What are the most predictive symptoms for meningitis?

Most Predictive Symptoms for Meningitis

The most common clinical characteristics of bacterial meningitis are fever, headache, neck stiffness, and altered mental status, though no single symptom is present in all patients and classic signs may be absent in many cases. 1, 2

Adult Presentation

• Fever is the most consistent symptom, present in 77-97% of adult cases 1, 2
• Headache is reported in 58-87% of adults with bacterial meningitis 1, 2
• Neck stiffness occurs in 65-83% of adult cases 1, 2
• Altered mental status is present in 30-69% of adult patients 1, 2
• Nausea/vomiting is reported in 45-74% of cases 1
• A petechial rash is identified in 20-52% of patients and is highly indicative of meningococcal infection (>90% of cases with rash) 1, 2
• Focal neurologic deficits occur in 15-34% of adult cases 1
• The classic triad of fever, neck stiffness, and altered mental status is present in only 41-51% of adult cases 1, 2, 3, 4

Pediatric Presentation

• Fever is the most common symptom in children beyond neonatal age (92-93% of cases) 1, 2
• Headache prevalence varies by age: reported in only 2-9% of children up to 1 year of age but in 75% of children older than 5 years 1, 2
• Vomiting occurs in 55-67% of pediatric cases 1, 2
• Neck stiffness is present in 40-82% of pediatric cases 1, 2
• Altered mental status is reported in 13-56% of pediatric cases 1, 2
• Seizures have been reported at hospital admission in 10-56% of children 1
• Petechial and purpuric rash is usually associated with meningococcal disease (61% of cases) but can also occur in pneumococcal meningitis (9% of cases) 1, 2

Neonatal Presentation

• Neonates typically present with nonspecific symptoms rather than classic meningeal signs 1, 2, 3
• Common symptoms include irritability, poor feeding, respiratory distress, pale or marble skin, and hyper- or hypotonia 2
• Fever is present in only a minority (6-39%) of neonatal cases 2
• Seizures occur in 9-34% of neonatal cases, more commonly with Group B streptococcal meningitis 2

Diagnostic Value of Clinical Signs

• Clinical signs alone have poor diagnostic accuracy for bacterial meningitis 1, 2
• Sensitivity of neck stiffness is only 51% in children and 31% in adults 1, 2
• Kernig sign has a sensitivity of 53% in children and 11% in adults 1, 2
• Brudzinski sign has a sensitivity of 66% in children and 9% in adults 1, 2
• Jolt accentuation (worsening of headache with horizontal head rotation) may be present 3
• Resistance to passive flexion of the neck is the most commonly observed meningeal sign 3

Clinical Pitfalls

• Absence of classic symptoms cannot be used to rule out bacterial meningitis 1, 2
• The younger the patient, the more subtle and atypical the symptoms 1, 2
• Immunocompromised patients may not display typical meningeal signs 3
• Elderly patients may present with only irritability, lethargy, and fever, without other common symptoms 5
• Antibiotic treatment before admission (occurring in up to 48.4% of patients in some studies) may alter the clinical presentation 6
• Factors associated with higher mortality include: advanced age, longer duration of symptoms before admission, absence of neck stiffness, altered mental status on admission, and low CSF glucose levels 6

Diagnostic Approach

• Cerebrospinal fluid examination remains essential for diagnosis when bacterial meningitis is suspected 1, 2, 3
• If bacterial meningitis is suspected and lumbar puncture is delayed, appropriate empirical antibiotic therapy should be started after blood cultures are obtained 3
• No published diagnostic algorithm has 100% sensitivity for bacterial meningitis 1