Sickle cell anemia also known as sickle cell disease is a genetic disorder of the red blood cells in which the body lacks enough healthy red blood cells to transport oxygen to the tissues and organs. In a normal situation, the red blood cells have a disc like shape which makes them flexible to travel through blood vessels. However, in sickle cell anemia, the red blood cells have an abnormal sickle or crescent like shape. This makes them rigid and sticky and prone to getting stuck in the small blood vessels which can block or slow down the blood flow hence disrupting oxygenation of the body tissues and organs. This can result in pain and organ damage.

Causes of Sickle Cell Anemia

Sickle cell anemia is caused by gene mutation that communicates with the body to produce the hemoglobin protein. Hemoglobin is an iron-rich compound that gives the blood its red color and helps the red blood cells to transport oxygen from the lungs to the rest of the body.

For the defective gene to be active, it has to be passed to the child by both mother and father.

Types of Sickle Cell Anemia

Hemoglobin enables the red blood cells to carry oxygen to the rest of body from the lungs and it normally has two beta chains and two alpha chains. Different mutations of these genes are the causes of the four major types of sickle cell anemia.

The different types of sickle cell anemia include:

• Hemoglobin SS disease: This is the most common type of sickle cell anemia and it is caused by inheriting the hemoglobin S gene copies from both parents resulting in the formation of hemoglobin Hb SS. It is also the most severe form of sickle cell anemia and patients suffering from it also experience the worst symptoms and at a much higher rate.
• Hemoglobin SC disease: This is the second most common type of sickle cell anemia and it is caused by inheriting the Hb S gene from one parent and the Hb C gene from the other. Patients suffering from Hb SC experience similar symptoms as those with Hb SS but their symptoms are less severe.
• Hemoglobin SB+ (beta) thalassemia: This affects the gene production of beta globin, reducing the size of the red blood cell because less protein is made. Its symptoms are not severe.
• Hemoglobin SB 0 (Beta-zero) thalassemia: This is the fourth type of sickle cell anemia and it involves the beta globin gene. Its symptoms can sometimes be more severe, and it is associated with a poor prognosis.
• Hemoglobin SD, hemoglobin SE, and hemoglobin SO: These types of sickle cell anemia are rare and do not present any symptoms.
• Sickle cell trait: Individuals who inherit the hemoglobin S mutated gene from one parent have the sickle cell trait. They may present reduced or no symptoms at all.

Symptoms of Sickle Cell Anemia

Symptoms of sickle cell anemia tend to appear at around 5 months of age, and they can change over time and vary from person to person. The symptoms include:

• Pain: This occurs when the sickle-shaped red blood cells block blood flow through the small blood vessels to the joints, abdomen, and chest.
• Anemia: Red blood cells normally live for 120 days before they need to be replaced. Sickle cells on the other hand live for only 10 to 20 days resulting in the individual having a shortage of red blood cells (anemia). This leads to the body not receiving enough oxygen and the individual fatigued.
• Frequent infections: The sickle cells can cause damage to the spleen making the patient vulnerable to infections.
• Swelling of the limbs: Blood flow blockage causes the hands and feet to swell.
• Vision problems: The sickle-shaped cells can block the small blood vessels that supply the eyes and cause damage to the retina resulting in vision problems.
• Delayed growth: The red blood cells not only provide the body with oxygen but also with nutrients that are required for growth. A shortage of them can lead to delayed or slow growth for children.

Risk Factors of Sickle Cell Anemia

An individual is at risk of sickle cell anemia if both parents carry the sickle cell trait. Individuals who are at a higher risk of being a carrier are usually from Africa, the Mediterranean, India, and Saudi Arabia.

Complications Caused by Sickle Cell Anemia

• Severe anemia: This can result from the fact that red blood cells only live for 10-20 days leaving the patient with shortage of healthy red blood cells and this can lead to the anemia becoming sever.
• Neurological complications: Blood flow to the brain can be blocked by the sickle cells leading to a stroke or seizures.
• Chest syndrome and heart disease: Sickle cell anemia interferes with oxygenated blood supply to different organs and this can lead to heart problems which can cause heart attacks, abnormal heart rhythms, and heart failure.
• Priapism: This is a painful lingering erection that can happen to men with sickle cell anemia. It occurs when the blood vessels to the penis are blocked and if left untreated can lead to impotence.
• Acute chest syndrome: Sickle cells blocking the blood flow to the lungs can result in fever, chest pain, and difficulty breathing which can be life threatening and requires immediate medical attention.
• Gallstones: When the red blood cells break down they produce bilirubin and a high amount of this substance in the body can result in gallstones.

Diagnosis of Sickle Cell Anemia

Diagnosis for sickle cell anemia involves a blood test to check for the defective hemoglobin gene. The physician will also take a detailed medical history in addition to asking about the symptoms.

Several blood tests can be done to look for sickle cell anemia and they include:

• Blood count to check an abnormal Hb level
• Blood films to reveal the red blood cells that appear abnormal
• Sickle solubility tests to show the presence of Hb S

Hb electrophoresis is needed to confirm the diagnosis of sickle cell anemia. It is used to measure the different types of hemoglobin in the patient’s blood.

Treatment of Sickle Cell Anemia

There are different types of treatment for sickle cell anemia, whose goal is to manage the symptoms. These include:

• Treating the underlying infection to avoid a sickle cell crisis
• Rehydration with IV fluids to help the red blood cells return to a normal state
• Blood transfusions with blood packed with red blood cells to help the body improve with transportation of oxygen and the required nutrients
• Pain medication to relieve the pain during a sickle cell crisis
• Hydrea or droxia medication to help increase production of hemoglobin
• Immunization to help prevent infections
• Bone marrow transplant in children younger than 16 years

 Next Step

At King’s College Hospital Dubai, we focus on offering an exemplary service. From initial consultation through to final diagnosis, treatment and beyond. Our multidisciplinary team of expert doctors and nurses, and technologists led by Dr Hassan Ghazal – an American triple board-certified Consultant Medical Oncologist and a Consultant Clinical Hematologist with more than 3 decades of clinical experience, are here to offer tailored management and treatment of your condition, and to answer any questions that you may have throughout your time with us. Whatever you need us for, we’re only a phone-call away.