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Flashcards in Anemia Deck (31):
1

Cytopenia

non-specific term for a reduction in the number of a cellular component of blood

2

Anemia

low hemoglobin concentration in blood

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Thrombocytopenia

low number of platelets in blood

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Leukopenia

low number of white cells in blood

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Neutropenia

low number of neutrophils (absolute neutrophil count or ANC <1.5)

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Pancytopenia

reduction of all three cell lines (anemia, thrombocytopenia, neutropenia)

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3 principles in considering blood count

Principle #1: a patient’s cell count is low (where is the problem?). Principle #2: consider the other cell counts (is this an isolated abnormality?). DIFFERENTIAL DIAGNOSIS: plan further diagnostic tests. Principle #3: consider the patient(how urgently do tests need to be done?)

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Normal life cycle of blood cells

Produced in bone marrow; released into peripheral blood; normal lifespan: RBC: 120d, pt: 7-10d, neut: 6-8h; senescence (RBC destroyed by spleen, pt consumed in clots or destroyed by spleen, neut consumed or apoptosis)

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What causes blood cell numbers to be low?

Bone marrow not working; or Peripheral problems, namely: Sequestered (engulfed by abnormally large spleen, or diluted in large blood volume); Consumption or loss (bleeding (RBC and pt), immune function (pt and neut), severe infection (neut))

10

What is likely causing pancytopoenia?

The more cell lines affected, the more likely it is bone marrow problem. Also see more immature cells released

11

Anemia

It’s not a diagnosis, just a condition - investigate. Hb < normal (130g/L for male, 120 for female). Symptoms depend on severity, rapidity of onset, age, comorbid contitions

12

General signs and symptoms of anemia

Quite nonspecific, so hard to ID sometimes. Fatigue; SOB & tachypnea (increased respiratory rate); Tachycardia (increased heart rate); decreased exercise tolerance; dizzy or lightheaded; worsening of pre-existing ischemic state (ie. patient with underlying coronary artery disease getting chest pain).

13

Anemia classification approaches

1. According to the MCV 2. According to the bone marrow response (reticulocyte count) 3. According to pathologic category: decreased production, increased loss or destruction, Sequestration

14

MCV approach

MCV < 80fL is microcytic anemia; MCV 80 - 100 fL is normocytic anemia; MCV > 100 is macrocytic anemia. But remember these are not mutually exclusive!

15

Microcytic anemia causes

iron deficiency; anemia of chronic; disease; Thalassemia trait (and disease); sideroblastic anemia; lead poisoning (last 2 less so)

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Macrocytic anemia causes

B12 or folate deficiency; liver disease, EtOH; high reticulocyte count; alcohol; Myelodysplasia; anemia from hypothyroidism (more rare)

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Iron deficiency

(MCV 60s to normocytic!) Not enough iron to make heme

18

Thalassemia trait or disease

(MCV 60-70s) Not enough globin chains to make Hb. Trait is “carrier” state, milder. Due to mutations in genes for a and ß glob in chains

19

Anemia of chronic disease

(MCV 75-85) Iron present but not readily available for use

20

VitaminB12/folate deficiency; Myelodysplasia, Drugs (chemotherapy, HIV drugs)

Impaired DNA synthesis; nuclear maturation and cytoplasm maturation are mismatched

21

Alcoholism, Liver disease, TSH

Altered/increased lipid content in cell membrane: redundant membrane

22

Reticulocytes

(young RBC, some remnants of nucleus still there) Contain residual protein synthesis machinery; have not achieved final compact red cell size

23

Reticulocyte count

Underused test. Consider ordering it if unexplained anemia. Should be about 1% normally, but should be high if you are responding to EPO

24

Normal response to anemia

Kidney detects low O2, release EPO, bone marrow produces new RBC (reticulocytes)

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Low reticulocyte count

abnormal marrow; deficiency of food for red cells (need iron and vitamin B12); low metabolic state; low erythropoietin because of renal failure. Marrow can’t respond!

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High reticulocyte count

bleeding, hemolysis. Marrow is responding BUT red cells being lost or destroyed faster than they can be replaced

27

Anemia by pathologic category

Increased loss or destruction: LOSS = Bleeding (obvious or occult) DESTRUCTION = Hemolysis (red cells being destroyed in the body). Sequestration (and dilution): dilutional = pregnancy, large IV boluses; sequestration = cells sequestered in the spleen (not so relevant to red cells). Decreased production: BIG category (mostly bone marrow)

28

Summary: initial investigation of anemia

1. MCV based: Microcytic: ferritin, +/- Hemoglobinopathy investigation; Macrocytic: B12/folate, liver enzymes, TSH. 2. Consider a Blood film: Confirms cell count abnormalities and may offer important clues if you have no idea what is going on, other cell lines are also down or if hemolysis is suspected. 3. Reticulocyte count (is the marrow working?). 4. Serum ferritin: assess iron stores

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Summary of pathologic category

picture

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Summary for classifications of anemia

table

31

Summary framework for diagnosis

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