Questions and Answers
What occurs during intravascular hemolysis?
What is a clinical feature of hemolytic anemia?
Which disorder results in spherocytes in the blood?
Which of the following is a feature of hereditary elliptocytosis?
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Aplastic crises in hemolytic anemia are occasionally caused by what virus?
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Which type of spherocytes result from acquired conditions such as antibodies on RBCs?
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What is the inheritance pattern of hereditary stomatocytosis?
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Pigment stones in patients with hemolytic anemia are primarily a result of what?
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What is the primary characteristic of hemolytic anemias?
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What happens to hemoglobin when red blood cells are hemolyzed?
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Which component is released into the plasma pool after hemolysis?
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Which of the following is a key pathophysiological change during hemolytic anemia?
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What is the expected result of erythroid hyperplasia in bone marrow during hemolytic anemia?
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How does the body respond to a decrease in circulating red blood cells in hemolytic anemia?
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What type of hemolysis is characterized by the destruction of red blood cells in the bloodstream?
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What abnormality is typically seen in reticulocytes during hemolytic anemia?
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What is the main consequence of a deficiency in Beta Spectrin or Ankyrin in hereditary spherocytosis?
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Which test shows increased red cell osmotic fragility in hereditary spherocytosis?
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What is typically observed in a complete blood count of a patient with hereditary spherocytosis?
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What characterizes the morphology of blood cells in hereditary spherocytosis?
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What does a high level of indirect bilirubin in serum indicate in hereditary spherocytosis?
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What can partly correct the autohemolysis observed in hereditary spherocytosis?
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In an osmotic fragility test, which concentration of NaCl is typically associated with the start of hemolysis in normal red blood cells?
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What is a common clinical manifestation of hereditary spherocytosis?
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Study Notes
Direct Coomb's Test
- Positive test indicates presence of antibodies on the surface of red blood cells.
- Important for diagnosing hemolytic anemias, differentiating between hereditary and acquired causes.
Mechanism of Spherocyte Formation
- Caused by cytoskeletal protein abnormalities in red blood cells.
- Deficiency of Beta Spectrin or Ankyrin leads to loss of membrane surface area.
- Spherocytes are formed as cells become more spherical in the spleen, leading to their destruction (extravascular hemolysis).
- Spherocytes are permeable to sodium influx, making cells more fragile.
Clinical Features of Hereditary Spherocytosis (HS)
- Common symptoms include jaundice, anemia, and splenomegaly.
- Jaundice is due to increased bilirubin production from hemolysis.
Laboratory Tests for HS
- Complete blood count reveals lower Hb, lowered hematocrit (PCV), and increased reticulocyte count.
- Blood film morphology shows spherocytosis and microspherocytes with polychromasia.
- Osmotic fragility test detects increased osmotic fragility in red cells; abnormal hemolysis at higher NaCl concentrations.
- Autohemolysis increases, partially corrected by glucose addition.
- Serum bilirubin (indirect) levels are elevated.
Types of Hemolysis
- Intravascular Hemolysis: Red blood cells destroyed within circulation; complications include hemoglobinuria.
- Extravascular Hemolysis: Removal of RBCs by reticuloendothelial system primarily in liver and spleen.
Classification of Hemolytic Anemias
- Hemolytic anemias defined as premature destruction of RBCs leading to decreased survival (<120 days).
- Increased breakdown of RBCs releases hemoglobin, leading to hyperbilirubinemia and hemolytic jaundice.
Red Cell Membrane Disorders
- Hereditary conditions such as Spherocytosis, Elliptocytosis, Stomatocytosis, and Acanthocytosis each exhibit unique cellular morphologies.
- Spherocytes indicate hereditary spherocytosis with autosomal dominant inheritance.
Mechanism of Hemolytic Anemia
- High breakdown of RBC leads to excess hemoglobin breakdown into bilirubin, causing hyperbilirubinemia.
- Increased reticulocyte production in response to decreased circulating RBCs, enhances erythropoietic activity.
- Bone marrow demonstrates increased activity with possible extramedullary hematopoiesis in severe cases.
Special Tests for HS
- Osmotic fragility test assesses red blood cell stability under osmotic stress.
- Indirect bilirubin is high, indicating increased breakdown of red blood cells and subsequent liver processing.
Risk of Aplastic Crises
- Occasional occurrences due to infections (e.g., Parvovirus B19) can exacerbate anemia in patients with hereditary spherocytosis.
Summary Definitions
- Hemolytic anemia results from a shorter life span of RBCs due to hemolysis, leading to increased erythropoietic activity to compensate for loss.
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Description
This quiz delves into the mechanisms involved in the formation of spherocytes, as well as related topics such as the normal RBC membrane and hereditary spherocytosis. It is aimed at medical students and professionals looking to enhance their understanding of blood cell morphology and pathology. Gain insights into the significance of the positive Direct Coomb's test in this context.
