Red Blood Cell Disorders Flashcards
What stimulates erythropoietin synthesis?
Hypoxaemia
Severe anaemia
Left shift in O2-binding curve
High altitude
What are reticulocytes a measure of
They are a marker of effective erythropoesis and correct bone marrow response/function. The % count can be falsely increased in anaemia so you just correct the value.
Where does extramedullary haematopoesis occur?
Liver & spleen
What causes a “hair on end” skull radiograph?
Accelerated erythropoesis expands the bone marrow cavity. This is in response to severe haemolysis: eg sickle cell disease
What is polychromasia?
Very immature RBC: blue discoloured cell without central pallor. If seen in blood = very over reactive BM
What are the possible causes of iron deficiency in premature babies?
Loss of iron from mother’s stores
Blood loss from venipuncture
Why does physiological jaundice occur in newborns?
The unconjugated bilirubin derived from the initial destruction of of foetal RBCs. Foetal RBCs containing HbF are destroyed by splenic macrophages over 6-9 months.
What are the diagnostic values for thalassaemia?
Increased Hb and haematocrit
Increased RBCS count
Microcytic
What does serum iron measure?
Iron bound to transferrin in the serum
Decreased - anaemia of chronic disease or iron deficiency
Increased - iron overload (haemochromatosis, sideroblastic anaemia)
What does serum total iron-binding capacity correlate to?
The concentration of transferrin. The concentration if transferrin in linked to ferritin storage in macrophages: decreased stores of ferritin = increased liver synthesis of transferrin
Where is erythropoietin synthesised?
Renal cortex by the interstitial cells in the peritubulur capillary bed.