Anaemia Flashcards
Define anaemia.
- a haemoglobin concentration lower than normal range.
- not a diagnosis on its own but a manifestation of an underlying disease and cause important to establish.
name a few signs and symptoms of anaemia.
- signs of insufficient O2 delivery to tissues.
- symptoms : SOB, palpitations, headache, lethargic.
- signs : Pallor, tachycardia, hypotension, systolic flow murmur, tachypnoea ( high RR).
what are some specific sign associated with anaemia, that may lead you to a diagnosis.
- Koilonychia ( spoon shaped nails) : iron deficiency.
- Angular stomatitis ( mouth corners inflamed) : iron deficiency.
- Glossitis ( inflamed, depapilation of tongue) : Vit B12 deficiency.
- Abnormal facial bones : thalassaemia.
why might anaemia develop?
break it down to RBC in BM, vessels, removal by spleen.
- BM : reduced erythropoiesis, abnormal haem, abnormal globin chains.
- Vessels : abnormal RBC, mechanical damage, abnormal metabolism.
- Spleen : increased removal by reticuloendothelial.
what might cause reduced or dysfunctional erythropoeisis?
- lack of production of EPO by kidney, in CKD.
- marrow unable to respond to EPO, after chemo/infection.
- marrow infiltrated by cancer cells or fibrous tissue.
- chronic diseases like rheumatoid arthritis where iron is not made available for marrow.
- myelodysplatic syndromes where abnormal clones of stem cells reduce capacity to make RBC + WBC.
why might defects in haemoglobin synthesis cause anaemia?
- SIDEROBLASTIC ANAEMIA : defects in haem synthesis pathway.
- insufficient iron in diet : iron deficiency anaemia.
- anaemia in chronic disease as functional iron deficient.
- mutations in globin chains in HB ( alpha/beta thalassaemia, sickle cell disease ).
how might abnormal structure and mechanical damage to RBC lead to haemolytic anaemia?
*inherited
- mutation in gene coding for plasma membrane cytoskeleton interactions.
- less flexible and more easily damaged and removed.
*acquired
- shear stress through defective heart valves.
- cell snagging on fibrin strands in small vessels with clots.
- heat burns or osmotic damage.
what defects in RBC metabolism can cause anaemia?
- G6PDH deficiency : cross-linking of HB and Heinz bodies, removed by spleen.
- Pyruvate kinase deficiency so glycolysis affected and RBC deficient in ATP and undergo haemolysis.
how might excessive bleeding cause anaemia?
- acute blood loss, like injury.
- chronic blood loss : heavy menstrual bleeding, haemorrhoids, GI bleeds, kidney or bladder tumours.
*treated with NSAID anti-inflammatory drugs.
*IRON LOST FROM BODY NOT RECYCLED!
how might the reticuloendothelial system play a part in anaemia development?
- damage in vessels, autoimmune haemolytic anaemias cause abnormal RBC so destroyed.
- by spleen leading to splenomegaly as working harder. NEVER NORMAL TO PALPATE SPLEEN below costal margin.
how might myelofibrosis cause anaemia?
- due to proliferative haemotopoietic stem cells.
- little space for haemotopoeisis.
- progenitor cells spill out of marrow into liver and spleen leading to extra-medullary haemopoeisis, so enlarged.
how might thalassemia cause anaemias?
- decreased or absent alpha or beta globin chain production.
- imbalance in composition of A2B2 so defective microcytic hypochromic RBC.
- severity depends on type.
what are reticulocytes and why are they important?
- immature RBC just released to blood, no nucleus and eliminate remaining mitochondria.
- 1% of all RBC, matures in 1 day.
- shows if marrow is capable of responding to conditions like anaemia, you’d expect high count to replenish.
what would microcytic/ macrocytic/ normocytic RBC indicate?
- microcytic : thalassaemia, chronic disease anaemia, iron deficiency, lead poisoning.
- macrocytic : vit B12, folate, liver disease.
- normocytic : BM failure.
what are the types of macrocytic anaemias?
- megaloblastic : DNA synthesis interfered and nucleus development retarded cell division delayed so large.
eg: Vit B12/ folate deficiency - macronormoblastic erythropoiesis : cytoplasm retained and erythroblasts larger than normal.
eg : liver disease, alcohol toxicity. - stress erythropoiesis : high reticulocytes and larger, high level of erythropoetin so expanded.
eg: recovery from haemorrhage, haemolytic anaemia.
