Hemopath 1 RBC Flashcards
(15 cards)
How is anemia classified based on mean cell volume (MCV), and what are the typical ranges?
• Microcytic: MCV < 80 fL
• Normocytic: MCV 80–100 fL
• Macrocytic: MCV > 100 fL
This helps determine the underlying mechanism of anemia.
What does hypochromia indicate on a peripheral blood smear, and what causes it?
Hypochromia = RBCs with less hemoglobin, appearing pale.
Common in iron deficiency anemia and thalassemia.
What is bilirubin, and how does its accumulation relate to hemolysis?
Bilirubin is a breakdown product of heme.
In hemolytic anemia, increased RBC destruction leads to excess unconjugated bilirubin, causing jaundice.
What is extravascular hemolysis, and where does it typically occur?
Occurs when macrophages in the spleen or liver destroy damaged or abnormal RBCs.
Common in hereditary spherocytosis and autoimmune hemolytic anemia.
What causes sickling in sickle cell anemia, and what triggers sickle crises?
HbS polymerizes under low oxygen, dehydration, or acidosis.
Leads to RBC sickling, hemolysis, and vascular occlusion.
Why are individuals with sickle cell trait usually asymptomatic?
They produce both HbA and HbS.
HbA prevents significant polymerization of HbS under normal conditions.
Why is fetal hemoglobin (HbF) protective in sickle cell disease?
HbF has no β-chains, so it doesn’t sickle.
Infants with high HbF levels are often asymptomatic until HbF declines around 6 months.
What clinical complications arise from sickle cell crises?
Vaso-occlusion causes pain crises, acute chest syndrome, stroke, priapism, and splenic infarction.
What is β-thalassemia major, and how does it affect erythropoiesis?
Caused by mutations in both β-globin genes.
Results in excess α-chains, ineffective erythropoiesis, severe anemia, and skeletal deformities from marrow expansion.
How do thalassemias typically appear on CBC and blood smear?
Microcytic, hypochromic anemia with target cells and anisopoikilocytosis on smear.
How do reactive oxygen species (ROS) contribute to RBC damage?
ROS damage RBC membranes and hemoglobin.
In G6PD deficiency, inability to detoxify ROS leads to episodic hemolysis and bite cells.
What is aplastic anemia, and what are common causes?
Bone marrow failure leads to pancytopenia (↓ RBCs, WBCs, platelets).
Causes include idiopathic, drugs, radiation, or viral infections (e.g., parvovirus B19).
What does pancytopenia on a CBC suggest about bone marrow function?
Indicates failure or suppression of all cell lineages — often due to aplastic anemia or marrow infiltration (e.g., leukemia, fibrosis).
What are schistocytes, and what condition are they associated with?
Schistocytes = fragmented RBCs.
Seen in microangiopathic hemolytic anemia (TTP, HUS, DIC), due to RBCs being sheared by fibrin strands.
What is Disseminated Intravascular Coagulation (DIC), and how does it affect RBCs?
DIC causes widespread clotting and bleeding due to consumption of clotting factors and platelets.
Leads to hemolysis and schistocyte formation.
