Definition:
The word "anemia" comes from the Greek term which means missing blood. Anemia is defined as a lower than normal hemoglobin concentration. The lower end of the normal rage is
g/L in men and
g/L in women. It is primarily important to distinguish pseudo-anemia and/or relative anemia (decreased hemoglobin concentrations as a result of increased plasma volume) from absolute anemia (decreased hemoglobin concentrations with a normal plasma volume). Relative anemia is typically observed during pregnancy (iron deficiency usually exists) and during infusion of large amounts of fluids.
Classification:
Anemias can both be classified based on their morphological criteria (erythrocyte indices) as well as pathophysiologic criteria.
| Classification based on erythrocyte indices | ||
|---|---|---|
|
| microcytic + hypochromic | Iron deficiency anemia Thalassemia |
| normocytic + normochromic | acute blood loss Anemia of chronic disorder, anemia of renal disease Hemolysis (partially macrocytic) Bone marrow infiltration |
| macrocytic | Megaloblastic anemia |
| Classification based on pathophysiology | ||
| 1. Increased cell loss or destruction | a) Internal or external bleeding b) Hemolysis (immunologic, hereditary, mechanical) c) Hypersplenisme (combination of hemolysis and sequestration) |
|
| 2. Decreased and/or ineffective production |
a) Proliferation and differentiation defects (aplastic anemia, myelodysplastic syndrome, anemia of renal disease) b) DNA synthesis defect (vitamin B12, folic acid), c) Hemoglobin synthesis defect ( iron deficiency, thalassemia) d) Uncertain or various mechanisms (anemia of chronic disorder, leukemia, bone marrow infiltration through tumors and malignant lymphomas) |
|
Clinical picture:
The symptoms are caused by hypoxia due to a decrease in hemoglobin concentration. Cardiac hyperactivity causes palpitations, tachycardia and heart murmurs. Other symptoms range from weakness, fatigue, and exercise intolerance or even dyspnea at rest. A pallor is the result of vasoconstriction which reroutes the blood to the oxygen dependent organs.
Hematology:
The various forms of anemia differ quite a bit from each other, particularly in the peripheral blood film. A diagnosis can often be established at this stage. However, this must still be confirmed by specific supplementary tests.