Glucose 6 Phosphate Dehydrogenase Deficiency
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Introduction
Glucose 6 Phosphate Dehydrogenase (G6PD) deficiency is the most common enzymatic disorder worldwide, affecting more than 200 million individuals. It causes bouts of acute hemolytic anemia following exposure to oxidizing substances.
Disease severity is classified by the magnitude of enzyme deficiency and degree of hemolysis.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.
Causes and Risk Factors
X-linked disease, with multiple identified mutations. It has the highest prevalence in the Middle East, Africa and Asia, and parts of the Mediterranean. G6PD deficiency is thought to protect against infection by malaria.
Oxidants known to precipitate acute hemolytic anemia include fava beans, antimalarials such as primiquine, or sulfonamides.
Pathophysiology
Enzyme deficiency leads to RBCs that are unable to protect themselves against oxidative stress, as can follow infection or drugs. Hemoglobin precipitates out, forming Heinz bodies, and splenic macrophages begin phagocytosing RBCs to form 'bite cells' or 'cookie cells'.
Signs and Symptoms
- history
- physical exam
History
Patients present with acute hemolytic anemia:
- dark urine (hemoglobinuria)
- jaundice
- pallor
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
blood smear: bite cells and Heinz bodies are characteristic.
evidence of hemolytic anemia:
- hemoglobinuria
- decreased haptoglobin
- increased LDH
- increased indirect bilirubin
G6PD levels can also be measured.
Diagnostic Imaging
Differential Diagnosis
Treatments
Following acute attacks, treatment is supportive, especially hydration. Transfusions are given as required. Phototherapy can be used to degrade bilirubin.
Prevention, through the avoidance of known precipitants, is important.
Consequences and Course
Chronic anemia is rare.
The Case of...
Case #2 - a small story wrapping it all up and asking about esp management.
Additional Resources
Topic Development
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