Sickle cell anemia is an inherited blood disorder that mostly
affects people of African ancestry, but also occurs in other ethnic
groups, including people who are of Mediterranean and Middle
Eastern descent.
More than 70,000 Americans have sickle cell anemia. And about 2
million Americans - 1 in 12 African Americans - have
sickle cell trait
, which means they carry a single
gene
for the disease, but do not have the disease itself.
What Is Sickle Cell Anemia?
Sickle cell anemia is a blood disorder that affects
hemoglobin
(pronounced:
hee
-muh-glow-bin), the protein found in red blood cells (RBCs) that
helps carry oxygen throughout the body.
Sickle cell anemia occurs when a person inherits two abnormal
genes (one from each parent) that cause their RBCs to change shape.
Instead of being flexible and disc-shaped, these cells are more
stiff and curved in the shape of the old farm tool known as a
sickle - that's where the disease gets its name. The shape is
similar to a crescent moon.
Red blood cells with normal hemoglobin (
hemoglobin A
, or
HbA
) move easily through the bloodstream, delivering oxygen to all of
the cells of the body. Normal RBCs are shaped like discs or
doughnuts with the centers partially "scooped out" and
are soft and flexible. They can easily "squeeze" through
even very small blood vessels.
Sickle cell anemia occurs because an abnormal form of hemoglobin
(
HbS
) is produced. HbS molecules tend to clump together, making red
blood cells sticky, stiff, and more fragile, and causing them to
form into a curved, sickle shape.
RBCs containing HbS can go back and forth between being shaped
normally and being sickle shaped until they eventually become
sickle shaped permanently. Instead of moving through the
bloodstream easily, these sickle cells can clog blood vessels and
deprive the body's tissues and organs of the oxygen they need
to stay healthy.
Unlike normal RBCs that last about 4 months in the bloodstream,
fragile sickle cells break down after only about 10 to 20 days,
which usually causes
anemia
. Anemia (pronounced: uh-
nee
-mee-uh) is what happens when the body's number of red blood
cells (or amount of hemoglobin) falls below normal. People who are
anemic often feel weak, tire more easily, and may appear "run
down."
People with sickle cell anemia can also experience complications
from impaired blood circulation and infection-fighting problems.
These include a higher risk of certain infections and stroke as
well as a condition called
acute chest syndrome,
which is caused by inflammation or trapped RBCs in the lungs.
Sickle cell anemia is not contagious, so you can't catch it
from someone else or pass it to another person like a cold or an
infection
. People with sickle cell anemia have inherited two sickle cell
genes
,
one from each parent. A child who has inherited the sickle cell
gene from only one parent will not develop the disease, but will
have sickle cell trait. People who have sickle cell trait don't
have sickle cell anemia or symptoms of the disease, but they can
pass the sickle cell gene on to their own children.
Because people with sickle cell trait don't have the
disease, they may never discover that they carry the gene.
That's why it's recommended that teens who are unsure of
their sickle cell status ask their doctors about testing. The
National Institutes of Health (NIH) recommends that all newborns be
screened for sickle cell disease, and testing at birth is now
required in almost every state. This helps infants with sickle cell
anemia get the care and treatment they need right away.
Signs and Symptoms
Teens with sickle cell anemia may develop
jaundice
(pronounced:
jon
-dis), a condition that results from the high rate of red blood
cell breakdown. Jaundice can cause the skin and the whites of a
person's eyes to develop a yellowish tint.
People with sickle cell anemia also may have bouts of severe
pain in the chest, stomach, arms, legs, or other parts of the body.
This is caused by sickle cells blocking blood flow through the
blood vessels in those areas. Feeling tired and having trouble
fighting infections are also common among teens with sickle cell
anemia, and they may grow more slowly and reach
puberty
later than other teens.
Periods of pain are commonly referred to as
pain
crises
, which vary in their severity, how often they happen, and how long
they last. Whereas one person may have only one sickle cell pain
crisis a year, another may experience them more often. Crises may
be brief, or may last hours, days, or even weeks. Symptoms can
develop in any body organ or tissue and include aching arms, legs,
hips, and shoulders. When people with sickle cell disease get acute
chest syndrome, they may have severe chest and abdominal pain,
fever, cough, and trouble breathing.
What Can Doctors Do?
To diagnose sickle cell anemia, doctors use a special blood test
called
hemoglobin
electrophoresis
(pronounced:eh-lek-tro-fuh-
ree
-sis) to look for HbS in a person's blood.
There is no cure for sickle cell anemia, and it is possible for
some people to be ill enough to die from the disease (although most
young people with sickle cell anemia don't die). Doctors can
provide treatments that help prevent complications from the
disease, though. Folic acid, a
vitamin
that helps the body produce new red blood cells, is often
prescribed for teens with sickle cell anemia. Pain medications help
relieve the symptoms of crises. And kids and teens who have sickle
cell disease should take
penicillin
or other antibiotics to help prevent infections.
Some crises can be managed at home with pain medicines, rest,
and extra fluids. But if a crisis is especially intense, a
teen may need to go to the hospital for intravenous (IV)
fluids and stronger pain medications. People with sickle cell
anemia may also use oxygen to help ease symptoms during a crisis or
an episode of acute chest syndrome.
Teens with sickle cell anemia may need to get transfusions of
healthy red blood cells to help carry oxygen to the tissues of
their bodies more effectively, and some may need many transfusions
on a regular basis.
Scientists are constantly researching ways to help people with
sickle cell anemia. Several new treatments, such as the drug
hydroxyurea, have helped reduce painful crises and episodes of
acute chest syndrome in adults with the condition. These drugs have
also decreased the need for hospitalization. Scientists are also
testing these and other drugs to see if they work for kids and
teens. In rare cases, people with severe sickle cell anemia may be
given a bone marrow transplant to help them produce healthy
hemoglobin and normal RBCs.
Scientists are also studying
gene therapy
as a treatment for sickle cell anemia. One day, doctors may be able
to stop the disease by changing or replacing the abnormal gene that
causes it.
What Can You Do to Stay Well?
With the right precautions, teens with sickle cell disease can
do most of the stuff other teens do. To stay as healthy as
possible, take these steps:
- Eat a balanced, healthy diet.
- Take vitamins, including folic acid supplements, as
prescribed.
- Drink plenty of fluids to prevent dehydration.
- Avoid extreme cold or heat.
-
Exercise
regularly, but in moderation. Exercise is important for staying
healthy, but overdoing it can trigger a crisis in some people,
particularly if they become dehydrated, overheated, or
exhausted.
- Get plenty of rest.
- Avoid
alcohol
,
drugs
, and
smoking
, which can aggravate sickle cell disease and its symptoms. Some
people with sickle cell disease are prone to lung problems, so
smoking is particularly risky and must be avoided.
- Avoid places low in oxygen. (For example, it's not a good
idea to go hiking at high altitudes or spend lots of time
swimming under water.)
- Prevent serious infections by contacting your doctor as soon
as illness symptoms start. Be sure to get any immunizations (such
as
pneumonia
and
flu
vaccines) that the doctor recommends, and
always
call your doctor if you have a high fever (over 101º
Fahrenheit).
- Learn as much as you can about the disease and see your
doctor regularly to help prevent complications.
Teens with sickle cell disease may need to put some limits on
their lives, but with the help of doctors, friends, and family,
they can manage the condition and live their lives to the
fullest.
Reviewed by:
James Fahner, MD
Date reviewed: June 2007
Originally reviewed by:
Robin E. Miller, MD
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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