Anaemia

Anaemia

Definition

Reduction of Hb <135g/l in men and <120g/l in women

Causes of anaemia

  • Increased loss
    • Haemorrhage
  • Increased destruction
    • Haemolysis
  • Deceased production
    • Iron / folate / Vit B12 deficience
    • Porphyrin deficiency (lead poisoning)
    • Bone marrow failure
      • absolute (myelodysplasia, leukaemia, aplastic anaemia)
      • relative (renal impairment, chronic infection)

Classification

  • normocytic
    • haemorrhage
    • haemolysis
    • leukaemia, myelofibrosis, aplasia
  • microcytic 
    • primarily result of HB synthesis failure
    • iron deficiency (diet, bleeding, parasites)
  • macrocytic
    • Megaloblastic (Vit B12, folate deficiency through reduced intake/ absorption)
    • Alcoholism and liver disease

Haemolysis screen

  • Full blood
  • Reticulocytes (increased as compensation mechanism)
  • Indirect bilirubin
  • LDH
  • Haptoglobin (freeHp) is reduced because HB binds to Hp. Only free Hp is measured
  • Ferritin
    • Iron storage protein
      • Reduced in iron deficiency
      • Increased in tumor, infection
  • Transferrin
    • Iron transport protein (normal saturation 30%)
      • Reduced in haemolysis
      • Increased in Iron deficiency and pregnancy

Transfusion

Red blood cells

Adverse effects

  • Citrate Toxicity?hypocalcaemia
  • Hypothermia
  • Jaundice
    • aged blood > Bilirubinaemia
  • Bacterial Contamination
  • Viral transmission (HIV HCV, CMV)
  • Haemolysis (ABO incompatibility)
    • flushing, pain, (infusion site, headache, back, chest), N&V, hypotension, circulatory arrest
  • Renal Impairment
  • Allergic and anaphylactoid Reactions
    • severity grading: Urticaria > nausea, mild hypotension > shock, bronchospasm > cardiac arrest
  • Immune Modulation
  • TRALI
    • paO2/fiO2 <300mmHg
    • within 6h of transfusion
    • recovery occurrs within 48 hrs

Platelets

Transfusion threshold

  • Bone marrow failure: <10-20×109/l
  • to maintain >50×109/l
  • in qualitative platelet disorder

NOT indicated

  • HUS, TTP, ITP (debateable)
  • uncomplicated cardiac bypass surgery

FFP

Indications

  • Replacement of single factor where specific factor unavailable
  • Reversal of warfarin as factor 7 source (in combination with Prothrombinex (9, 10, 2, little 7)
  • DIC
  • bleeding post transfusion and abnormal clotting tests
  • In HUS, TTP (bridge to plasmapheresis)