Bacterial Meningitis: Recognizing Symptoms Across Age Groups

Bacterial meningitis is a severe and potentially life-threatening infection of the central nervous system caused by bacteria. It typically develops acutely or subacutely, affecting individuals of all ages with varying clinical presentations. While common signs such as fever, headache, and neck stiffness are widely recognized, symptom expression can differ significantly depending on the patient's age and immune status. Early detection is critical to prevent complications and improve outcomes.

Symptoms in Newborns and Infants

In neonates and young infants, bacterial meningitis often presents with non-specific and subtle symptoms that can easily be mistaken for other common illnesses. These may include excessive sleepiness, irritability, jitteriness, poor feeding, decreased muscle tone, episodes of apnea (pauses in breathing), jaundice, diarrhea, and generalized weakness. Although fever or abnormally low body temperature may occur, they are not always present, making diagnosis particularly challenging in this vulnerable population.

Seizures are reported in 15% to 34% of affected infants, and approximately 5% may develop hydrocephalus due to impaired cerebrospinal fluid drainage. Given the lack of classic meningitis signs, healthcare providers must maintain a high index of suspicion when evaluating unwell newborns.

Clinical Presentation in Children

Older infants and children tend to develop symptoms more rapidly—often within hours to a day. The hallmark signs include high fever, severe headache, drowsiness, irritability, confusion, photophobia (sensitivity to light), nausea, vomiting, neck stiffness, and back pain. These symptoms reflect the inflammation of the meninges surrounding the brain and spinal cord.

Notably, around 20% of pediatric patients experience seizures before arriving at the emergency department. Because symptoms can mimic viral infections or migraines, timely medical evaluation is essential to distinguish bacterial from less serious conditions.

Common Signs in Adults

Adults with bacterial meningitis usually exhibit the classic triad of symptoms: headache, neck stiffness, and altered mental status, often accompanied by fever. However, research indicates that only about 41% of patients display all three classic signs simultaneously. Some individuals, especially those already taking pain relievers or corticosteroids, may not exhibit neck rigidity despite having severe infection.

In addition to systemic symptoms, adults may develop focal neurological deficits such as weakness, speech difficulties, or vision changes, which suggest possible brain involvement or increased intracranial pressure.

Atypical Manifestations in Older Adults

Individuals aged 65 and older may present with atypical or muted symptoms. Classic signs like fever, headache, and nuchal rigidity are frequently absent. Instead, altered mental status—such as confusion, disorientation, or lethargy—is often the most prominent feature. This delayed or subtle presentation increases the risk of misdiagnosis and treatment delays, contributing to higher morbidity and mortality rates in elderly populations.

Additional Clinical Features and Complications

Beyond the core symptoms, certain associated findings can provide diagnostic clues. For example, patients infected with Neisseria meningitidis or Streptococcus pneumoniae may develop a characteristic rash—often petechial or purpuric—that does not blanch under pressure. This skin manifestation is a medical emergency and warrants immediate intervention.

Seizures are a notable complication across age groups, occurring in up to one-third of infants and one-fifth of children. Hydrocephalus, though less common, may develop due to obstructed CSF flow and requires neuroimaging for diagnosis. Other potential sequelae include hearing loss, cognitive impairments, and long-term neurological disability if treatment is delayed.

Importance of Early Recognition and Treatment

Given the rapid progression of bacterial meningitis, early recognition of symptoms—especially in vulnerable groups like infants and the elderly—is crucial. Clinicians should consider meningitis in any patient presenting with unexplained fever, altered mental status, or meningeal signs. Prompt lumbar puncture, blood cultures, and empiric antibiotic therapy can be lifesaving.

Public awareness and vaccination against common causative agents such as Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis play vital roles in prevention and reducing disease burden worldwide.