• Anemia, or deficient or malfunctioning red blood cells (RBC), is the most common blood disorder that affects ~25% of people globally.
• Three mechanisms: Blood loss, decreased RBC production, and increased RBC destruction.
• Risk factors for anemia:
  • Most commonly seen in children, females, chronically ill, and elderly
  • Vegan diet -> Vit B12 deficiency anemia
  • Alcoholism -> folate deficiency anemia
  • Hereditary -> hemoglobinopathies
  • Intestinal disorders (ie. IBD)
  • Chronic diseases (ie. Kidney disease, Cancer, thyroid disease, liver disease, Rheumatoid arthritis or other autoimmune disease)
  • Infections
  • Menstruation
  • Pregnancy
• Characterizing the anemia as microcytic, normocytic, or macrocytic using the MCV à helps to guide further investigations and management.

 Clinical Presentation

• Weakness, general fatigue, dyspnea, tachycardia, dizziness, cold hands/feet, pallor.
• Severity depends more on the rate of anemia development than the absolute Hemoglobin Hgb) value.
  • Acute -> life-threatening symptoms.
  • Chronic -> body compensates – greater loss of RBCs before symptoms appear.

 Diagnostic Criteria:

• Adult non-pregnant females: Hgb < 120 g/L or Hct < 36% (0.36)
• Adult pregnant females:
  • 1^st trimester: Hgb < 110 g/L
  • 2^nd trimester: Hgb < 105 g/L
  • 3^rd trimester: Hgb < 110 g/L
• Adult males: < 130 g/L or Hct < 41% (0.41)
• Children and Adolescents:
  • Birth (term infant): < 135 g/L
  • 1 month: < 107g/L
  • 2 months: < 94 g/L
  • 3 – 6 months: < 95 g/L
  • 6 months – 2 yrs: < 105 g/L
  • 2 – 12 yrs: < 115 g/L
  • 12 – 18 years:
    • Males: < 130 g/L
    • Females: <120 g/L

General laboratory Investigations

• CBC:
  • Hemoglobin
  • Hematocrit
  • Complete WBC count
  • Differential WBC count
  • Platelet count
  • MCV
  • Mean corpuscular hemoglobin concentration (MCHC)
  • RDW (RBC distribution width)
• Reticulocyte count
• Peripheral blood smear

Imaging

• Imaging modality depends on suspected source.

Characterize the Anemia

• Microcytic = MCV <80 fL
  • Ddx:
    • Iron deficiency
      • Most common
      • Bleeding is the leading cause
    • Thalassemia
    • Anemia of chronic disease
  • Additional Labs:
    • Serum iron
    • Total iron binding capacity (TIBC)
    • Transferrin Saturation
    • Serum ferritin
      • Adults (ug/L):
        • < 15 = diagnostic of iron deficiency
        • 15-30 = probable
        • >30 = unlikely
        • >100 = normal
        • ≥600 = consider iron overload
      • Children (ug/L):
        • < 12 diagnostic of iron deficiency
        • 12-20 possible iron deficiency

• Normocytic = Normal MCV: 80-100 fL
  • High reticulocyte count:
    • DDx:
      • Hemolytic Anemia – Inherited or Acquired
        • Sickle cell disease, thalassemia, microangiopathic hemolytic anemias
      • Blood loss
    • Additional Labs:
      • Serum Bilirubin
      • Lactate Dehydrogenase
      • Haptoglobin
    • Low reticulocyte count:
      • DDx:
        • With Pancytopenia:
          • Aplastic anemia
          • Leukemia
          • Bone marrow infiltration
          • Myelodysplastic Syndromes (MDS)
          • Myelofibrosis
          • TB
          • Amyloidosis
          • Drugs –ie. Chemotherapy
        • Non-Pancytopenia:
          • Red cell aplasia
          • Renal/Liver disease
          • Anemia of chronic disease
        • Additional Labs:
          • Renal function tests
          • Liver function tests
          • Erythropoietin
          • Bone marrow aspiration

• Macrocytic = MCV >100 fL
  • Two types, megaloblastic (megaloblasts and hypersegmented neutrophils on peripheral smear) or non-megaloblastic.
  • DDX:
    • Non-megaloblastic:
      • Liver disease
      • Reticulocytosis
      • Alcoholism
      • Myelodysplasia
      • Hypothyroidism
    • Megaloblastic:
      • B12 deficiency
      • Folate deficiency
      • Drugs that impair DNA synthesis (Methotrexate, chemotherapy, sulfa)
    • Additional Labs:
      • Serum Vit. B12
      • Folate
      • TSH
      • Liver function panel

1. https://usingbloodwisely.ca/

   
   

1. Therapeutics Initiative. Intravenous (IV) iron for severe iron deficiency. TI UBC. 2015.

   
   

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3. Wang M. Iron deficiency and other types of anemia in infants and children. AFP. 2016;93(4):270-8.

   
   

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6. Braunstein EM. Evaluation of Anemia. Merck Manual. 2020.

   
   

7. Government of Canada. First Nations and Inuit Health Branch (FNIHB) Clinical Practice Guidelines for Nurses in Primary Care – Chapter 10 Hematology, Metabolism and Endocrinology. GC. 2010.

   
   

8. Moses S. Anemia Chapter: Normocytic Anemia. Fpnotebook. 2020.

   
   

9. British Columbia Ministry of Health. Iron Deficiency- Diagnosis and Management. BC Guidelines. 2019.