A 28-year-old man from Delhi presents to the emergency department with a 2-day history of high-grade fever (39.5°C), severe frontal headache, and neck stiffness. On examination, he is alert but irritable, with positive Kernig's and Brudzinski's signs. Blood pressure is 110/70 mmHg, heart rate 110/min. A lumbar puncture is performed: CSF is turbid, protein 180 mg/dL, glucose 35 mg/dL (serum glucose 95 mg/dL), WBC count 450/μL (90% neutrophils). Gram stain shows gram-negative diplococci. Blood and CSF cultures are pending. Which is the most appropriate empiric antibiotic regimen for this patient?

Question

Accepted Answer

D. Ceftriaxone 2 g IV 12-hourly + Vancomycin 15–20 mg/kg IV 8–12-hourly. ## Clinical Diagnosis

**Key Point:** The CSF profile (low glucose, high protein, neutrophil predominance) and gram-negative diplococci on Gram stain are pathognomonic for *Neisseria meningitidis* (meningococcal meningitis).

## Empiric Antibiotic Regimen

**High-Yield:** In bacterial meningitis, empiric therapy must cover:
- *Streptococcus pneumoniae* (most common in adults)
- *Neisseria meningitidis* (second most common)
- *Listeria monocytogenes* (in immunocompromised, age >50, or neonates)

The **gold standard empiric regimen** is:

| Drug | Dose | Rationale |
| --- | --- | --- |
| **Ceftriaxone** | 2 g IV 12-hourly (4 g/day total) | Excellent CSF penetration; covers pneumococci and meningococci |
| **Vancomycin** | 15–20 mg/kg IV 8–12-hourly | Added for penicillin-resistant *S. pneumoniae*; synergistic with cephalosporin |

**Clinical Pearl:** Vancomycin is added empirically in all meningitis cases until susceptibilities are known, because penicillin-resistant pneumococcal meningitis carries high mortality if vancomycin is delayed.

**Mnemonic: "CVL for Meningitis"** — **C**eftriaxone, **V**ancomycin, **L**isteria coverage (ampicillin if age >50 or immunocompromised).

## Why This Patient Fits the Regimen

Although Gram stain shows gram-negative diplococci (suggesting meningococcal meningitis), empiric therapy must still include vancomycin and cephalosporin because:
1. Cultures take 24–48 hours; clinical diagnosis is not 100% certain.
2. Co-infection or misidentification on Gram stain can occur.
3. Meningococcal meningitis itself has improved outcomes with cephalosporin + vancomycin.

[cite:Harrison 21e Ch 383]

Answer

A. Penicillin G 2 million units IV 4-hourly + Gentamicin 5 mg/kg IV daily

Answer

B. Ampicillin 2 g IV 4-hourly + Gentamicin 5 mg/kg IV daily

Answer

C. Chloramphenicol 1 g IV 6-hourly alone

Explanation

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