Sickle cell disease
Sickle cell disease is an inherited blood disorder that is characterized by production of abnormal hemoglobin, which is a protein in red blood cells that carries oxygen to the tissues.
Normal hemoglobin cells are smooth and are round in shape.They are flexible and are able to move within the blood vessels easily. Red blood cells with sickle hemoglobin are stiff, sticky and take on a crescent shape under certain conditions. When this happens they do not pass through blood vessels easily and there can be a blockage of normal blood flow and the red cells can break apart (hemolyze). This blockage is what causes pain, anemia and many of the other complications of sickle cell disease.
Sickle cell disease typically affects people of African or Caribbean descent, but may also be found in people from the Middle East, India, Latin America or the Mediterranean. One of every 625 African Americans are born with some form of sickle cell disease.
Different types of sickle cell disease
There are different types of sickle cell disease. Three of the most common are:
- Sickle cell anemia (hemoglobin SS): the most common form, with significant anemia and often with the most severe complications
- Hemoglobin S-Beta thalassemia: inheritance of both the sickle cell and thalassemia gene; less severe anemia than hemoglobin SS; may have similar although less severe degree of complications
- Sickle cell-hemoglobin C disease (hemoglobin SC): milder degree of anemia and complications
What is sickle cell trait?
Sickle cell trait (hemoglobin AS): Normal adult hemoglobin in addition to sickle hemoglobin; one in twelve African Americans have trait; no significant complications are associated, but offspring may be born with a form of sickle cell disease depending on parents diagnosis; genetic counseling is recommended.
Diagnosing sickle cell disease
The state of Illinois, as well as many other states, performs a “newborn screening test” on all infants within the first few days of life in order to detect serious and life threatening diseases such as sickle cell disease. If newborn testing is positive for sickle cell disease, the infant should be referred to a comprehensive sickle cell program where family history and additional testing will be done to confirm the diagnosis. Early testing is essential in order to begin the specialized care each child with sickle cell disease needs and to counsel all family members on preventive treatment measures and serious complications.
What are some complications of sickle cell disease?
Complications of the condition may include any of the following:
- Anemia, which is the most common finding in all forms of sickle cell disease: Stiff, sticky red blood cells block the blood vessels and break apart causing a decrease in red blood cell number. Severe anemia can make a child look pale and tire easily because of a decreased ability to carry oxygen to the body; normal growth and development may also be delayed.
- Painful crisis (vaso-occlusive crisis): When sickled blood cells clog a blood vessel, blood flow is cut off causing variable degrees of pain. Pain may occur anywhere in the body including hands and feet (dactylitis- in infants and young children), chest, arms, back or legs.
- Splenic dysfunction: Over time, the spleen (a body organ that is involved with fighting infection) becomes scarred due to progressive sickling and doesn't function normally. When this happens there is an increased risk of serious infections which may be life threatening especially in children under 5 years of age.
- Acute chest syndrome: This complication involves the clumping together of sickle cells that blocks blood and oxygen flow to a part of the lung. The condition can include fever, chest pain and breathing problems. It also may be life threatening.
- Splenic sequestration:This term describes pooling of blood in the spleen that can cause a sudden drop in hemoglobin. This severe anemia can sometimes be life-threatening.
- Stroke: a sudden and severe complication of sickle cell disease that occurs when sickled cells block blood and oxygen flow to a part of the brain. Without treatment a child who has had one stroke has a significant risk of recurrence.
- Additional problems may occur due to the abnormal sickle cells and can affect any organ in the body:
o Jaundice, yellowing of eyes or skin
o Increased infections
o Bone and joint damage
o Gallstones
o Kidney damage
o Eye damage
Treatment of sickle cell disease
Early diagnosis and prevention of complications is key when a child has sickle cell disease. Treatment may include all or some of the following:
- Penicillin “prophylaxis”: Twice daily antibiotic as prevention measure due to increased risk of infections
- Pain medications
- Increase fluid intake
- Blood transfusion may be recommended in certain situations
- Hydroxyurea: A medication that may be recommended for certain children in order to decrease amount or severity of complications.
- Stem cell transplant: For certain children this may be an option.