Anemia

Dr. Meg-angela Christi M. Amores

What is Hematopoeisis?

• It is the process by which the formed elements of the blood are produced

• Erythropoeisis: production of erythrocytes (red blood cells)

• Regulatory hormone: EPO (erythropoeitin)– kidney

Erythropoeisis

• Critical elements:– EPO production– iron availability– the proliferative capacity of the bone marrow– effective maturation of red cell precursors

Anemia

• Often recognized by abnormal screening tests• Less commonly presents signs and symptoms

unless advanced• Acute anemia – due to blood loss or hemolysis– If acute blood loss, hypovolemia results

• Hypotension is the issue, not anemia• 10 – 15% blood loss- signs of vascular instability• >30% - postural hypotension, tachycardia• >40% - hypovolemic shock (confusion, dyspnea,

diaphoresis, hypotension, tachycardia)

Anemia

• Acute anemia – due to blood loss or hemolysis– Acute hemolysis• Symptoms: fatigue, loss of stamina, breathlessness,

and tachycardia (particularly with physical exertion)• Most often only occurs when advanced (hgb <7 mg/dL)

Approach to patient

• History:– Nutritional (food, drugs, alcohol)– Family history– G6PD deficiency

• PE:– Findings of infection– blood in the stool, lymphadenopathy,

splenomegaly, or petechiae– forceful heartbeat, strong peripheral pulses, and a

systolic "flow" murmur

Pallor

• skin and mucous membranes may be pale if the hemoglobin is <80–100 g/L (8–10 g/dL)

• If palmar creases are lighter in color than the surrounding skin when the hand is hyperextended, the hemoglobin level is usually <80 g/L (8 g/dL)

Laboratory Evaluation

Normal Hgb and Hct levels

CBC

• Components of CBC help in the classification of anemia:– Microcytosis - reflected by a lower than normal

MCV (<80)– Macrocytosis - high values (>100) of MCV– MCH and MCHC reflect defects in hemoglobin

synthesis - hypochromia

Peripheral blood smear

• provides important information about defects in red cell production

• the blood smear also reveals variations in cell size (anisocytosis) and shape (poikilocytosis)

Reticulocyte count

• key to the initial classification of anemia• Normally, the reticulocyte count ranges from 1–

2% and reflects the daily replacement of 0.8–1.0% of the circulating red cell population

• reticulocyte count provides a reliable measure of red cell production

• In the face of established anemia, a reticulocyte response less than two to three times normal indicates an inadequate marrow response.

Tests of Iron Supply and storage

• serum iron• TIBC• percent transferrin saturation• serum ferritin is used to evaluate total-body

iron stores

Bone Marrow examination

• Indications:– patients with

hypoproliferative anemia and normal iron status

– can diagnose primary marrow disorders such as myelofibrosis, a red cell maturation defect, or an infiltrative disease

Functional Classification

1. marrow production defects (hypoproliferation)2. red cell maturation defects (ineffective

erythropoiesis )3. decreased red cell survival (blood loss

/hemolysis)

Hypoproliferative Anemia

• 75% of all anemia• reflects absolute or relative marrow failure • Majority are due to mild to moderate iron

deficiency or inflammation• can result from marrow damage, iron

deficiency, or inadequate EPO stimulation• normocytic, normochromic red cells• Key diagnostic tool: IRON studies

Hypoproliferative Anemia

• anemia of acute or chronic inflammation– serum iron (low), TIBC (normal or low), percent

transferrin saturation (low), and serum ferritin (normal or high)

• mild to moderate iron deficiency – (low serum iron, high TIBC, low percent transferrin

saturation, low serum ferritin)

Maturation disorders

• anemia with an inappropriately low reticulocyte production index, macro- or microcytosis on smear, and abnormal red cell indices

• ineffective erythropoiesis that results from the destruction within the marrow

• vitamin B12 or folic acid deficiency, drug damage, or myelodysplasia

Blood Loss / Hemolytic Anemia

• Red blood cell indices >2.5x the normal• stimulated erythropoiesis • typically normocytic or slightly macrocytic• Hemolysis – least common form of anemia– present in different ways– paroxysmal nocturnal hemoglobinuria– Hemoglobinopathies– hereditary spherocytosis

Treatment

• Severe anemia: red cell transfusions • acute or gradual onset: determined by the

documented cause(s) of the anemia• important to evaluate the patient's iron status

fully • Chronic kidney disease: Recombinant EPO