Symptoms of Meningitis
Bacterial meningitis commonly presents with fever, headache, neck stiffness, and altered mental status in adults, though the classic triad of fever, neck stiffness, and altered mental status occurs in only 41-51% of cases—meaning you cannot rule out meningitis based on absent classic symptoms. 1, 2
Common Presenting Symptoms in Adults
The most frequent clinical features include:
- Headache: Present in 58-87% of adult cases 1, 2
- Fever (>38°C): Occurs in 77-97% of cases 1, 2
- Neck stiffness: Found in 65-83% of patients 1, 2
- Altered mental status: Reported in 30-69% of cases 1, 2
- Nausea/vomiting: Occurs in 74% of patients 1
- Petechial/purpuric rash: Identified in 20-52% of cases, with over 90% indicating meningococcal infection 1, 2
- Coma: Present in 14-16% at presentation 1
- Focal neurologic deficits: Occur in 15-34% of cases 1
Critical Diagnostic Pitfall
The classic triad (fever, neck stiffness, altered mental status) is present in only 41-51% of bacterial meningitis cases, and classic meningeal signs have extremely poor sensitivity. 1, 2 Specifically:
- Neck stiffness sensitivity: only 31% in adults 1, 2
- Kernig sign sensitivity: only 11% in adults 1, 2
- Brudzinski sign sensitivity: only 9% in adults 1, 2
Therefore, bacterial meningitis should never be ruled out solely on the absence of classic symptoms—this is a Grade A recommendation. 1, 2
Age-Specific Presentations
Neonates (≤28 days)
- Nonspecific symptoms predominate: irritability, poor feeding, respiratory distress, pale or marbled skin 2
- Fever present in only 6-39% of cases 2
- Hyper- or hypotonia may be present 2
- Seizures occur in 9-34% of cases 2
Children (beyond neonatal age)
- Fever is most common: 92-93% of cases 2
- Vomiting: 55-67% of cases 2
- Neck stiffness: 40-82% of cases 2
- Headache: 2-9% in children <1 year, 75% in children >5 years 2
- Altered mental status: 13-56% of cases 2
- Petechial rash: 61% with meningococcal disease, 9% with pneumococcal 2
Treatment Approach
Immediate empiric antibiotic therapy must be initiated as soon as blood cultures are obtained—never delay antibiotics while awaiting diagnostic confirmation, as mortality remains high in untreated bacterial meningitis. 3, 4
Empiric Antibiotic Regimen
- Ceftriaxone 2-4g IV daily provides coverage for the most common bacterial causes including meningococcal and pneumococcal meningitis 3, 5
- Administer over 30 minutes in adults, 60 minutes in neonates to reduce bilirubin encephalopathy risk 5
- For meningitis specifically, ceftriaxone is FDA-approved for infections caused by Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae 5
Additional Considerations
- CSF examination should be performed unless contraindications exist (papilledema, focal neurologic signs requiring CT first) 1, 3
- Approximately 25% of patients may present with septic shock 2
- The younger the patient, the more subtle and atypical the symptoms 2
- Therapy should continue for at least 2 days after signs and symptoms resolve, with usual duration 4-14 days (10 days minimum for Streptococcus pyogenes) 5