What is the purpose of hemoglobin?
To transport oxygen on red blood cells.
What is the inheritance pattern of Sickle Cell Anemia?
Autosomal Recessive
How does the HbS variant cause Sickle Cell Anemia?
When the HbS variant of hemoglobin loses oxygen tension, it triggers a polymerization reaction causing the red blood cells to form into rigid sickle shaped cells.
How is pain evaluated by clinicians?
Pain intensity scale, numeric rating scale, visual analog scale, verbal descriptor scale, pain diary
What shape are sickle cells?
Sickled shape, "C-shaped"
What is Sickle Cell Anemia?
An inherited blood disorder that causes red blood cells to sickle, decreasing their ability to carry oxygen and pass through vasculature.
What kind of mutation constitutes the HbS allele?
Glutamic Acid > Valine
MISSENSE mutation
What are common triggers for Sickle Cell crisis?
Any event that lowers oxygen tension; i.e. hypoxia (high altitudes), infections, dehydration, acidosis, sudden temperature changes, stress, pregnancy.
What kind of pain killers are often given to Sickle Cell patients?
NSAIDs, Opiods, Dilaudid, Crizanlizumab
What is normal blood pressure range?
90/60 mmHg - 120/80 mmHg
What are the 4 major hemoglobin variants?
HbS, HbC, HbSβ thalassemia, HbF
What kind of mutation constitutes the HbC allele?
Glutamic Acid > Lysine
MISSENSE mutation
Describe the clinical presentation of a patient with Sickle Cell Anemia.
Jaundice/icterus most likely due to ineffective erythropoiesis or hemolysis, fatigue, dactylitis
How is HbF protective from Sickle Cell Anemia?
HbF prevents HbS polymerization
Why is the prevalence of Sickle Cell Anemia significantly higher in African American populations?
HbS carriers are protected from Malaria
What is Sickle Cell Trait?
Heterozygous form of Sickle Cell - usually no symptoms (mild if any)
Describe compound heterozygosity.
Two alleles of the same gene have a mutation, but the mutations are different.
How does vaso-occlusive crisis occur?
Sickle cells adhere to endothelium and disrupt microcirculation which causes vascular occlusion and tissue infarction (organs not getting O2)
Why is hydroxyurea used to treat Sickle Cell Anemia?
stimulates erythropoiesis (RBC formation) and increases fetal hemoglobin
What is the Choosing Wisely Campaign?
An initiative from the American Board of Internal Medicine (ABIM) to promote conversations between clinicians and patients by helping patients choose care that is supported by evidence, not duplicative (wasteful), free from harm and truly necessary.
Draw the oxygen saturation curves for HbF, HbA and HbS on the board (label axis)
Describe allelic heterozygosity
Variants in a single gene can cause different and distinct clinical phenotypes.
How often are sickled cells replenished in the body compared to normal cells?
Sickled cells are replenished every 10-20 days and normal RBC lifespan is 90-120 days.
What is the current curative option for Sickle Cell Disease?
Allogenic bone marrow transplant
When is a blood transfusion permissible for Sickle Cell Anemia patients?
In patients experiencing acute chest syndrome, aplastic anemia, splenic sequestration, acute anemia, acute hepatic sequestration and severe intraheptaic cholestasis.