Sickle cell disease Flashcards
1
Q
inheritance
A
AR
2
Q
what mutation
A
point mutation adenine to thymine which causes valine to replace glutamic acid in b globin amino acid chain. HbS instead of HbA
3
Q
how do sickle cells form
A
HbS polymerises when DEoxygenated -> FBCs deformed -> sickle cells -> haemolysis, blocked small vessels
4
Q
fbc findings
A
anaemia
raised reticulocytes
5
Q
what happens to bilirubin
A
raised
6
Q
diagnostic tests
A
film shows sickle cells
sickle solubility test is +ve
hb electrophoresis confirms diagnosis
7
Q
rx sickle cell
A
hydroycarbamide - promotes foetal hb synthesis. used in pts with frequent crisis
8
Q
complications of sickle cell
A
splenic infarction -> infection susceptibility (40% childhood SS deaths) poor growth CKD gallstones stroke acute chest syndrome pulmonary HTN
9
Q
what is a vaso occlusive crisis triggered by
A
cold
dehydration
infection
hypoxia
10
Q
features of vaso occlusive crisis
A
mesenteric ischaemia cs infarction avascular necrosis femeroal head leg ulcers priapism
11
Q
what is an aplastic crisis caused by and what is it
A
parvovirus b19 (same virus that causes slapped cheek syndrome) sudden reduction in marrow production
