RBC Disorders - Normocytic Anemia Extravascular Hemolysis Flashcards
What causes the sickle shape sickle cell anemia? What increases risk so sickening? What does HBF do for sickle cell anemia? How is it treated?
HBS polymerizes when deoxygenated and these polymers aggregate to form the sickle shape. Increased risk of sickling occurs with hypoxemia, dehydration and acidosis. HbF protects against sickling for the first few months of life. Treat with hydroxyurea to increase HBF levels.
What causes sickle cell anemia? What population does a target?
It is an autosomal recessive mutation in Beta globin chain and arises went two abnormal beta genes are present causing greater than 90% HbS in RBCs. It is carried by 10% of African individuals due to a protective role against falciparum malaria.
What are some complications related to red blood cell membrane damage?
Extravascular hemolysis, intravascular hemolysis and massive erythroid hyperplasia.
What are the manifestations of extravascular hemolysis?
Anemia, jaundice with unconjugated hyperbilirubinemia, and increased risk for gallstones.
What are the manifestations of intravascular hemolysis?
RBCs with damaged membranes dehydrate leading to hemolysis with decreased haptoglobin and target cells.
Can you see sickle cell’s and target cells and sickle cell trait?
No. Only for sickle cell disease.
What does metabusulfite do? What are its results in sickle cell disease vs. sickle cell trait?
It causes cells with any amount of HbS to sickle. Positive results for both.
How can you confirm the presence and amount of HbS?
Using Hb electrophoresis to distinguish between sickle cell disease and sickle cell trait.
A one-year-old baby boy who’s been previously diagnosed with sickle cell anemia comes to you with symptoms of extensive sickling. What is the common presenting sign? What organ is particularly damaged?
Common presenting sign is dactylitis which is swollen hands and feet due to vasoocllusive infarcts in bones. Spleen is damaged via autosplenectomy.
What are the consequences of autosplenectomy?
A. Increased risk of infection with encapsulated organisms such as strep pnemoniae and H influenza . B. Increased risk of salmonella Paratyphi osteomyelitis c. Howell – jolly bodies on blood smear.
What are the five complications of extensive cycling?
A. Dactylitis B. Autosplenectomy C. Acute chest syndrome D. Pain crisis. E. Renal papillary necrosis
37-year-old female comes to your clinic complaining of chest pain and shortness of breath. X-ray shows lung infiltrates and during the interview she mentioned that she had a bout of pneumonia last week. What does she have? What is important about this disease?
She has acute chest syndrome. It is vaso-occlusion in pulmonary microcirculation. It is the most common cause of death in adult patients.
What causes sickle cell trait? How many HbS in RBCs should you have for sickle cell trait? Where do these RBCs sickle?
Sickle cell trait is the presence of one mutated and one normal beta chain resulting in less than 50% HbS in red blood cells. These RBCs sickle in the renal medulla due to extreme hypoxia and hypertonicity. This leads to microscopic hematuria and a decreased ability to concentrate urine.
The 27-year-old lady presents to clinic with mild anemia due to extravascular hemolysis. When doing genetic sequencing you find that she has an autosomal recessive Tatian in hemoglobin. Which chain of hemoglobin does she have to mutation? What would you see on blood smear?
She has hemoglobin C. Autosomal recessive mutation in beta chain of hemoglobin where normal glutamic acid is replaced by lysine. On blood smear you will see HBC crystals.
What proteins are involved in hereditary spherocytosis and how do you get anemia?
Ankyrin, spectrun, or band 3.1. Spherocytes are less able to maneuver through splenic sinusoids and are consumed by splenic macrophages resulting in anemia.
