Term
| What is extravascular anemia? |
|
Definition
| phagocytosis of erythrocytes by macrophages within the spleen, liver, and bone marrow |
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Term
| What happens to the haptoglobin-Hb complex created by intravascular hemolysis? |
|
Definition
| metabolized by the reticuloendothelial system |
|
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Term
| What happens to hemoglobin when the binding capacity of haptoglobin is exceeded? |
|
Definition
| free Hb is present in the blood and then in the urine |
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|
Term
| Besides hemoglobin, what else is released into the circulation by intravascular hemolysis? |
|
Definition
| lactate dehydrogenase (LDH) |
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|
Term
| What happens to heme in extravascular hemolysis? |
|
Definition
| spleen reticuloendothelial cells breakdown heme into indirect (unconjugated) bilirubin --> conjugated in the liver --> excreted in urine and feces |
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|
Term
| T/F Intravascular and extravascular hemolysis are both accompanied by increases in LDH and decreases in haptoglobin. |
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Definition
| yes but intravascular hemolysis has way greater increases in LDH and decreases in haptoglobin than extravascular |
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|
Term
| What is the morphology of PBS in intravascular versus extravascular hemolysis? |
|
Definition
intravascular= schistocytes, agglutination
extravascular= microspherocytes |
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|
Term
| What type of hemolysis is associated with increased free Hb? |
|
Definition
|
|
Term
| What metabolites are found in the urine of patients with intravascular hemolysis? |
|
Definition
| hemoglobin and hemosiderin |
|
|
Term
| What metabolites are found in the urine and feces of patients with extravascular hemolysis? |
|
Definition
|
|
Term
| What type of hemolysis is associated with increased indirect bilirubin? |
|
Definition
|
|
Term
| What's the difference between hemoglobinopathy and thalessemia? |
|
Definition
| hemoglobinopthy is d/t abnormalities of hemoglobin structure; thalessemia is d/t abnormalities of hemoglobin synthesis |
|
|
Term
| What is hemoglobin compoased of? |
|
Definition
| 4 polypeptide chains (2 pairs of globin chains) with a prosthetic group called a heme group on each chain |
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|
Term
|
Definition
|
|
Term
| Where is the site of heme synthesis? |
|
Definition
| eryhtroid precursors of bone marrow |
|
|
Term
| Where is the site of globin synthesis? |
|
Definition
| cytoplasm of normoblasts and reticulocytes (not in mature RBCs) |
|
|
Term
| Where in the genome are the globin genes? |
|
Definition
chr. 16 has embryonic and alpha chains
chr. 11 has gamma, delta, and beta chains |
|
|
Term
| What is the main norma ladult hemoglobin? |
|
Definition
|
|
Term
| What is the rule of thumb for % breakdown of different hemoglobins for normal adults? |
|
Definition
|
|
Term
| What is the major Hb in newborn? |
|
Definition
|
|
Term
| What hemoglobin accounts for 1.5-4% of normal adult Hb? |
|
Definition
|
|
Term
| Hb F is increased in what diseases? |
|
Definition
| beta thalessemia and sickle cell anemia |
|
|
Term
| HbA2 is increased in what diseases/ |
|
Definition
| beta thalessemia, megaloblastic anemia |
|
|
Term
| HbA2 is decreased in what diseases? |
|
Definition
| iron deficiency and sideroblastic anemia |
|
|
Term
| What is embryonic hemoglobin composed of? |
|
Definition
|
|
Term
| What part of the hemoglobin molecule is abnormal in hemoglobinopathies? |
|
Definition
| globin chain (usually the beta chain) |
|
|
Term
| What tests are often used to diagnose hemoglobinopathies? |
|
Definition
| Hb electrophoresis, high performance liquid chromatography (HPLC), special studies (globin chain analysis) |
|
|
Term
| What is the pH of alkaline Hb electrophoresis? |
|
Definition
| pH of 8.4 (cellulose acetate) |
|
|
Term
| What is the distribution of Hbs on alkaline electrophoresis? |
|
Definition
| C, E, O, A2 --> S, D, G --> F --> A --> HbH, Hb Barts |
|
|
Term
| What is the pH of acid Hb electrophoresis? |
|
Definition
|
|
Term
| What is the distribution of Hbs on an acid electrophoresis? |
|
Definition
| C-> S -> A, G, E, O, D, A2 -> F |
|
|
Term
| What percent of A.A. are heterozygous for HbS? |
|
Definition
|
|
Term
| When does sickle cell anemia manifest? |
|
Definition
| no symptoms in neonate becuase of HbF but often manifests at 3-6 months of age |
|
|
Term
| What is the life expectancy of Sickle cell patients? |
|
Definition
|
|
Term
| Describe the mutation of sickle cell anemia? |
|
Definition
| point mutation on chr. 11. Glu-> val at position six of beta globin |
|
|
Term
|
Definition
| crystals of polymerized HbS that forms at low oxygen tension |
|
|
Term
| What is the RBC lifespan of a patient with sickle cell anemia? |
|
Definition
|
|
Term
| What kinds of infections are sickle cell patients susceptible to? |
|
Definition
| S. pneumoniae, osteomyelitis and staphylococcal infections |
|
|
Term
| Can sickle cell patients get aplastic crisis? |
|
Definition
| yes, happens when they are infected with parvovirus |
|
|
Term
| Where do sickle cell pts often get ifnarcts? |
|
Definition
|
|
Term
| What are precipitating factors for vasoocclusive (pain) crises in sickle cell anemia? |
|
Definition
| hypoxia, acidosis, fever, infection, dehydration, exposure to cold |
|
|
Term
| How long does a sickle cell acute pain crisis last? |
|
Definition
|
|
Term
| What are the clinical characteristics of acute pain crisis with sickle cell? |
|
Definition
| abdominal pain, bone or joint pain and fever |
|
|
Term
| What areas are affected by vasoocclusive events in sickle cell? |
|
Definition
| musculoskeletal or soft tissue |
|
|
Term
| When do sickle cell patients have splenomegally/ |
|
Definition
| until age 8 (have autosplenectomy due to repeated infarctions) |
|
|
Term
| Osteomyelitis in a sickle cell patient is often caused by ... |
|
Definition
|
|
Term
| What percent of sickle cell patients get aseptic necrosis of the femoral head? |
|
Definition
|
|
Term
| What is another name for and what causes hand-foot syndrome? |
|
Definition
| sickle cell dactylitis; ischemic necrosis of small tubular bones causing bilateral painful swelling of dorsal hands and feet |
|
|
Term
| How long does sickle cell dactylitis last? |
|
Definition
|
|
Term
| What does hand foot syndrome look like on xray? |
|
Definition
|
|
Term
| At what age do patients get hand foot syndrome? |
|
Definition
| peaks around 2 years (range from 6 months to 8 years, but uncommon after 4 years) |
|
|
Term
| At what age do patients get acute splenic sequestration crisis? |
|
Definition
| early childhood (6 months to 3 years) |
|
|
Term
| What is the treatment for acute splenic sequestration crisis? |
|
Definition
| hemodynamic support and RBC transfusion |
|
|
Term
| Sickle cell patients have infections commonly caused by what organisms? |
|
Definition
| strep pneumo, h. influenza, mycoplasma, salmonella |
|
|
Term
| What predisposes sickle cell patients to infection? |
|
Definition
| functional asplenia, decreased pneumococcal opsonin formation, increased bacterial load from GI ischemia |
|
|
Term
| What renal problems are associated with sickle cell patients? |
|
Definition
| inability to produce concentrated urine, painless hematuria, nephrotic syndrome, and increased incidence of UTIs |
|
|
Term
| Why are sickle cell patients unable to produce a concentrated urine? |
|
Definition
| anoxic damage to the renal medullae because of low oxygen tension in the medulla |
|
|
Term
| Why do sickle cell patients get painless hematuria? |
|
Definition
|
|
Term
| What types of patients are susceptible to aplastic crises? |
|
Definition
| those with chronic hemolytic anemias are susceptible |
|
|
Term
| Aplastic crises can be caused by what 3 things? |
|
Definition
| infection (parvovirus B19), toxic drugs, or folic acid deficiency |
|
|
Term
| What is the course of an aplastic crisis? |
|
Definition
| transient and self-limiting (7-10 days) hemoglobin may drop to 2-3 gm %, leukopenia may occur, thrombocytopenia is rare |
|
|
Term
| What are the pulmonary complications of sickle cell? |
|
Definition
| local infection and acute chest syndrome |
|
|
Term
| What is acute chest syndrome? |
|
Definition
| vascular occlusions in the pulmonary vessels, common cause of death (esp adults), precipiatated by pneumonia, infarction, or fat emboli; symptoms of chest pain, wheezing, and dyspnea |
|
|
Term
| Where do sickle cell patients get leg ulcers? |
|
Definition
| medial side of the leg above the ankle (b/c of high venous pressure causing ischemia) |
|
|
Term
| Sickling in the liver sinusoids causes... |
|
Definition
| sharp RUQ pain, cholestasis with hyperbilirubinemia (sometimes > 100mg%), other abnormal LFTs, (must distinguish from acute cholecystitis) |
|
|
Term
| What types of gallstones are associated with hemolytic disorders? |
|
Definition
| calcium bilirubinate stones in diseases like sickle cell anemia, thalassemia, hereditary spherocytosis, artificial cardiac valves |
|
|
Term
| What is a typical CBC of a sickle cell pt? |
|
Definition
| normochromic, normocytic anemia with reticulocytosis (increased RDW), often neutrophilia and thrombocytosis |
|
|
Term
| What is the blood morphology of patients with sickle cell anemia? |
|
Definition
| target cells, sickle cels, NRBCs, and Howell-Jolly and pappenheimer bodies. |
|
|
Term
|
Definition
| screening test for SC anemia. HbS is insoluble in the solution and will be turbid and opaque |
|
|
Term
| What is the % breakdown of hemoglobin types in sickle cell patients? |
|
Definition
| > 80% HbS, 0% HbA, 1-20% HbF, 2-4.5% HbA2 |
|
|
Term
| What is the treatment for HbSS? |
|
Definition
| RBC transfusion or exchange transfusion, hydroxyurea or nitric oxide therapy, hematopoietic stem cell transplant in some cases |
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