Macrocytosis and macrocytic anaemia

Question 1

macrocytosis and macrocytic anaemia are the same thing, true or false

Answer 1

false

Question 2

define macrocytic anaemia

Answer 2

anaemia with red cells being abnormally larger than normal (^MCV)

Question 3

what are the units of MCV

Answer 3

femtolitres

Question 4

in a blood film, what is used as reference for RBC size

Answer 4

the nucleus of a small, mature lymphocyte is used as a reference for RBC size as it is unchanging

Question 5

what are the main causes of macrocytic anaemia

Answer 5

genuine / true

spurious / false

Question 6

what are genuine causes of macrocytic anaemia

Answer 6

megaloblastic

non-megaloblastic

Question 7

what accumulates in developing erythroblasts/normoblasts

Answer 7

Hb

Question 8

what happens when Hb concentration has reached threshold

Answer 8

erythroblasts stop dividing and enucleation occurs to become a reticulocyte

Question 9

define erythroblast

Answer 9

normal red cell precursor with a nucleus

Question 10

define megaloblast

Answer 10

large red cell precursor with an immature nucleus - open chromatin seen

Question 11

what is the main cause of megaloblastic anaemias

Answer 11

lack of red blood cells due to defects in DNA synthesis and nuclear maturation

Question 12

RNA synthesis and Hb accumulation are preserved in megaloblasts, true or false

Answer 12

true

Question 13

what happens in the lineage of megaloblasts

Answer 13

EPO causes expansion of primitive precursors

cell division reduces and apoptosis occurs resulting in fewer overall cells

Question 14

what happens when Hb concentration threshold is reaches in a megaloblast

Answer 14

enucleation occurs which leaves behind a bigger than normal red cell ie macrocyte

Question 15

what are causes of megaloblastic anaemia

Answer 15

B12 deficiency
folate deficiency
drugs
inherited conditions

Question 16

what are B12 and folate and their functions

Answer 16

essential cofactors in biochemical reactions
blood cells - DNA synthesis and nuclear maturation
neuro - DNA modification and gene activity

Question 17

in which foods is B12 found

Answer 17

meat and meat products

Question 18

describe the absorption of B12 in the GI tract

Answer 18

acid in the stomach causes B12 to dissociate from meat and bind to haptocorrin
gastric parietal cells secrete IF
B12 and haptocorrin compound and IF travel to gut
pancreatic secretion increase pH and cause B12 to dissociate from haptocorrin and bind to IF
B12 and IF complex travel to distal gut and are internalised by cells with cubulin receptors in ileum

Question 19

what is pernicious anaemia

Answer 19

autoimmune condition attacking gastric parietal cells resulting in IF deficiency and B12 malabsorption and deficiency

Question 20

how is folate absorbed in the gut

Answer 20

converted to monoglutamine

and absorbed in jejunum

Question 21

how long do B12 stores last in the body

Answer 21

2-4 years

Question 22

how long do folate levels last in the body

Answer 22

4 months

Question 23

what are symptoms of B12 and folate deficiency

Answer 23

fatigue, SOB, pallor
weight loss, diarrhoea, infertility
sore tongue, jaundice
developmental delay

Question 24

symptoms of B12 deficiency alone

Answer 24

neurological: 
neuropathy 
dementia 
psychiatric 
SCDC

Question 25

how can you diagnose megaloblastic anaemia in the lab

Answer 25

``` macrocytic anaemia (low Hb, raised MCV) pancytopaenia in some blood film = macrovalocytes + hypersegmented neutrophils B12 + folate assays - not accurate antibodies: anti-IF, anti-GPC ```

Question 26

causes of B12 deficiency

Answer 26

``` diet atrophic gastritis pernicious anaemia gastrectomy SBBO coeliac crohns inherited deficiencies ```

Question 27

causes of folate deficiency

Answer 27

``` diet alcoholics pregnancy malignancy malabsorption haemolysis anticonvulsants ```

Question 28

treatment of megaloblastic anaemia

Answer 28

treat cause lifelong B12 injections folic acid tablets 5mg PO OD only transfuse if emergency

Question 29

causes of non-megaloblastic anaemia

Answer 29

red cell membrane changes may or may not be associated with anaemia: - alcohol - liver disease - hypothyroidism marrow failure - associated with anaemia - myelodysplasia - myeloma - aplastic anaemia

Question 30

what is spurious macrocytosis

Answer 30

normal RBC volume but MCV is high

Question 31

causes of spurious macrocytosis

Answer 31

reticulocytosis | cold agglutins

Question 32

why can patients with pernicious anaemia appear mildly jaundiced

Answer 32

due to intramedullary haemolysis

Question 33

what is ineffective erythropoeisis

Answer 33

RBCs die prematurely in bone marrow

Question 34

pancytopaenis can complicate severe megaloblastic anaemia, true or false

Answer 34

true

Question 35

nuclear maturation defects only effect red blood cells, true or false

Answer 35

false, it can affect al lineages

Question 36

in someone with macrocytic anaemia, if you did a bone marrow aspirate, would it be hypo/normo/hypercellular and why

Answer 36

hypercellular there is a problem of cell division where you either produce large progeny or cells undergo apoptosis so there is a lot of premature red cell death hypoxia is detected by kidneys which release EPO which increases cell turnover. There is a lot of activity in the bone marrow, but not much to show for it.

Question 37

why might you get jaundice in megaloblastic macrocytic anaemia

Answer 37

defective cell division means there is also premature RBC destruction IN THE MARROW and apoptosis of cells, this releases Hb which is broken down to bilirubin causing icterus/jaundice