64 Questions
Which of the following is a possible cause of Cold Agglutinin Disease?
Mycoplasma infection
What type of infection is associated with Cold Agglutinin Disease?
Mycoplasma
Cold Agglutinin Disease has an association with which of the following conditions?
Lymphoproliferative diseases
Cold Agglutinin Disease is categorized as which of the following?
An idiopathic condition
Which one of these diseases is not associated with Cold Agglutinin Disease?
Celiac disease
Which of the following infections can cause cold antibody-mediated hemolysis?
Mycoplasma pneumoniae
At what temperature do warm antibodies optimally react with red blood cells?
37°C
Which of the following is NOT a cause of warm antibody-mediated hemolytic anemia (AIHA)?
Mycoplasma pneumoniae
What is the term for hemolysis induced by drugs?
Drug-related hemolysis
Which of the following conditions is associated with allo-immune hemolytic anemia?
Hemolytic disease of the newborn
Which type of antibody is typically involved in the pathogenesis of Paroxysmal Nocturnal Hemoglobinuria (PNH)?
IgM
What consequence might occur when IgM leads to red cell agglutination in colder extremities?
Cyanosis and ischemia in extremities
Which proteins are missing from the red cells in Paroxysmal Nocturnal Hemoglobinuria?
CD55 and CD59
What laboratory sign is typically observed in a blood smear for patients with PNH?
RBC agglutination
Which condition is commonly associated with a falsely high MCV, MCH, and MCHC in patients with PNH?
RBC agglutination
What triggers may initiate bouts of hemolysis in PNH patients?
Exercise
Which of the following is a less common but potential progression of PNH?
Aplastic anemia
What is a characteristic urinary finding in patients with PNH?
Hemoglobinuria
What is a hallmark feature of Microangiopathic Hemolytic Anemias?
Presence of schistocytes on the peripheral smear
Which diagnostic test is used for detecting the deficiency of CD55 and CD59 in red cells?
Flow cytometry
What is the cause of red blood cell destruction in individuals with PNH?
Complement system attacking red blood cells lacking protective proteins
Which of the following is NOT a cause of Microangiopathic Hemolytic Anemias?
Macrocytic anemia
Which test was historically used as the definitive diagnostic test for PNH?
Ham's test
Which feature is usually NOT seen in the diagnosis of Non-Immune Hemolytic Anemia?
Positive DAT
Which of the following activities has NOT been associated with mechanical damage to red cells causing hemoglobinuria?
Swimming
What year did two track runners report dark urine after races?
1964
Which condition can cause hemolysis due to IgM leading to red cell agglutination in the cold?
Cold-induced hemolysis
Which of the following is a cause of hemolysis associated with chemical agents?
Arsine gas
Which type of polycythemia is influenced by the patient's age?
Absolute
Which substance can accumulate from dialysis fluid exposed to certain pipes, leading to hemolysis?
Copper
Which type of lysis is classified under acquired hemolytic anemias?
Both intravascular and extravascular lysis
What is necessary to confirm a heterozygote carrier of beta thalassemia?
Quantitation of HbA2 by HPLC
Which routine chemistry test is typically elevated in thalassemia major and intermedia?
Indirect bilirubin
Why are iron status, total iron binding capacity, and ferritin levels assessed in suspected thalassemia cases?
To differentiate thalassemia from iron deficiency anemia
What is the role of globin chain testing in thalassemia diagnosis?
To determine the ratio of globin chains produced
In immune-mediated hemolysis, how are RBCs coated for recognition by the reticuloendothelial system (RES)?
By IgG or complement
What happens when RBC phagocytosis is incomplete due to IgG?
Spherocytes result
What results when RBCs are coated with IgM in immune-mediated hemolysis?
Autoagglutination
What characterizes polycythemia?
Increase in red cell mass
What is primary polycythemia also known as?
Polycythemia vera
Which of the following conditions is most likely to cause relative polycythemia?
Dehydration
What is the red cell mass status in relative polycythemia?
Normal
Which factor is NOT associated with causing secondary polycythemia?
Plasma loss
Which age group is relative polycythemia far more common in?
Young or middle-aged men
What is commonly found in the bone marrow of neonates with polycythemia?
Mild fibrosis in some cases
Which blood smear characteristic is typical of polycythemia in neonates?
Packed film appearance
Which of the following is increased in the blood film of most polycythemia cases?
Neutrophil count
What is usually low in primary polycythemia (PV)?
Serum erythropoietin
What feature is increased in circulating blood in polycythemia?
Erythroid progenitors
Which element is absent in the bone marrow of neonates with polycythemia?
Stainable iron
Which hematologic mutation is found in nearly 100% of patients with polycythemia vera?
JAK2
Which of the following is NOT a typical clinical feature of polycythemia vera?
Weight gain
What is the major cause of death in 10-40% of patients with polycythemia vera?
Thrombosis
What percentage of patients with polycythemia vera typically present with splenomegaly?
75%
Which of the following laboratory findings is typical in polycythemia vera?
Increased neutrophil alkaline phosphatase (NAP) score
At what age is polycythemia vera most commonly diagnosed?
Over 55 years
What symptom is characteristically triggered after a hot bath in patients with polycythemia vera?
Itching
By what mechanism does polycythemia vera increase the risk of blood clots?
Decreased blood flow and increased blood thickness
What is a potential cause of delayed cord clamping in infants?
Twin to twin transfusion syndrome
Which condition is associated with secondary polycythemia due to physiological erythropoietin increase?
High altitudes
Which is NOT a cause of polycythemia in normal healthy infants?
Heavy cigarette smoking
Which condition can lead to a physiologically inappropriate increase in erythropoietin?
Renal cancer
What is the cause of familial (congenital) polycythemia?
Mutations in the EPO receptor gene
In which scenario would increased red cell mass be appropriate due to erythropoietin levels?
Pulmonary disease
Study Notes
Acquired Hemolytic Anemias: Immune-Mediated Hemolysis
- Immune-mediated hemolysis occurs when RBCs react with autoantibodies with or without complement, leading to premature destruction of RBCs by the reticuloendothelial system.
- There are two types of hemolysis: intravascular and extravascular.
Auto-Immune Hemolytic Anemias
- Classification of auto-immune hemolytic anemias:
- Warm antibody-mediated
- Cold antibody-mediated
- Paroxysmal cold hemoglobinuria
- Drug-related hemolysis
- Allo-immune
- Hemolytic transfusion reactions
- Hemolytic disease of the newborn
- Paroxysmal Nocturnal Hemoglobinuria
Cold Agglutinin Disease
- Causes of cold agglutinin disease:
- Idiopathic
- Mycoplasma pneumoniae
- Infectious mononucleosis
- Lymphoproliferative disease
- Pathogenesis of cold agglutinin disease:
- Pathogenic antibodies are usually IgM, which bind to RBCs in the cooler extremities.
- Complement-coated RBCs can be lysed directly within the vessel (intravascular hemolysis) or engulfed by complement receptors on macrophages within the liver (extravascular hemolysis).
Paroxysmal Nocturnal Hemoglobinuria
- Pathogenesis of paroxysmal nocturnal hemoglobinuria:
- An acquired disease in which an abnormal stem cell clone gives rise to abnormal RBCs, WBCs, and platelets all missing proteins attached to the cell surface by a GPI anchor.
- This results in chronic intravascular hemolysis with or without obvious hemoglobinuria.
- Diagnosis of paroxysmal nocturnal hemoglobinuria:
- Haptoglobin levels are decreased.
- LDH levels are increased.
- Schistocytes are present in the peripheral smear.
- Flow cytometry using immunofluorescent staining of RBCs with a monoclonal antibody to CD55 and CD59 reveals their deficiency.
Non-Immune Hemolytic Anemia Classification
- Classification of non-immune hemolytic anemia:
- Mechanical trauma to RBCs
- Microangiopathic hemolytic anemia
- Infections
- Drugs, chemicals, and venoms
- Thrombotic thrombocytopenic purpura (TTP)
- Hemolytic uremic syndrome
- DIC
- Malignant hypertension
- Eclampsia (HELLP syndrome)
- Metastatic cancer
Polycythemia
- Classification of polycythemia:
- Absolute polycythemia
- Relative polycythemia
- Absolute polycythemia:
- Primary polycythemia (polycythemia vera)
- Secondary polycythemia
- Relative polycythemia:
- Red cell volume is normal, but plasma volume is reduced
- Causes: cardiovascular problems, cigarette smoking, dehydration, plasma loss
Primary Polycythemia Vera
- Definition: a rare myeloproliferative disorder in which there is increased production of RBCs and sometimes also of granulocytes and platelets.
- Clinical features:
- Headache, dyspnea, numbness or tingling in the fingers
- Blurred vision and night sweats
- Itching, characteristically after a hot bath
- Redness of the skin especially the face
- Weight loss
- Hypertension
- Splenomegaly
- Thrombosis
- Laboratory findings:
- Hb, Hct, and RBC count are increased
- Neutrophil leukocytosis is seen in over half of patients
- A raised platelet count is present in about half of the patients
- JAK2 mutation is present in the BM and PB granulocytes in nearly 100% of patients
Secondary Polycythemia
- Definition: an increase in RBC mass due to some other conditions
- Causes:
- Placental red cell transfusion
- Placental insufficiency with increased fetal erythropoiesis secondary to intra-uterine hypoxia
- High altitudes
- Pulmonary disease and alveolar hypoventilation
- Cardiovascular disease
- Increased affinity hemoglobin
- Heavy cigarette smoking
- Renal cancer
- Tumors such as uterine, hepatocellular carcinoma
This quiz covers acquired hemolytic anemias, immune-mediated hemolysis, and thalassemia. Topics include intravascular and extravascular lysis, quantitation of HbA2, and routine chemistry tests for thalassemia.
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