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MOHDIII - Unit 2 > Anemia & Red Cell Disorders > Flashcards

Anemia & Red Cell Disorders Flashcards

1
Q

definition of anemia

A
  • decreased O2 carrying capacity of blood: decreased erythrocytes and/or decreased amount of hemoglobin per cell
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2
Q

RBC measurements

A
  • hemoglobin
  • hematocrit
  • RBC count
  • RBC indices
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3
Q

RBC indices

A
  • MCV: mean cell volume = Hct/RBC (size)
  • MCHS: mean cell hemoglobin concentration = Hg/Hct (central pallor)
  • MCH: mean cell hemoblobin = Hg/RBC
  • RDW: red cell distribution width= anisocytosis (variation in red cell size)
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4
Q

Clinical features of anemia

A
  • weakness
  • fatigue
  • pallor
  • rapid pulse
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5
Q

Classification of anemia: physiologic

A
  • blood loss: acute & chronic
  • increased rate of destruction: hereditary & acquired
  • impaired red cell production
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6
Q

Classification of anemia: morphologic

A
  • microcytic (MCV100fl): B12, folate deficiency, reticulocytosis
  • normocytic (MCV80-100fl): many disorders
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7
Q

Acute blood loss

A
  • early on major problem in loss of blood VOLUME
  • hemodilution then lowers hemoglobin level
  • increase in reticulocyte count occurs 1 week after acute hemorrhage
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8
Q

Chronic blood loss

A
  • anemia occurs when hemorrhage exceeds bone marrow regerative capacity or if iron stores are depleted
  • bleeding is MAJOR cause of IRON deficiency anemia
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9
Q

Hemolytic anemia

A
  • red cells destroyed in peripheral blood

- RBC survival

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10
Q

Lab findings in hemolytic anemia

A
  • increased indirect bilirubin & LDH
  • decreased haptoglobin: free Hg binds and cleared by liver
  • increased reticulocytes and polychromasia on blood smear
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11
Q

Mechanisms of hemolysis

A
  • intracorpuscular: membrane defect: hereditary pherocytosis, enzyme defect: G6PD deficiency, disorder of Hg synthesis: sickle cell, thalassemia
  • extracorpuscular: anti RBC antibodies, vascular wall defects, toxins
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12
Q

Intravascular hemolysis

A
  • RBCs destroyed w/in vessels
  • increased Hg, decreased haptoglobin, urine positive for hemoglobin and hemosiderin
  • Ex: fragmentation hemolysis (DIC, TTP), marathon running
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13
Q

Extravascular hemolysis

A
  • RBCs destroyed w/in macrophages, mainly in spleen
  • urine is negative for hemoglobin and hemosiderin
  • Ex: hereditary spherocytosis
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14
Q

Hereditary spherocytosis

A
  • autosomal dominant common in euopeans (1/5000)
  • deficiency of spectrin, band 3, or ANKYRIN* most common
  • decreased membrane stability–spherocytes–removed by spleen
  • splenectomy is curative but only needed if severe hemolysis
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15
Q

G6PD deficiency

A
  • abnormalities in hexose-monophosphate shunt (decreased protection against oxidant stress
  • cells cannot reduce glutathione due to lack of NADPH
  • most common are G6PD A- & G6PD mediterranean
  • DIAGNOSIS made by quantitating levels of G6PD in blood
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16
Q

G6PD deficiency: inheritance & hemolysis

A
  • X linked
  • hemolysis occurs when patient is exposed to drugs, becomes infected, or eats FAVA BEANS
  • hemolysis is self limited: stay away from above
  • avoidance of oxidant stress is major therapy
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17
Q

Histology of G6PD deficiency

A
  • heinz bodies: increased Hg on one side of RBC

- blister cells: spleen eats half of RBC that has too much Hg

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18
Q

Sickle cell anemia

A
  • VALINE substituted for GLUTAMIC acid at position 6 of B-globin gene
  • globin chains aggregate under deoxygenating conditions in the HOMOZYGOUS condition
  • sickle cells removed by macrophages and cause vascular occlusion: bone pain, splenic atrophy
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19
Q

Sickle cell trait

A
  • heterozygous condition, 8% of african americans

- benign condition

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20
Q

Sickle cell histology

A
  • howell jolly bodies: small purple dots in RBCs = remnants of nuclei
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21
Q

Hemoglobin distribution in sickle cell anemia

A
  • have Hg S and no Hg A
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22
Q

Thalassemia

A
  • decreased alpha or beta chain production
  • hypochromic microcytic anemia
  • ineffective erythropoiesis & hemolysis
  • heterozygosity leads to protection from plamodium falciparum malaria
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23
Q

Alpha thalassemia

A
  • gene DELETION of one to all four alpha globin chains
  • one or two gene deletion asymptomatic with microcytosis, +/- minimal anemia in two gene deletion
  • three gene deletion leads to moderate anemia
  • four gene deletion leads to HYDROPS FATALIS - intrauterine death
24
Q

Beta thalassemia

A
  • POINT mutations in beta globin gene
  • most commonly due to SPLICING mutations
  • decrease beta chain formation & excess alpha chains precipitate causing membrane damage
25
Q

Beta thalassemia trait

A
  • heterozygosity for beta gene mutation
  • mild anemia w/ microcytosis
  • lab testing reveals an increase in A2 level (increased alpha2:delta 2) –which amounts to ~5% total Hg (higher than normal)
26
Q

Clinical and histologic findings in beta thalassemia

A
  • systemic iron overload
  • microcytic red cells: increased central pallor, decreased MCV & MCHC
  • ## prominent facial bones, x-ray of skull shows hair on end appearance due to increase erythropoiesis
27
Q

Acquired hemolytic anemias

A
  • immune hemolytic anemia

- fragmentation hemolytic anemia

28
Q

Immune hemolytic anemia

A
  • antibodies develop to part of red cell membrane
  • IgG (most common) bound to red cell which is removed by spleen leading to formation of SPHEROCYTES, which are sequestered by spleen
  • DIRECT ANTIGLOBULIN (COOMBS) test is positive
29
Q

Fragmentation hemolytic anemia

A
  • schistocytes are characteristic
  • microangiopathic hemolytic anemia due to microvascular thrombi: DIC or TTP
  • mechanical heart valves
30
Q

Anemia of decreased production

A
  • decreased reticulocytes: nutritional deficiencies, chronic disease, stem cell disorder in marrow
31
Q

Megaloblastic anemia - impaired DNA synthesis

A
  • morphologic findings: oval macrocytes, hypersegmented neutrophils (more than 5 lobes), hypercellular marrow w/ nuclear/cytoplasmic asynchrony
  • example of ineffective erythropoieses
32
Q

Causes of B12 deficiency

A
  • dietary: rare, strict vegans
  • post gastrectomy, malabsorption, fish tapeworm
  • pernicious anemia (most common): autoimmune w/ antibodies to IF
  • neurologic defects: demyelination of posterior columns
33
Q

Folate deficiency

A
  • dietary: rare but seen in premature infants & pregnant women
  • malabsorption
  • increased utilization: hemolytic anemia
  • stored in live, last 2-4 months
  • no neurologic defects
34
Q

Why B12 and folate are necessary

A
  • needed for DNA synthesis
35
Q

Tests to differentiate b/w B12 & folate deficiency

A
  • methylmalonic acid: B12=HIGH, folate=NORMAL

- both will have high homocysteine

36
Q

Treatment of B12 or folate deficiency

A
  • B12 or folate replacement

- hematologic symptoms of B12 deficiency can be treated w/ administration of folate but neurologic symptoms may progress

37
Q

Type of anemia seen w/ folate and B12 deficiency

A

megaloblastic anemia

38
Q

Iron deficiency

A
  • common cause of anemia

- causes: dietary, increased requirement (kids, pregnancy), blood loss (GI, menstrual)

39
Q

Morphology of iron deficiency anemia

A
  • microcytic hypochromic cells: increased central pallor
40
Q

Lab studies in iron deficiency

A
  • decreased serum iron
  • increased total iron binding capacity (transferrin)
  • decreased iron saturation
  • decreased serum FERRITIN
41
Q

Bone marrow appearance in iron deficiency

A
  • prussian blue stain will show no stores = no blue stain appearance
42
Q

Iron deficiency treatment

A
  • iron supplementation: oral or IV

- diagnose and treat the cause of blood loss

43
Q

Anemia of chronic inflammation

A
  • normocytic or mildly microcytic anemia due to chronic inflammatory states or infections
  • very common
  • mild anemia (Hct = 30%)
  • symptoms & treatment relate to underlying disease
44
Q

Anemia of chronic inflammation: etiology

A
  • inflammatory cytokines stimulate hepcidin (iron regulatory protein) synthesis: iron sequestered in macrophages, decreased intestinal absorption of iron, Hg synthesis is impaired b/c iron is not delivered to erythrocytes
45
Q

Iron studies in amemia

A
  • iron deficiency: decreased ferritin, Fe, stores; increased transferrin
  • chronic disease: decreased Fe, transferrin; increased ferritin, stores
  • all others: decreased transferrin; increased stores, ferritin, Fe
46
Q

Aplastic anemia

A
  • marrow failure with pancytopenia (decreased all cell production)
  • mostly idiopathic
  • normocytic or mildly macrocytic anemia, leukopenia, thrombocytopeina
  • NEED TO DO BM TO DIAGNOSE
47
Q

BM appearance in aplastic anemia

A
  • no hematopoetic cells

- all FAT

48
Q

Treatment of aplastic anemia

A
  • immunosuppressive medications: b/c cells are destroying their own marrow stem cells
  • bone marrow transplant
49
Q

Myelophthisic anemia

A
  • caused by marrow replacement: metastatic cancer, leukemia/lymphoma, fibrosis
50
Q

Anemia of renal failure/uremia

A
  • decreased erythropoietin stimulation of erythroid precursors: treat by giving EPO
  • anemia in myelodysplastic syndromes: neoplastic stem cell clone develops which has a maturation defect
51
Q

Polycythemia

A
  • too many red cells
  • primary: polycythemia vera
  • secondary: high altitude, erythropoietin secreting tumors
52
Q

Polycythemia vera

A
  • one of myeloproliferative neoplasms
  • elevated Hct
  • disease of late middle age
  • symptom: PRURITIS (itching) after bathing
53
Q

BM and blood smear in polycythemia vera

A
  • BM has increased red cell precursors (increased megakaryocytes)
  • increased red cells in blood smear
54
Q

Genetics of polycythemia vera

A
  • mutation in JAK 2 gene (V617F)

- leads to increased proliferation of BM cells

55
Q

EPO levels in polycythemia vera

A
  • decreased

- due to increased red cells

56
Q

Treatment for polycythemia vera

A
  • phlebotomy
57
Q

Polychromasia

A
  • bigger and bluer immature red cells

MOHDIII - Unit 2 (23 decks)

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