Anemia
Basics
Description
Description
- Reduction below normal in the mass of RBCs
- Measured by 1 or more of the major RBC components:
- Hemoglobin (Hgb): Concentration of the major oxygen-carrying component in whole blood
- Hematocrit (Hct): Percent volume of whole blood occupied by intact RBCs
- RBC count: RBCs contained in a volume of whole blood
- Adult female: Hgb <12 g/dL or Hct <37%
- Adult male: Hgb <14 g/dL or Hct <42%
- Normal blood count values depend on age:
- Birth: Hgb 16.5, Hct 51
- 1 yr: Hgb 12, Hct 36
- 6 yr: Hgb 12.5, Hct 37
- Adult male: Hgb 14, Hct 42
- Adult female: Hgb 12, Hct 37
- Hgb/Hct depend on oxygen pressure:
- Increased in neonates and people living above 4,000 ft
- Hgb, Hct, and RBC count are concentrations:
- Dependent on RBC mass and plasma volume
- Values decrease if RBC mass decreases or plasma volume increases
- Anemia is an indication of an underlying disorder or deficiency
Etiology
Etiology
- Never a normal variant:
- May be the first manifestation of a systemic disorder
- Always seek a cause
- Excessive blood loss (most common cause):
- Trauma
- GI bleed
- Menstruation
- Hemolysis (increased RBC destruction, RBC lifespan <100 d):
- Hypersplenism
- Autoimmune hemolytic anemia
- Mechanical trauma (prosthetic heart valves, vasculitis, thrombotic thrombocytopenic purpura [TTP], hemolytic uremic syndrome [HUS], or disseminated intravascular coagulation [DIC])
- Toxins
- Infections (malaria, babesiosis)
- Membrane abnormalities
- Intracellular RBC abnormalities (G6PD, sickle cell anemia, or thalassemia)
- Decreased RBC synthesis:
- Classified by measurement of RBC size
- Hypochromic/microcytic:
- Iron deficiency
- Thalassemia
- Sideroblastic
- Chronic disease
- Normochromic/macrocytic:
- Hypothyroidism
- Folate deficiency
- Vitamin B12 deficiency
- Liver disease
- Myelodysplasia
- Certain leukemias
- Normochromic/normocytic:
- Aplastic anemia
- Chronic renal failure
- Malignancy
- Adrenal insufficiency
- Hyperparathyroidism
- Alcohol abuse
- Acute blood loss
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Citation
Schaider, Jeffrey J., et al., editors. "Anemia." 5-Minute Emergency Consult, 6th ed., Lippincott Williams & Wilkins, 2020. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307502/1.2/Anemia.
Anemia. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307502/1.2/Anemia. Accessed October 15, 2024.
Anemia. (2020). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (6th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307502/1.2/Anemia
Anemia [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. [cited 2024 October 15]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307502/1.2/Anemia.
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