A patient with bacterial meningitis has CSF glucose of 20 mg/dL with simultaneous serum glucose of 90 mg/dL (CSF:serum ratio 0.22). Which mechanism PRIMARILY accounts for hypoglycorrhachia in bacterial meningitis?
- A Increased glucose consumption by activated immune cells and bacteria within the CSF
- B Impaired GLUT-1 mediated glucose transport across inflamed blood-brain and blood-CSF barriers ✓
- C Increased CSF protein competing with glucose for transport across the choroid plexus
- D Systemic hypoglycemia induced by bacterial endotoxins reducing plasma glucose available to CSF
Correct answer: B. Impaired GLUT-1 mediated glucose transport across inflamed blood-brain and blood-CSF barriers
Explanation
The primary mechanism of hypoglycorrhachia in bacterial meningitis is impairment of GLUT-1-mediated facilitated glucose transport across the inflamed blood-brain barrier and blood-CSF barrier (choroid plexus). Inflammation disrupts carrier-mediated transport. While bacterial and leukocyte metabolism (option A) does consume glucose and contributes, studies show that even after sterilizing the CSF, glucose remains low — indicating transport impairment is the dominant mechanism. Options C and D are not valid physiological mechanisms.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.