A 5-year-old boy is undergoing a lymphadenoctomy to treat a poorly draining lymph node abscess. He has a history of recurrent skin abscesses. Cultures from his abscess are growing Staphylococcus aureus, which is sensitive to the current antibiotic regimen, but the abscess has failed to improve. Evaluation of the patient's neutrophils by dihydrorhodamine flow cytometry shows an absence of fluorescence. This patient's condition is most likely due to impaired activity of which of the following enzymes?

Question

A 5-year-old boy is undergoing a lymphadenoctomy to treat a poorly draining lymph node abscess.  He has a history of recurrent skin abscesses.  Cultures from his abscess are growing Staphylococcus aureus, which is sensitive to the current antibiotic regimen, but the abscess has failed to improve.  Evaluation of the patient's neutrophils by dihydrorhodamine flow cytometry shows an absence of fluorescence.  This patient's condition is most likely due to impaired activity of which of the following enzymes?

Quizplus · Accepted Answer

Eductional Objective: Chronic granulomatous disease is due to NADPH oxidase deficiency, which leads to an inability of neutrophils to generate a respiratory burst and produce the reactive oxygen species necessary to kill organisms in their phagolysosomes.  Absence of fluorescence on dihydrorhodamine flow cytometry testing can confirm the diagnosis.

A 5-Year-Old Boy Is Undergoing a Lymphadenoctomy to Treat a Poorly