell disease that differ in symptoms and severity. The type of sickle cell disease depends on the specific genetic defect that your child has inherited.
The types of sickle cell disease include:
Sickle cell trait (HbAS)
- A person has an HbS gene and normal hemoglobin A gene (HbA).
- Under normal circumstances, these children have no symptoms of sickle cell disease.
Sickle cell anemia (HbSS)
- child has two HbS genes, one inherited from each parent
- most common and most severe form of sickle cell disease
- variety of symptoms and complications of sickle cell disease occur
- severe, chronic anemia is common
Sickle cell with hemoglobin C disease (HbSC)
- child has one HbS gene and one defective hemoglobin C gene (HbC)
- mild to moderate anemiamay occur
- some complications of sickle cell disease may occur but to a milder degree
- comes in two forms: sickle beta zero and sickle beta plus
- child has one HbS gene and one beta thalassemia gene
- mild to severe anemiamay occur
- children may experience a broad range of sickle cell symptoms and disease severity
Other forms of sickle cell disease (compound heterozygotes), including HbSE, HbSO and HbSD:
- child has one HbS gene and another abnormal hemoglobin gene
- symptoms vary depending on the specific genetic defect
How likely is it for a child to develop sickle cell disease?
The following are the most common ways a child can develop sickle cell disease:
- If both parents have sickle cell trait, each of their children will have 25 percent chance of having sickle cell disease.
- If one parent has sickle cell disease and the other has sickle cell trait, each of their children will have a 50 percent chance of having sickle cell disease and a 50 percent chance of having sickle cell trait.
- If one parent has sickle cell disease and the other does not, all of their children will have sickle cell trait, but none of them will have sickle cell disease.
About 70,000 people in the United States have sickle cell disease. It mostly affects children of African descent and Hispanics of Caribbean ancestry, but also is found in those with Middle Eastern, Indian, Latin American, Native American and Mediterranean heritage. Millions worldwide suffer complications from sickle cell disease; 2 million African-Americans, or 1 in 12, have the sickle cell trait.
Symptoms and complications
What are the symptoms of sickle cell disease?
Each child may experience symptoms differently. The symptoms of sickle cell disease can vary greatly depending on the specific type of the disease.
Symptoms and complications of sickle disease may include:
- most common symptom of all the sickle cell diseases
- if chronic, may delay healing, and normal growth and development
Pain crisis (also called vaso-occlusive crisis)
- occurs when the flow of blood is blocked to an area because the sickle-shaped cells have become stuck in the blood vessel
- pain can occur anywhere but most often occurs in the bones of the arms, legs, chest and spine
- painful swelling of the fingers and toes (dactylitis) can occur in infants and toddlers
- priapism, a painful sickling that occurs in the penis
- any interruption in blood flow to the body can result in pain, swelling and possible death of the surrounding tissue not receiving adequate blood and oxygen
Acute chest syndrome
- when sickle-shaped cells stick together and block the flow of oxygen in the tiny vessels in the lungs
- can be life-threatening
- often occurs suddenly, when the body is under stress from infection, fever or dehydration
- resembles pneumonia and includes fever and breathing symptoms such as cough or difficulty catching breath.
- multiple episodes can cause permanent lung damage
Bacterial sepsis and infection
- Most children, by toddlerhood, no longer have a functioning spleen.
- The spleen is important in the body’s defense against serious bacterial infections; therefore, children with sickle cell are at risk for life-threatening bacterial infections.
- Fever is a symptom that must be evaluated immediately to rule out a life-threatening bacterial infection.
Splenic sequestration (pooling)
- pooling of sickle-shaped cells in the spleen, causing a sudden drop in hemoglobin
- can be life threatening if not treated promptly
- spleen can become enlarged and painful from the increase in blood volume
- spleen becomes scarred and permanently damaged after repeat episodes
- repeated episodes of sequestration requires surgical removal of the spleen
- This is a sudden and severe complication that can occur in children with sickle cell disease.
- Sickle-shaped cells can block the major blood vessels that supply the brain with oxygen.
- Any interruption in the flow of blood and oxygen to the brain can result in devastating neurological impairment.
- Symptoms of a stroke can include: weakness, particularly on one side of the body; slurred speech, seizure, confusion, dizziness or loss of coordination, or severe headache.
- Having had one stroke, a child is much more likely to have more strokes and requires preventative therapy.
- common sign and symptom of sickle disease
- results from excess red blood cells being destroyed in the spleen
Any and all major organs are also affected by sickle cell disease. The liver, heart, kidneys, gallbladder, eyes, bones and joints can suffer damage from the abnormal function of the sickle cells and their inability to flow through the small blood vessels correctly. Problems may include:
- increased bacterial infections (blood, bone, lung)
- leg ulcers
- bone/joint damage
- early gallstones
- kidney damage and loss of body water in the urine
- eye damage
Q: Will my child be OK?
A: Your child’ long-term health will depend on the type of sickle defect he has and whether complications are prevented and treated appropriately. In the past, patients with severe sickle cell disease had significantly diminished life expectancies. Today, however, thanks to the development of hydroxyurea and the availability of blood transfusions and iron chelators, most children with sickle cell disease can expect to live relatively long and healthy lives.
Q: Can my child participate in sports or other athletic activities?
A: The sports and activities that your child can participate in will depend on his specific type of sickle cell disease and other factors. Your child’s physician will make specific recommendations on the types of activities that may be appropriate for your child. That said, many children with mild forms of the disease have little or no physical limitations.
Q: Where will my child be treated?
A: Children treated through our Sickle Cell Disease Program will receive care in our hematology clinic on the sixth floor of the Fegan building. For many appointments and certain procedures, your child can also receive care at one of our satellite offices.
Q: What services are available to help my child and my family cope?
A: We offer a variety of support services to help you, your child and your family deal with the long-term effects of sickle cell disease.
Questions to ask your doctor
After your child is diagnosed with sickle cell disease, you may feel overwhelmed with information. It can be easy to lose track of the questions that occur to you.
Lots of parents find it helpful to jot down questions as they arise—that way, when you talk to your child’s doctors, you can be sure that all of your concerns are addressed.
Here are some questions to get you started:
- What specific type of sickle cell disease does my child have?
- What symptoms might my child experience?
- How will my child’s symptoms be managed?
- What are the potential complications? How can I help my child avoid them and recognize them if they do occur?
- Should my child be on hydroxyurea?
- Will my child need transfusions?
- How often will my child need to come in for follow-up care?
- Can my child play sports?
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Reviewed by Matthew Heeney, MD,
© Children’s Hospital Boston, 2011