Glucose-6-phosphate deficiency

Background

• Abbreviation: G6PD
• X-Linked recessive; protects against Malaria
• Mild form exists, which predominantly affects men of African decent. It is typically self-limited because it affects older RBCs (with less G6PD left)
• More severe form occurs predominantly in men of Mediterranean descent (specifically Greeks and Italians). Causes a more severe hemolytic anemia because RBCs of any age are involved
• Nonimmune mediated hemolytic anemia
• Stress or drugs can cause hemoglobin precipitation within the RBC
  • Leads to removal of the cell from circulation via the spleen

Precipitants

• Infection
• Fava beans
• Medications
  • Nitrofurantoin
  • Phenazopyridine
  • Dapsone
  • Chloramphenicol
  • Antimalarials (e.g. quinine, mefloquine)
  • Sulfonamides
  • Ciprofloxacin, norfloxacin
  • Methylene blue
  • Vitamin K analogues (e.g. warfarin)

Clinical Features

• Fatigue
• Hemolytic anemia
• Jaundice
• Splenomegaly

Differential Diagnosis

Anemia

RBC Loss

• Hemorrhage

RBC consumption (Destruction/hemolytic)

• Hereditary
• Acquired
• Microangiopathic Hemolytic Anemia (MAHA)
• Autoimmune hemolytic anemia

Impaired Production (Hypochromic/microcytic)

• Iron deficiency
• Anemia of chronic disease
• Thalassemia
• Sideroblastic anemia

Aplastic/myelodysplastic (normocytic)

• Marrow failure
• Chemicals (e.g. ETOH)
• Radiation
• Infection (HIV, parvo)

Megaloblastic (macrocytic)

• Vitamin B12/folate deficiency
• Drugs (chemo)
• HIV

Evaluation

Workup

• CBC
  • Heinz Bodies
• Retic Count
  • Retic count high
    • Coombs negative: G6PD, SCD, spherocytosis, microangiopathic hemolysis

Management

• Identify and discontinue precipitating agent
• Supportive care for anemia, with transfusions rarely needed
• Hemolysis usually self-limited, resolving within 8-14 days
• Infants
  • Prolonged neonatal jaundice due to G6PD deficiency may require phototherapy
  • Exchange transfusion for severe neonatal jaundice

Alternative Antibiotics

• Cephalexin (Keflex)

Complications

• Severe hemolysis and anemia
• Cardiovascular collapse

Also See

• Anemia
• Malaria

References

Authors

Ross Donaldson