Glucose 6-Phosphate Dehydrogenase Deficiency

The hexose monophosphate shunt pathway depends on the enzyme glucose-6-phosphate dehydrogenase (G6PD). More than 200 million people worldwide have G6PD deficiencies, which partially shield them from malaria.

Haemolytic episodes arise during environmental stress:

• Viral and bacterial infections
• Drugs – sulfur drugs, antimalarials, nitrofurantoin
• Toxins – naphthalene
• Metabolic acidosis
• Fava beans

Presentation:

• An acute hemolytic crisis within hours of exposure to oxidant stress leads to hemoglobinuria, anemia, and sometimes cardiovascular collapse.
• Self-limited since only older RBCs are destroyed
• Oxidation of hemoglobin forming Heinz bodies: visualized by supravital stain, e.g., crystal violet
• Splenic removal of Heinz bodies → ‘bite cells’

Management:

• It seeks to eliminate precipitating medications or meals and address underlying infections.
• Acute transfusion support may be life-saving