G6PD Deficiency

Aka: G6PD Deficiency, G6PD, Favism

1. See Also
   1. Hemolytic Anemia
2. Epidemiology
   1. Caucasians of Mediterranean ancestry (Class II)
      1. Greek patients
      2. Jewish patients
      3. Sardinian patients (from island of Italy)
   2. Black patients or African descent (Class III)
   3. Asian patients
   4. Filipino patients
3. Pathophysiology
   1. Glucose-6-phosphate dehydrogenase (G6PD)
      1. Catalyzes NADP to NADPH (pentose phosphate path)
      2. NADPH prevents oxidative damage to cells
      3. RBCs depend on G6PD for sole pathway to NADPH
      4. RBCs are most susceptible to insufficient G6PD
   2. Methemoglobin (Fe3+) may form spontaneously
      1. Methemoglobin is typically reduced to normal Hemoglobin (Fe2+) by cellular mechanisms
      2. NADPH is important in combating oxidative stress and converting Hemoglobin back to Fe2+
      3. However in G6PD Deficiency, this fails and Methemoglobinemia is unchecked
   3. Results in acute Hemolytic Anemia
   4. Drug-induced Hemolysis affects older cells
      1. Younger cells have adequate enzyme levels to survive
   5. G6PD mutations occur on distal long arm of C Chromosome
      1. X -Linked Disorder
4. Causes
   1. See Medications in G6PD Deficiency
      1. Onset within 72 hours of intake
   2. Infection (most common cause)
      1. Salmonella
      2. Eschirichia coli
      3. Beta-hemolytic Streptococcus
      4. Rickettsia
      5. Viral Hepatitis
      6. Influenza A
   3. Fava beans (Italian Broad Beans)
      1. Bell Beans
      2. Broad Beans
      3. English Dwarf Beans
      4. Haba Beans
      5. Horse Beans
      6. Pigeon Beans
      7. Silkworm Beans
      8. Tic Beans
5. Symptoms and Signs
   1. Usually asymptomatic
   2. See Hemolytic Anemia for acute episodes
6. Differential Diagnosis
   1. See Drug-Induced Hemolytic Anemia
   2. See Hemolytic Anemia Causes
7. Labs
   1. See Hemolytic Anemia
   2. See G6PD Deficiency Detection
8. Complications
   1. Increased risk of Sepsis
9. Prevention
   1. Avoid precipitating factors
      1. See Medications in G6PD Deficiency
      2. Keep Immunizations up-to-date
   2. Treat Anemia following Hemolytic Anemia episode
      1. Iron Supplementation
      2. Folic Acid supplementation
   3. Measures that are not recommended (no benefit)
      1. Splenectomy
      2. Vitamin E
      3. Selenium
10. References
    1. Golan in Goldman (2000) Cecil Medicine, p. 873-75
    2. Beutler (1994) Blood 84:3613-36 [PubMed]
    3. Frank (2005) Am Fam Physician 72:1277-82 [PubMed]
    4. Phillips (2018) Am Fam Physician 98(6): 354-61 [PubMed]