B12 and folate deficiencies

Question 1

importance of b12/folic acid

Answer 1

needed for DNA synthesis- bone marrow, epithelial surfaces eg mouth, gonads and embryos need it the most

Question 2

clinical features of B12/folate deficiency

Answer 2

anemia, jaundice (RBC broken down), glossitis (inflamed tongue) and cracks in mouths (angular cheilosis), weight loss, and problems with fertility

Question 3

causes of macrocytic anaemia+ tests

Answer 3

VIT B12/FOLATE DEFICIENCY (test these)

liver disease (liver function tests) hypothyroidism (thyroid function tests), immunosurpressant drugs, and haematological disorders eg reticulocytosis (reticulocyte count)

Question 4

normal RBC maturation

Answer 4

erythroblasts to normoblasts (early/intermediate+ late), then reticulocytes, then RBC

nucleus becomes smaller and smaller, and cytoplasm gets more pink (as more haem produced)

Question 5

what kind of anaemia is due to b12/folate deficiency

Answer 5

macrocytic (high MCV) and MEGALOBLASTIC (change in appearance of red cell precursors in bone marrow)- disrupted maturation of nucleus and cytoplasm unlike normal maturation

Question 6

types of cells in megoblastic anemia

Answer 6

anisocytosis (change in size/shapes)

larger RBC with nuclei

hypersegmented neutrophils (number of segments/circles in neutrophil)- would check Vit b12 and folate levels if seen

Question 7

folate in diet

Answer 7

found in fresh leafy veggies, but destroyed by cooking/canning

Question 8

those most at risk of folate deficiency

Answer 8

poor ppl, elderly, alcoholics

often occurs during pregnancy, premature babies, cancer and haemolytic anaemia (where demand for folate increases due to increased DNA synthesis)

Question 9

lab diagnosis of folate deficiency

Answer 9

FBC and film (high MCV/ megaloblastic changes) + high serum folate levels

Question 10

consequences of folate deficiency

Answer 10

megaloblastic, macrocytic anaemia

neural tube defects in fetus eg spina bifida- take folic acid before conception

increased risk of thrombosis due to issues with HOMOCYSTEINE metabolism- elevated levels can cause atherosclerosis

Question 11

consequences of B12 deficiency

Answer 11

neural problems like peripheral neurophathy eg absent reflexes, optic issues, dementia

can cause paraesthesia (tingling hands/feets), muscle weakness, issues walking

Question 12

causes of B12 deficiency

Answer 12

POOR ABSORPTION main issue- also dietary intake (vegans), and infections

Question 13

normal B12 absorption

Answer 13

B12 combines with intrinsic factor made in stomach- complex absorbed in small intestine (ileum)

Question 14

cause of impaired B12 absorption

Answer 14

low IF due to stomach issues+ antibodies to IF or parietal cells (PERNICIOUS anemia- due to low IF)

diseases of ileum eg crohns/coeliac disease

infections eg H pylori

drugs eg metformin+ proton pump inhibitors

Question 15

testing for cause of low B12

Answer 15

antibody tests for IF, parietal cells or coeliac disease

test for infections

Question 16

shilling test

Answer 16

not used anymore- drink radiolabelled B12 and measure excretion in urine- if in urine, you have absorbed it (has gone through kidneys): if no radioactivity, haven’t absorbed it

then repeat test with IF as well (if wasn’t radioactive before but now is, means pernicious anemia)

Question 17

treatment of B12 deficiency

Answer 17

inject B12 every 3 months (often intramuscularly), not ORALLY

Question 18

tests for someone who has megaloblastic anemia

Answer 18

do vit b12/folate test first