What are the signs and symptoms of meningitis?

Signs and Symptoms of Meningitis

The classic triad of fever, neck stiffness, and altered mental status is present in less than 50% of bacterial meningitis cases, so clinicians must maintain a high index of suspicion even when these cardinal features are absent. 1, 2

Core Clinical Features in Adults

The most common presenting symptoms in adults include:

• Headache occurs in 58-87% of cases 2
• Fever is present in 77-97% of cases 2
• Neck stiffness appears in 65-83% of cases 2
• Altered mental status is reported in 30-69% of cases 2
• Vomiting is a frequent accompanying symptom 1

The absence of two or more signs among fever, headache, neck stiffness, and altered mental status effectively rules out meningitis with a 95% negative predictive value. 3

Age-Specific Presentations

Neonates and Infants

• Present with nonspecific symptoms including irritability, poor feeding, respiratory distress, pale or marbled skin, and abnormal muscle tone 2
• Fever is present in only 6-39% of neonatal cases 2
• Seizures occur in 9-34% of cases, more commonly with Group B streptococcal infection 2

Children Beyond Infancy

• Fever is the most common symptom (92-93% of cases) 2
• Headache increases with age: 2-9% in children under 1 year versus 75% in children over 5 years 2
• Vomiting occurs in 55-67% of cases 2
• Neck stiffness is present in 40-82% of cases 2

Elderly Patients

• More likely to have altered consciousness than younger patients 1
• Less likely to have neck stiffness or fever 1
• May present with only irritability or lethargy 4

Rash Characteristics

• Petechial or purpuric rash is present in 20-52% of adult patients 2
• When rash is present with meningitis, the causative organism is Neisseria meningitidis in 92% of cases (petechial in 89%) 1
• However, 37% of meningococcal meningitis patients have no rash 1
• Rash can also occur in pneumococcal meningitis (9% of cases) 2

Meningococcal Sepsis-Specific Features

Beyond meningitis signs, patients with meningococcal sepsis may present with:

• Hypotension and shock (occurs in 10-20% of meningococcal disease cases) 1
• Cold peripheries and prolonged capillary refill time due to peripheral vasoconstriction 1
• Oliguria from reduced renal perfusion 1
• Rapid deterioration even if initially appearing well 1

Critical Diagnostic Pitfalls

Poor Sensitivity of Classic Signs

Kernig's and Brudzinski's signs are not helpful for diagnosis due to extremely poor sensitivity despite high specificity:

• Kernig sign: 53% sensitivity in children, only 11% in adults 2
• Brudzinski sign: 66% sensitivity in children, only 9% in adults 2
• Neck stiffness: 51% sensitivity in children, 31% in adults 2

Clinical Diagnosis Limitations

• Individual symptoms like fever, vomiting, headache, and neck stiffness are poor discriminators when considered independently 1
• Clinical signs alone have poor diagnostic accuracy for bacterial meningitis 2
• The absence of classic symptoms cannot rule out bacterial meningitis 2, 5

Additional Diagnostic Clues

Important historical factors to ascertain:

• Travel history 1
• Source of infection such as otitis media or sinusitis 1
• Contact with another person with meningitis or sepsis 1
• Immunosuppression (corticosteroids, chemotherapy, HIV/AIDS) suggests unusual pathogens 4
• Recent head trauma or neurosurgery 6

Subacute Presentations

For tuberculous meningitis specifically:

• Subacute course over weeks (typically >3 weeks) strongly favors TB over acute bacterial causes 7
• Clinical history of more than 5 days is independently predictive of TB meningitis with 93% sensitivity 7

Key Clinical Principle

Concern from either the referring physician or a family member should always be taken seriously, given the variable and often atypical presentations. 1 Urgent hospital referral is mandatory when meningitis is suspected due to the possibility of rapid deterioration and high mortality if treatment is delayed. 1, 8