A 19-year-old man with bacterial meningitis presents with fever (39.2°C), headache, and neck stiffness. Vital signs show BP 118/76, HR 104, RR 18, SpO2 98% on room air. He receives ceftriaxone 2 g IV every 12 hours. CSF analysis demonstrates adequate antibiotic penetration with ceftriaxone levels of 4.2 mcg/mL. However, head CT imaging reveals purulent meningitis with persistent inflammation. Blood cultures remain negative. Which mechanism best explains inadequate bacterial eradication in the CNS despite adequate drug delivery?
- A)Ceftriaxone is inactivated by bacterial beta-lactamases in the CSF
- B)Ceftriaxone achieves only 10-20% CSF levels relative to serum, insufficient bactericidal activityGABARITO
- C)The patient's immune system is destroying ceftriaxone in the CNS
- D)The blood-brain barrier actively pumps ceftriaxone back into serum
- E)Meningitis-causing bacteria are inherently resistant to all third-generation cephalosporins
Explicação
Even with meningitis and blood-brain barrier inflammation increasing penetration, cephalosporins achieve only 10-20% of serum concentrations in CSF. This subtherapeutic CSF concentration may be insufficient for bacterial eradication. Higher IV dosing (e.g., 2 ... Ver explicação completa e trilha adaptativa →