HEME- Lecture 4- Intro to anemia

define anemia

the decrease in the competence of blood to carry oxygen to the tissues, therefore causing hypoxia (or decrease in RBC count and hemoglobin concentration)

Two main causes of anemia

1) RBC loss or destruction exceeds production

2) production is impaired

what test is used to screen for anemia

hemoglobin and hematocrit

causes of anemia

blood loss, accelerated hemolysis, nutritional deficiency, bone marrow replacement, infection, toxicity, hematopoetic stem cell arrest or damage, hereditary or acquired defect, unknown/idiopathic

acute blood loss symptoms- none

lose 1000mL or 20% BV

acute blood loss symptoms- circulatory collapse and shock

lose 1500-2000 mL or 30-40% BV

acute blood loss symptoms- imminent death

lose 2500 mL or 50% BV

how does the body adapt to anemia

increase blood flow and increase oxygen use by tissues

what shift is anemia

right shift

increase or decrease: 2,3-BPG

increase

increase or decrease: O2 associated with hemoglobin

decrease

increase or decrease: blood pH

decrease

increase or decrease: PCO2

increase

what is the Bohr effect

a decrease in the amount of oxygen associated with hemoglobin and other respiratory compounds in response to a lowered blood pH (which results from an increased concentration of CO2 in the blood)

exent of adaptation to anemia is influenced by (6)

1) severity of anemia

2) competency of the cardiovascular and respiratory systems

3) oxygen needs

4) duration of anemia

5) cause of the anemia

6) presence and severity of coexisting disease

diagnosis of anemia

pt history and symptoms, physical examination, laboratory examination

Hb ref for male

14-18 g/dL

Hb ref for female

12-16 g/dL

Hb ref for infant

14-22 g/dL

Hct ref for male

42-52%

Hct ref for female

37-47%

what is the rule of 3

Hb x 3 = Hct ± 3

RBC indicies: MCV

80-100 fL

RBC indicies: MCH

27-31 pg

RBC indicies: mean cell Hb concentration

32-36%

normocytic

80-100 fL

macrocytic

>100 fL

microcytic

<80 fL

normochromic

32-36%

hypochromic

<32%

other tests for anemia

reticulocyte count, Hb electrophoresis, bone marrow, dithionate solubility, DAT, osmotic fragility, iron studies, folate and B12 studies, peripheral smear exam (for cell morphology)