Haematology - Anaemia and cells Flashcards
What is microcytic anaemia? List some causes
Microcytic anaemia (MCV <80fl)
- Haem defect: iron deficient anaemia, anaemia of chronic disease, sideroblastic/lead poisoning
- Globin defect: thalassemia
List some causes of normocytic anaemia
- Recent blood loss
- BM failure
- Renal failure
- Early anaemia of chronic disease
- Pregnancy (increased plasma volume)
List some causes of macrocytic anaemia
- Megaloblastic: vit B12 or folate deficiency, anti-folate drugs (methotrexate, phenytoin), cytotoxics (hydroxycarbamide)
- Non-megaloblastic: reticulocytosis, alcohol or liver disease, hypothyroidism, myelodysplasia
Haemolytic anaemia: what is the mechanism of intravasclar haemolysis and list some causes
Intravascular haemolysis
- Mechanism: RBCs breakdown in blood vessels: breakdown products and free Hb are in circulation
Causes:
- Immune causes - allo-antibodies: transfusion reactions, haemolytic disease of newborn
- Non-immune causes:
- Primary red cell disorders: enzyme disorders (G6PD deficiency, PK deficiency), paroxysmal nocturnal haemoglobinuria (PNH)
- Non-red cell disorders: microangiopathic haemolytic anaemia, mechanical destruction, infection (malaria)
What blood results would point towards an intravascular haemolytic anaemia?
- Blood results: LDH +++, unconjugated bilirubin (+++), haemoglobinuria, haemoglobinaemia, haptoglobin (depleted b/c binds to free Hb), schistocytes on blood film
Haemolytic anaemia: explain the mechanism and list some causes of extravascular haemolytic anaemia
- Mechanism: RBCs removed by macrophages in liver and spleen
Causes:
- Immune – auto-antibodies: cold AIHA, warm AIHA, paroxysmal cold, haemoglobinuria
- Non-immune:
- Primary red cell disorders: membrane disorders (hereditary spherocytosis/elliptocytosis, haemoglobin disorders (sickle cell)
- Non-red cell disorders: hypersplenism
What blood results would you expect to see in extravascular haemolytic anaemia?
- Blood results: LDH + (variable), unconjugated bilirubin (+), haptoglobin (low or absent), spherocytes
What is this?
Neutrophil or polymorph
dense nucleus with 2-5 lobes, pale cytoplasm with irregular outline and fine granules. Lifespan is 6-10 hours in blood.
What is this?
- Eosinophil
- Cytoplasmic granules are coarser than neutrophils and stain more deeply red and rarely have more than 3 nuclear lobes. Longer blood transit time than for neutrophils – enter inflammatory exudates and have special role in allergic responses, defence against parasites and removal of fibrin formed during inflammation.
What is this?
- Basophil
- only occasionally seen in peripheral blood – have dark cytoplasmic granules which overlie nucleus and contain heparin and histamine. Become mast cells in tissues and have IgE attachment sites and their degranulation is associated with histamine release.
What is this?
- Monocyte
- larger than other peripheral leukocytes and have large central oval or indented nucleus with clumped chromatin – stains blue.
What is this?
- Lymphocyte
- immune-competent cells that assist the phagocytes in defence of the body against infection and other foreign invasion
What are B lymphocytes?
- Mature in BM and circulate in peripheral blood until they undergo recognition of antigen
- B-cell receptor is a membrane-bound immunoglobulin and after activation this is secreted as free soluble immunoglobulin
- B cells mature into memory B cells or plasma cells.
What are T lymphocytes?
- T cells: develop from immature cells that migrate to thymus where they differentiate into mature T cells during passage from cortex to medulla.
- During this: self-reactive T cells are deleted and T cells with some specificity for HLA molecules are selected
- Mature helper cells express CD4+ (extracellular pathogens) and CD8+ (intracellular pathogens)
What are NK cells?
Natural Killer cells: cytotoxic CD8+ cells that lack the T-cell receptor. Designed to kill targets that have low level of expression of HLA I molecules (viral or malignant cells)
