Hemolytic Anemia (updated 2023) - CRASH! Medical Review Series

Introduction

This tutorial provides a comprehensive overview of hemolytic anemia, focusing on its causes, classification, diagnostic tests, and treatments. Understanding hemolytic anemia is essential for medical students and healthcare professionals, particularly those preparing for licensing exams.

Step 1: Identify Hemolytic Anemia

• Recognize that hemolytic anemia results from the destruction of red blood cells.
• Common symptoms include:
  • Anemia (fatigue, weakness)
  • Jaundice (yellowing of skin and eyes)
  • Dark urine (due to bilirubin)
  • Splenomegaly (enlarged spleen)

Step 2: Classify Hemolytic Anemia

• Classify hemolytic anemia based on the Coombs test results:
  • Coombs Positive: Indicates autoimmune hemolytic anemia (AIHA).
  • Coombs Negative: Suggests other types, such as hereditary spherocytosis or G6PD deficiency.

Step 3: Perform Initial Laboratory Tests

• In addition to routine anemia tests, order the following:
  • Serum LDH: Elevated in hemolysis.
  • Haptoglobin: Low in hemolysis (binds free hemoglobin).
  • Total Bilirubin: Elevated due to hemolysis.
  • Peripheral Smear: To assess red blood cell morphology.

Step 4: Conduct Coombs Testing

• Direct Coombs Test: Determines the presence of antibodies on red blood cells.
  • Positive result indicates autoimmune hemolytic anemia.
  • Negative result suggests non-autoimmune causes.

Step 5: Analyze Hemolytic Anemia Types

• Warm Autoimmune Hemolytic Anemia:

  • Mediated by IgG antibodies.
  • Treatment: Prednisone (steroids) and folate supplementation.

• Cold Autoimmune Hemolytic Anemia:

  • Mediated by IgM antibodies, worsens in cold conditions.
  • Treatment: Avoid cold exposure, folate supplementation.

• Drug-Induced Hemolytic Anemia:

  • Associated with recent drug exposure (e.g., cephalosporins).
  • Treatment: Withdraw the offending drug, consider folate supplementation.

• Hereditary Spherocytosis:

  • Involves a defect in red blood cell membrane causing fragility.
  • Treatment: Folate replacement and possible splenectomy.

• G6PD Deficiency:

  • X-linked recessive condition leading to oxidative stress on red blood cells.
  • Treatment: Avoid triggering substances (e.g., certain drugs, fava beans).

• Paroxysmal Nocturnal Hemoglobinuria:

  • Caused by a deficiency in membrane proteins leading to complement-mediated destruction of red blood cells.
  • Symptoms: Cola-colored urine, especially in the morning.
  • Treatment: Eculizumab (monoclonal antibody).

Step 6: Monitor and Follow-Up

• Regular follow-up is crucial to manage and monitor symptoms and treatment response.
• Ensure vaccinations are up to date if splenectomy is performed.

Conclusion

Understanding hemolytic anemia involves recognizing symptoms, performing appropriate tests, and differentiating between types based on Coombs testing. Treatment varies based on the type of anemia but often includes folate supplementation and managing underlying causes. For further learning, consider reviewing specific treatments and management strategies for each subtype of hemolytic anemia.