Sickle Cell Disease (SCD): Symptoms, Causes. Types, Risks and Complications | Max Hospital

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Exploring Sickle Cell Disease (SCD): Types, Symptoms and Causes

By Dr. Faran Naim in Hematology

Jun 20 , 2024 | 8 min read

Sickle cell disease (SCD) is a group of inherited blood disorders in which red blood cells contort into a sickle shape and become rigid and sticky. These misshapen cells clump together and start dying early, causing a shortage of healthy red blood cells (sickle cell anemia), and can also block blood flow in small blood vessels (sickle cell crisis). The condition may present a variety of symptoms, ranging from mild to severe.

What are the Symptoms of Sickle Cell Disease?

Sickle cell disease (SCD) can cause a wide range of symptoms, which can vary in severity and frequency among individuals. Here are the common symptoms associated with SCD:

  • Severe pain episodes (pain crises) in the bones, joints, abdomen, and chest.
  • Chronic fatigue and weakness due to anemia.
  • Shortness of breath from reduced oxygen-carrying capacity.
  • Pale skin and mucous membranes
  • Frequent infections due to spleen damage
  • Swelling in the hands and feet (dactylitis)
  • Delayed growth and development in children
  • Vision problems caused by damage to the blood vessels in the eyes
  • Jaundice (yellowing of the skin and eyes) from the breakdown of red blood cells
  • Acute chest syndrome, characterized by chest pain, fever, and difficulty breathing
  • Stroke or other neurological complications
  • Organ damage, particularly to the spleen, liver, kidneys, and lungs
  • Leg ulcers or sores

What Causes Sickle Disease?

Sickle cell disease is caused by a genetic mutation that affects the hemoglobin protein in red blood cells. This mutation leads to the production of abnormal hemoglobin known as hemoglobin S (HbS). Here’s a detailed look at the causes:

  • Genetic Mutation: SCD is caused by a mutation in the HBB gene, which provides instructions for making the beta-globin subunit of hemoglobin. In people with SCD, this mutation results in the production of hemoglobin S instead of the normal hemoglobin A. When oxygen is released from hemoglobin S, it can cause the red blood cells to become rigid and form a sickle shape.
  • Autosomal Recessive Inheritance: SCD is inherited in an autosomal recessive pattern. This means that a person needs to inherit two copies of the sickle cell gene (one from each parent) to have the disease. Individuals who inherit one sickle cell gene and one normal gene are carriers, known as having sickle cell trait, and typically do not show symptoms of the disease.

Genetic Inheritance Patterns

  • Sickle Cell Disease (HbSS): Occurs when a person inherits two sickle cell genes (one from each parent). This is the most common and severe form of SCD.
  • Sickle Hemoglobin-C Disease (HbSC): Occurs when a person inherits one sickle cell gene and one gene for hemoglobin C, another abnormal hemoglobin. This form is usually less severe than HbSS.
  • Sickle Beta-Plus Thalassemia (HbSβ+thal): Occurs when a person inherits one sickle cell gene and one gene for beta-thalassemia (a different type of abnormal hemoglobin). The severity can vary.
  • Sickle Beta-Zero Thalassemia (HbSβ0thal): Occurs when a person inherits one sickle cell gene and one gene for beta-zero thalassemia, which produces no beta-globin. This form can be as severe as HbSS.

How the Mutation Causes Symptoms

  • Red Blood Cell Shape: The sickle-shaped cells are less flexible and can stick to the walls of blood vessels, causing blockages that prevent blood flow and oxygen from reaching parts of the body.
  • Cell Lifespan: Normal red blood cells live for about 120 days, but sickle cells only last 10 to 20 days, leading to a constant shortage of red blood cells, known as hemolytic anemia.
  • Blockages: The rigid, sickle-shaped cells can block blood flow in small blood vessels, causing pain crises, organ damage, and an increased risk of infections.

Who’s at Risk of Developing Sickle Cell Disease?

Sickle cell disease (SCD) is an inherited condition, so the primary risk factors are related to genetics and family history. Here are the main factors that increase the risk of developing SCD:

Genetic Factors

  • Family History: SCD is passed down from parents to children through genes. A child is at risk of developing SCD if both parents carry the sickle cell gene.
  • Carriers (Sickle Cell Trait): Individuals with one normal hemoglobin gene and one sickle cell gene (HbAS) are carriers, known as having sickle cell trait. If both parents have sickle cell traits, there is a 25% chance with each pregnancy that their child will inherit two sickle cell genes and develop SCD.

Ethnic and Geographical Factors

  • African Descent: SCD is most common among people of African descent. The prevalence is particularly high in Sub-Saharan Africa.
  • Mediterranean, Middle Eastern, and Indian Descent: People from Mediterranean countries (such as Greece and Italy), the Middle East, and India also have higher rates of SCD.
  • Hispanic Americans: Individuals of Hispanic descent, especially those from Central and South America, are also at increased risk.

Global Distribution

  • Endemic Malaria Regions: The sickle cell trait provides some protection against malaria, which explains the higher prevalence of the sickle cell gene in regions where malaria is or was common. This includes parts of Africa, the Mediterranean, the Middle East, and India.

What are the Complications of Sickle Cell Disease?

If ignored, SCD can lead to various complications such as:

  • Stroke: Blocked blood flow to the brain can cause a stroke, leading to potential neurological damage.
  • Acute Chest Syndrome: Characterized by chest pain, fever, and difficulty breathing, this can be life-threatening and requires immediate medical attention.
  • Organ Damage: Chronic lack of oxygen can damage organs such as the liver, kidneys, spleen, and lungs.
  • Infections: Increased susceptibility to infections due to spleen damage or removal.
  • Pulmonary Hypertension: High blood pressure in the lungs' arteries can cause heart strain and lead to heart failure.
  • Delayed Growth and Development: Children with SCD often grow more slowly and reach puberty later than their peers.
  • Vision Problems: Damage to the blood vessels in the eyes can lead to vision loss.
  • Gallstones: The breakdown of red blood cells increases the risk of gallstones.
  • Leg Ulcers: Chronic sores or ulcers on the legs can develop and be difficult to heal.
  • Priapism: Painful, prolonged erections can occur and may lead to impotence if not treated.
  • Kidney Damage: Chronic damage to the kidneys can lead to hematuria (blood in the urine) and kidney failure.
  • Bone Damage: Reduced blood flow can cause the death of bone tissue (avascular necrosis), particularly in the hips and shoulders.
  • Mental Health Issues: Chronic pain and the stress of living with a severe illness can lead to depression and anxiety.

How is Sickle Cell Disease Diagnosed?

Sickle cell disease (SCD) is diagnosed through various tests that can detect the abnormal hemoglobin S gene. Early diagnosis is essential for effective management and treatment. Here are the primary methods used to diagnose SCD:

  • Newborn Screening: Sickle cell disease is often diagnosed at birth through routine newborn screening programs. A blood test can detect the presence of hemoglobin S, the defective form of hemoglobin that causes sickle cell disease.
  • Blood Tests: Specific blood tests are used to diagnose sickle cell disease:

Hemoglobin Electrophoresis: This test separates different types of hemoglobin and can identify abnormal hemoglobin S.

Complete Blood Count (CBC): Measures the levels of red blood cells, hemoglobin, and other components of the blood to check for anemia.

Sickle Cell Test: A blood smear can reveal sickle-shaped red blood cells under a microscope.

  • Prenatal Testing: Pregnant women with a family history of sickle cell disease or who are carriers of the sickle cell gene can undergo prenatal testing. Methods include:

Amniocentesis: A sample of amniotic fluid is taken to test for the sickle cell gene.

Chorionic Villus Sampling (CVS): A sample of placental tissue is tested for the sickle cell gene.

  • Genetic Testing: Genetic testing can confirm the diagnosis by identifying mutations in the HBB gene that causes sickle cell disease. This is particularly useful for diagnosing carriers of the sickle cell trait and for family planning.

Early diagnosis through these methods is crucial for managing sickle cell disease effectively and improving the quality of life for affected individuals.

What is the Treatment for Sickle Cell Disease?

The treatment for sickle cell disease (SCD) focuses on managing symptoms, preventing complications, and improving the quality of life. While there is no universal cure for SCD, several treatments can help manage the condition effectively:


Various medications are used to manage the symptoms and complications of SCD.

  • Pain Relievers: Over-the-counter or prescription pain medications are used to manage pain crises.
  • Hydroxyurea: This medication helps reduce the frequency of pain crises and the need for blood transfusions by stimulating the production of fetal hemoglobin, which prevents red blood cells from sickling.
  • Antibiotics: Penicillin or other antibiotics are often prescribed to young children to prevent infections.
  • Folic Acid Supplements: To help with the production of new red blood cells.
  • L-glutamine (Endari): This medication can reduce the frequency of pain crises.

Blood Transfusions

Regular blood transfusions can help reduce the risk of stroke, treat severe anemia, and manage other complications. Exchange transfusions, where sickled blood is replaced with healthy blood, are sometimes used in severe cases.

Bone Marrow Transplant (Stem Cell Transplant)

Stem Cell Transplant is the only potential cure for SCD and involves replacing the patient's bone marrow with healthy bone marrow from a compatible donor. It is typically reserved for severe cases due to the risks involved.

Gene Therapy

Emerging treatments in gene therapy aim to correct the genetic mutation causing SCD. This is started in few western countries but still investigational in India.

Supportive Therapies

Additional treatments to support overall health and manage complications.

  • Oxygen Therapy: Used during acute chest syndrome or severe respiratory distress.
  • Hydration: Ensuring adequate fluid intake to help prevent and manage pain crises.
  • Vaccinations: Keeping up to date with vaccinations to prevent infections.

Lifestyle and Home Remedies

Patients are encouraged to adopt healthy lifestyle practices to manage their condition. These include:

  • Stay Hydrated: Drinking plenty of fluids helps reduce the risk of sickle cell crises.
  • Healthy Diet: Eating a balanced diet rich in fruits, vegetables, and whole grains.
  • Avoid Extreme Temperatures: Both cold and heat can trigger sickle cell crises.
  • Regular Exercise: Moderate exercise can improve overall health, but intense exercise should be avoided.

In addition, regular visits to healthcare providers for monitoring and managing the disease are also important.

Final words

While sickle cell disease presents significant challenges, early diagnosis and tailored treatment plans can greatly enhance the quality of life for those affected. If you or a loved one is dealing with sickle cell disease, you can count on Max Hospitals to offer comprehensive care to help manage this condition effectively. Don’t waste any more time in seeking professional guidance from the specialists at Max Hospitals. Book a consultation and ensure the best possible care and support for your health needs.