Basic Facts About Sickle Cell Disease (SCD)

Nevada Newborn Screening Program

All newborns should be screened for sickle cell disease (SCD), even if they look healthy. If left undetected and untreated, SCD can lead to severe health problems and even death, early in childhood.

What is Sickle Cell Disease (SCD)?

SCD is an inherited blood disorder that results in chronic health problems. People with SCD have abnormal hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen from the lungs to the rest of the body. Abnormal, or sickle-shaped, hemoglobin cannot deliver enough oxygen to the rest of the body. This causes individuals with SCD to experience episodes of pain. Over time, the lack of oxygen damages the organs, especially the spleen, brain, lungs and kidneys. SCD also causes anemia, or a low number of red blood cells.

There are several types of SCD, including hemoglobin SS, hemoglobin SC and hemoglobin S-beta thalassemia. The most common type of SCD is hemoglobin SS. The different types of SCD have some unique symptoms and some in common. It is important to find out which type of SCD your child has and talk with your doctor for more specific information about that condition.

What Causes SCD?

SCD is an inherited condition that occurs when the body makes abnormally shaped hemoglobin. Normal hemoglobin is shaped like a disk or doughnut so that it can move through the blood vessels easily. In people with SCD, hemoglobin is long and narrow, or "sickleshaped". Sickle cells are stiff and can be caught up with each other to form clumps within the blood vessels, so oxygen is not delivered effectively. Therefore, the body tissues and organs lack oxygen. When there is not enough oxygen in the body tissues, anemia, pain and organ damage can occur. Sickle cells also die more quickly than normal red blood cells. The bone marrow cannot make enough new cells to replenish the blood supply. Having too few red blood cells causes anemia.

SCD is not contagious. You cannot get SCD from living with, touching, or spending time with a person with SCD. SCD does not affect intelligence or the ability to learn. People with SCD are able attend regular school when they are healthy. Many people with SCD have finished college and have full-time jobs.

How Common is Sickle Cell Anemia?

Sickle cell anemia is more common in certain populations and ethnicities. It is most common in people of African descent. It affects one out of every 375 African American infants. However, it is also common in people whose families come from South or Central America (especially Panama), the Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia.

What are the Symptoms of SCD?

SCD causes minimal effects in some people and more serious problems in others. Most people with SCD do not develop all of the symptoms. Symptoms can be chronic (on going or long-term) or acute (immediate or short-term). It is important to be educated about the symptoms so that they can be properly managed. The symptoms of SCD are related to anemia, pain or the effects of SCD on specific body parts.

Most infants do not show signs of SCD until they are a few months old. Often, the first sign of SCD is pain or swelling in the child’s hands or feet when small blood vessels become blocked. This causes some

Signs of anemia include:

  • Fatigue (feeling tired or weak)
  • Shortness of breath
  • Dizziness
  • Headaches
  • Cold hands or feet
  • Pale skin
  • Chest pain

Most people with SCD experience pain at some point in their life. An episode of pain that occurs because tissues do not have enough oxygen is called a sickle cell crisis. Some people with SCD have one or fewer pain episodes each year, while others can have more than fifteen episodes. Sickle cell crises can affect any part of the body, but most often affect the bones, lungs, abdomen and joints. Crises can be acute, lasting hours or days, or chronic, lasting weeks to months. They can be mild or severe. Many times, the exact cause of a sickle cell crisis is unknown, but it is likely that many factors contribute. Dehydration and infection are known to increase the chance of having a crisis. In children with SCD, sickle cell crises are the leading cause of hospitalizations and missed days of school.

What is the Treatment for SCD?

Children with SCD are cared for by a team of specialists, including a hematologist, a doctor who specializes in treating blood disorders. The main goal of treatment is to prevent complications, and lessen them when they do occur. Your child’s individual treatment plan may depend on the symptoms that s/he is experiencing. Parents’ awareness of signs of complications is crucial to providing rapid treatment.

  • Prevent infection: Infection is the leading cause of death in children with SCD. It is very important that children with SCD take penicillin daily to prevent infection.
  • Vaccinations: Have your child receive all of the usual childhood vaccinations according to the regular schedule. In addition, children with SCD should receive meningococcal vaccine to prevent meningitis (infection of the lining of the brain), pneumococcal vaccine to protect against other serious bacterial infections, and yearly flu shot.
  • Hand Washing: Teach your child good hand washing techniques.
  • Pain Management: Mild sickle cell crises can be treated with over-the-counter pain medications (such as acetaminophen and ibuprofen) or heating pads. More severe pain may be managed with prescription drugs or hospitalization. Some adults with severe SCD take a drug called hydroxyurea to prevent crises. The long-term effects of using this drug during childhood are unknown.
  • Blood transfusion: May be used to treat a sickle cell crisis or prevent stroke. However, frequent blood transfusions can cause the body to have a dangerously high level of iron. Talk with your doctor about the risks and benefits of blood transfusions.
  • Testing: Blood and urine sample testing can determine how a person’s red blood cells are working and check for infection and organ damage. Some doctors recommend brain-imaging studies to check for blood clots in the brain and X-rays to check for lung infection and bone damage.
  • Eye Check-ups: Routine eye check-ups are important to prevent vision problems or blindness from damaged blood vessels in the eye. Children who have difficulty seeing may have trouble in school.
  • Activities: Children with SCD should avoid activities that expose them to extreme temperatures (swimming in cold water) or high altitudes (backpacking, hiking and skiing). If participating in these activities, children should plan for temperature differences (i.e., use of gloves, warm clothes) and approach activities with caution and prevention of symptoms in mind. Children with SCD can participate in other normal activities, but should make sure to stay hydrated and rest when tired.
  • Nutrition: To prevent pain crises, children with SCD need to drink plenty of water, especially when the child is sick, active or in hot weather. Most children with SCD have bedwetting episodes, for which there are strategies such as limiting drinks before bedtime and waking the child during sleep to urinate.
  • Children older than one year of age may take folic acid daily to stimulate red blood cell production.
  • Since some children with SCD, especially those receiving blood transfusions, accumulate iron in their blood, they should not be given iron supplements.
  • Call your doctor at the start of any illness.
When Should Sickle Cell Screening Occur?
At Birth
  • Newborn babies should be screened for sickle cell status (SCD or SCT) as early as 24-48 hours after birth.
  • In the U.S. (all 50 states and the District of Columbia), babies are screened for sickle cell status as part of the newborn screening program.
  • A positive newborn screening test means your baby likely has a condition reported but you need more testing by your baby’s doctor to know for sure.
In adulthood

Screening for sickle cell status may be done as part of the care you and your partner receive before or during pregnancy, or after your baby is born.

Both SCT and SCD are conditions that are genetically inherited or passed down from your parents.

SCD is different from SCT; one cannot turn into the other. SCD causes many disabling symptoms like anemia (causes a person to feel tired, weak or short of breath), severe pain, or even stroke. SCT does not make you sick. In fact, screening tests might show that you have SCT and yet you usually never have physical symptoms.

The best way to find out if and how SCD runs in a person’s family is for the person to see a genetic counselor. These professionals have experience with genetic blood disorders. The genetic counselor will look at the person’s family history and discuss with him or her what is known about SCD in the person’s family. It is best for a person with SCD to learn all he or she can about this disease before deciding to have children.

It is important to complete blood tests at the different points in time recommended by your doctor because the body produces different types of hemoglobin in infancy and adulthood. In the first few months of life, all babies still have some fetal hemoglobin. Therefore, the levels of the different types of hemoglobin need to be compared at different time points in order to establish a definitive diagnosis.

Visit the following websites for more information:

References:

  • Centers for Disease Control
  • National Center on Birth Defects and Developmental Disorder
  • newbornscreening.info
  • babysfirstest.org