Haemolytic Anemia Notes

When evaluating a patient for haemolytic anemia, several crucial indicators should be assessed to establish a clear diagnosis and guide treatment. These indicators include:

• Unconjugated Bilirubin Levels: Elevated levels can indicate increased breakdown of red blood cells, as unconjugated bilirubin is produced when haemoglobin is degraded.

• Anemia: The presence and severity of anemia must be evaluated, typically measured in terms of hemoglobin concentration and hematocrit levels.

• Reticulocyte Count: A high reticulocyte count indicates the bone marrow’s response to anemia, suggesting active erythropoiesis in response to hemolysis.

The initial evaluation should involve specific tests for haemolysis, which include:

• Lactate Dehydrogenase (LDH): Elevated LDH levels indicate tissue damage or hemolysis, as it is released when red blood cells undergo lysis.

• Full Blood Count (FBC): This test assesses the overall blood cell counts, including red blood cells, white blood cells, and platelets, which can help in evaluating the severity of anemia and possible underlying causes.

• Bilirubin Levels: Total bilirubin, including both conjugated and unconjugated fractions, provides insight into liver function and hemolysis.

• Haptoglobin Levels: Low haptoglobin levels indicate that haptoglobin is binding free hemoglobin released from lysed red cells, often seen in hemolytic processes.

• Direct Coombs Test (DAT): This test helps to determine whether there are antibodies attached to the surface of red blood cells, which would suggest an autoimmune hemolytic anemia.

Blood Film Analysis

A blood film is crucial in identifying specific morphological changes in red blood cells that indicate the cause of haemolysis. Observations may include:

• Spherocytes: These are spherical red blood cells that can indicate conditions like hereditary spherocytosis.

  • If the DAT is negative and there’s a family history of anemia, hereditary spherocytosis should be suspected due to genetic inheritance.

  • If the DAT is positive, it suggests an autoimmune disease, such as autoimmune hemolytic anemia.

• Schistocytes: The presence of schistocytes, which are fragmented red blood cells, indicates mechanical damage due to shear stress.

  • Conditions such as thrombotic microangiopathy, mechanical trauma from vessels, or march haemoglobinuria can cause schistocytes.

• Bite Cells, Blister Cells (Pruse Cells or Pre-keratocytes), Helmet Cells (Horn Cells or Keratocytes), and Triangle Fragments: These abnormally shaped red cells are associated with oxidative stress and are noted in conditions such as G6PD deficiency, where red blood cells are prone to hemolysis during oxidative challenges.

• Other causes of haemolysis: Commonly associated conditions include:

  • Hemoglobinopathies, such as Sickle cell anemia (which leads to vaso-occlusive crises) and Thalassemia (arising from genetic mutations affecting hemoglobin production).

  • Infections: Certain infections, most notably those caused by pathogens such as malaria or clostridium species, can lead to hemolysis.

  • Drugs: Some medications can cause drug-induced hemolytic anemia through either an immune-mediated process or direct toxicity to red blood cells.

  • Fever and Thermal Injury: Increased temperatures can lead to the destabilization of red blood cells.

  • Malaria: In relevant clinical settings, thick and thin blood films should be meticulously examined to rule out malaria, as it can precipitate acute hemolytic anemia.

Additional Information

Understanding the shapes and types of abnormal red blood cells is vital in diagnosing the underlying cause of haemolytic anemia accurately. Bite cells, blister cells, helmet cells, and triangle fragments are key indicators of potential oxidative damage and stress affecting red blood cell integrity. Distinguishing these abnormalities is essential for tailoring the management of haemolytic anemia effectively, as they can point directly towards specific causative conditions that require targeted therapeutic interventions.