Macrocytic anaemia

Question 1

common cause/reasons which result in megaloblastic anaemia

Answer 1

• Folic acid deficiency
• Vit. B12 deficiency
• Abnormalities in B12, Folate metabolism enzymess
• Defects in DNA synthesis

Question 2

which cell line/s are affected by megaloblastic anaemia

Answer 2

typically all 3 cell lines affected
RBC
- macrocytic, normo/hypochromic
- ovalocytes, dacrocytes, poikilocytes
WBC: 
- hypersegmented neutrophils
- Neutropenia
Plts:
- Lrg, thrombocytopenia

Question 3

The importace of Vit B12 & the result if deficient

Answer 3

Vit B12 important for:
• Methylmalonic acid -> succinyl CoA (in haeme synthesis)
• Homocysteine -> methionine (w/ folate)

Deficiency
=> Lack of product
=> buildup of substrate

Question 4

Describe pernicious anaemia

Answer 4

• AutoImm. disease w/ Ab to intrinsic factor for B12 ≠ absorption of intrinsic factor-B12 complex
=> Vit B12 deficiency

Question 5

The importace of folic acid & the result if deficient

Answer 5

Folic acid important for:
• homocysteine -> Methionine (w B12)
• Homocysteine -> methionine (w/ folate)

Deficiency
=> misincorporation of dUTP instead of dTTP

Question 6

name a few B12 assays

Answer 6

• Serum B12 assay
• Immunoassay (also for folate assay)
• Radioimmunoassay (also for folate assay)
• functional assays (also for folate assay)

Question 7

other causes of macrocytosis (non-megaloblastic)

Answer 7

• artefactual: aggregates of 2-3 RBC
• reticulocytosis: bc inc erythropoeisis
• alcoholism: ROUND not oval
• liver disease: dec folate
• hyper- /hypo- thyroidism