9: Approach to anaemia diagnosis Flashcards
What is anaemia?
Reduction in Hb concentration
i.e a lack of red blood cells
Anaemia can be defined as having a Hb concentration of <__% population average.
< 95%
In what physiological states can a person’s Hb concentraiton decrease?
Childhood growth
Pregnancy
Menstruation
Apart from a full blood count, what other investigations exist for anaemia?
Reticulocyte count
Blood film
Vit B12 / Folate / Iron levels
Bone marrow biopsy
In which causes of anaemia is reticulocyte count raised?
Blood loss
Haemolytic anaemias
If reticulocyte count is raised, how would you tell the difference between anaemia caused by blood loss or haemolysis?
Breakdown products raised in haemolysis, not blood loss
so check serum bilirubin, iron
What causes hypochromic microcytic anaemia?
iron deficiency
thalassaemia
lead poisoning
congenital sideroblastic anaemia
What are some causes of macrocytic anaemia?
Megaloblastic - Vit B12 / folate deficiency; myelodysplasia
Non-megaloblastic - alcohol, liver disease, hypothyroidism
What are two causes of spurious macrocytosis?
Reticulocytosis
Cold agglutinins
What are some causes of normocytic anaemia?
Bone marrow failure
Malignancy
Renal impairment
Chronic disease
What is renal anaemia?
Anaemia caused by impaired kidney function i.e an inability to produce EPO
If the kidneys are damaged, which hormone will they struggle to produce?
What type of anaemia does this cause?
EPO
Hypoproliferative normocytic anaemia
___ disease can cause a normocytic anaemia.
Renal disease
Chronic disease
Which protein, released by the liver, inhibits iron exit from enterocytes?
Hepcidin
What can cause increased production of hepcidin leading to a lack of iron in the circulation?
Inflammation in chronic disease
In chronic disease, the ___ released during the inflammatory response can cause changes leading to anaemia.
cytokines
What happens to
a) iron availability
b) EPO production
c) bone marrow proliferation
in chronic disease?
a) Iron availability decreases
b) EPO production decreases
c) Bone marrow proliferation decreases
What type of anaemia does chronic disease cause?
Either normocytic due to hypoproliferation of RBCs
Or microcytic due to less available iron
Why do some patients with anaemia of chronic disease respond to iron supplementation?
Not all patients have anaemia due to less available iron
Chronic disease also causes hypoproliferative anaemia so iron might not be the problem
Is MCV absolutely or relatively low in microcytic anaemia?
Relatively low
So may not be below reference range but that doesn’t mean the patient isn’t iron deficient
What is the best measurement for diagnosing iron deficiency?
Serum ferritin
What are the problems with using serum ferritin to diagnose iron deficiency?
Serum levels are only a representation of levels within liver
Ferritin is an acute phase protein which increases in inflammation
What are some microscopic features of red blood cells in iron deficiency anaemia?
Target cells
Rod form / pencil cells
What must you think about when reticulocyte count is raised?
Blood loss and/or haemolysis
Why does reticulocytosis increase MCV without causing an actual macrocytic anaemia?
Reticulocytes are bigger than normal red cells
What are some microscopic features of megaloblastic anaemia?
Megaovalocytes
Hypersegmented neutrophils
