A 22-year-old male presents to the emergency department with a 2-day history of fever (39.5°C), severe headache, neck stiffness, and photophobia. On examination, he has a petechial rash on the trunk and lower extremities. Blood culture and CSF analysis are pending. Gram stain of CSF shows gram-negative diplococci. Which of the following is the most appropriate initial antibiotic therapy?

Question

Accepted Answer

B. Ceftriaxone 2 g IV 12-hourly plus vancomycin 15–20 mg/kg IV 8–12-hourly. ## Clinical Diagnosis

This patient presents with classic meningococcal meningitis: fever, neck stiffness, photophobia, petechial rash, and gram-negative diplococci on CSF Gram stain.

**Key Point:** Neisseria meningitidis is the most common cause of bacterial meningitis in young adults and adolescents.

## Antibiotic Selection

**High-Yield:** The standard empiric therapy for meningococcal meningitis is **ceftriaxone (or cefotaxime) plus vancomycin**. This combination is used because:

1. **Ceftriaxone** achieves excellent CSF penetration and covers N. meningitidis, S. pneumoniae, and gram-negative organisms.
2. **Vancomycin** is added empirically to cover penicillin-resistant S. pneumoniae and provides additional coverage until susceptibilities are known.

**Clinical Pearl:** Once N. meningitidis susceptibility is confirmed (usually penicillin-susceptible), vancomycin can be discontinued and ceftriaxone continued as monotherapy. However, initial empiric dual therapy is the standard of care because meningitis is a medical emergency and S. pneumoniae must be covered until ruled out.

**Mnemonic:** **VCCM** — Vancomycin + Cephalosporin (3rd generation) + Corticosteroids (dexamethasone) + Meningitis.

## Why Ceftriaxone + Vancomycin?

| Feature | Ceftriaxone | Vancomycin |
|---------|-------------|----------|
| CSF penetration | Excellent (10–20% of serum) | Moderate (15–30% of serum) |
| N. meningitidis coverage | Yes | Yes |
| S. pneumoniae coverage (including resistant strains) | Yes (if susceptible) | Yes (always) |
| Gram-negative coverage | Yes | No |

**Clinical Pearl:** Dexamethasone (10 mg IV) should be given concurrently or just before the first antibiotic dose to reduce inflammation and improve outcomes, particularly in pneumococcal meningitis.

Answer

A. Fluoroquinolone (levofloxacin) 500 mg IV 12-hourly alone

Answer

C. Chloramphenicol 1 g IV 6-hourly alone

Answer

D. Penicillin G 4 million units IV 4-hourly alone

Explanation

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