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30 Cards in this Set
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What is anemia of pregnancy?
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Not truly "anemia" ie decreased whole body RBCs, but rather a relative drop in hematocrit due to an increase in plasma volume.
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What are primary causes of iron deficiency anemia?
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Adults - chronic blood loss, esp. menorrhagia or GI lesions(may be occult- think colon cancer)
Infants - dietary iron deficiency (especially premature infants). Can also occur rarely in the elderly. |
Increased iron requirement in pregnancy (fetus can deplete maternal stores), infants and adolescents (may outgrow borderline iron stores)
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What findings would you expect in a patient with iron deficiency?
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pallor, fatigue, dyspnea on exertion, occasionally angina in persons with CAD. When extreme, glossitis, gastritis, spooning of the nails, Plummer-Vinson syndrome (partial obstructing upper esophageal web). Hypochromic, microcytic anemia with decreased hemoglobin/hematocrit/RBC count. Decreased serum iron, increased total iron binding capacity. Decreased iron stores (decreased hemosiderin in bone marrow, decreased serum ferritin)
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What is the differential diagnosis for hypochromic microcytic anemia? how would you differentiate them?
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Iron deficiency anemia, anemia of chronic disease, and B-thalassemia minor all present as hypochromic, microcytic anemia. In anemia of chronic disease, serum iron is low but TIBC is also low (as opposed to high in iron deficiency anemia). In B-thalassemia minor, A2 hemoglobin is increased.
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What deficiencies lead to megaloblastic anemia?
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Large, abnormal erythroid precursors are seen in deficiencies of folate or B12. They lead to decreased DNA synthesis and nuclear-cytoplasmic asynchrony (cytoplasm matures, nuclear development delayed). End result is ineffective erythropoiesis.
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What blood and bone marrow findings are expected in folate and B12 deficiency?
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Pancytopenia, oval macrocytosis (MCV often greater than 110), hypersegmented PMNs (more than 5 lobes), and megaloblastic hyperplasia of the bone marrow. Measuring B12 and folate levels further specify type of anemia.
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same for both deficiencies. B12 can also have neuro signs
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An older individual presents with lemon-yellow skin, glossitis, and ataxic gait, as well as pancytopenia on peripheral blood smear. What cancer is the patient at higher risk for? What lab findings might you expect?
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Pernicious anemia (caused by chronic autoimmune gastritis) can lead to all of these findings, and increased the risk of gastric adenocarcinoma. In addition to those general for megaloblastic anemia, lab findings include anti-intrinsic factor antibodies and an abnormal Schilling test (i.e. abnormal B12 absorption, also may occur with Crohn's, blind-loop syndrome, giant tapeworm infestation.)
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Also associated with achlrohydria, as well as anti-intrinsic factor and antiparietal cell antibodies
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What can cause vitamin B12 deficiency?
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Pernicious anemia, total gastric resection (can't produce intrinsic factor), disorders of the distal ileum (site of absorption), strict vegan diet (only found in animal products), blind loop syndrome (bacterial overgrowth in surgically induced intestinal blind loop resulting in depletion of B12), broad spectrum antibiotics (bacterial overgrowth resulting in B12 depletion), Giant Fish Tapeworm infestation.
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A patient is taking phenytoin and presents with anemia. What type of anemia is likely? Why?
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Likely megaloblastic anemia due to interference with absorption of folate. OCP can have the same affect, while folic acid antagonist chemotherapy, intestinal malabsorption caused by sprue or Giardia, severe dietary deprivation (alcoholics/fad dieters), pregnancy or hemolytic anemia (both increase demand) can also cause folate deficiency in one way or another
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No neurological abnormalities
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A patient with long standing rheumatoid arthritis presents with hypochromic, microcytic anemia and low serum iron. What lab test would you want to make a confident diagnosis?
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Total iron binding capacity (high in iron deficiency, low in anemia of chronic disease). Anemia of chronic disease from non chronic inflammatory states is often normochromic and normocytic, or in the case of renal disease moderately macrocytic.
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What agents can cause pancytopenia with markedly hypocellular bone marrow?
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Radiation exposure, benzene and other organic compounds, chloramphenicol (sometimes dose-related, reversible effect, sometimes severe, idiosyncratic non-reversible), alkylating agents used in treating neoplasms, parvovirus (B19), Hepatitis C virus. (other therapeutic drugs can also cause aplastic anemia)
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Aplastic anemia
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Decreased serum haptoglobins, reticulocytosis, and high indirect bilirubin point to what process?
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Hemolytic anemia. Also, increased urine urobilinogen, hemoglobinemia and hemoglobinuria, hemosiderosis, normoblastic erythroid hyperplasia, polychromatophilia (larger RBC that stain with bluish cast-residual stainable RNA), moderately increased MCV (up to 105, due to larger size of reticulocytes)
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A patient has hemoglobin in his urine in the morning after sleeping. What gene is defective? How is the diagnosis made?
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The patient has paroxysmal nocturnal hemoglobinuria, an aquired intracorpuscular defect. Somatic mutation in the PIG-A gene causing impaired synthesis of the GPI anchor for a number of cell surface proteins, including CD55, CD59, and C8 binding proteins, which protect blood cells from complement mediated lysis. Diagnosis involves flow cytometry demonstrating CD59 negative RBCs.
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Intravascular hemolytic anemia, pancytopenia, and increased incidence of venous thrombosis
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What underlying conditions can lead to hemolytic anemia with a positive direct Coombs test?
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The Coombs test reflects the binding of IgG sutoantibody to RBCs; i.e. warm antibody hemolytic anemia. SLE, Hodgkin disease, and non-Hodgkins lymphoma are all associated with this.
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Shows general features of intravascular hemolytic anemia and spherocytosis due to loss of membrane proteins during passage of antibody coated cells through spleen. Clinically suggested (along with other immune hemolytic anemias) by hemolytic anemia of recent onset
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What infections are associated with cold agglutinin disease? What antigen do they react to?
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Infectious mononucleosis and Mycoplasma pneumoniae infection are both associated with cold agglutinins (helpful in diagnosis of mycoplasma). Antibodies are often directed against the I blood group antigen.
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IgM
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A newborn is born with severe hyperbilirubinemia. The mother is Rh- (D antigen -), while the child is Rh+ (D antigen +). What is the primary consequence you are concerned about? What other problem can arise from fetal hemolytic anemia?
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The disease can result in kernicterus, the staining of the basal ganglia and other CNS structures by unconjugated bilirubin which can lead to neurological damage. Additionally, hemolytic anemia of the fetus can lead to stillbirth or hydrops fetalis--heart failure with massive generalized edema.
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erythroblastosis fetalis
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A patient has an increased MCHC. What type of gene defect would you expect? What test might you order to make your diagnosis?
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A mutation in spectrin, ankyrin, protein 4.1, or another erythrocyte membrane skeletal protein leading to defective RBC membrane integrity. An erythrocyte osmotic fragility test in hypotonic saline (leading to rupture) would help confirm the diagnosis of hereditary spherocytosis
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splenomegaly often prominent
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An African American patient has RBCs with "bites" and remembers a self-limited bout of hemolytic anemia after taking an anti-malarial drug. What is the inheritance pattern of this disorder?
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X-linked disorder leading to a deficiency in G6PD.
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Most common enzyme deficiency hemolytic anemia. Also occurs in Mediterranean populations, may be protective against malaria. Fava beans and various oxidant drugs can trigger hemoglobinemia/hemoglobinuria
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What are primary characteristics of sickle cell disease?
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Severe hemolytic anemia, chronic leg ulcers, repeated infarctions of lung and spleen (large and congested when young, eventually becomes small and fibrosed-susceptible to encapsulated organisms), aplastic crises (usually virally provoked-parvovirus), infectious complications (Salmonella osteomyelitis)
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Homozygous hemoglobin S (mutation in codon 6 of B-globin gene substituting Val for Glu), heterozygous with hemoglobin C, B-thalassemia (both somewhat milder). Sickle cell preparation positive any time hemoglobin S is present (including carriers)
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What disease(s) have blood cells that are spherical?
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Hereditary spherocytosis, autoimmune hemolysis
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What disease(s) have blood cells that are elliptical?
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Hereditary elliptocytosis (ovalocytosis) - Autosomal dominant disorder that may show hemolytic anemia and splenomegaly. Often does not cause anemia.
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What disease(s) have blood cells that are macro-ovalocyte?
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Megaloblastic anemia (folate, B12 deficiencies), bone marrow failure.
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Also hypersegmented PMNs
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What disease(s) have blood cells that are helmet-cells/schistocytes?
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traumatic hemolysis (due to artificial heart valve, DIC)
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What disease(s) have blood cells that are sickle shaped?
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Sickle cell anemia (HbS/HbS, HbS/HbC, HbS/B-thalassemia)
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What disease(s) have blood cells that are teardrop shaped?
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Myeloid metaplasia with myelofibrosis
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What disease(s) have blood cells that are spiny-appearing/star shaped (acanthocytes)?
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abetalipoproteinemia (main issue is patients have poor absorption of fats)
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What disease(s) have blood cells that are targetoid?
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HbC homozygotes, asplenia, liver disease, thalassemias
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What disease(s) have blood cells that are poikilocytes (nonuniform shapes)?
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TTP/HUS, microvascular damage, DIC
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What disease(s) have blood cells that are Burr cells (similar to helmet cells)?
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TTP/HUS
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What Hb is elevated in B-thalassemia major?
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HbF (α2γ2) ie fetal hemoglobin
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defect in promoter, intron, or coding region of both B-globin genes
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