General Anemia Flashcards

1
Q
A
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2
Q

RBC

Lifespan
Phagocytized by

A

~120 days

Eventually phagocytized in reticuloendothelial system

  • Macrophages in the liver and spleen
    Accumulated damage to the aging RBC renders it unfit to circulate, leading to destruction - Senescence
  • RBC component recycling
  • Red cell destruction stimulates erythropoiesis
    Mediated by EPO
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3
Q
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4
Q

RBC

how much HGB per RBC?

A

several thousand

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5
Q

Anemia

Definition

A

Reduction in the volume (hematocrit) of or concentration (hemoglobin) of RBCs when compared to similar values from a reference population

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6
Q

Anemia

Mechanisms of disease

A

RBCs destroyed ~100 days or less, RBC production can’t keep up and patient becomes anemic
Ineffective erythropoiesis
Insufficient erythropoiesis
Blood loss
Acute blood loss
Chronic blood loss
Hemolysis
Increased RBC hemolysis

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7
Q

Expression of amount (units) for HgB, Hct, RBC

A

Hgb = expression of amount (g/dL)
Hct = expression of volume (% or decimal fraction)
RBC = expression of number (#/mm3)

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8
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9
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10
Q

erythropoietin (EPO)

general
Where is it produced and what’s it do

A

Primarily Kidney (90%) & Liver (10%)
Stimulates RBC production when O2 is low (hypoxia)
Hypoxia + EPO = INCREASED RBCs

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11
Q

HGB concentration

general

A
  • In anemia, hypoxic signal in kidneys (mainly) and liver results in ↑EPO.
  • As Hct falls, plasma EPO ↑↑↑
  • In anemia due to impaired RBC production: erythroid progenitors are unresponsive to ↑EPO.
  • In anemia is due to hemolysis or blood loss, elevated EPO levels maximize RBC production.
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12
Q

5 Main Compensatory Responses to anemia

A
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13
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14
Q

02- Hgb dissociation curve

Left shift

A
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15
Q

O2 Hgb dissociation curve

right shift

A
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16
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17
Q

Anemia

classifications

2

A

Decreased production of RBCs

Accelerated loss of RBCs

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18
Q

decreased RBC production

examples

A
  • Marrow failure
    Decreased raw materials
    RBC defects
    Myelodysplasia (Example: Leukemia)
  • Renal failure
    Decreased EPO
  • Lack of nutrients (iron, B12, folate).
    Due to dietary lack
    Malabsorption (pernicious anemia, celiac disease)
    Blood loss (iron deficiency)

Bone marrow disorders (aplastic anemia, myelodysplasia, tumor)
Bone marrow suppression (drugs, chemotherapy, irradiation)
Think about the patient
Have we intentionally or inadvertently given a drug that is suppressing the marrow?
Nutrients may be present, but the bone marrow is shut down

19
Q

Decreased RBC production

Low levels of hormones which stimulate RBC production

A

Chronic renal failure (low EPO)
Hypothyroidism
Hypogonadism

Think about the patient
Is the patient on dialysis
Are there signs of hypothyroidism or hypoandrogenism?

20
Q

Decreased RBC production

Anemia of chronic disease/anemia of inflammation

A

Evolutionary defense strategy of the body to limit availability of iron for invading microbes

Iron studies are normal, but the iron is unavailable to microbes…and to the patient

21
Q

Accelerated loss of RBCs

Destruction of RBCs

A

Differentials:
* Inherited hemolytic anemias
Sickle cell disease, thalassemia major
* Acquired hemolytic anemias
Autoimmune hemolytic anemia, TTP/HUS, malaria
* G6PD deficiency
RBCs are not stable during oxidative stress, so they get destroyed

22
Q

Accelerated Loss of RBCs: Destruction

Primary prevention
Screening

A

Screening
Infants at 9-12 months age
High risk infants/children any age
Pregnant women

23
Q

Anemia

Hx of a medical condition known to result in anemia

A

Tarry stools in a patient with ulcer-type pain,
Known rheumatoid arthritis or renal failure

24
Q

Anemia Hx

Is anemia recent origin or lifelong?

A

Recent anemia is almost always an acquired disorder
Lifelong anemia, particularly if positive FHx, is likely inherited

25
Q

anemia Hx

Ethnicity and country of origin may be helpful

A

Thalassemias and other hemoglobinopathies are common in patients from the Mediterranean, Middle East, sub-Saharan Africa, and Southeast Asia

26
Q

Hx

Meds, supplements, other

A

Medications and supplements
Prescribed and OTC
Use of:
Alcohol (folate deficiency)
Aspirin and NSAIDs (GI blood loss)
History of blood transfusions
Exposure to toxic chemicals in the workplace/environment

27
Q

Hx

Liver disease

A

Hypersplenism secondary to portal hypertension may be removing RBCs (and platelets) from circulation
Deficiency of coagulation factors synthesized by liver may be causing blood loss
Aplastic anemia (decreased RBC production) may follow hepatitis

28
Q

Anemia

Symptoms

A
29
Q

Anemia

Signs (8)

A
30
Q
A
31
Q

RBC INDICES

A
32
Q

Anemia:

Hbg, Hct, MCV, MCH, RDW

CBC

A

Complete blood count:

  • Hgb
    Protein in RBCs that carries oxygen to tissue
  • Hct
    Volume of RBCs: Volume of blood
  • MCV – indication of RBC size
    Macrocytic, normocytic, or microcytic
  • MCH – Average hgb content in RBC
    Hyperchromic, normochromic, or hypochromic
  • RDW – indication of RBC size variation
    Anisocytosis
33
Q
A
34
Q
A
35
Q

why is MCV important?

A
36
Q

Morphology Classification

Microcytic(5)

A

Microcytic (MCV <80 µ3):
Iron deficiency
Thalassemia
Chronic disease/inflammation
Sideroblastic anemia
Lead poisoning

37
Q

Morphology Classification

Normocytic

A

Normocytic (MCV 80-100 µ3):
Acute blood loss
Chronic disease
Hypersplenism
Bone marrow failure
Hemolysis

38
Q

Morphology Classification

Macrocytic

A

Macrocytic (MCV >100 µ3):
B12 or folate deficiency
Hemolysis with reticulocytosis
Chemotherapy
Hypothyroidism
MDS

39
Q

Reticulocyte Count

A

of immature RBCs released from bone marrow into peripheral circulation
Normal levels 0.5%-1.5%

40
Q

Increased reticulocyte count

A
41
Q

decreased reticulocyte count

A
42
Q

additional labs for anemia work up

10

A
43
Q
A
44
Q
A