Post on 01-Jun-2015
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ANEMIA
Very common
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Causes Impaired ability of the bone marrow to
produce sufficient numbers of erythrocytes
Accelerated destruction or loss of RBCs
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Acute anemia Nearly always due to blood loss or
hemolysis Acute blood loss
Features of hypovolemia dominate the clinical picture
Hemoglobin levels do not indicate the volume of blood lost
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Blood loss Sudden loss of > 30% of the blood
volume Postural hypotension
>40% (i.e., >2 L in the average-sized adult) Hypovolemic shock
Tachycardia Tachypnea Sweating Hypotension Mental confusion
Require immediate volume replacement
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Chronic anemia When anemia develops over weeks
May not cause any signs or symptoms until the hemoglobin fall to < 8 g/dL.
Total blood volume is normal or increased Tachcardia 2,3-bisphosphoglycerate rise
Shifts the oxygen dissociation curve to the right Improves O2 release to the tissues
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Which is the most useful of all the RBC indices MCV
Useful in classification and determination of the cause of anemia
MCV = (hematocrit X 10) / (RBC count X 106)
Normal MCV is 82 to 98fL Microcytosis - < 80fL Macrocytosis > 100fL
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Red cell distribution width Automated cell counters give the red cell
volume distribution width Normal = 13 to 15% Elevated RDW suggests variation in red
cell size, i.e. anisocytosis seen in iron deficiency
In beta-thalassaemia trait, the RDW is normal
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Microcytic anemia1. Iron deficiency2. Thalassaemia3. Congenital sideroblastic anaemia
4. Anaemia of chronic disease
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Megaloblastic anaemia B12 or folate deficiency Cytotoxic drugs Myelodysplasia Hypothyroidism Liver disease
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What is the cause of dimorphic anemia? Where two populations of red cells are seen,
the blood film is said to be dimorphic Seen in
Combined iron and folate deficiency Following treatment of anaemic patients with the
haematinic Microcytosis with elevated number of reticulocytes (therapy
of iron deficiency anemias)
Transfusion of RBC (normal volume) in a macrocytic or microcytic (hypochromic) anemia
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