Blood cell abnormalities Flashcards
Name one cause of reduced synthesis of haem?
Iron deficiency
Anaemia of chronic disease
What do you call a condition in which there is an inherited defect leading to reduced synthesis of globin ?
Thalassemia
What are some mechanisms of anaemia?
Reduced production of RBS/ haemoglobin in bone marrow
loss of blood from body
Reduced survival of red blood cells
Pooling of red blood cells in a large spleen
What is microcytic anaemia? What are the causes?
Small RBCs usually also hypochromic
Haem - iron deficiency
Can be caused by
blood loss - menstrual or hookworm
diet - vegetarian
absorption - coeliac disease or H.pylori gastritis
increased requirement - pregnancy or infancy
What are the 3 stages of iron depletion?
Iron depletion - storage iron reduced
Iron deficiency - low serum ion and transferrin saturation
iron deficiency anaemia - low haemoglobin and haematocrit
What are some clinical features of microcytic anaemia?
Pallor fatigue breathlessness
Failure of intellectual development in children
Features of underlying causes - Spoon nails (koilonychia) are soft nails that look scooped out
angular cheilitis
What is macrocytic anaemia?
average cell size is increased
Macrocytic anaemias usually result from abnormal haemopoiesis so that the red cell precursors continue to synthesize haemoglobin and other cellular proteins but fail to divide normally
As a result, the red cells end up larger than normal
What are some causes of macrocytic anaemia?
- megaloblastic erythropoiesis
delay in maturation of the nucleus while the cytoplasm continues to mature and the cell continues to grow
A megaloblast is an abnormal bone marrow erythroblast
It is larger than normal and shows nucleocytoplasmic dissociation
Lack of vitamin B12 or folic acid (megaloblastic anaemia)
Use of drugs interfering with DNA synthesis
Liver disease and ethanol toxicity
Recent major blood loss with adequate iron stores (reticulocytes increased)
Haemolytic anaemia* (reticulocytes increased)
Why does an increased proportion of red blood cells lead to increased MCV?
Young red cells are about 20% larger than mature red cells so if there is an increased proportion of young red cells (polychromasia/reticulocytes) in the circulation, the average cell size (MCV) will be increased
What is seen on a blood film for those with megalobastic anaemia?
Tear drop cells
Hypersegmented neutrophils
Oval macrocytes
What is normocytic anaemia? what are the causes?
Normal staining and size of red blood cells but low Hb overall
Recent blood loss - GI bleeding trauma
Failure of production of red blood cells - early stages of iron deficiency, bone marrow failure or supression (chemo), bone marrow infiltration (leukaemia),
Pooling of red cells in the spleen - hypersplenism -cirrhosis, splenic sequestration in sickle cell anaemia
What is anaemia of chronic disease?
Give some examples of common causes
Usually an underlying inflammatory aspect to the disease
Rheumatoid arthritis Autoimmune diseases Malignancy Kidney disease Infections such as TB or HIV
What is the pathogenesis of anaemia of chronic disease?
Cytokines like TFNa and interleukins from the chronic condition lead to a decrease in erythropoietin production and prevent normal flow of iron from duodenum to red blood cells - hepcidin influences this
What are some lab clues for someone with anaemia of chronic disease?
High C-reactive proteins (unlike iron deficiency)
High ferritin
Low transferrin
acute phase proteins increase
What is polychromasia and how can this be seen?
When do you usually have a high count?
Blue tinge to cells due to higher ribosomal RNA in young RBCS in addition to the normal pink
Haemolytic anaemia and recent blood loss
also as a response to treatment with iron, vitamin B12 and folic acid
What is polycythaemia and what is usually increased during this?
Too many red cells in the circulation
Hb, RBC and Hct are all increased compared with normal subjects of the same age
What is pseudo-polycythaemia?
Reduced plasma volume
higher concentration in blood