What Is Sickle Cell Anemia?
Sickle cell anemia, or sickle
cell disease (SCD), is a genetic disease of the red blood cells (RBCs).
Normally RBCs are shaped like discs, which gives them the flexibility to travel
through even the smallest blood vessels. However, with this disease, the RBCs
have an abnormal crescent (“sickle”) shape.
This makes them sticky and rigid. They can get trapped in small vessels and
block blood from reaching different parts of the body. This can cause pain and
SCD is an autosomal recessive
condition. You need two copies of the gene to have the disease. If you have
only one copy of the gene, you are said to have sickle cell trait.
What Are the Symptoms of
Sickle Cell Anemia?
Symptoms of sickle cell anemia
usually show up at a young age. They may appear in babies as early as 4 months
old, but generally occur around the 6-month mark.
While there are multiple types
of SCD, they all have similar symptoms at different levels of severity. These
fatigue or irritability (from anemia)
- fussiness (in
(from associated kidney problems)
(yellowing of the eyes and skin)
- swelling and
pain in hands and feet
- chest pain
What Are the Types of
Sickle Cell Disease?
Hemoglobin is the protein in
RBCs that carries oxygen. It normally has two alpha chains and two beta chains.
The four main types of sickle cell anemia are caused by different mutations in
Hemoglobin SS Disease
Hemoglobin SS disease is the
most common type of sickle cell disease. It occurs when you inherit copies of
the hemoglobin S gene from both parents. This forms hemoglobin known as Hb SS.
As the most severe form of SCD, individuals with this form also experience the
worst symptoms at a higher rate.
Hemoglobin SC Disease
Hemoglobin SC disease is the
second most common type of sickle cell disease. It occurs when you inherit the
Hb C gene from one parent and the Hb S gene from the other. Individuals with Hb
SC have similar symptoms to individuals with Hb SS. However, the anemia is less
Hemoglobin SB+ (Beta)
Hemoglobin SB+ (beta)
thalassemia affects beta globin gene production. The size of the red blood cell
is reduced because less beta protein is made. If inherited with the Hb S gene,
you will have Hemoglobin S Beta thalassemia. Symptoms are not as severe.
Beta-zero thalassemia is the
second type of beta thalassemia. It has similar symptoms to Hb SS anemia.
However, sometimes the symptoms of beta-zero thalassemia are more severe. It is
associated with a poorer prognosis.
People who only inherit a
mutated gene from only one parent are said to have sickle cell trait. They may
have no symptoms or reduced symptoms.
Who Is at Risk for Sickle
Children are only at risk for
sickle cell if both parents carry sickle cell trait. A blood test
called a hemoglobin
electrophoresis can also determine which type you might carry.
People from regions that have
endemic malaria are more likely to be carriers. This includes people from:
- Saudi Arabia
What Complications Can
Arise from Sickle Cell Anemia?
SCD can cause severe
complications. These complications appear when the sickle cells block vessels
in different areas of the body. Painful or damaging blockages are called sickle
Anemia is a shortage
of RBCs. Sickle cells are easily broken. This breaking apart of RBCs is called
chronic hemolysis. RBCs generally live for about 120 days. Sickle cells live
for a maximum of 10 to 20 days.
Syndrome occurs when sickle-shaped RBCs block blood vessels
in the hands or feet. This causes the hands and feet to swell. It can also
cause leg ulcers. Swollen hands and feet are often the first sign of sickle
cell anemia in babies.
Splenic sequestration is a
blockage of the splenic vessels by sickle cells. It causes a sudden, painful
enlargement of the spleen.
Delayed growth often
occurs in people with SCD. Children are generally shorter but regain their
height by adulthood. Sexual maturation may also be delayed. This happens
because sickle cell RBCs can’t supply enough oxygen and nutrients.
include seizures, bleeding in the brain, or even coma. They are caused by brain
blockages. Immediate treatment should be sought.
Blindness is caused
by blockages in the vessels supplying the eyes. This can damage the retina.
Skin ulcers in the
legs can occur if small vessels there are blocked.
Heart Disease and Chest Syndrome
interferes with blood oxygen supply, it affects the blood vessels. Over time,
this can lead to an enlarged heart and subsequent heart disease. This can also
lead to pain known as chest syndrome. High blood pressure (hypertension) and
stroke may also develop.
Priapism is a
lingering, painful erection that can be seen in some men with sickle cell. This
happens when the blood vessels in the penis are blocked. It can lead to
impotence if left untreated.
Gallstones are one
complication not caused by a vessel blockage. Instead, they are caused by the
breakdown of RBCs. A byproduct of this breakdown is bilirubin. High levels of
bilirubin can lead to gallstones. These are also called pigment stones.
How Is Sickle Cell Anemia
All newborns in the United
States are screened for sickle cell disease. Prebirth testing looks for the
sickle cell gene in your amniotic fluid.
In children and adults, one or
more of the following procedures may also be used to diagnose sickle cell.
Detailed Patient History
This condition often first
appears as acute pain in the hands and feet. Patients may also have:
- severe pain in
enlargement of the spleen
- ulcers of the
- heart problems
Your doctor may want to test
you for sickle cell anemia if you have any of the symptoms mentioned above.
blood tests can be used to look for SCD:
counts can reveal an abnormal Hb level in the range of 6 to 8 g/dL
- blood films may
show RBCs that appear as irregularly contracted cells
solubility tests look for the presence of Hb S
electrophoresis is always needed to confirm the diagnosis of sickle cell. It
measures the different types of hemoglobin in the blood.
How Is Sickle Cell Anemia
A number of different
treatments are available for SCD:
- Antibiotics like
penicillin may be given from 2 months of age to 5 years. They help prevent
pneumonia in sickle cell patients.
oxygen is given through a mask. It makes breathing easier and improves
oxygen levels in the blood.
medication is used to relieve the pain during a sickle crisis. You may
need over-the-counter drugs or strong prescription pain medication like
- Hydroxyurea (Droxia,
Hydrea) helps to increase production of fetal hemoglobin. It may reduce the
number of blood transfusions.
- Immunizations can
help prevent infections. Patients tend to have lower immunity.
- Surgery may
be used to treat persistent and painful erections.
Bone marrow transplant has
been used to treat sickle cell anemia. Children younger than 16 years of age
who have severe complications and have a matching donor are the best
Blood transfusions can
also treat sickle cell anemia. Packed red cells are removed from donated blood
and given to patients. This improves transport of oxygen and nutrients.
There are things you can do at
home to help your sickle cell symptoms:
- Use heating
pads for pain relief.
- Take folic
acid supplements, as recommended by your doctor.
fruits, vegetables, and whole-wheat grains are important and can help your body
make more RBCs.
- Drink more
water to reduce the chances of sickle cell crises.
regularly and reduce stress to reduce crises, too.
Support groups can also help
you deal with this condition.
What Are the Long-Term
Outcomes of Sickle Cell Disease?
The prognosis of the disease
varies. Some patients have frequent and painful sickle cell crises. Others only
rarely have attacks.
Sickle cell anemia is an
inherited disease. Talk to a genetic counselor if you are worried that you
might be a carrier. This can help you understand possible treatments,
preventive measures, and reproductive options.