10-28-14 B12 & Folate Metabolism & Absorption

Question 1

Megaloblastic macrocytic anemia is characterized by ___

Answer 1

large erythrocytes High MCV (>100fL) Normal MCHC levels

Question 2

What is the clinical presentation of megaloblastic macrocytic anemia?

Answer 2

Lethargy, weakness, yellow/waxy pallor, loss of weight & appetite, diarrhea

Question 3

What do RBCs look like in Megaloblastic Macrocytic Anemia?

Answer 3

Macrocytic, normochromic cells, oval macrocytes

Question 4

What does megaloblastic macrocytic anemia look like in the bone marrow?

Answer 4

large erythroblasts (megaloblasts)

Question 5

Why do macrocytic cells become so big?

Answer 5

Decreased DNA synthesis due to lack of B12 or Folate, which leads to decreased mitosis, but cytoplasm continues to expand.

Question 6

What are some neurological symptoms of Megaloblastic macrocytic anemia?

Answer 6

• Peripheral neuropathy
  
  • Pins and needles
  • Loss of ambulation
  • Loss of memory
• Megaloblastic madness

Question 7

Production of RBCs is dependent on folate and vitamin B12, if these are deficient, how does this cause megaloblastic macrocytic anemia?

Answer 7

DNA synthesis is retarded. Slowing down the synthesis of DNA directly limits the production of erythroblasts.