Sickle Cell Anemia Flashcards
Normal type of hemoglobin
Hemoglobin A
Abnormal type of hemoglobin in sickle cell anemia
hemoglobin S
This is where a person has abnormal hemoglobin S (normal hemoglobin is hemoglobin A) on their red blood cell.
Sickle Cell Anemia
This type of hemoglobin is very sensitive to oxygen changes, which causes the red blood cell to change it’s shape. This can lead to many complications (sickle cell crisis).
what to remember about hemoglobin S
it is very sensitive to low O2 in the body. anything that causes the body to increase its demand for oxygen, like higher altitude, dehydration or infection, will cause the red blood cells then to change their shape, to become sickle shaped. They will be stiff and sticky. They will block blood flow into tissues. Patient can enter into sickle cell crisis
sickle shaped RBC live span
tend to rupture and break down at about 20 days. this is where the anemia comes from. They are much weaker. The bone marrow can’t keep up with production. Spleen helps to recycle old RBC and it gets overworked. Blood flow can get blocked to spleen because of sticking together of RBC. Spleen also helps fight infection and if spleen is not working, then these patients will be at risk of infection as well
___________is the most common and severe form of sickle cell disease.
Sickle Cell anemia
How do people get sickle cell anemia?
They’re born with it! The person inherited two hemoglobin S genes from EACH parent. Therefore, it is an autosomal recessive disorder.
Again, this means in order for sickle cell disease to occur in a person they must have received TWO abnormal hemoglobin S genes for each of their parents (one from each). This disease is HOMOGYZOUS (Hemoglobin SS).
The parents normally don’t show signs and symptoms of the disease. They will each possess Hemoglobin A and S (one NORMAL hemoglobin and one ABNORMAL hemoglobin). This is known as SICKLE CELL TRAIT. It is rare for people who have sickle cell trait to show signs and symptoms of the disease because they usually have just enough normal hemoglobin to prevent sickling of the red blood cells. However, if two people with sickle cell trait have a child, there is a 25% chance the child will develop sickle cell disease.
caused by the inheritance of a gene for a structurally abnormal portion of the hemoglobin chain
Sickle Cell Anemia
Which population is most at risk for developing Sickle Cell disease?
Sickle cell anemia is most common in African-Americans.
WHY? According to the CDC.gov, it’s because 1 in 12 African-Americans in the US have the sickle cell trait, so it can easily be passed to their offspring. Other patient populations affected by this genetic disorder include: Middle Eastern, Asian, Caribbean, and Eastern Mediterranean.
In sickle cell anemia, hemoglobin _________ is partly or completely replaced by abnormal hemoglobin ________
A; S
it is caused by the inheritance of a gene for a structurally abnormal portion of the hemoglobin chain
Sickle Cell anemia tends to be diagnosed in the _________
very young pediatric populations like at 6-8 months of age
Many times (usually around 6 to 7 months) a parent will notice that their baby is all of the sudden extremely fussy (like the child is in constant pain), feverish, and has unusual swelling in the hands and feet (dactylitis…hand-foot syndrome). These signs and symptoms present because the baby’s RBCs have started to sickle and cause extreme pain. The sickling decreases blood flow to the extremities (hence hands and feet) and organs.
WHY do S/S of sickle cell anemia appear around 6-8 months perhaps and not at birth or around 2 to 3 months?
Because in utero and during the first 6 months of age, the baby has fetal hemoglobin (remember this because we talk about this type of hemoglobin for the treatment of this condition with the medication Hydroxyurea) in their system that is the main carrier of oxygen. However, around the age of 6 months this type of hemoglobin diminishes and the type of hemoglobin their genetic code gave them takes over…..which is unfortunately hemoglobin SS.
Sickle cell anemia testing is part of newborn screening in most hospitals. Tests used include:
Dithionite (Sickledex): a blood test that assesses for abnormal hemoglobin S…it doesn’t differentiate between if the person has sickle cell trait or sickle cell disease.
Therefore, a hemoglobin electrophoresis will need to be performed. This is a blood test that assesses for various types of hemoglobin.
a normal red blood cell is
round, smooth and concave with flat centers on both sides
no nucleus present
Benefits: easily squeeze through our vessels, carry O2
hemoglobin can really only carry oxygen well if there is the ________________ type of hemoglobin, A
normal