red cells + physiological anaemias

Question 1

what is anemia

Answer 1

reduction in red cells or their haemoglobin content

overall a reduction in haemoglobin

Question 2

anaemia aetiologies

Answer 2

blood loss
increased destruction (haemolysis)
lack of production
defective production

Question 3

substances required for red cell production

Answer 3

metals: iron, copper, cobalt, manganese
vitamins: B12, folic acid, thiamine, VitB6, C, E
amino acids
hormones: erythropoetin, GM CSF, androgens, thyroxine

Question 4

how long does red cell last in circulation

Answer 4

120 days

Question 5

where are red cells broken down

Answer 5

reticuloendothelial system

macrophages in spleen, liver, lymph nodes, lungs etc

Question 6

red cell breakdown (hameolysis)

Answer 6

within reticuloendothelial system, globin (of haemoglobin) is reutilised. Haem molecule is recycled
porforin ring of haem molecule is broken down into bilirubin

Question 7

what happens to bilirubin from RBC breakdown

Answer 7

bound to albumin in plasma before it reaches liver - uncongugated

Question 8

biconcave shape

Answer 8

maximum area for O2 transfer

small, squigy so can squeeze through capillaries of microvasculature

Question 9

skeletal proteins of red cell membrane

Answer 9

band 3
anykrin
alpha + beta spectrin

if have defects then abnormal cytoskelton and inc cell destruction

Question 10

hereditary spherocyosis

Answer 10

genetic abnormality, loose red cell skeletal integrity and become spherical shape

life span of cell reduced due to being recognised as abnormal and so removed from circulation quicker

Question 11

hereditary spherocyosis proteins that can be affected

Answer 11

anykrin 
alpha spectrin
beta spectrin 
band 3
protein 4.2

Question 12

hereditary spherocyosis clinical presentation

Answer 12

anaemia
jaundice
splenomegaly
pigment gallstones

Question 13

hereditary spherocyosis treatment

Answer 13

folic acid
transfusion
splenectomy if anaemia, very severe phenotype

Question 14

red cell enzymes

Answer 14

glucose 6-phosphate dehydrogenase - needed for glycolysis and pentone phosphate shunt

Question 15

glucose 6-phosphate dehydrogenase deficiency

Answer 15

cells less able to protect themselves from oxidative damage so breakdown of RBCs

Question 16

pyruvate kinase deficiency

Answer 16

build up of metabolites in glycolytic pathway,
particularly 2,3DPG
haemolysis of RBC

Question 17

glucose 6 phosphate dehydrogenase

Answer 17

protects red cell proteins (hg) from oxidative damage and free radicals

Question 18

clinical presentation of G6PD deficiency

Answer 18

anaemia
neonatal jaundice
splenomegaly
pigment gallsones

Question 19

triggers to haemolysis in G6PD deficiency

Answer 19

infection
acute illness e.g. DKA
drugs: antimalarials, suphonamides, sulphones, apririn

Question 20

haemoglobin structure

Answer 20

2 beta chains
2 alpha chains

1 heme molecule (which has porforin ring + iron) assoc with each chain

Question 21

normal adult haemoglobin composed of:

Answer 21

2 alpha chains
4 alpha genes
2 beta chains
2 beta genes - downstream from beta chain genes are delta and gamma gene chains

Question 22

haemoglobinopathies

Answer 22

inherited abnormalities of haemoglobin synthesis

reduced or absent globin chain production e.g. thalassaemia

mutations leading to structurally abnormal globin chain e.g. sickle cell

Question 23

sickle cell haemoglobin composed of

Answer 23

2 alpha chains

2 beta sickle chains

Question 24

sickle cell mutation

Answer 24

point mutation - glutamine replaced by valine

Question 25

sickle cell pathophys

Answer 25

sickled RBCs cause damage of microvasculature
cells dehydrated and friable

damage to vascular endothelium - coagulation and vaso-occlusion

Question 26

sickle cell presentation

Answer 26

• painful vaso-occlusive crisis (bone pain - bone infarction)
• chest crisis: lungs, hypoxia
• stroke - sickling in brain
• inc infection risk
• chronic haemolytic anaemia
• sequestration crisis

Question 27

painful crisis in sickle cell

Answer 27

severe pain: need analgesia (often opiates)
hydration
oxygen
antibiotics

Question 28

management of sickle cell - longterm

Answer 28

vaccination
penicillin prophylaxis
folic acid

Question 29

management of sickle cell - acute attacks

Answer 29

hydration 
oxygen 
treat infection 
analgesia
blood transfusion

Question 30

thalassaemias

Answer 30

reduces or absent globin chain production

alpha thalassaemia
beta thelassaemia

Question 31

hymozygous alpha zero thalassaemi

Answer 31

no alpha chains

incompatible with life

Question 32

beta thalassaemia major

Answer 32

no beta chains
have capacity for alpha chains to combine with delta or gamma chains
transfusion dependent anaemia

Question 33

thalassaemia minor

Answer 33

trait or carrier state

hypochromic microcytic red cell indices (small red cells and mild anaemia)