What is the appropriate diagnosis and treatment for a patient presenting with meningeal inflammation, back pain, and subsequent flulike symptoms, suggestive of meningitis?

Acute Bacterial Meningitis: Immediate Diagnosis and Treatment

This patient presenting with meningeal inflammation, back pain, and flu-like symptoms requires immediate empirical antibiotic therapy for suspected acute bacterial meningitis within 1 hour of presentation, as delay in treatment is strongly associated with increased mortality and poor neurological outcomes. 1, 2

Immediate Actions (Within First Hour)

Stabilization and Assessment

• Stabilize airway, breathing, and circulation immediately as the highest priority 3
• Document Glasgow Coma Scale (GCS) score for prognostic value and monitoring 1, 3
• Obtain blood cultures within 1 hour of arrival, before antibiotics if possible 1, 2
• Assess for signs of severe sepsis or shock: rapidly evolving rash, limb ischemia, cardiovascular instability, delayed capillary refill, cold/dusky extremities 3

Critical Care Decision

• Involve intensive care teams immediately if the patient has: 3
  • Rapidly evolving rash
  • GCS ≤12
  • Cardiovascular instability or severe sepsis
  • Uncontrolled seizures
  • Respiratory compromise
• Consider intubation for GCS <12 3

Diagnostic Approach

Lumbar Puncture Timing

Perform lumbar puncture within 1 hour of arrival ONLY if no contraindications exist. 1 If LP cannot be performed within 1 hour, commence antibiotics immediately after blood cultures and perform LP as soon as possible thereafter. 1

Contraindications to Immediate LP (Require CT First)

• Focal neurological signs 1
• Presence of papilledema 1
• Continuous or uncontrolled seizures 1
• GCS ≤12 1
• History of CNS disease (mass lesion, stroke, focal infection) 2
• Age ≥60 years 2
• Immunocompromise 2

Critical Point: If CT is indicated, administer antibiotics FIRST, then obtain CT, then perform LP only if no mass effect or elevated intracranial pressure is present. 2 Never delay antibiotics for imaging. 2

Empirical Antibiotic Therapy

Standard Adult Regimen (Age <60 years, Immunocompetent)

Administer immediately within 1 hour of presentation: 2, 3

• Ceftriaxone 2g IV every 12 hours 2, 3, 4
  • OR Cefotaxime 2g IV every 6 hours 3
• PLUS Vancomycin 15-20 mg/kg IV every 8-12 hours 2, 3
  • Essential in areas with penicillin-resistant Streptococcus pneumoniae (>1% prevalence) 2, 5

Modified Regimen for High-Risk Patients (Age ≥60 or Immunocompromised)

Add Listeria coverage: 2, 3

• Amoxicillin 2g IV every 4 hours in addition to ceftriaxone and vancomycin 2, 3
• Risk factors for Listeria monocytogenes include: age >50 years, diabetes mellitus, immunosuppressive drugs, cancer, other immunocompromising conditions 2

Rationale for Empirical Coverage

• Streptococcus pneumoniae causes approximately 72% of bacterial meningitis in adults 5
• Neisseria meningitidis causes approximately 11% of cases 5
• Ceftriaxone provides excellent CSF penetration and covers both organisms 4, 6
• Vancomycin is essential for resistant pneumococcal strains 2, 5

Adjunctive Dexamethasone Therapy

Administer dexamethasone 10mg IV every 6 hours immediately before or simultaneously with the first antibiotic dose. 2, 3 This reduces mortality and neurological morbidity in pneumococcal meningitis. 2 Continue for 4 days if pneumococcal meningitis is confirmed or probable. 3

Important caveat: Stop dexamethasone if Listeria monocytogenes is confirmed, as it may worsen outcomes in listeria meningitis. 5

Infection Control Measures

Implement respiratory isolation immediately until meningococcal disease is excluded or the patient receives 24 hours of ceftriaxone. 3, 7 Use droplet precautions and surgical masks for close contact with respiratory secretions. 3, 7

Common Pitfalls to Avoid

Critical Errors That Increase Mortality

• Delaying antibiotics for imaging or LP in patients with severe sepsis, shock, or rapidly evolving rash 2, 3
  • Even a 1-hour delay is associated with increased mortality 2
• Forgetting Listeria coverage in patients ≥60 years or immunocompromised 2, 3
  • Listeria is not covered by ceftriaxone alone 2
• Inadequate dosing that fails to achieve adequate CSF penetration 2
• Not obtaining blood cultures before starting antibiotics 1, 2
  • However, never delay antibiotics beyond 1 hour to obtain cultures 2

Fluid Resuscitation in Septic Patients

If the patient presents with predominantly sepsis or rapidly evolving rash: 1

• Give antibiotics immediately after blood cultures 1
• Commence fluid resuscitation with initial bolus of 500ml crystalloid 1
• Follow Surviving Sepsis guidelines 1
• Target mean arterial pressure ≥65 mmHg 3
• Use norepinephrine as first-line vasopressor if needed 3
• Do NOT perform LP at this time 1

Expected CSF Findings in Bacterial Meningitis

Bacterial meningitis typically shows: 2

• Elevated WBC (>2000/μL) 5
• Decreased glucose (<34.23 mg/dL or CSF:serum glucose ratio <0.4) 2, 5
• Elevated protein (>2.2 g/L) 5
• Neutrophilic or lymphocytic predominance 2

The presence of hypoglycorrhachia (low CSF glucose) is a critical distinguishing feature that mandates treating for bacterial meningitis first, as this finding strongly suggests bacterial etiology. 2

Duration of Therapy (Once Pathogen Identified)

Pathogen-Specific Treatment

• Streptococcus pneumoniae: Continue ceftriaxone 2g IV every 12 hours for 10-14 days 3, 6
• Neisseria meningitidis: Continue ceftriaxone 2g IV every 12 hours for 5 days 3, 6
  • Give single dose ciprofloxacin 500mg PO for eradication 3
• Listeria monocytogenes: Amoxicillin 2g IV every 4 hours for 21 days 3

General Duration

Generally, continue therapy for at least 2 days after signs and symptoms of infection have disappeared, with usual duration of 4-14 days depending on organism and clinical response. 4 In complicated infections, longer therapy may be required. 4

Monitoring for Complications

Half of adults with bacterial meningitis develop focal neurologic deficits during their clinical course, and one-third develop hemodynamic or respiratory insufficiency. 1 Monitor closely for:

• Cerebrovascular complications (cerebral infarctions, hemorrhage, venous sinus thrombosis) 1
• Hydrocephalus requiring external ventricular drain 1
• Seizures 1
• Hearing loss (occurs in 5-35% of patients) 1

Perform cranial imaging (MRI preferred over CT for superior resolution) if neurologic deterioration occurs. 1