CP39 - HAEMOGLOBINOPATHIES and OBSTETRIC HAEMATOLOGY

Question 1

what controls the production of RBC?

Answer 1

by erythropoietin which is produced in the kidneys in response to tissue oxygen concentration

Question 2

what are some physiological changes in pregnancy

Answer 2

plasma volume expands in pregnancy by 50%

red cell mass expands by 25%

MCV increases physiologically in pregnancy due to mobiliation of iron

Question 3

when does physiological anaemia happen

Answer 3

pregnancy

Question 4

what happen to the WBC during pregnancy

Answer 4

WBC is present in the placenta as pregnancy forces them out of bone marrow

Question 5

what happen to the platelet account during pregnancy

Answer 5

Platelet count falls after 20weeks and thrombocytopenia is most marked in late pregnancy

Question 6

what state does pregnancy put thrombosis?

Answer 6

pregnancy is a pro-thrombotic state

Question 7

what sort of condition is sickle cell anaemia?

Answer 7

haemolytic anaemia

Question 8

what are the underlying causes to the admintion of the sickle cells anaemia to hospital?

Answer 8

sickle cells depositino on vessels and block blood flow and cause ischemia

then the ischaemia of the tissue cause painful episodes - hospital

Question 9

which type of haemoglobulin is the normal type

Answer 9

Hb - A

Question 10

what is sickle cells trait

Answer 10

it is the presence of only one copy of the sickle cell gene ie heterozygous

Hb-A/S - Hb-S 45%, Hb-A 55%

Question 11

when does sickle cells trait become a clinical problem

Answer 11

when severe hypoxia

Question 12

what is the genetic make up of sickle cell disease

Answer 12

Hb S/S

Question 13

what is the clinical feature for sickle cell disease

Answer 13

decreased RBC count , RBC sickle cell shape

Hb S > 95

Question 14

what are some acute complications for sickle cell disease?

Answer 14

vasco-occlusive crisis - hans and feet (dactylitis), chest syndrome, abdo pain

Question 15

what is the medical emergency for sickle cell disease

Answer 15

sequestration crisis - blockage of major blodd vessels (spleen, liver)

Question 16

what are some chronic complications for sickle cell disease?

Answer 16

Hyposplenism - due to infarction and atrophy of spleen.

Renal disease: medullary infarction with papillary necrosis.
Tubular damage - can’t concentrate urine (bed-wetting at night). Glomerular – chronic renal failure/dialysis

Avascular necrosis (AVN) –femoral/humeral heads

Leg ulcers, osteomyelitis, gall stones, retinopathy, cardiac, respiratory

Question 17

what are some treatment for sickle cell diseases

Answer 17

penicillin from 6 months

acute crisis

vaso-occlusive - analgesia

priapism (persistent and painful erection of the penis)

transfusion - splenic sequestration, aplastic crisis, pre-operative, acute chest crisis

Exchange: Acute chest crisis, acute stroke, pre-operative.

Regular exchange: Primary and secondary stroke prevention

Hydroxycarbamide - increases Hb F (time delay to polymerisation, reduced adhesion to endothelium, enhances NO)

Bone marrow transplant

Question 18

what is thalassaemia

Answer 18

it is a genetic condition which causes production of Hb with different ratios of alpha and beta chains

Question 19

what is the composition of alpha thalassaemia

Answer 19

all 4 chains are alpha - generally not survivable

Question 20

what is the pathogenesis in beta thalassaemia

Answer 20

Reduced rate of production of beta-globin chains (pathology caused by excess alpha chains)

Question 21

what is the chain composition of thalassaemia major ?

Answer 21

both copy of the genes produce beta chain - ie produce little to none Hb-A - often fatal if untreated

Question 22

what is the histology of beta-thalassaemia trait?

Answer 22

microcytic hypochrontic Hb which resemble iron deficiency

Question 23

what is the main histology of β-THALASSAEMIA MAJOR

Answer 23

lots of nucleated red cells

Question 24

what is the pathology of β-THALASSAEMIA MAJOR?

Answer 24

anaemia (alpha chain excess)

increase bone marrow activity (to increase production of RBC by the body) - skeletal deformity

enlarged and overactive spleen - increase transfusion requirement

Question 25

what are some clinical features for thalassaemic?

Answer 25

short stature, limb growth, maxillary hypertrophy, frontal bossing due to expanded bone marrow (thalassaemic facies)

Question 26

what is the aim of transfusion for thalassaemia major?

Answer 26

to suppress the production of erythropoietin as there is a normal level of Hb

Question 27

what are some complication for transfusion?

Answer 27

iron overloading

Question 28

what is the treatment β-THALASSAEMIA MAJOR?

Answer 28

transfusion and iron chelation therapy (to remove excess iron)

desferrioxamine

new oral iron chelators

Question 29

what is a complication for iron rich environment?

Answer 29

infection - can live in iron-rich environment

also decrease CD4/8 ratio