Wednesday, September 17, 2008

Megaloblastic Anemia vs Macrocytic Anemia

Megaloblastic anemia describes any anemia in which the RBC precursors are of a large size. The earliest recognized immature form is designated as the promegaloblast or megalocytic rubriblast, followed by the megalocytic prorubricyte, megalocytic rubricyte, and megalocytic metarubricyte in the maturation sequence. This cell line occurs because of impaired DNA synthesis due to vitamin B12 and/or folic acid deficiency. This deficiency causes nuclear plasm asynchrony, in which the nuclear maturation events do not occur in sequence nor in the time interval of development they are supposed to. This disruption produces the extra large RBC’s.

The term “megaloblastic” may infer any of the blood cell maturation lines. Megaloblastic anemia is not to be confused with macrocytic anemia. Where megaloblastic anemia is due to faulty DNA synthesis, macrocytic anemia is a secondary problem due to a primary disorder such as [1] liver disease, [2] acute hemorrhage, or [3] severe anemic episode. Macrocytic anemia is characterized by a MCV range of 105 to 115 fL (indicating thin cells or target cells), although the MCV may go from 100 fL to 130 fL and if severe, may be up to 160 fL. The retic count tends to run from 10 to 25% where it is normal for a megaloblastic condition. In megaloblastic anemia the MCV may range from 100 fL to 160 fL with the MCH elevated but the MCHC is usually normal.

Clinical symptoms for the macrocytic and megaloblastic anemia include [1] pallor, [2] mouth soreness, [3] glossitis, [4] lethargy, [5] asthenia, [6] anorexia, [7] weight loss, [8] diarrhea followed by constipation, and [9] headaches. In megaloblastic anemia, the patient may also experience [1] paresthesia (numbness in hands and feet), and [2] changes in proprioception (movement, posture, and equilibrium). If the condition is not corrected, the patient may experience sudden involuntary movements or convulsions and progress to ataxia (defective movements). This is a progressive disease in which the spinal cord may degenerate and/or the patient may become psychotic.

The psychotic stage is known as megaloblastic madness. Megaloblastic anemic disorders are vitamin-dependent of which pernicious anemia describes a condition caused by the absence of intrinsic factor resulting in a B12 deficiency. Other causes may be due to increased requirements for B12 and/or folic acid. Drugs, malabsorption, and dietary deficiencies have been known to contribute to the manifestation of this anemic disorder.

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