Step Up: Hematology

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Step Up: Hematology
2011-10-06 10:05:34
internal medicine rotation

internal medicine rotation, hematology
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  1. Name four compensatory mechanisms that help maintain oxygen delivery to the tissues in a patient with anemia
    • Increased CO (increased HR and SV)
    • Increased extraction ratio
    • Right-shift of the O2 dissociation curve due to increased BPG
    • Increased plasma volume
  2. Things to consider in a patient with anemia
    • Fhx of hemophilia, G6PD, thalassemia
    • Bleeding
    • Chronic illness
    • Alcoholism (folate and B12 deficiency)
  3. What effect does one unit of packed RBCs have on Hb and Hct?
    • Hb goes up 1 point
    • Hct goes up 3 points
  4. What is the effect of transfusing mismatched blood?
    • Intravascular hemolysis--activated complement will punch holes in the RBC membranes
    • Patients experience fever, chills, nausea, vomiting, flank pain, and back pain
  5. What is the MCV cutoff for microcytic anemia?
    Under 80
  6. DD for microcytic anemia
    • Fe deficiency
    • Thalassemia
    • Sideroblastic (impaired protoporphyrin synthesis from lead poisoning, alcohol, or pyridoxine deficiency)
  7. DD of macrocytic anemia
    • B12 or folate deficiency
    • Liver disease (impaired plasma membrane protein synthesis results in abnormally shaped RBCs)
  8. DD of normocytic anemia
    • Aplastic anemia
    • Bone marrow fibrosis
    • Tumor
    • Anemia of chronic disease (chronic inflammation, malignancy)
    • Renal failure (decreased epo)
  9. Major diagnosis to rule out in an elderly patient with iron deficient anemia
    Colon cancer
  10. Lab results for Fe deficient anemia
    • Low ferritin and serum iron
    • High TIBC and transferrin
  11. Which type of microcytic anemia is characterized by an increased RDW?
    Fe deficiency
  12. Desferroxamine
    Fe chelating agent, used to prevent CHF from Fe overload in patients who undergo constant transfusions (e.g. thalassemia patients)
  13. What test should be performed on a patient with iron deficient anemia who does not respond to iron treatment?
    Gel electrophoresis, to rule out a thalassemia
  14. Causes of sideroblastic anemia
    • chloramphenicol
    • INH
    • alcohol
    • lead
    • collagen vascular disease
    • Malignancy (myelodysplastic syndromes)
  15. Non-idiopathic causes of aplastic anemia
    • Radiation exposure
    • Meds (chloramphenicol, carbamazepine)
    • Viral infection (Hep B, Hep C, , HPV, EBV, CMV, herpes, HIV)
    • Chemicals (benzene, insecticides)
  16. Which reactions is B12 a cofactor for?
    • Conversion of homocysteine to methionine
    • Conversion of methylmalonyl CoA to succinyl CoA
  17. For how long can B12 stores in the liver last?
    Up to 3 years
  18. Where is B12 absorbed?
    Terminal ileum
  19. Causes of B12 deficiency
    • Pernicious anemia
    • Gastrectomy
    • Poor diet
    • Crohn's disease, ileal resection
    • Diphyllobothrium latum infection
    • Bacterial overgrowth
  20. How can folate deficiency be distinguised from B12 deficiency
    • Both are associated with elevated serum homocysteine, but only B12 deficiency is associated wtih elevated methylmalonic acid.
    • Also, only B12 deficiency is associated with peripheral neuropathy
  21. Lab results in hemolytic anemia
    • Elevated reticulocytes and LDH
    • Low haptoglobins
    • Elevated indirect bilirubin
  22. In what disease may Heinz bodies be seen?
  23. Manifestations of sickle cell anemia
    • Blood--chronic hemolytic anemia
    • Heart--high output CHF, due to anemia
    • CNS--stroke
    • GI--gallstones, infarct, abdo pain
    • Bones--pain, osteomyelitis, avascular necrosis
    • Lungs--infection, acute chest syndrome
    • Kidneys--hematuria, papillary necrosis, renal failure
    • Eyes--proliferative retinopathy, retinal infarct
    • Genitalia--priapism
  24. Effect of parvovirus B19 infection on a sickle cell anemia patient
    Aplastic crisis
  25. Acute chest syndrome
    • Caused by repeated pulmonary infacts
    • Presents similarly to pneumonia, with chest pain, respiratory distress, infiltrates, and hypoxia
  26. Splenic sequestration crisis
    • Rapid splenomegaly and hypovolemic shock, caused by pooling of blood in spleen
    • Potentially fatal complication of SCD and thalassemia
  27. Symptoms of hereditary spherocytosis
    • Hemolytic anemia
    • Jaundice
    • Gallstones
    • Splenomegaly
    • Hemolytic cisis
  28. Treatment of choice for hereditary spherocytosis
  29. Bite cells and Heinz bodies on peripheral blood smear
  30. Warm AIHA
    • IgG autoantibodies attack RBC membranes
    • RBCs are sequestered in spleen, causing splenomegaly
    • May be secondary to lymphoma, leukemia, SLE, and alpha-methyldopa
  31. Cold AIHA
    • IgM autoantibodies attack RBC membranes
    • RBCs are sequestered in the liver
    • Can be secondary to mycoplasma pneumonia or infectious mono
  32. Symptoms of PNH
    • Chronic intravascular hemolysis
    • Hemoglobinuria
    • Normochromic, normocytic anemia, due to complement-mediated destruction of RBCs in the spleen
    • Pancytopenia
    • Venous thrombosis
    • Abdo, back, and MSK pain
  33. Ham's test
    • Incubate RBCs in acidic serum, which will activate complement
    • Normal RBCs will not be affected, but the RBCs of a PNH patient will lyse
  34. Heparin-induced thrombocytopenia
    • Heparin can induce either platelet aggregation (type I) or antibody-mediated destruction of platelets (type II)
    • Administration of heparin will cause clots
  35. ITP
    • Antibody-mediated destruction of platelets
    • Patients present withpetechiae and ecchymoses
    • NO splenomegaly
    • Splenectomy induces remission in 70-80% of cases
  36. How low does the platelet count need to be for spontaneous bleeding to occur?
    Usually below 20,000
  37. Classic pentad of TTP
    • Microangiopathic hemolytic anemia
    • Thrombocytopenia
    • Acute renal failure
    • Fever
    • Fluctuating, transient neurological signs
  38. Treatment for TTP
    Plasmapheresis, ASAP
  39. Most common hereditary bleeding disorder
    • vWF, caused by deficient von Willebrand's factor
    • Ristocetin-induced platelet aggregation will be low
  40. Effect of vitamin K deficiency on PT and PTT
    • PT is prolonged (factor VII has the shortest half-life of all the clotting factors, so it gets depleted first, when there is not enough vit K)
    • PTT is normal (but eventually also gets prolonged, when the other factors are depleted)
  41. Why does liver disease cause coagulopathy?
    • Decreased production of clotting factors
    • Cholestasis impairs vitamin K absorption
    • Potal hypertension causes hypersplenism, resulting in platelet sequestration
  42. Factor V Leiden
    • Normally, protein C inhibits clotting factors V and VIII, preventing hypercoagulability
    • In Factor V Leiden, factor V is resistant to inhibition by protein C, resulting in hypercoagulability
    • Associated with hyperhomocysteinemia
  43. What should be given to a patient on heparin or warfarin with severe bleeding?
  44. What is a target INR in most cases?
  45. Symptoms of multiple myeloma
    • Hypercalcemia
    • Renal failure
    • Anemia
    • Lytic bone lesions, especially in the back, chest, and mandible
    • Recurrent infections, due to deficiency in normal Igs
  46. Monclonal spike (M protein) on gel electrophoresis
    Multiple myeloma
  47. RBCs in rouleaux formation (stacked together)
    MM--hyperglobulinemia causes RBCs to stick together
  48. Diagnosis of Waldenstrom's macroglobulinemia
    • IgM over 5 g/dL
    • Bence-Jones proteinuria in 10% of cases
    • NO lytic bone lesions
  49. Symptoms of Waldenstrom's macroglobulinemia
    • Lymphadenopathy
    • Splenomegaly
    • Anemia
    • Abnormal bleeding
    • Hyperviscosity of the blood (can lead to retinal vessel dilation and blindness)
  50. MGUS
    • IgG spike on electrophoresis with Bence-Jones proteinuria
    • Under 20% progress to MM
    • Don't treat, just follow carefully