Hematology – Anemia: By Karima Khamisa M.D.

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Hematology – Anemia
Whiteboard Animation Transcript
with Karima Khamisa, MD
https://medskl.com/Module/Index/anemia

In evaluating a patient with anemia, it is critical to determine if the patient is clinically stable or unstable. Red blood cell transfusions may be necessary in patients with symptomatic anemia (that is, those with angina, hypotension, shortness of breath, palpitations, syncope, or pre-syncope). The hemoglobin value alone does not determine if a patient requires a blood transfusion.

Anemia is usually due to one of three processes:

Bleeding
Bone marrow production problems, or
Hemolysis, which is excessive red cell breakdown.

Hospitalized or complex patients may have multifactorial anemia, with a combination of the above processes.

Anemia can also be classified by red cell size:

Microcytic anemia can be due to thalassemia, iron deficiency, or anemia of chronic disease.
Macrocytic anemia can be caused by B12/folate deficiency, alcohol use, chronic liver disease, drugs (such as methotrexate), reticulocytosis, aplastic anemia, myelodysplastic syndrome, or hypothyroidism.
Normocytic anemia may involve a combination of factors and is best evaluated using a mechanistic approach.

In cases of acute anemia, the blood smear must be reviewed to assess for:

Fragmentation of red cells (which may indicate a life threatening condition such as thrombotic thrombocytopenic purpura) or
The presence of blast cells (which are immature white cells seen in acute leukemia).

Anemia in the ambulatory care setting may be chronic and patients may remain asymptomatic for some time.

In young menstruating women, iron deficiency is an extremely common cause of anemia
In the elderly, iron deficiency anemia may indicate serious GI pathology, which must be further investigated.
In patients with multiple co-morbidities, anemia of chronic disease may be present.
Multiple myeloma should also be considered in older patients with a normocytic anemia.Investigations will be guided by a thorough history and physical examination. It is important to document any history of bleeding or constitutional symptoms, family history of anemia, and to review all new and existing medications, particularly NSAIDs or anticoagulants. Basic blood tests should include: a peripheral blood smear, reticulocyte count, ferritin, B12, TSH, creatinine, and liver function tests/liver transaminases.

An urgent referral to a hematologist is appropriate in patients with suspected bone marrow dysfunction that requires a bone marrow aspirate or biopsy to confirm the diagnosis or if the patient has abnormalities on blood smear indicating fragmentation hemolysis.

To wrap up:

In approaching a patient with anemia, first establish if they are stable or unstable.
Use two complimentary approaches to guide further investigations:
Determine the mechanism of anemia (bleeding, a bone marrow production problem, or excessive red cell breakdown), and next
Look at the size of the red cells and determine if the anemia is microcytic, normocytic, or macrocytic.
Review the blood smear for critical findings such as red cell fragments or immature white cells (blasts).
Remember: transfuse the patient with anemia only if they are symptomatic.