Approach to Anaemia Flashcards
What is anaemia defined as?
Reduction in Hb concentration below that which is optimum for that person or reduction in Hb concentration <95% range for population
When is anaemia likely to present?
When Hb <130g/l in men and <120g/l in women
What are some investigations that can be done for anaemia?
History/examination, FBC indices, reticulocyte count, blood film, haematinics, bone marrow biopsy, specialised test
What are the classes of anaemia?
Decreased production and increased loss or destruction of red cells
What are the types of anaemia that cause decreased production?
Hypoproliferative = reduced amount of erythropoiesis
Maturation abnormality = erythropoiesis present but ineffective
What are the causes of maturation abnormality that lead to decreased production?
Cytoplasmic defects = impaired haemoglobinisation
Nuclear defects = impaired cell division
What are some causes of increased loss or destruction of red cells?
Bleeding and haemolysis
What is reticulocyte count a useful marker of?
Red cell production
What is increased red cell production a sign of?
Regenerative anaemia = increased loss of red cells
What should be looked for if reticulocytosis is present?
Red cell breakdown products
How can reticulocyte count and breakdown products be used to identify bleeding as a cause of anaemia?
Reticulocytosis present but no red cell breakdown products = red cells are gone so nothing to breakdown
How can reticulocyte count and breakdown products be used to identify haemolysis as a cause of anaemia?
Reticulocytosis present with increased red cell breakdown products = increased unconjugated serum bilirubin and urinary urobilinogen
Why does reticulocytosis cause splenomegaly?
Work hypertrophy of macrophage rich tissues occurs
How much can normal marrow increase red cell production?
By 3-4 fold
What is anaemia with a lesser reticulocyte response a sign of?
At least partly due to impaired red cell production = reticulocyte should be appropriately increased for degree of anaemia
What is MCH a measure of?
Cell haemoglobin content
What is the underlying mechanism of hypochromatic microcytic anaemia?
Due to problems with haemoglobin formation
What is the most common cause of hypochromatic microcytic anaemia?
Iron deficiency = may be due to anaemia of chronic disease reducing iron availability to red cells
What are some other causes of hypochromatic microcytic anaemia?
Rarely haem defects = lead poisoning, congenital sideroblastic anaemia
Globin defects = thalassaemias
What is the underlying mechanism of macrocytic anaemia?
Due to nuclear maturation defects causing failure of cell division
What are some causes of macrocytic anaemia?
B12/folate deficiency = causes megaloblastic anaemia
Myelodysplasia and drugs (chemotherapy)
Why is there apparent agglutination in macrocytic anaemias?
Due to reticulocytosis
What are some causes of macrocytosis without significant anaemia?
Hypothyroidism, alcohol, liver disease
What type of anaemia causes normochromic normocytic anaemia?
Hypoproliferative
