Haem path + obstrectics Flashcards
what is the difference in haemoglobinopathy testing in antenatal vs postnatal
a - FBC, reproductive choice
p - at 5 days, heel prick test - early detection of blood pathologies
what are 4 potential haematological changes that occur during pregnancy
phsyiolgial macrocytic anaemia
lecucocytosis
gestational thrombocytonpenia
coagulation
what is physiological macrocytic anaemia in pregnancy
plasma volume expands and RBC mass increases and MCV increased
what is leucocytosis
mainly neutrophilia
levels rise after 2nd month
left shift - spilling out of cells than normally live in bone
what is gestational thrombocytopenia
low platelet count after 20 weeks and thrombocytopenia in late pregnancy
how does increased coagulation occur in pregnancy
increase in plasma fibrinogen and factors VII, V, VIII, vWF, X, XII
evidence of platelet activation
where do the chains of immunoglobulins come from
alpha from chromosome 16
gamma, delta, beta from chromosome 11
describe the development of Hb and how long ti takes
from yolk sac to liver/spleen to bone marrow
takes about 6 months
what are haemoglobulinopathies and what inheritance pattern does it follow
changes in globin genes or expression
AR inheritence
give four examples of haemoglobinopathies
sickle cell
A thalassaemia
B thalassaemia
thalassaemia intermedia
what the difference between adult and foetal Hb
adult - 95% AHb, 3.5% BHb, 1% gamma
what is sickle cell disease
substitutions of valine for glutamic acid in position 6 in the beta globes chain = aggregation and polymerisation at low oxygen tensions
what are the two types of sickle cell disease
heterozygous (HbA/HbS)
homozygous (HbS/HbS)
describe heterzygous sickle cell disease and the severity
45% HbS, 55% HbA
no problems unless extreme hypoxia
milder phenotype
describe homozygous sickle cell and the severity
HbS/HbS chronic haemolytic anaemia 95% HbS HbS polymerases to form long fibrils which distort the RBC membrane - gets stuck in vessels = ischameia and pain = sickle cell crisis clot formation
what are the acute vs chronic problems associated with sickle cell disease
a - vaso-occlusive crisis, septicaemia , jaundice
c - hyposplenism, renal disease, avascular necrosis
what is the treatment of sickle cell anaemia
hydration, analgesia, transfusion, hydroxycarbamide
what is the most common single gene disorder
thalassaemia
what is thalassaemia
rate of global chains produced, causes ineffective erythropoeisis and anaemia
describe alpha vs beta thalassaemia
4 genes for alpha chains
1 or 2 deleted = alpha thalassaemia
3 deleted = HbH disease
4 deleted = hydros fetalis
beta chain = 2 genes
what is hydros fetalis
deletion of all 4 alpha chain Hb genes = HF due to severe anaemia
what is HbH disease
a thalassaemia where there is reduced alpha global formation 3 genes deleted
what does B thalassaemia resemble
iron deficiency
if you’re born with major b thalassemia with both beta genes deleted what is the likely prognosis
die of HF or infection in first few years
how do you diagnose b thalassaemia
lots of nucleated red cells
what is the pathogenesis of b thalasaemia
anaemia = increased marrow activity = enlarged and overactive spleen
hair on end skull
where would you see hair on end skull formation
b thalassaemia
how do you treat b thalassaemia
transfusion - suppress marrow RBC but can cause excess iron toxicity
what is thalassaemia intermedia
miild form of the conditions
RBC breakdown and leads to pulmonary hypertension
what are the main differences between sickle cell and thalassaemia
s - abnormal Hb produced at normal rate
t - normal Hb produced at abnormal rate
