Summary
Highlights
Dr. K introduces G6PD deficiency and presents a case of a 34-year-old man from Greece with fatigue, yellow eyes, and skin, recently treated with antibiotics. He emphasizes the importance of differential diagnoses before focusing on G6PD deficiency.
The video explains that G6PD is an enzyme vital for the pentose phosphate pathway, protecting cells from oxidative damage. It details how G6PD produces NADPH, which regenerates glutathione. Without sufficient G6PD, glutathione cannot be regenerated, leading to severe cell damage and death due to unchecked oxygen radicals.
G6PD deficiency is common in areas where malaria was endemic, as it provides an advantage against the disease by reducing the lifespan of red blood cells, thus limiting malaria parasite replication. It is an X-linked disorder, meaning males are more frequently and severely affected than females. The severity varies from class one (most severe) to class five (asymptomatic), with variants like the Mediterranean and A-minus types.
G6PD deficiency commonly presents in two ways: neonatal jaundice, typically several days after birth, which is treated with phototherapy to prevent kernicterus; and hemolytic episodes triggered by exposure to certain medications (e.g., primaquine, sulfamethoxazole), foods (e.g., fava beans, known as favism), or severe infections. These episodes result in sudden jaundice, pallor, and dark urine.
Diagnosis involves identifying Heinz bodies (abnormal protein collections) and helmet or bite cells in red blood cells on a peripheral smear. The most sensitive diagnostic test is the fluorescent spot test, which detects NADPH production. Other tests include methemoglobin tests. Crucially, testing should be performed when the patient is asymptomatic to avoid false-negative results, as the most deficient cells clear during a hemolytic event. Treatment involves removing the trigger and providing supportive care during a hemolytic episode.