1. What is sickle cell anemia?

It is a type of hemoglobin disorder (hemoglobinopathy) in which there is an inherited structural abnormality in one of the globin chains, namely Beta-chain. The HbS differs from HbA in a single aminoacid. It contains valine instead of glutamine at position 6 of the aminoacid sequence. This change leads to a change in the hemoglobin structure and function, and under certain conditions the red blood cells deform from the disc like shape to a crescent or sickle shape. When these cells become irreversibly deformed, they become rigid and cannot pass through small capillaries; they also become fragile and removed by macrophages early.


This results in:

* Chronic anemia because of continuous early destruction of the cells by the reticuloendothelial system especially the spleen.

* Blockage of narrow capillary passages leads to obstruction of blood flow into tissues, which causes acute and chronic pain (painful crises).

* Loss of splenic function due to repeated small infarcts.




2. How is sickle cell anemia inherited?

The inheritance of sickle cell anemia follow5 the autosomal recessive pattern when both parents are carriers, (i.e. Sickle cell trait; HbA+S) there is a 25% risk of occurrence of sickle cell anemia (HbSS). The risk of having a carrier child is 50% in each pregnancy. If one parent only is a carrier, the risk of having a carrier child is 50% in each pregnancy. When sickle cell anemia or carrier status has been diagnosed in a relative, especially a first-degree relative, carrier testing is suggested for other family members to identify carrier couples at risk of having affected offspring.



3. What are the clinical manifestations of sickle cell anemia?

Clinical manifestations usually present in the first or second year and the clinical picture, is related to the chronic anemia punctuated by the occurrence of various crises. The clinical expression of sickle cell anemia is very variable. Some patients have an almost normal life, while others develop severe crises and many even die in early childhood. Clinical problems include chronic anemia, which affects growth, may cause delay in the development of secondary sex characteristics and may also lead to weakness of cardiac muscle. Bilirubin stones from chronic hemolysis can cause gall bladder disease. A painful crisis is the most common cause of hospital admissions, manifested by severe pain in various parts of the body; especially the limbs, back and abdomen. The painful crises may last anywhere from a few hours to days. Young children suffer from pain and swelling of the joints of the hands and feet. Repeated infarcts may affect the hips, shoulder and vertebrae. Infections, fever, cold, dehydration, operations, etc frequently precipitate painful crises.
Other problems include,

* Strokes due to brain infarctions.

* Lung infarctions - known as acute chest syndrome
characterized by chest pain, dyspnoea, cough and fever.

* Increased susceptibility to infections such as
osteomyelitis, pneumococcal infection and meningitis.

* Eye abnormality e.g. retinal detachment and proliferative retinopathy.

* Skin ulcers on the legs.

* Kidney function is affected.

Although the symptoms of anemia are usually mild, occasionally "sicklers" develop severe anemia due to severe hemolytic crises, sequestration crises (when blood is pooled within organs e.g. spleen) or aplastic crises (when the bone marrow Fails to produce red blood cell. Carriers do not generally exhibit clinical manifestations except possibly with extreme hypoxia.



4. How can sickle cell anemia be diagnosed?

Sickling of red blood cells can easily be demonstrated in the laboratory, on a plain glass slide. Hb electrophoresis will show the percentage of HbS and other hemoglobins. Developments in DNA technology allow for precise diagnosis even in the early months of fetal life. Sickle cell trait is also easily diagnosed using the same methods.



5. What is the treatment options for sickle cell disease?

The only potential cure for this condition is bone marrow transplantation. The risks of mortality and morbidity from this procedure are still high. Trials are in progress with drugs such as butyrate and hydroxyurea, which may ameliorate the symptoms of the disease. Treatment at present consists of prophylactic and supportive treatment.
Prevention of severe attacks of painful crises:

* Avoid factors known to precipitate crises especially dehydration, infection, cold, anoxia.

* Good general nutrition and hygiene, plenty of fluid intake.

* Folic Acid supplementation to meet increased demand.

* Use of Penicillin to prevent pneumococcal infection.

* Pneumococcal and H-influenza type-b vaccination in addition to routine vaccination.

* Supportive and symptomatic treatments include, use of analgesics for pain relief, fluids, early diagnosis and treatment of infection.

Blood transfusions may be needed repeatedly, either to treat severe anemia or to reduce HbS concentration in debilitating crises or strokes.



6. What is the effect of sickle cell anemia on pregnancy?

There is an increased incidence of fetal wastage (spontaneous abortions, stillbirths, and neonatal deaths) among pregnant woman with sickle-cell anemia. During pregnancy, anemia is often exacerbated and the incidence of vaso-occlusive crises may increase. An obstetrician and hematologist should closely supervise pregnant women with sickle-cell anemia.



7. How early it can be diagnosed?

Early diagnosis of sickle-cell anemia is facilitated by newborn screening before the onset of symptoms. Prenatal diagnosis for HbSS is available by Chorionic Villus biopsy (at about 10 weeks) or amniocentesis (at about 15-17 weeks gestation). When both partners in a couple are sickle cell trait, or when one partner is sickle cell trait and the other Beta-thal trait or HbD trait, they have to be counselled concerning future pregnancies.

For further details, please contact your doctors.

.

B. About Sickle cell anemia

1. What is sickle cell anemia?
It is a type of hemoglobin disorder (hemoglobinopathy) in which there is an inherited structural abnormality in one of the globin chains, namely Beta-chain. The HbS differs from HbA in a single aminoacid. It contains valine instead of glutamine at position 6 of the aminoacid sequence. This change leads to a change in the hemoglobin structure and function, and under certain conditions the red blood cells deform from the disc like shape to a crescent or sickle shape. When these cells become irreversibly deformed, they become rigid and cannot pass through small capillaries; they also become fragile and removed by macrophages early.


This results in:

* Chronic anemia because of continuous early destruction of the cells by the reticuloendothelial system especially the spleen.

* Blockage of narrow capillary passages leads to obstruction of blood flow into tissues, which causes acute and chronic pain (painful crises).

* Loss of splenic function due to repeated small infarcts.


2. How is sickle cell anemia inherited?
The inheritance of sickle cell anemia follow5 the autosomal recessive pattern when both parents are carriers, (i.e. Sickle cell trait; HbA+S) there is a 25% risk of occurrence of sickle cell anemia (HbSS). The risk of having a carrier child is 50% in each pregnancy. If one parent only is a carrier, the risk of having a carrier child is 50% in each pregnancy. When sickle cell anemia or carrier status has been diagnosed in a relative, especially a first-degree relative, carrier testing is suggested for other family members to identify carrier couples at risk of having affected offspring.

3. What are the clinical manifestations of sickle cell anemia?
Clinical manifestations usually present in the first or second year and the clinical picture, is related to the chronic anemia punctuated by the occurrence of various crises. The clinical expression of sickle cell anemia is very variable. Some patients have an almost normal life, while others develop severe crises and many even die in early childhood. Clinical problems include chronic anemia, which affects growth, may cause delay in the development of secondary sex characteristics and may also lead to weakness of cardiac muscle. Bilirubin stones from chronic hemolysis can cause gall bladder disease. A painful crisis is the most common cause of hospital admissions, manifested by severe pain in various parts of the body; especially the limbs, back and abdomen. The painful crises may last anywhere from a few hours to days. Young children suffer from pain and swelling of the joints of the hands and feet. Repeated infarcts may affect the hips, shoulder and vertebrae. Infections, fever, cold, dehydration, operations, etc frequently precipitate painful crises.
Other problems include,

* Strokes due to brain infarctions.

* Lung infarctions - known as acute chest syndrome
characterized by chest pain, dyspnoea, cough and fever.

* Increased susceptibility to infections such as
osteomyelitis, pneumococcal infection and meningitis.

* Eye abnormality e.g. retinal detachment and proliferative retinopathy.

* Skin ulcers on the legs.

* Kidney function is affected.

Although the symptoms of anemia are usually mild, occasionally "sicklers" develop severe anemia due to severe hemolytic crises, sequestration crises (when blood is pooled within organs e.g. spleen) or aplastic crises (when the bone marrow Fails to produce red blood cell. Carriers do not generally exhibit clinical manifestations except possibly with extreme hypoxia.

4. How can sickle cell anemia be diagnosed?
Sickling of red blood cells can easily be demonstrated in the laboratory, on a plain glass slide. Hb electrophoresis will show the percentage of HbS and other hemoglobins. Developments in DNA technology allow for precise diagnosis even in the early months of fetal life. Sickle cell trait is also easily diagnosed using the same methods.

5. What is the treatment options for sickle cell disease?
The only potential cure for this condition is bone marrow transplantation. The risks of mortality and morbidity from this procedure are still high. Trials are in progress with drugs such as butyrate and hydroxyurea, which may ameliorate the symptoms of the disease. Treatment at present consists of prophylactic and supportive treatment.
Prevention of severe attacks of painful crises:

* Avoid factors known to precipitate crises especially dehydration, infection, cold, anoxia.

* Good general nutrition and hygiene, plenty of fluid intake.

* Folic Acid supplementation to meet increased demand.

* Use of Penicillin to prevent pneumococcal infection.

* Pneumococcal and H-influenza type-b vaccination in addition to routine vaccination.

* Supportive and symptomatic treatments include, use of analgesics for pain relief, fluids, early diagnosis and treatment of infection.

Blood transfusions may be needed repeatedly, either to treat severe anemia or to reduce HbS concentration in debilitating crises or strokes.

6. What is the effect of sickle cell anemia on pregnancy?
There is an increased incidence of fetal wastage (spontaneous abortions, stillbirths, and neonatal deaths) among pregnant woman with sickle-cell anemia. During pregnancy, anemia is often exacerbated and the incidence of vaso-occlusive crises may increase. An obstetrician and hematologist should closely supervise pregnant women with sickle-cell anemia.

7. How early it can be diagnosed?
Early diagnosis of sickle-cell anemia is facilitated by newborn screening before the onset of symptoms. Prenatal diagnosis for HbSS is available by Chorionic Villus biopsy (at about 10 weeks) or amniocentesis (at about 15-17 weeks gestation). When both partners in a couple are sickle cell trait, or when one partner is sickle cell trait and the other Beta-thal trait or HbD trait, they have to be counselled concerning future pregnancies.

For further details, please contact your doctors.