Definition:—A condition in which either a portion of the entire blood has been lost, as in hemorrhage, or in which there has been a reduction of the quantity of the red blood corpuscles, or a reduction of the hemoglobin of these red cells.
When the total quantity of blood has been reduced as in hemorrhage, the condition is known as oligemia; when the disease is a reduction of the red corpuscles the condition is known as oligocythemia; when there is a deficiency in the hemoglobin the term oligochromemia is applied.
A reduction of hemoglobin from any cause usually induces pallor, and we are apt to conclude that paleness of the skin or of the countenance is an invariable accompaniment of all anemias. This sign cannot be relied upon. There are cases of paleness in which the conditions are hereditary or at least congenital from various reasons, independent of deficient hemoglobin. Deficient vascularity may be the cause. On the other hand, there may be a condition of anemia in a patient who, from increased vascularity of the countenance, shows no pallor. Again, there may be such an increase in the quantity of hemoglobin in the corpuscles that a loss of quite a quantity of the red corpuscles will result in no reduction in the normal quantity of the hemoglobin, and in no pallor.
When anemia is the result of a disorder of the blood or of the blood making organs primarily, the condition is known as primary, idiopathic, or essential anemia. When hemorrhage has occurred or when disease elsewhere in the system has acted upon the blood or upon the blood making organs, when, from any extraneous cause, as breathing impure air, a reduction of the normal hemoglobin is the result, the condition is classed as secondary anemia.
The Eclectic Practice of Medicine with especial reference to the Treatment of Disease, 1910, was written by Finley Ellingwood, M.D.