• Virtual Rounds Session 7: Anemia (Premed Shadowing)

Virtual Rounds Session 7: Anemia (Premed Shadowing)

Throughout each premed virtual shadowing session, you will actively participate by answering and asking questions about the week’s proposed case. Like an in-person shadowing experience, we strive to stimulate students intellectually and ultimately reaffirm their interest in medicine.

 

Introduction – Anemia 

Red blood cells are essential for the transportation of oxygen to vital tissues and structures in the body. In the presence of anemia, there can be a multitude of effects – including heart failure. It is important to not only identify anemia itself but pinpoint the cause (etiology) of the anemia since treatment may vary correspondingly.

Case Highlights 

A 53 y/o M presents to the ED with his spouse for a 3-month history of lethargy. He notes that for the past few months he has been tired to the point where he cannot complete activities of daily living (ADLs). The patient describes a one-week history of RLQ pain as well as intermittent N/V/D. For the past two weeks he has noted that when he wakes up at night, he has unsteadiness on his feet of which he does not notice during the day. He describes SOB, weakness, HA, and dizziness but denies fevers, myalgias, chest pain, or LOC. Of note, the patient recently immigrated from Scandinavia, specifically Denmark where he often indulged in dishes that contain raw fish. No significant PMH and no home treatments for this episode of symptoms.

Pathology 

  1. A low hemoglobin concentration or red blood cell mass defines anemia. Anemia is divided by the Mean Corpuscular Volume (MCV), which is the mean size of the red blood cells. In the peripheral blood smear, you can use the size of lymphocytes or other cells as a “ruler” to gauge the size of the other cells. 
  • Microcytic: <80 fL
    • Small red blood cells
    • Ex. Thalassemias (deficiency in alpha or beta genes in hemoglobin), lead poisoning

Above: Microcytosis | Credit: ASH Image Bank

  • Normocytic: 80-100 fL
    • Normal red blood cells
    • Can be further differentiated by hemolytic (Ex. sickle cell anemia, G6PD deficiency) vs. non-hemolytic (Ex. anemia of chronic disease, aplastic anemia)
  • Macrocytic: >100 fL
    • Large red blood cells 
    • Ex. Vitamin B12 or folate deficiency
      • Often see hypersegmented neutrophils in the peripheral blood

Above: Hypersegmented neutrophils | Credit: ASH Image Bank

Above: Differentiation of anemia based on the MCV | Credit: First Aid for the USMLE 2020

2. There are a multitude of risk factors for anemia which include but are not limited to:

  • Dietary considerations
    • Diet 
    • Parasites
  • Gastrointestinal comorbidities 
    • Crohn’s disease
    • Celiac disease 
    • Previous GI surgeries (short gut syndrome, malabsorption)
  • Menstruation
  • Pregnancy 
  • Chronic conditions → anemia of chronic disease
  • Genetics / Autoimmune 
    • Thalassemia 
    • Sickle Cell anemia
    • G6PD deficiency 
    • Hereditary spherocytosis  
    • Pyruvate kinase deficiency

3. On physical exam, we might notice pallor of the skin and anterior rim of the eye as well as lethargy, tachycardia, hypotension, abdominal pain, or neurological disturbance (if anemia secondary to B12 deficiency).

4. As alluded to previously, anemia is associated with a number of complications. For instance, long standing anemia can lead to high output heart failure, abnormal heart rhythms (arrhythmias) severe combined degeneration of the cord (SCD, associated with B12 deficiency), neural tube defects (associated with folate deficiency), increased risk of infections, or death.

5. Diagnosis depends on a combination of the clinical picture/presentation of the patient as well as laboratory studies such as:

  • Most important (CBC)
    • Hemoglobin / hematocrit 
    • MCV
  • Follow-up:
    • B12 / Folate levels 
      • MMA (methylmalonic acid – differentiates between folate and B12 deficiency as B12 deficiency reveals an increased MMA)
    • Iron studies 
    • Enzymes:
      • G6PD
      • Pyruvate Kinase
    • Genetics (Hb Electrophoresis)
      • Sickle cell 
      • Thalassemia 
      • HbC Deficiency

6. Treatment depends on the cause of the anemia as we must treat the underlying cause.

  • Iron deficiency = iron 
  • B12 deficiency = B12 
    • D.Latum = praziquantel 
  • Folate Deficiency = folate 
  • Sickle Cell = hydroxyurea, hydration 
  • G6PD = avoid triggers 

 Take home points

    1. Anemia has significant impacts on a multitude of organ systems with complications that may potentially be irreversible. 
    2. A low hemoglobin concentration or RBC mass defines anemia though is differentiated by the MCV and classified as microcytic, normocytic, or macrocytic anemia 
    3. A hemoglobin <7.0 mg/dL necessitates transfusion. 
    4. Be cognizant of causes of anemia such as D.Latum (fish tapeworm, as in this particular case) that can lead to a macrocytic anemia due to vitamin B12 deficiency. 
    5. Pinpoint the cause of the anemia as the treatment may be different from one type of anemia to another. For instance, iron deficiency anemia requires a different treatment than vitamin B12 or folate deficiency.

Watch the virtual shadowing session here:

Fill out this form throughout the session: