Definition

The textbook definition of anemia is a reduction of the absolute number or mass of circulating red blood cells.  This then causes a global reduction in the oxygen carrying capacity of the patient’s circulatory system.  Clinically, we use hemoglobin and hematocrit as the surrogate markers and define anemia as 2 SD below the mean for gender:

• Men
  • Hemoglobin < 13.5 g/dL
  • Hematocrit < 41%
• Women
  • Hemoglobin < 12.0 g/dL
  • Hematocrit < 36%

Patel KV. Haematologica. 2008;93(9):1281-1283.

• Special Populations
  • Athletes
    • May have a baseline anemia due to:
      • Dilution from increased plasma volume
      • Hemolytic breakdown from exercise
      • Exercise induced cytokines decreases RBC production
    • A normal H/H in a competitive athlete may suggest performance enhancing drugs
  • High altitudes
    • May have elevated hemoglobin concentration as baseline
  • Smokers
    • Baseline higher hemoglobin due to carboxyhemoglobin

General Causes of Anemia

There are two general approaches you can use to help identify the cause of anemia in adults.

• The Kinetic Approach (the mechanisms responsible for the low hemoglobin)
  • 3 independent mechanisms
    • Decreased RBC production
      • Lack of nutrients
      • Bone marrow failure
      • Decreased erythopoetic stimulation factors
        • Erythropoietin, T3, androgens
      • Inflammation
    • Increased RBC destruction
      • Hemolysis, hypersplenism
    • Blood loss
• The Morphologic Approach (categories based on RBC size and reticulocyte response)
  • Macrocytic (MCV > 100 fL)
    • Vitamin B12, folate, EtOH, liver disease
    • Any condition causing reticulocytosis
  • Microcytic (MCV < 80 fL)
    • 3 most common in clinical practice
      • Iron deficiency
        • ↓ serum iron, ↓ serum ferritin, ↑ TIBC
      • Alpha or beta thalassemia minor
        • Normal iron studies
      • Anemia of chronic disease
        • ↓ serum iron, normal serum ferritin, ↓ TIBC

History Questions

• Is the patient symptomatic?
  • Fatigue, dyspnea, bleeding, bruising, dizziness, syncope
• Any history of weight loss, night sweats, fever, anorexia?
  • Infection or malignancy
• Past medical history for chronic illness
  • PUD, renal disease, autoimmune conditions, liver disease, past malignancies
• Family history for hemoglobinopathies
• Social history for alcohol use
• Occupational exposures

Physical Exam Findings

• Pallor
  • Palms, nail beds, face, conjunctiva
• Jaundice
• Hepatosplenomegaly
• Lymphadenopathy
• Petechiae, purpura, bruising
• Bone tenderness

Laboratory Testing

Anemia is usually first diagnosed by CBC.  Once you have a documented low H/H, then you need order follow-up studies to help differentiate the cause of the anemia.  These include:

• RBC indices
  • MCV, MCH, MCHC, RDW
• Reticulocyte count and index
• Peripheral smear
  • Helmet cells or schistocytes à microangiopathic hemolysis
  • Microspherocytes à autoimmune hemolysis
  • Tear drop RBC à myelofibrosis
  • Bite cells à oxidative hemolysis
  • Parasites à malaria, babeosis
  • Hypersegmented neutrophils à Vitamin B12 or folate deficiency
  • Nucleated RBC
  • Siderocytes
  • Target cells à thalassemias
• WBC and platelet count from CBC
• If hemolysis is suspected:
  • ↑ Serum LDH, ↓ serum haptoglobin, and ↑ serum indirect bilirubin
  • Direct Coombs test (antibodies against RBC)
• Bone marrow evaluation

Schrier SL, et al. Approach to adults with anemia. In: Up To Date. Waltham, MA (Accessed 03/23/2016)

The Cottage Physician Management

Something new I thought I would bring to the PAINE Podcast.  As you all know, I am quite a fan of medicine and antiquity.  Shortly after I married my wife, her grandfather past away from a progressive esophageal cancer.  One of the things I was able to keep when helping clean out his house, was a copy of The Cottage Physician printed in 1893.  It was basically a handbook on how to treat common ailments of the time. I will try to add excerpts from this book when appropriate so you can have a sense of how medicine was practiced in the late 19^th century.

The Cottage Physician. 1863

References

1. Patel KV. Variability and heritability of hemoglobin concentration: An opportunity to improve understanding of anemia in older adults.  Haematologica.  2008;93(9):1281-1283.
2. Beutler E, Waalen J. The definition of anemia: what is the lower limit of normal of the blood hemoglobin concentration?. Blood. 2006;107(5):1747-50.
3. Shaskey DJ, Green GA. Sports haematology. Sports Med. 2000;29(1):27-38.
4. Ruíz-argüelles GJ. Altitude above sea level as a variable for definition of anemia. Blood. 2006;108(6):2131.
5. Nordenberg D, Yip R, Binkin NJ. The effect of cigarette smoking on hemoglobin levels and anemia screening. JAMA. 1990;264(12):1556-9.
6. Hillman RS, Ault KA, Leporrier M, Rinder HM. Clinical Approach to Anemia.  In: Hematology in Clinical Practice.  5^th McGraw-Hill. New York. 2010.
7. Tefferi A. Anemia in adults: a contemporary approach to diagnosis. Mayo Clin Proc. 2003;78(10):1274-80.
8. Nardone DA, Roth KM, Mazur DJ, Mcafee JH. Usefulness of physical examination in detecting the presence or absence of anemia. Arch Intern Med. 1990;150(1):201-4.
9. Hung OL, Kwon NS, Cole AE, et al. Evaluation of the physician’s ability to recognize the presence or absence of anemia, fever, and jaundice. Acad Emerg Med. 2000;7(2):146-56.