Introduction to Anaemia Flashcards
Categorise by size of red cell
Mean corpuscular volume: 80-100fL
Microcytic: iron deficiency, inherited disorders of Hb
Macrocytic: B12/folate deficiency, myelodysplasia
Normocytic: anaemia of chronic disease, acute haemorrhage, renal failure
Reticulocyte count
causes polychromasia on a blood film
Indicates rate of production of RBCs
low during precursor deficiencies/bone marrow infiltration
high in chronic bleeding, haemolysis
B12 Deficiency
- Pernicious anaemia: autouimmune, deficiency of intrinsic factor, can’t absorb B12, check for autoantibodies and treat with B12 injections
- Dietary
- Malabsorption: Coeliac’s/Crohn’s disease, or post gastric/ileal surgery
Folate Deficiency
Dietary
Malabsorption
Excess utilisation (pregnancy)
Alcohol and drugs (phenytoin, methotrexate)
Anaemia of chronic disease
Causes: chronic inflammation, infection, autoimmune, cancer, renal failure
Poor utilisation of iron
Dysregulation of iron haemostasis (decreased transferrin)
Impaired proliferation of erythroid progenitors (blunted response to EPO)
Sickle Cell Anaemia
Increased turnover of RBCs - survival only 20 days
Sickle cell crisis - triggered by low O2 blood level
Management: analgesics, hydration, transfusion
Mechanism: HbS forms long filamentous strands, and RBCs become inflexible/spiky
Thalassemia
Insufficient production of Hb
Imbalance of alpha and beta chains
Autosomal recessive
Enlarged spleen, liver and heart
Bone Marrow Infiltration
Leukaemia: non specific symptoms, bone marrow failure
Lymphoma: lymphadenopathy, weight loss
Myeloma: anaemia, hypercalcaemia, renal failure, bone lesions
Bone marrow sample obtained from iliac crest
Worldwide Impact
increased risk of morbidity in children impaired physical and cognitive development poor pregnancy outcome contributes to 20% of maternal deaths reduced work productivity
Iron Deficient Anaemia
Causes: bleeding, nutritional deficiency, increased requirements
Confirm with iron studies - ferritin, serum Fe, transferrin
Iron deficiency is not a diagnosis - other investigations needed to find underlying cause
Diagnostic tests for iron
Serrum Ferritin: storage form of iron, low = iron deficient
Serum Fe: labile in blood, for reflects recent intake
Serum transferrin: carrier molecule for iron gut to stores, homeostatic ally goes up if iron is deficient, reflects total iron binding capacity of blood
% transferrin saturation: sensitive measure of iron status, reflects proportion bound, low TF sats = iron deficiency
Signs and Symptoms
Symptoms: tiredness, breathlessness, palpitations, headache
Signs: skin pallor, pale conjunctivae, tachypnoea, tachycardia
Main causes: inadequate synthesis (deficiency/bone marrow dysfunction); blood loss or consumption (haemolytic anaemia - increased roc destruction)