Do seizures cause meningitis in adults?

From the Guidelines

Seizures do not cause meningitis in adults, but rather can be a complication of meningitis itself, occurring in approximately 15% of patients with acute bacterial meningitis. This is based on the evidence from the UK Joint Specialist Societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults 1. The relationship between seizures and meningitis is more accurately described as meningitis potentially causing seizures due to the inflammation and irritation of brain tissue.

Key points to consider include:

• Meningitis is primarily caused by infections, certain medications, cancers, or autoimmune disorders, not by seizures.
• Seizures are associated with a worse outcome in patients with acute bacterial meningitis, highlighting the importance of prompt anticonvulsant treatment when seizures are suspected or proven 1.
• The management of meningitis focuses on treating the underlying cause, which might include antibiotics, antiviral medications, or other specific treatments, and controlling complications such as raised intracranial pressure and seizures.

In clinical practice, if an adult presents with both seizures and symptoms suggestive of meningitis, such as severe headache, fever, neck stiffness, sensitivity to light, or confusion, immediate medical attention is necessary to identify and treat the underlying cause appropriately. The evidence supports the notion that seizures are a symptom or complication rather than a cause of meningitis, guiding the approach to diagnosis and management 1.

From the Research

Seizures and Meningitis in Adults

• Seizures can be a complication of bacterial meningitis in adults, but the frequency of seizures causing meningitis is not directly established in the provided studies 2, 3, 4, 5, 6.
• Bacterial meningitis can cause seizures, with a reported frequency of 17% in one study 4 and 27% in another study 3.
• The occurrence of seizures in adults with bacterial meningitis is associated with severe CNS and systemic inflammation, structural CNS lesions, pneumococcal meningitis, and predisposing conditions 4.
• Seizures can be a presenting manifestation of meningitis, and patients taking antibiotics who develop a seizure require a lumbar puncture to exclude meningitis 6.
• There is no direct evidence to suggest that seizures cause meningitis in adults, but rather that meningitis can cause seizures as a complication 2, 3, 4, 5, 6.

Frequency of Seizures in Meningitis

• A study found that 121 out of 696 episodes (17%) of community-acquired bacterial meningitis were associated with seizures 4.
• Another study reported that 31 out of 117 patients (27%) with culture-proven community-acquired bacterial meningitis had seizures during hospitalization 3.
• The time interval between the onset of bacterial meningitis and the occurrence of seizures can range from 1 to 21 days, with a mean of 4 days 3.

Outcome of Seizures in Meningitis

• Patients with seizures due to bacterial meningitis have a higher mortality rate compared to those without seizures, with a reported mortality rate of 41% in one study 4.
• Seizures can also lead to long-term outcomes such as chronic epilepsy, with 2 out of 31 patients progressing to chronic epilepsy in one study 3.
• The presence of seizures is associated with a poorer outcome in patients with bacterial meningitis, with a higher frequency of focal cerebral abnormalities and structural CNS lesions 4.