Hemolytic Anemia

Aka: Hemolytic Anemia, Hemolysis

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II. Definitions

  1. Hemolytic Anemia
    1. Premature Red Blood Cell destruction prior to their normal 120 day life span

III. Types

  1. Extravascular Hemolysis (most common)
    1. Splenic and Hepatic Clearance of defective RBCs
    2. Mechanisms
      1. Splenic Sequestration and Phagocytosis due to poorly deformable RBCs
      2. Antibody mediated Hemolysis by Phagocytosis or complement mediated destruction
  2. Intravascular Hemolysis (Microangiopathic Hemolytic Anemia)
    1. RBC membrane injury (Trauma, autoimmune, infection)
    2. Mechanisms
      1. Direct cellular obstruction (toxins, Trauma, lysis)
      2. Fragmentation Hemolysis by external sheearing forces
      3. Oxidative Hemolysis

IV. Pathophysiology

  1. Mechanisms of RBC destruction

V. Causes

  1. See Hemolytic Anemia Causes
  2. See Autoimmune Hemolytic Anemia
  3. See Microangiopathic Hemolytic Anemia
  4. Common Causes
    1. Hereditary RBC Disorders
      1. Favism (G6PD Deficiency)
      2. Hemoglobinopathy (e.g. Sickle Cell Anemia)
      3. Hereditary Spherocytosis
    2. Lymphoproliferative Disorders
      1. Chronic Lymphocytic Leukemia
      2. Non-Hodgkin's Lymphoma
    3. Iatrogenic Hemolytic Anemia
    4. Medications (Most common cause)
      1. See Drug-Induced Hemolytic Anemia
    5. Connective Tissue Disorders
      1. Systemic Lupus Erythematosus
      2. Rheumatoid Arthritis
    6. Infection
      1. Epstein Barr Virus (Mononucleosis)
      2. Cytomegalovirus (CMV)
      3. Mycoplasma pneumonia
    7. Miscellaneous
      1. Paroxysmal Cold Hemoglobinuria

VI. History

  1. Diarrhea
    1. Hemolytic Uremic Syndrome
  2. Cancer History
    1. Warm Autoimmune Hemolytic Anemia
  3. Fever
    1. Autoimmune Hemolytic Anemia
    2. Disseminated Intravascular Coagulation (DIC)
    3. Hemolytic Uremic Syndrome (HUS)
    4. Other infections (e.g. Mononucleosis, Mycoplasma)
      1. See Hemolytic Anemia Causes
  4. Hematuria
    1. Paroxysmal Nocturnal Hemoglobinuria
    2. Intravascular Hemolysis
  5. Hemolytic Anemia Family History
    1. Sickle Cell Anemia
    2. Thalassemia
    3. G6PD Deficiency
    4. Hereditary Spherocytosis
  6. Medications
    1. See Drug-Induced Hemolytic Anemia
  7. Transfusion
    1. Transfusion Reaction

VII. Symptoms

  1. See Anemia
  2. Fatigue
  3. Dyspnea on exertion
  4. Back pain
  5. Fatigue
  6. Dark Red Urine (appears as Gross Hematuria)

VIII. Signs

  1. See Anemia
  2. Lymphadenopathy
  3. Splenomegaly
  4. Hepatomegaly
  5. Low grade fever
  6. Jaundice
  7. Pallor
  8. Hypotension
  9. Tachycardia

IX. Labs

  1. Complete Blood Count
    1. Normocytic Anemia is most common
  2. Direct Antibody Test (Direct Coombs test)
  3. Reticulocyte Index >3% (Reticulocytosis)
    1. Normal response within 3-5 days of Anemia onset
  4. Serum Haptoglobin decreased
  5. Liver Function Tests
    1. Lactate Dehydrogenase (LDH) elevated
    2. Serum Unconjugated Bilirubin (Indirect Bilirubin) elevated
  6. Urinalysis
    1. Hemosiderinuria (requires prussian blue staining)
    2. Hemoglobinuria
  7. Peripheral Smear
    1. Spherocytes (very difficult to identify on Peripheral Smear)
      1. See osmotic fragility with reflex Band 3 Protein below
      2. Congenital spherocytosis (Negative Direct Coombs)
      3. Immune Hemolytic Anemia (Positive Direct Coombs)
    2. Schistocytes
      1. Microangiopathic Anemia (eg. Heart Valve Hemolysis)
    3. Hypochromic Microcytic Anemia
      1. Thalassemia
    4. Sickle Cells
      1. Sickle Cell Anemia
    5. Bite and Blister Cells or Heinz Bodies (oxidative Hemolysis resulting in partial Phagocytosis)
      1. G6PD Deficiency
  8. Other labs
    1. G6PD Activity
    2. Radionuclide RBC survival study
    3. Hemoglobin electrophoresis
      1. Indicated for Sickle Cell Anemia or Thalassemia
    4. Infection evaluation (if fever or travel)
      1. Blood Cultures for Clostridium perfringens
      2. Babesia Serology
      3. Blood smears for Malarial Hemoglobinuria
    5. Osmotic fragility with reflex to Band 3 Protein (much more sensitive for Spherocytosis)
      1. Available as panel from Mayo
      2. Identifies Hereditary Spherocytosis

X. Diagnosis

  1. Acute Jaundice or Hematuria AND
  2. Anemia AND
  3. Other Lab criteria (see above)
    1. Reticulocytosis
    2. Lactate Dehydrogenase increased
    3. Unconjugated Bilirubin increased
    4. Serum Haptoglobin decreased

XI. Management

  1. Treat underlying cause
  2. Corticosteroids (if not contraindicated)
  3. Splenectomy (refractory to steroids)
  4. IV Immunoglobulin

XII. References

  1. Golan in Goldman (2000) Cecil Medicine, p. 867-84
  2. Dhaliwal (2004) Am Fam Physician 69:2599-606 [PubMed]
  3. Phillips (2018) Am Fam Physician 98(6): 354-61 [PubMed]

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