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Chapter 100. Megaloblastic Anemias (Part 6)

Psychiatric disturbance is common in both folate and cobalamin deficiencies. This, like the neuropathy, has been attributed to a failure of the synthesis of SAM, which is needed in methylation of biogenic amines (e.g., dopamine) as well as of proteins, phospholipids, and neurotransmitters in the brain (Fig. 100-1). Associations between lower serum folate or cobalamin levels and higher homocysteine levels and the development of Alzheimer's disease have been reported. A 2-year double-blind placebo-controlled randomized clinical trial involving healthy subjects 65 years old given folate, cobalamin, and vitamin B 6 supplements showed no benefit on cognitive performance, whereas a 3-year. | Chapter 100. Megaloblastic Anemias Part 6 Psychiatric disturbance is common in both folate and cobalamin deficiencies. This like the neuropathy has been attributed to a failure of the synthesis of SAM which is needed in methylation of biogenic amines e.g. dopamine as well as of proteins phospholipids and neurotransmitters in the brain Fig. 100-1 . Associations between lower serum folate or cobalamin levels and higher homocysteine levels and the development of Alzheimer s disease have been reported. A 2-year double-blind placebo-controlled randomized clinical trial involving healthy subjects 65 years old given folate cobalamin and vitamin B6 supplements showed no benefit on cognitive performance whereas a 3-year FACIT study did show benefit. Hematologic Findings Peripheral Blood Oval macrocytes usually with considerable anisocytosis and poikilocytosis are the main feature Fig. 100-2A . The MCV is usually 100 fL unless a cause of microcytosis e.g. iron deficiency or thalassemia trait is present. Some of the neutrophils are hypersegmented more than five nuclear lobes . There may be leukopenia due to a reduction in granulocytes and lymphocytes but this is usually 1.5 x 109 L the platelet count may be moderately reduced rarely to 40 x 109 L. The severity of all these changes parallels the degree of anemia. In the nonanemic patient the presence of a few macrocytes and hypersegmented neutrophils in the peripheral blood may be the only indication of the underlying disorder. Figure 100-2 4 Souri Fjuor AS. K ip r ŨL. B unw ld E. H uí r SL Longe DL J m ion IL. .oicitio Htrrisoa f ữĩ 17Eh Edrtit rr cceiĩmedicine.com Copyright c Th Mrijtiií-HIIJ C4F p nl fr fot AJI Jighíi J f .