Sickle Cell Disease (Pediatric)
What is sickle cell disease?
Sickle cell anemia (SCA) describes a group of inherited red blood cell disorders. People with sickle cell disease have abnormal hemoglobin, hemoglobin S or sickle hemoglobin, the protein in red blood cells that carries oxygen. Sickle cell disease is a lifelong condition and its severity varies from child to child.
Normal red blood cells with normal hemoglobin are shaped like discs, flexible, and move readily through large and small blood vessels to deliver oxygen. Red blood cells in children with sickle cell disease are stiff rods and change into a crescent, sickle shape.
Sickle-shaped cells are inflexible and may stick to blood vessel walls, causing a blockage that slows or stops blood flow and hinders oxygen delivery to the body’s tissues. Decreased tissue oxygen may cause a “pain crisis,” attacks of sudden and severe pain.
Red cell sickling and poor oxygen delivery also may damage the body’s organs, including the spleen, brain, eyes, lungs, liver, heart, kidneys, and bones.
What causes sickle cell disease?
Abnormal hemoglobin S in red blood cells is caused by a small defect in the gene that directs the production of the beta globin part of hemoglobin. Children with sickle cell disease inherit two abnormal hemoglobin genes, one from each parent.
What are the types of sickle cell disease?
When a child has two hemoglobin S genes (Hemoglobin SS), it’s called sickle cell anemia, the most common and often most severe form of this condition. Hemoglobin SC disease and hemoglobin Sβ thalassemia are two other common forms of sickle cell disease.
Who is affected by sickle cell disease?
This condition may be detected at birth in babies born in the United States. Some children with sickle cell disease will start to have symptoms before age one, while others develop the condition later.
What are the symptoms and complications of sickle cell disease?
Children with this condition may have a variety of issues, including:
- Mild to moderate anemia is caused by the rapid destruction of sickle red blood cells compared to normal red blood cells.
- Pain crises are the most common complication and can occur without warning and strike almost anywhere in the body but frequently affect the lower back, extremities, abdomen, and chest. A crisis may be initiated by a febrile illness, dehydration, or stress.
- Acute chest syndrome may occur when sickling in blood vessels of the lungs deprive a child’s lungs of oxygen. Areas of lung tissue are damaged and cannot exchange oxygen properly. Symptoms are chest pain, fever, shortness of breath, and coughing.
- Stroke is another serious manifestation of sickle cell disease and occurs when sickled cells block blood flow to a part of the brain. Symptoms depend on which part of the brain is affected and may include weakness of an extremity, loss of balance, trouble speaking, and severe headaches.
- Children with sickle cell disease have many complications related to increased susceptibility to bacterial infections. Pneumonia, meningitis, and bone infections are common and may be related to a dysfunctional spleen unable to act as a bacterial filter to remove the organisms from the blood stream.
How is sickle cell disease diagnosed?
Every state in the United States requires that every newborn baby is tested for sickle cell disease as part of a newborn screening program. The screening detects the presence of the abnormal hemoglobin S. For babies that screen positive for this condition, diagnosis is confirmed by a simple blood test to determine if they make sickle hemoglobin, hemoglobin S, or another type of abnormal hemoglobin, such as C, or β thalassemia.
In addition, a hemoglobin electrophoresis test can tell if a parent has a normal hemoglobin component or carries a gene for sickle cell disease and could potentially pass sickle cell trait on to a child.
What is the treatment for sickle cell disease?
Managing the complications of sickle cell disease is complex and requires specialized care. Treatment may include:
- Hydroxyurea increases the amount of hemoglobin F by reducing the level of hemoglobin S and thus reduces or prevents several complications of sickle cell disease.
- Penicillin lowers the chance of having a severe infection caused by the pneumococcus bacteria.
- Immunization with vaccines such against pneumococcus, meningococcus, and influenza.
- Doing frequent blood tests to establish a “baseline” for problems like anemia.
- Transcranial Doppler Ultrasound Screening on a yearly basis to determine if the child is at higher risk for stroke.
- Some children benefit from a red blood cell transfusion regimen that has normal hemoglobin and may decrease blockage in the blood vessels and improve oxygen delivery to tissues and organs.
- Hematopoietic stem cell transplantation is the only cure for sickle cell disease. This procedure entails taking healthy stem cells from the bone marrow or blood of a donor and injecting them into the child with this condition. The donor’s stem cells make a home in the child’s bone marrow, gradually replacing the sickle cells and producing healthy red blood cells.