Sickle Cell Anemia

Definition

Sickle Cell Anemia (SCA) is an inherited disorder characterized by a diminished amount of healthy red blood cells (RBC’s) to adequately supply your body with oxygen. Normally, your red blood cells are round and flexible. They travel through your blood vessels very smoothly.  In SCA, some of the red blood cells are shaped like a sickle. Some have described them to look like the shape of a crescent moon.  These irregularly shaped RBC’s can become stuck in small blood vessel and cause the flow of blood to be slower or even obstruct the vessel.

Etiology or Causes

The sickling of the red blood cells can be triggered by stress or traumatic events such as fever, dehydration, physical exertion, infection, excessive cold exposure, hypoxia and acidosis. As the red blood cell sickle, they become viscous or sticky. This causes the blood cells to clump together and to become stuck in the blood vessel, resulting in decreased flow of blood to the tissues. This blood vessel occlusive process can lead to lack of oxygen to the body tissue, which results in tissue injury and quite possibly, tissue death.

Signs and Symptoms

The signs and symptoms of SCA may often not manifest themselves until the child is at least 4 month of age. Those symptoms are as follows:

Pain – Commonly known as sickle cell crisis, these periodic episodes of pain is a major symptom of this disorder. Pain occurs when these sickled RBC’s block blood flow to the body tissue. Pain can occur in any part of the body, but the most common areas affected are the chest, abdomen and bone joints. The pain will vary in intensity and also in duration, lasting from a few hours and up to a few weeks. These pain episodes may be experience by the person only a few times during their lifetime or they can occur as often as a dozen times per year. A person in crisis may have to be hospitalized if the crisis is severe enough.

Anemia – The anemia is a result of the fragility of the sickle cell. These cells will break apart and die. The red blood cell has a normal lifetime of 120 days. The sickle cell will live for an average of 20 days. The premature deaths of the red blood cell result in a deficiency of red blood cells circulating in your body. It affects your body by limiting the amount of oxygen being carried in your circulation, which results in lack of energy / fatigue.

Delay Growth – Your red blood cells are responsible for supplying your body with oxygen and nutrients needed for growth. A deficiency in red blood cells can result in retarded growth in children and delayed puberty in teenagers.

Infection – Sickled red blood cells can cause damage to your spleen, a vital organ in the fight against infections. If your spleen is damaged, your body becomes more vulnerable to infections. A common practice in the health care community is for the PCP (primary care provider) to vaccinate the child and to prescribe antibiotic to prevent life-threatening illnesses.

Hand-Foot Syndrome – When sickled shaped red blood cells circulate in your bloodstream they can have a tendency to block the flow of blood out of the hands and feet of tiny blood vessels. This can result in the hands and feet becoming swollen. This symptom tends to be more prevalent in infants and may present as the first sign of SCA.

Problems with Vision – This is another case where the tiny blood vessel of an organ, in this case the eyes, become plugged up by the sickled red blood cell. This results in damage to the retina, which is the vision processing component of the eye.

Potential Problems

Acute Stroke – The sickle cells may obstruct the flow of blood to the brain either partially or completely, causing a cerebral vascular accident or stroke. The following are signs and symptoms of a stroke: facial drooping, numbness and weakness in the arms and legs, speech difficulties, seizures and loss of consciousness. If you child is displaying these symptoms, you should seek medical attention immediately.

Damage to organs – With SCA, the blood is typically low in oxygen content. You also have the problem of the sickle cell obstructing the flow of blood to vital organs. When your organs, such as the kidneys, liver, and spleen, are chronically deprived to oxygen-rich blood, they can be damaged.

Acute Stroke– The sickle cell may obstruct the flow of blood to the brain either partially or completely, causing a cerebral vascular accident or stroke.  The signs and symptoms of a stroke includes, facial drooping, numbness and weakness in your extremities, slurred speech

Acute Chest Syndrome – Another potential problem with SCA patients is a condition known as acute chest syndrome. This condition is a result of sickle cells blocking the flow of blood to parts of the lungs. It is characterized by fever, chest pain and difficulty breathing. This is another situation that requires immediate medical attention.

Gallstones – The development of gallstones is a potential problem which is a result of the red blood cells breaking down and producing a substance known as bilirubin.

Pulmonary Hypertension – This is a condition which is more common in adults than with children who have Sickle Cell Anemia. It is characterized by the blood pressure in the lungs becoming elevated. Symptoms manifested are shortness of breath and fatigue. It can become life-threatening, so seek immediate medical attention, if this occurs.

Priapism – Sickle cells can block the flow of blood in the blood vessels of the penis, as it does with other body organs. This can lead to a very painful, long lasting erection known as priapism. This condition can cause damage to the penis and eventually lead to impotence.

Stasis ulcers – SSA can cause open sores to develop on the legs, also known as, stasis ulcers.

Diagnostic Test

Sickle cell disease usually is diagnosed at birth with a blood test during routine newborn screening tests. If a child tests positive on the screening test, a second blood test (called a hemoglobin electrophoresis) should be performed to confirm the diagnosis. Other findings of the blood test will include the following:

Reticulocyte count – this will be elevated.

Hemoglobin – The baseline is usually 7-10 mg / dl. This will be significantly lower.

Peripheral Blood Smear – there will be a presence of sickle-shaped cells.

Platelet count – This will be increased.

Erythrocyte Sedimentation Rate – This will be elevated.

Abnormal Liver Function Test – Elevated Bilirubin levels in the blood.

Because kids with sickle cell disease are at an increased risk of infection and other health complications, early diagnosis and treatment to prevent problems is important. Currently, all 50 states require newborn screening programs for sickle cell disease by law or by rule.

Treatment and Prevention

Blood Transfusions – A blood transfusion is a common treatment modality for the management of SSA. With a transfusion, you are essentially decreasing the amount of red blood cells that can sickle by adding normal red blood cells. This treatment have been proven to be efficacious in the reducing the risk for strokes in children.

Bone marrow transplant offers the only cure for SCA. The procedure is complex and has some risks involved. Finding the appropriate donor offers some unique challenges in itself. A bone marrow transplant, also known as, a stem cell transplant is a multi-step process. The first step involves finding a person, a donor (often a sibling), who will agree to contribute their bone marrow stem cells to the diseased person. The donor will then be tested to determine if their stem cells will be a match to the recipients. If the donor and the recipient share the same Human Leukocyte Antigens (abbreviated as HLA), they are said to be a “match.” This means that their tissues are immunologically compatible with each other. Even if an appropriate donor can’t be found and the patient never has a bone marrow transplant, kids with SCA can still lead a relatively normal life.

Medications -There are medications that are available to assist the child to manage the pain. Immunizations and daily doses of antibiotics can help prevent life threatening infections. The most common drug prescribed is penicillin and those in the penicillin family, such as amoxicillin. These are usually prescribed until the child is at least 5 years of age. Along with the regularly scheduled child immunizations, the pneumococcal, meningococcal and influenza vaccines are often added to the child’s vaccination schedule. Hydroxyurea is a drug that has been approved by the Food and Drug administration for use in adults with SCA. However, some pediatricians and pediatric hematologist are prescribing this drug in certain circumstances. This medication works by reactivating fetal hemoglobin production in place of the production of hemoglobin S. It also disrupts the sickling process and makes red blood cells less sticky. Consequently, this leads to fewer painful episodes, as well as, diminished intensity of them.

Exchange Transfusion – Another treatment modality is the use of exchange transfusion. This complex, procedure entails the exchanging of the patient’s red blood cells with normal red blood cells, resulting in a decrease in the percentage of sickled cells circulating.

Prognosis – The survival rate has drastically improved over the years. It is estimated that approximately 90% of patient’s survive to the age of 20 and 50% to the age of 50.