“Low Haemoglobin He- <120g/L in females and <140 g/L in males”

Risk Factors
  • Modifiable:
    • Poor diet
  • Non-Modifiable:
    • Sex (female)
    • Extremes of age
    • Lactation
    • Pregnancy
    • FHx of haemolytic anaemia
    • Previous surgery e.g. resection of the stomach
Aetiology
  • Decreased or ineffective marrow production
    • Lack of iron, vitamin B12 or folate (dietary insufficiency, poor absorption)
    • Hypoplasia/myelodysplasia
    • Invasion by malignant cells
    • Renal failure
    • Anaemia of chronic disease
  • Normal marrow production but increased removal of cells
    • Blood loss (menorrhagia, GI haemorrhage)
    • Haemolysis
    • Hypersplenism
Pathophysiology
  • Normocytic anaemia:
    • Cells released into plasma is unable to keep up with demand (chronic disease) with decreased RBC lifespan, disturbance of erythropoiesis due to decreased sensitivity to physiological stimuli and decreased iron utilisation
  • Microcytic anaemia:
    • Component parts of Hb aren’t readily available (iron deficiency, defective globin chains) so undergo more division than normal with lower MCV when released into
  • Macrocytic anaemia:
    • RBCs unable to synthesis new bases so undergo fewer cell divisions resulting in a high MCV (B12 and folate deficiency)
Clinical Presentation
  • Symptoms:
    • TIred
    • Lightheaded
    • Shortness of breath
    • Development/worsening of ischaemic symptoms (angina, claudication)
    • Headache
  • Signs:
    • Mucous membrane pallor
    • Tachypnoea
    • Raised JVP
    • Tachycardia
    • Flow murmurs
    • Ankle oedema
    • Postural Hypotension
  • Jaundice- haemolytic anaemias
  • Neurological signs e.g. peripheral neuropathy, dementia- in B12 deficiency anaemia
  • Leg ulcers, stroke, features of pulmonary HTn- in Sickle cell anaemia
Investigations
  • Mean cell volume (MCV)- measures average volume of RBC, suggesting the cause:
    • Low MCV = microcytic anaemia, suggests:
      • Iron deficiency- most common cause (hypochromic cells, increased variation in RBC shape e.g. pencil-shaped, target shaped)
      • Thalassaemia- MCV ‘too low’ for Hb level and the red cell level is high- need a DNA test for definitive diagnosis
      • Sideroblastic anaemia (very rare)
    • Normal MCV = normocytic anaemia, suggests:
      • Acute blood loss
      • Anaemia of chronic disease
      • Bone marrow failure (suspect if WCC or platelets are low)
      • Renal failure
      • Hypothyroidism
      • Haemolysis
      • Pregnancy
    • High MCV = macrocytic anaemia, suggests:
      • Vitamin B12 (oval RBCs, hypersegmented neutrophils) or folate deficiency
      • Myelodysplasia
      • Alcohol excess or liver disease
      • Cytotoxics e.g. Hydroxycarbamide
      • Marrow infiltration
      • Hypothyroidism
      • Reticulocytosis
      • Antifolate drugs e.g. Phenytoin
  • Hb levels, Ferritin levels, B12 levels, Folate levels, TSH, LFT, TFT, bone marrow biopsy, bilirubin, LDH, haptoglobin, urinary urobilinogen, RBC lifespan (chromium labelling), sickle solubility test, Hb electrophoresis
Management
  • Idiopathic
    • Oral iron until Hb is normal (~3m) (IV iron if the oral route is ineffective)
  • Anaemia of chronic disease:
    • Treat underlying disease more vigorously
    • Erythropoietin (effective in raising Hb level)
    • Iron given parenterally can overcome the functional iron deficiency
  • Folate deficiency anaemia:
    • Treat with folic acid (never without B12 unless the patient is known to have a normal B12 level)
    • Blood transfusions rarely needed
  • Pernicious anaemia
    • Treat the cause if possible
    • If low B12 is due to malabsorption, injections are needed
      • Replenish stores with hydroxocobalamin IM alternate days
      • Maintenance dose= IM injection every 3m for life
    • If the cause is dietary, then oral B12 can be given after the initial acute course
  • SCA
    • Hydroxycarbamide if infrequent crises
    • Prophylactic abx and immunisations should be given to stop splenic infarction
    • BM transplant may be curative (but is still controversial)
  • Thalassaemia related anaemia:
    • Promote fitness and healthy diet
    • Folate supplements may help
    • Regular lifelong transfusions
    • Iron chelators to prevent iron overload
    • Ascorbic acid to increase urinary excretion of iron
    • Splenectomy if hypersplenism persists
    • Hormonal replacement or treatment for endocrine complications
    • Histocompatible marrow transplant
Complications
  • Severe fatigue- can’t complete everyday tasks
  • Pregnancy- women with folate deficiency anaemia may be more likely to have complications, such as premature birth.
  • Heart problems- can lead to arrhythmia, enlarged heart, HF
  • Rapid blood loss can be fatal
  • Life-threatening C/X for sickle cell anaemia (acute chest syndrome, stroke

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