Flashcards in Week 231 - Anaemia: Deck (36):
Week 231 - Anaemia: What are the causes of microcytic anaemia?
• Iron Deficiency
• Anaemia of chronic disease
Week 231 - Anaemia: What does Ferritin represent?
Intracellular iron stores, but it also an acute phase protein.
Week 231 - Anaemia: What are the broad causes of iron deficiency?
• Poor intake
• Reduced absorption
• Increased losses
• Increased demand
Week 231 - Anaemia: What can cause reduced absorption of iron?
• Abnormal bowel - Crohns, Coeliac, Gastritis.
• Lack of Bowel - Bypass, resection.
• Interference - PPIs, Calcium supplements, Thalins, Chocolate
Week 231 - Anaemia: What can cause increased losses of iron?
• Occult blood loss
Week 231 - Anaemia: What is the life span of an erythrocyte?
Week 231 - Anaemia: Outline Erythropoiesis.
1) Erythropoietin (EPO) is synthesized primarily from the renal cortex.
2) EPO stimulates stem cells within the bone marrow to differentiate into erythroid precursors.
3) EPO continues to stimulate primitive erythroid cells in the bone marrow and induce maturation.
4) Macrophages surround these cells in the bone marrow to become erythroblastic islands.
Week 231 - Anaemia: Production of erythropoietin is triggered by what?
Tissue hypoxia (Oxygen tension within the tubules of the kidney)
Week 231 - Anaemia: How does chronic renal disease cause anaemia and what is the morphology of it?
The production of EPO is reduced as this takes place in the renal cortex. There is therefore a reduction in red blood cell production.
- The cells will be normocytic.
Week 231 - Anaemia: What is the cell line of erythropoiesis?
Week 231 - Anaemia: What is a reticulocyte? Why are they important?
• 'Teenager' of erythropoiesis.
• Raised following haemorrhage, haemolytic anaemia.
• They provide an excellent measure of red cell production and the age of the red cell population.
Week 231 - Anaemia: Why does iron deficiency lead to microcytic anaemia?
• Iron is the rate limiting step of erythropoiesis.
• Without adequate iron, the cells will divided more leading to a reduced size.
Week 231 - Anaemia: Why does B12 and folate deficiency lead to a macrocytic anaemia?
• These are key building blocks for DNA synthesis and cell mitoses.
• Inadequate amounts of B12 and folate lead to less divisions resulting in erythrocytes being pumped into blood at a larger size.
Week 231 - Anaemia: What would the iron profile be in someone with iron deficiency? (Serum iron, TIBC, Ferritin, Serum soluble transferrin receptors)
• Serum Iron - Reduced
• TIBC (total iron-binding capacity) - Increase since the body works hard to bind any free iron.
• Ferritin - Reduced
• Serum soluble transferrin receptors - Increased
Week 231 - Anaemia: How is vitamin B12 absorbed?
• Stomach - B12 binds with intrinsic factor to form a complex.
• Terminal ileum - Travels through the small intestine where it is absorbed in the terminal ileum.
Week 231 - Anaemia: What is pernicious anaemia?
• This is the leading cause of B12 deficiency.
• IgG autoantibodies target gastric parietal cells which produce intrinsic factor, which therefore reduces the amount of IF-B12 complexes that can be formed and absorption is reduced.
Week 231 - Anaemia: What are the proteins that make up the red blood cell membrane?
Spectrin, actin, Protein 4.1 and ankyrin.
Week 231 - Anaemia: What is hereditary spherocytosis?
• Abnormal spectrin gene (Important protein in red blood cell membrane)
• Causes the membrane to malfunction.
• The sheer forces of the microcirculation cause the cell to deform.
• The cell becomes a spherocyte, which is a small, rigid, spherical erythrocyte.
• The cell can then haemolyse causing anaemia.
Week 231 - Anaemia: What is LDH and what is it's significance?
• Lactate Dehydrogenase
• Enzyme that is released on the destruction of red cells, therefore high concentrations in blood provides an indicator for haemolysis.
Week 231 - Anaemia: The breakdown of what forms bilirubin?
Week 231 - Anaemia: What are the two key compensatory mechanisms of anaemia and how do they present?
• Cardiac compensation - Increased stroke volume and heart rate, this can present with palpitations, tachycardia and heart murmurs.
• Skin - Pallor can occur as vasodilation occurs to redistribute oxygen to the vital organs.
Week 231 - Anaemia: Why does anaemia that has a rapid onset cause more problems than slower progressive anaemia?
There is less time for the oxygen dissociation curve and cardiovascular system to adapt.
Week 231 - Anaemia: What nail changes do you get anaemia and what type is it specific to?
Koilonychia (Spoon Nails) - Iron deficient anaemia
Week 231 - Anaemia: What is atrophic glossitis?
• Red large swollen tongue.
• It is a specific sign that is seen in both Vitamin B12 and folate deficiency.
Week 231 - Anaemia: What is angular stomitis?
• Fissuring at the corners of the mouth.
• Specific sign of both vitamin B12 and folate deficiency.
Week 231 - Anaemia: What are the causes of macrocytic cells?
• In terms of anaemia - B12 and folate deficiency.
• Alcohol is the most frequent cause in general.
• Macrocytic cells may also be present in Liver disease, Hypothyroidism, Hypoxia, Cytotoxic drugs, pregnancy.
Week 231 - Anaemia: What is the function of the haemopoietic system?
• Transport - Cells, oxygen, hormones, drugs.
• Surveillance - Cells, cytokines, proteins.
• Temperature regulation
Week 231 - Anaemia: What are the component parts of the haemopoietic system?
• Bone - Scaffold and cells.
• Blood - Vessels and cells
• Lymph - Vessels, cells, Spleen and thymus.
Week 231 - Anaemia: What is responsible for the differentiation of red blood cells and where does it come from?
• EPO (Erythropoietin) - Renal cortex.
Week 231 - Anaemia: What is responsible for the differentiation of white blood cells and where does it come from?
• GCSF, GMCSF - Granulocyte colony stimulating factor and granulocyte-macrophage colony stimulating cells - Both are released from the marrow stomal cells.
Week 231 - Anaemia: What is responsible for the differentiation of platelets and where does it come from?
• TPO (Thrombopoietin) - Marrow stomal cells.
Week 231 - Anaemia: Lymphoid stem cells give rise to which mature cells?
• Lymphocytes (B+T).
• Natural killer cells.
Week 231 - Anaemia: Myeloid progenitor cells give rise to which mature cells?
• Red cells, platelets.
• Monocytes, Neutrophils
• Eosinophils, Basophils.
Week 231 - Anaemia: During fetal development where does haematopoiesis take place?
- Aorta, gonad, mesonephros.
Week 231 - Anaemia: What are the side effects of oral iron?
• Nausea and vomiting
• Black faeces