Term
| What happens to Hgb S upon deoxygenation and what is the result? |
|
Definition
| It polymerizes, decreasing solubility and increasing viscosity |
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Term
| What % of AA's carry Hgb S and what fraction of AA births are homozygous for Hgb SS? |
|
Definition
| 8% of AA's are carriers and 1/400 are homozygous |
|
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Term
| What are the key lab features for Hgb SS? |
|
Definition
| Positive sickle cell preparation and hemoglobin S band in Hemoglobin electrophoresis |
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Term
| What happens to the spleen in Sickle cell disease and why? |
|
Definition
| Hyposplenism due to infarctions |
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Term
| What types of inclusions are seen in a blood smear in sickle cell? |
|
Definition
| Howell Jolly bodies (normally removed by spleen) |
|
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Term
| What does the Sickle hemoglobin prep reveal and why? |
|
Definition
| Sickled cells since it Deoxygenates blood (which is what induces the sickleing) |
|
|
Term
| What does Hemoglobin F do to sickling? |
|
Definition
| Hemoglobin F interferes with polymer formation and sickling |
|
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Term
| What is the treatment for sickle cell and how does it work? |
|
Definition
| Hydroxyurea; It increases Hgb F concentration to prevent sickling |
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Term
| What are the two major infectious complications resulting from Sickle Cell? |
|
Definition
| Hyposplenism which causes encapsulated bacterial infections and Bone Infarction leading to Osteomyelitis from Salmonella and S. aureus infections |
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|
Term
| What is the most common cause of death in Sickle cell patients? |
|
Definition
|
|
Term
| Describe Acute Chest Syndrome |
|
Definition
| Rapid onset of localized or diffuse pulmonary infiltrates |
|
|
Term
| What is the treatment for Acute Chest Syndrome? |
|
Definition
| RBC transfusion to reduce Hgb S <30%, antibiotics, respiratory therapy (oxygen if hypoxic) |
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Term
| What 4 conditions will Transfusional Therapy help treat in Sickle Cell patients? |
|
Definition
| Splenic Sequestration, ACS, Priapism, and Stroke Prevention |
|
|
Term
| What are the clinical symptoms of Sickle Cell Trait, and what should the patients undergo? |
|
Definition
| Asymptomatic except in very low Oxygen pressures; Patients should undergo Genetic Counseling |
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|
Term
| Hemoglobin Electrophoresis 25 |
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Definition
|
|
Term
| What are the clinical symptoms of HbS/Beta-Thalassemia heterozygotes? |
|
Definition
| Similar to HbSS but No spleen infarction, Low MCV (decreased total hemoglobin/cell) |
|
|
Term
| Describe the Hb A and Hb A2 levels in Sickle beta-thalassemia on hemoglobin electrophoresis |
|
Definition
| Absent Hb A but a relative increase in Hb A2 on hemoglobin electrophoresis |
|
|
Term
| Compare severity and Hb A levels in Beta+-Thalassemia to that of HbS/Beta-Thalassemia |
|
Definition
| Beta+-Thalassemia is milder and produces small amounts of Hb A |
|
|
Term
| What is the second most common hemoglobinopathy among AAs and what do heterozygotes show on blood smear? |
|
Definition
| Hb C; Hb C trait individuals show target cells and irregularly contracted cells |
|
|
Term
| What do homozygous Hb C individuals show on blood smear and on gross exam? |
|
Definition
| Hemoglobin crystals; Splenomegaly on gross exam |
|
|
Term
| Patients doubly heterozygous for Hb beta S and Hb beta C have what disease and describe its severity compared to Hb SS? |
|
Definition
| Hb SC disease; less severe that Hb SS |
|
|
Term
| What happens to the spleen in Hb SC patients? |
|
Definition
| Splenomegaly (as opposed to Hyposplenism in Hb SS patients due to infarcts) |
|
|
Term
| What Hb bands would you expect to see on Hb electrophoresis in Hb SC patients? |
|
Definition
|
|
Term
| What types of bands would you expect to see in patients with Unstable Hemoglobins? |
|
Definition
|
|
Term
| What can differentiate Unstable Hemoglobins from G6PD deficiency? |
|
Definition
| Unstable Hemoglobins will show Heinz bodies like G6PD, but they will have normal G6PD levels |
|
|
Term
| What are the two types of Autoimmune Hemolytic Anemias (AIHA) and what antibody mediates them? |
|
Definition
| Warm autoantibodies (IgG) and Cold Agglutination (IgM) |
|
|
Term
| AIHA from Warm autoantibodies (IgG) is ___ _______ mediated RES destruction |
|
Definition
| Fc receptor (the portion that macrophages recognize for phagocytosis in the spleen) |
|
|
Term
| Describe the extent of compliment fixation and location of hemolysis in Warm autoantibody (IgG) AIHA |
|
Definition
| Little/No complement fixation and extravascular hemolysis |
|
|
Term
| What happens in Cold Agglutinin (IgM) and what type of hemolysis is it? |
|
Definition
| Agglutination of RBCs in cold temps (4C) via complement fixation followed by cell lysis; it is Intravascular hemolysis |
|
|
Term
| Warm Ab cause the formation of what type of RBCs and what is the result? |
|
Definition
| Spherocytes; decreased membrane stability leading to splenic enlargement and RBC destruction |
|
|
Term
| What happens if the density of antibodies on RBCs becomes heavy enough to fix complement? |
|
Definition
| Kupffer cells get pissed and start to destroy RBCs as well (a primary reason for failure of splenectomy in some AIHA patients) |
|
|
Term
| What proteins do RBCs have to protect against complement fixation? |
|
Definition
| CD55 (DAF or Decay Accelerating Factor) and CD59 (Protectin) which protects against MAC formation by inactivating complement at low levels |
|
|
Term
| What conditions can cause secondary warm AIHA? |
|
Definition
| SLE (Systemic Lupus) and CLL (B-cell lymphoproliferative disorders) and drugs like alpha-methyldopa |
|
|
Term
| What conditions can cause secondary cold AIHA? |
|
Definition
| SLE, CCL, and Mycoplasma pneumonia infections or Mono |
|
|
Term
| How does the Direct Antiglobulin Test (DAT) work? |
|
Definition
| Anti-human globulin is added to a washed blood sample and if there are anti-RBC antibodies on the surface of the RBCs, it'll detect them and cause agglutination |
|
|
Term
| Describe the Indirect Antiglobulin Test (IAT) |
|
Definition
| Blood sample of patient has the RBCs removed and Reagent RBCs are then added to the serum. If antibodies are present in the serum of the patient, they will bind to the Reagent RBCs and cause agglutination once Anti-Human Globulin is added |
|
|
Term
| What are the three main treatment suggestions for AIHA? |
|
Definition
| Prednisone initially follwed by Splenectomy if it is a recalcitrant case and Rituximab to reduce Ab production |
|
|
Term
| In what manner are RBCs lysed in cold agglutinin disease? |
|
Definition
| Complement mediated hemolysis |
|
|
Term
| What are Cold agglutinin antibodies usually directed against on RBCs? |
|
Definition
|
|
Term
| What happens when IgM bound RBCs are rewarmed in cold agglutinin disease? |
|
Definition
| The IgM comes off but the complement stays fixed, resulting in C3 mediated phagocytosis or lysis if MAC forms |
|
|
Term
| What condition can cause primary cold agglutinin? |
|
Definition
|
|
Term
| What conditions can cause secondary cold agglutinin? |
|
Definition
| Mycoplasma pneumonia infections or EBV (Mono) |
|
|
Term
| What can Extreme cases of Cold Agglutinin disease result in? |
|
Definition
| Ischemic Necrosis of tissues |
|
|
Term
| What can Chronic Cold Aggultinin present as diagnostically? |
|
Definition
| Artificially high MCV due to agglutination and a positive Direct Coombs test (DAT) for complement but negative for IgG |
|
|
Term
| What is a rapid screening test used for Cold aggultinin disease? |
|
Definition
| 4-5 drops of blood in Wasserman tube submerged in ice bath for 30 seconds to determine if agglutination occurs, followed by reversal of agglutination when rewarmed |
|
|
Term
| What is the main treatment option for Cold Agglutinin Disease? |
|
Definition
| Avoid cold and treat the underlying disease |
|
|
Term
| Why is a splenectomy rarely helpful in Cold Agglutinin Disease? |
|
Definition
| Most C3b coated RBCs are destroyed in the Liver |
|
|
Term
| *What is Microangiopathic Hemolytic Anemia (MAHA) and what cells are found on blood smear? |
|
Definition
| Intravascular hemolysis associated with RBC fragmentation forming *Schistocytes |
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