Hemolytic Anemia: Hemoglobinopathies Overview
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Questions and Answers

Which type of sickle crisis is characterized by low reticulocyte numbers?

  • Painful (vaso-occlusive) crisis
  • Splenic sequestration crisis
  • Hemolytic crisis
  • Aplastic crisis (correct)

    • What is a common clinical finding in hemolytic crises?

  • High reticulocyte count (correct)
  • Enlarged spleen (correct)
  • Pallor and rapid pulse (correct)
  • Low hemoglobin levels

    • Which organs are at greatest risk due to sickle cell anemia?

  • Heart and lungs
  • Skin and muscles
  • Liver and pancreas
  • Spleen, kidney, and bone marrow (correct)

    • What condition can lead to kidney failure in patients with sickle cell anemia?

    <p>Hyposplenism</p> Signup and view all the answers

    Which of the following can trigger a vaso-occlusive crisis?

    <p>Infection</p> Signup and view all the answers

    What is the chance of offspring carrying the trait if one parent is heterozygous for an abnormal hemoglobin?

    <p>One in two</p> Signup and view all the answers

    What will be the genotype of all offspring if one parent is homozygous for an abnormal hemoglobin?

    <p>All will carry the abnormality</p> Signup and view all the answers

    When both parents are heterozygous for an abnormal hemoglobin, what is the ratio of normal to heterozygous to homozygous offspring?

    <p>1:2:1</p> Signup and view all the answers

    If one parent is homozygous and the other is heterozygous for an abnormal hemoglobin, what is the chance of being homozygous or heterozygous?

    <p>50% homozygous, 50% heterozygous</p> Signup and view all the answers

    What is the probability of not inheriting any abnormality if both parents have different abnormal hemoglobins?

    <p>25%</p> Signup and view all the answers

    How many amino acids are present in the α-chains of hemoglobin?

    <p>141</p> Signup and view all the answers

    HbF refers to which type of hemoglobin?

    <p>Fetal hemoglobin</p> Signup and view all the answers

    What does HbS stand for?

    <p>Sickle cell hemoglobin</p> Signup and view all the answers

    What is a primary treatment option for preventing complications in sickle cell anemia?

    <p>Exchange blood transfusion</p> Signup and view all the answers

    What significant change is caused by the mutation in HbC disease?

    <p>Lysine replaces glutamic acid at position 6</p> Signup and view all the answers

    Which of the following is NOT a goal of therapeutic approaches for sickle cell anemia?

    <p>Enhance sickle cell proliferation</p> Signup and view all the answers

    What characteristic is typically observed in the red blood cells of individuals with HbC disease?

    <p>Normocytic and normo- or hyperchromic cells</p> Signup and view all the answers

    Which country has a reported high incidence of HbC disease?

    <p>Ghana</p> Signup and view all the answers

    What laboratory finding is common in HbSC disease?

    <p>Moderate to severe normocytic/normochromic anemia</p> Signup and view all the answers

    Which clinical manifestation is likely to occur due to a homozygous mutation of the beta-globin gene?

    <p>In the neonate at birth</p> Signup and view all the answers

    Which test can help diagnose sickle cell disease through hemoglobin separation?

    <p>Hb electrophoresis</p> Signup and view all the answers

    Which of the following is a common cutaneous manifestation of sickle cell anemia?

    <p>Painful leg ulcers</p> Signup and view all the answers

    What is a potential hematologic crisis related to sickle cell anemia?

    <p>Hemolytic crisis</p> Signup and view all the answers

    Which of the following complications is associated with renal issues in sickle cell anemia?

    <p>Renal papillary necrosis</p> Signup and view all the answers

    What is a nonhematologic complication commonly observed in individuals with sickle cell anemia?

    <p>Arthritis</p> Signup and view all the answers

    Which bacterial organism is commonly implicated in infections related to sickle cell anemia?

    <p>Staphylococcus aureus</p> Signup and view all the answers

    Which of the following symptoms can occur due to autosplenectomy in sickle cell anemia?

    <p>Increased infection susceptibility</p> Signup and view all the answers

    What is the characteristic replacement in hemoglobin that defines sickle cell trait?

    <p>Valine for glutamic acid</p> Signup and view all the answers

    Which clinical feature is associated with genitourinary complications in sickle cell anemia?

    <p>Priapism</p> Signup and view all the answers

    What is a typical cardiovascular manifestation of sickle cell anemia?

    <p>Enlarged heart</p> Signup and view all the answers

    What percentage of hemoglobin S is typically produced in a person with sickle cell trait?

    <p>40%</p> Signup and view all the answers

    Which gastrointestinal symptom might patients with sickle cell anemia experience?

    <p>Cholelithiasis</p> Signup and view all the answers

    What is a common symptom for individuals with sickle cell trait during crisis states?

    <p>Sickling of red blood cells</p> Signup and view all the answers

    At what age is diagnosis of sickle cell disease typically made?

    <p>After 6 months</p> Signup and view all the answers

    What is the primary cause of death in sickle cell anemia patients?

    <p>Congestive heart failure</p> Signup and view all the answers

    Which viral infection is associated with sickle cell anemia complications?

    <p>Cytomegalovirus</p> Signup and view all the answers

    What is the life expectancy of individuals with sickle cell disease with proper treatment?

    <p>50 years</p> Signup and view all the answers

    What type of hemoglobin is indicated by a large band in the hemoglobin S position quantifying at 95%?

    <p>Hemoglobin S</p> Signup and view all the answers

    What is a characteristic feature of hereditary pyropoikilocytosis (HP)?

    <p>Increased pencil-shaped cells</p> Signup and view all the answers

    In a patient with suspected sickle cell trait showing negative solubility test results, what is the most likely explanation for an apparent A-S pattern in electrophoresis?

    <p>Patient has hemoglobin AS, and the solubility test is incorrect.</p> Signup and view all the answers

    What percentage of target cells was revealed in the peripheral smear?

    <p>70%</p> Signup and view all the answers

    What type of hemoglobin might a normal adult show with 70% hemoglobin A and 30% hemoglobin A2?

    <p>Hemoglobin A2</p> Signup and view all the answers

    If a patient's solubility test is negative, which hemoglobin could they likely not have?

    <p>Hemoglobin AS</p> Signup and view all the answers

    What condition is associated with increased bite cells?

    <p>G6PD deficiency</p> Signup and view all the answers

    What would a negative result from a solubility test in a sickle cell trait patient imply?

    <p>Absence of sickle cell gene</p> Signup and view all the answers

    Study Notes

    Hemolytic Anemia: The Hemoglobinopathies

    • Hemoglobinopathies are a group of qualitative or quantitative inherited abnormalities in the structure of hemoglobin.
    • These abnormalities result from alterations in the DNA genetic code for one or more globin chains leading to changes in RBC deformability and electrophoretic mobility.

    Objectives

    • List examples of Hemoglobinopathies and their nomenclature.
    • Describe the cause of Sickle Cell Anemia and list the clinical and laboratory findings.
    • List the findings of hemoglobin C disease and SC disease.
    • List characteristics of hemoglobin D, E, and other variants.

    Nomenclature

    • The first discovered hemoglobin was HbS (crescent or sickle cell).
    • Alphabetical letters are used according to electrophoretic mobility, starting with C.
    • Geographic place names are also used, like Hb Koeln.
    • Letters and geographic places identify hemoglobins with identical mobility via electrophoresis.
    • The letter M is given to hemoglobins that tend to form MetHb.

    Hemoglobinopathies: Classification

    • Structural variants: Altered structure of the globin chain.
    • Disorders with reduced rate of synthesis: Reduced rate of synthesis of one or more globin chains.
    • HPFH (Hereditary Persistence of Fetal Hb): Failure to complete the normal neonatal switch.
    • Abnormal Hbs without clinical significance: Abnormal Hbs without clinical effects.

    The Globin Gene Clusters

    • The α-chains have 141 amino acids each.
    • The β-like chains have 146 amino acids each.

    Review of Normal Hb Structure

    • A hemoglobin molecule consists of four globin chains, each centered around a heme group.
    • Each heme group contains a porphyrin ring with an iron atom in the center.
    • Most adult hemoglobin has two alpha chains and two beta chains.

    Sickle Cell Anemia

    • The most common type of severe hemoglobinopathy.
    • 8% of African Americans are heterozygous for HbS.
    • In Africa, the gene frequency approaches 30%.
    • HbS is protective against Plasmodium falciparum malaria.
    • HbS is common in Mediterranean, South & Central America, and India.
    • Valine substitutes glutamic acid in the 6th position of the β chain, causing sickling.

    Sickle Cell Anemia: Pathophysiology

    • On deoxygenation, HbS undergoes polymerization forming stiff sickle shapes.
    • This changes the RBCs to elongated, crescentic, or sickle shapes.
    • Low O2, low pH, and dehydration promote sickling.
    • Initially, sickling of RBCs is reversible upon oxygenation. However, repeated episodes cause irreversible damage.
    • Damage occurs via repetitive damage during events called crises.
    • The presence of HbA and HbF in cells with HbS influence the degree of sickling.

    Factors Enhancing Sickling

    • Degree of oxygenation (HbS sickles at lower oxygen tension).
    • Low pH
    • Low temperature
    • Dehydration
    • Infections
    • Vascular stasis (blood viscosity increases, slows circulation time)
    • Osmolarity affects sickle cells in hypertonic mediums.
    • Number of HbS in RBCs (high HbS intensifies sickling)

    Sickle Cell Anemia: Clinical Findings

    • Three types of sickle crises: aplastic, hemolytic, and painful (vaso-occlusive)
    • Organ damage
    • Crisis and infarction of organs

    SCD: Clinical Findings

    • Organs at greatest risk include the spleen, kidneys, and bone marrow.
    • Vaso-occlusive crisis occurs with an increased bone marrow response to hemolytic anemia
    • Crisis can be initiated by many physiological factors, including surgery, trauma, pregnancy, and high altitudes.
    • Sickle cell anemia (HbSS disease) is diagnosed early in life, presenting with severe chronic anemia, Hb 6-8 g/dl, and jaundice.

    Lab Diagnosis of Sickle Cell Anemia

    • CBC
    • Retic count
    • Peripheral blood smear (PB smear)
    • Hemoglobin electrophoresis
    • Hb A2 and Hb F measurement
    • Other laboratory findings include red blood cell (RBC) indices, many sickle cells, and numerous fragmented cells.

    Hemoglobin C Disease and Trait

    • Hgb C disease: Lysine replaces glutamic acid at position 6 on both beta chains.
    • Clinical symptoms: mild chronic hemolytic anemia with splenomegaly.
    • RBC morphology: typically normo/hyperchromic with numerous target cells and occasionally intracellular rodlike C crystals, microspherocytes, and fragmented cells and folded cells.
    • Retic is slightly increased.
    • HbC migrates with Hgb A2, E, O.

    HbS with Other Abnormal Hbs

    This category details conditions resulting from two abnormal genes. These conditions have varying severities.

    HbD Disease & Trait

    • Caused by glycine replacing glutamic acid at position 121 on the beta chain.
    • Found primarily in Middle Eastern and Indian populations.
    • Homozygotes and heterozygotes are typically asymptomatic.

    HbE Disease & Trait

    • Caused by lysine replacing glutamic acid at position 26 on the beta chain.
    • More prevalent in Southeast Asian, African, and African-American populations.
    • Homozygous patients generally show little to no anemia, while heterozygous patients are asymptomatic.

    HbOArab or HbO oman

    • Has a severity similar to HbSS.
    • Has two mutations on one chain: Glu6Val and Glu121Lys.
    • Heterozygotes generally exhibit an abnormal Hb between 14 and 20%.

    HbS/β-thalassemia

    • Mild to severe clinical presentations.
    • Resembles HbSC condition.

    Hb Variants with Altered Oxygen Affinity

    • High affinity hemoglobins are seen in heterozygotes.
    • Patients often experience erythrocytosis and congenital polycythemia but are usually asymptomatic.
    • Diagnosis involves measuring PO2.
    • Low affinity hemoglobins exhibit mild anemia and cyanosis.

    Treatment

    • Exchange blood transfusion
    • Hydroxyurea
    • Bone marrow transplantation
    • Gene therapy

    Assessment Questions

    • Questions testing knowledge of clinical findings, diagnosis, and treatments.

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    Hemolytic Anemia: The Hemoglobinopathies PDF

    Description

    This quiz focuses on hemoglobinopathies, specifically the genetic abnormalities related to hemoglobin structure that can lead to conditions such as Sickle Cell Anemia and Hemoglobin C disease. Participants will explore examples, nomenclature, causes, and clinical findings associated with various hemoglobin variants. Test your knowledge about these inherited disorders and their implications on red blood cell function.

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