Infectious Diseases · NEET PG Preparation Medicine
A 60-year-old male with type 2 diabetes mellitus is admitted with diabetic ketoacidosis. Over the next 48 hours, he develops acute onset left-sided f…
Practice question from Infectious Diseases (NEET PG Preparation Medicine), with the correct answer and a step-by-step solution.
hard · MCQ · Q-9A9002
A 60-year-old male with type 2 diabetes mellitus is admitted with diabetic ketoacidosis. Over the next 48 hours, he develops acute onset left-sided facial pain, nasal congestion with black necrotic turbinates, and a proptotic left eye with ophthalmoplegia. Biopsy of the nasal mucosa demonstrates broad, non-septate hyphae branching at right angles. Which of the following is the primary pathophysiological mechanism that predisposes this patient to this infection?
- A.Neutrophil dysfunction and hyperglycemia creating an acidic environment favoring fungal growthCorrect answer
- B.Impaired cell-mediated immunity due to lymphopenia
- C.Decreased production of secretory IgA in the mucosal membranes
- D.Complement deficiency leading to defective opsonization of encapsulated bacteria
Solution
The clinical picture and histology (broad, non-septate hyphae branching at 90 degrees) are diagnostic of Mucormycosis (Rhizopus, Mucor species). Ketosis and hyperglycemia impair phagocytic killing by neutrophils. Furthermore, these fungi thrive in high-glucose, acidic environments and produce the enzyme ketone reductase, which allows them to utilize free iron released in DKA.
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