Sickle Cell Anemia - Types, Causes, Symptoms, Diagnosis, and Treatment

Why Is It Called Sickle Cell Anemia?

Sickle cell anemia (SCA) is also called sickle cell disease (SCD). It is a genetic blood disorder affecting about 7.74 million people worldwide, with nearly 515,000 babies born each year.

Normally, red blood cells or RBCs are round and carry oxygen easily. In SCA, they become hard, sticky, and sickle-shaped, which blocks blood flow and reduces oxygen delivery to the body.

These abnormal cells survive only 10 to 20 days, compared to 120 days for healthy red blood cells, leading to anemia.

What Causes Sickle Cell Anemia?

Sickle cell anemia happens due to changes in the HBB gene, which helps make beta-globin, an important part of hemoglobin or Hb. Hb helps blood carry oxygen to all parts of the body.

When the HBB gene mutates, normal hemoglobin becomes hemoglobin S (HbS). This causes red blood cells to become hard, stiff, and sickle-shaped. Sickle cell disease is inherited, so the risk depends on whether one or both parents carry the sickle cell gene.

If both parents carry the sickle cell trait, there is a 1 in 4 chance that their child may have sickle cell disease. When only one parent is a carrier, the child may inherit the gene and become a carrier without developing the disease.

If both parents have sickle cell disease, there is a 100 percent chance their child will inherit the condition. Genetic counseling helps families learn about the chances of passing certain health conditions to a baby before pregnancy.

What happens in the body?

• The changed HBB gene makes abnormal hemoglobin (HbS).

• When oxygen levels are low, HbS sticks together.

• This forms long, stiff chains inside red blood cells.

As a result, red blood cells become:

• Hard.

• C-shaped (sickle-shaped).

• Sticky.

What this leads to:

• Blood vessels can get blocked.

• Less oxygen reaches the body.

This causes:

• Pain attacks (pain crises).

• Organ damage.

• Long-term anemia.

This process is called sickling, where red blood cells change shape and block normal blood flow.

Who Is at Higher Risk?

Sickle cell disease is more common in people with ancestry from Sub-Saharan Africa, India, Mediterranean countries, the Middle East, and the Caribbean regions. In India, it is seen more often in certain tribal populations, where the condition has a higher prevalence.

Interestingly, carrying one sickle cell gene may provide partial protection against severe malaria, explaining why the condition is more common in malaria-prone regions.

Around 80% of sickle cell disease cases occur in Sub-Saharan Africa. Mortality rates remain significantly higher in low-resource countries due to delayed diagnosis and limited access to treatment.

Different Types of Sickle Cell Disease: What Are They?

1. HbSS Disease: The most severe and common form of sickle cell disease.

2. HbSC Disease: Usually causes milder symptoms.

3. HbS beta+ Thalassemia: Mild to moderate form of the disease.

4. HbS beta0 Thalassemia: Severe symptoms, similar to HbSS disease.

5. Rare Types

• • HbSD.

  • HbSE.

  • HbSO.

What Are the Symptoms of SCD or Sickle Cell Anemia?

Symptoms usually begin around 6 months of age. Common symptoms include:

1. Anemia

Signs:

• Fatigue.

• Weakness.

• Dizziness.

• Pale skin.

• Breathlessness.

2. Pain Crisis (Vaso-Occlusive Crisis or VOC)

• VOC (vaso-occlusive crisis) occurs when sickled red blood cells block blood vessels, reducing blood flow and causing severe pain. The pain can affect the chest, back, abdomen, joints, arms, and legs.

• These pain episodes may last from a few hours to several days.

• Common triggers of sickle cell pain crises include dehydration, extreme cold or heat, stress, infections, and high altitude, all of which can reduce oxygen levels or affect blood flow.

3. Frequent Infections

• Children with sickle cell disease may get serious infections more easily because their spleen may not work properly. They may develop pneumonia (lung infection), meningitis infection around the brain and spine), and blood infections (when germs spread in the blood).

4. Delayed Growth

Children may experience:

• Slow growth.

• Delayed puberty.

5. Jaundice

Causes:

• Yellow eyes.

• Yellow skin.

6. Swollen Hands and Feet:

Due to blocked blood flow.

7. Stroke

Symptoms:

• Weakness on one side.

• Facial drooping.

• Sudden confusion.

• Vision loss.

• Severe headache.

What Are the Possible Problems of Sickle Cell Disease?

Without treatment, complications may become life-threatening.

Common complications include:

1. Acute Chest Syndrome

A medical emergency causing:

• Chest pain.

• Fever.

• Difficulty breathing.

2. Stroke: Blood supply to the brain gets blocked.

3. Pulmonary Hypertension: High pressure in the lung blood vessels.

4. Splenic Sequestration: Sudden enlargement of the spleen causes severe anemia.

5. Blindness: Blocked eye vessels damage the retina.

6. Avascular Necrosis

Bone tissue can die when it does not get enough blood supply.

Often affects:

• Hip.

• Shoulder.

7. Gallstones: Caused by increased bilirubin.

8. Leg Ulcers: Painful wounds, usually near the ankles.

9. Blood Clots (DVT)

Can increase risk of:

• Pulmonary embolism.

10. Priapism: Painful, prolonged erection in males.

11. Pregnancy Complications

Higher risk of:

• Miscarriage.

• Preterm birth.

• Preeclampsia.

When Should Someone Go to the Emergency Room?

Seek immediate emergency care (ER) if any of the following occur:

• Fever more than or equal to 101.5°F (38.5°C) (possible serious infection).

• Sudden weakness or inability to move one side of the body.

• Slurred speech, drooping face, or confusion (signs of stroke).

• Severe chest pain with difficulty in breathing (possible acute chest syndrome).

• Signs of low oxygen, like blue lips or severe trouble breathing.

• Severe headache with vomiting or vision changes.

• Seizures or loss of consciousness.

• Sudden abdominal swelling or extreme pain in children.

These symptoms can become life-threatening within hours and require urgent hospital care.

How Is Sickle Cell Disease Diagnosed?

Tests include:

1. Newborn Screening: It helps in early detection and improves survival.

2. Blood Tests: It checks the hemoglobin levels and the carrier status.

3. Hemoglobin Electrophoresis: It will help identify abnormal hemoglobin types.

4. Genetic Testing: Detects HBB mutations.

5. Prenatal Testing: It can be diagnosed before birth.

Newborn screening helps find sickle cell anemia early, so treatment can start sooner and lower the risk of serious health problems. The PEN-Plus care model helps people get regular treatment and ongoing care to better manage the disease and improve long-term health.

What Is the Treatment Plan?

There is no full cure yet, but with proper treatment and care, symptoms can be managed.

1. Hydroxyurea: It helps to reduce pain crises and lower hospital admissions.

2. L-glutamine (Endari): It is approved for reducing pain episodes.

3. Crizanlizumab (Adakveo): It helps prevent vaso-occlusive crises.

4. Blood Transfusions: Used to treat severe anemia and help prevent stroke.

5. Antibiotics: Prevent infections in children.

6. Vaccinations: Important vaccines that help protect against serious infections include the pneumococcal vaccine, influenza (flu) vaccine, and meningococcal vaccine.

7. Bone Marrow Transplant: A stem cell (bone marrow) transplant is currently the only widely available treatment that may cure neuroblastoma in some children, but it is not suitable or effective for every patient.

8. Innovative Treatments: Recent gene therapies, which are FDA-approved, including Casgevy and Lyfgenia (2023), may help reduce severe symptoms and complications of sickle cell disease.

These modified genes are involved in producing healthy hemoglobin and may reduce severe symptoms.

Gene therapy represents one of the biggest advances in sickle cell treatment.

How Long Can People Live With Sickle Cell Disease?

Improved treatment has increased survival. Many individuals now live into their:

• 40s and 50s or longer

• Early diagnosis improves outcomes significantly.

Pregnancy in sickle cell disease requires special monitoring.

Risks Include:

• More pain episodes during pregnancy.

• Higher risk of miscarriage.

• Early (preterm) delivery.

• High blood pressure in pregnancy (preeclampsia).

• Babies may be born underweight or with low birth weight.

Recommended Care:

• Talk to a genetic counselor before pregnancy to learn about the chances of passing certain health conditions to your baby and understand your options.

• Go for regular doctor check-ups during pregnancy, especially if your pregnancy is high-risk, to monitor your health and your baby’s growth.

• Take folic acid supplements exactly as recommended by your doctor, as they support healthy blood cell production.

• Drink enough water, take care of your health, and avoid infections to help lower the chance of problems during pregnancy.

• Talk with your doctor and plan your hospital delivery early so you and your baby can get the right care when needed.

With proper care, many women can have safe pregnancies.

Can Women With Sickle Cell Disease Become Pregnant?

Yes, but pregnancy is considered high-risk.

Women should receive:

• Genetic counseling.

• Specialized prenatal care.

• Emergency planning.

How Can Someone Prevent Pain Crises?

• Lifestyle measures:

• Drink enough water.

• Avoid extreme temperatures.

• Get enough sleep.

• Prevent infections.

• Attend regular doctor visits.

• Avoid smoking.

Conclusion:

Living with sickle cell anemia can be challenging, as this inherited blood disorder may cause pain, infections, and other serious health problems.

New therapies and regular care help patients live longer and healthier lives.

If you or a family member has symptoms or a family history of sickle cell disease, consult a doctor online for expert guidance and timely care.

Key Takeaways

• Sickle cell disease happens because of a change in the HBB gene.

• Sickled red blood cells live only 10 to 20 days, while normal cells live about 120 days.

• It can cause pain attacks (vaso-occlusive crisis or VOC), stroke, and chest problems.

• New medicines like Casgevy and Lyfgenia can help people feel better.

• Finding it early and getting treatment helps people live longer and stay healthier.