What is the appropriate management for an adult patient presenting with a febrile seizure?

Febrile Seizures in Adults: A Critical Clarification

Febrile seizures do not occur in adults—this is a pediatric condition by definition, occurring only in children aged 6 months to 5 years. 1, 2, 3 If an adult presents with a seizure accompanied by fever, this represents an entirely different clinical entity requiring urgent evaluation for serious underlying pathology, particularly central nervous system infection.

Understanding the Terminology Error

The term "febrile seizure" is strictly defined as a seizure occurring with fever in children between 6 months and 60 months of age, without CNS infection or other identifiable acute cause. 2, 3 This is not simply a descriptive term for "seizure with fever"—it represents a specific benign pediatric syndrome with distinct pathophysiology involving cytokine-mediated neuronal hyperexcitability. 4

What You're Actually Dealing With: Adult Seizure with Fever

When an adult presents with seizure and fever, this is classified as a provoked (acute symptomatic) seizure requiring immediate investigation for life-threatening causes. 5

Critical Immediate Actions

Patients with altered mental status, fever, or new focal neurologic deficit require extensive evaluation. 5

• Strongly consider CNS infection (meningitis/encephalitis) as the primary concern—this is a medical emergency with significant mortality if untreated 5, 6, 7
• Perform lumbar puncture unless contraindicated by signs of increased intracranial pressure 5
• Obtain emergent neuroimaging (CT head) to rule out mass lesion, abscess, or hemorrhage before LP if focal deficits present 7
• Check immediate bedside glucose—hypoglycemia is readily correctable and can present with seizure 5, 6

Essential Laboratory Workup

The history and physical examination predict most metabolic abnormalities, but not all cases. 5

• Comprehensive metabolic panel: Hyponatremia is the most common electrolyte cause of seizures 6, 8
• Serum calcium and magnesium: Hypocalcemia can trigger seizures at any age, even without prior history 6, 8
• Renal function: Uremia causes seizures in renal failure patients 7, 8
• Toxicology screen: Cocaine, tricyclic antidepressants, and other toxic ingestions can cause seizures 7
• Blood cultures: If sepsis or bacteremia suspected 5

Seizure Management Algorithm

For active seizures not self-limiting within 5 minutes (status epilepticus):

1. First-line: Benzodiazepines at appropriate dosing 6
2. Second-line (if seizures continue): Fosphenytoin, levetiracetam, or valproic acid—all have similar efficacy (45-47% seizure cessation within 60 minutes) 6

The mortality rate for status epilepticus ranges from 5% to 22%, reaching as high as 65% in refractory cases. 5

Treatment Principles for Provoked Seizures

Identify and treat the underlying cause rather than initiating long-term antiseizure medications. 6 The seizure is a symptom of the acute illness, not a primary seizure disorder.

• Correct metabolic abnormalities (electrolytes, glucose, uremia) 6, 8
• Treat infection aggressively with appropriate antimicrobials 5
• Use short-acting antiepileptic medications (e.g., lorazepam IV) only for acute seizure control if not self-limiting 6
• Do not initiate chronic antiepileptic therapy for single provoked seizures 6

High-Risk Populations Requiring Special Attention

Immunocompromised patients (HIV, transplant recipients) have higher rates of infectious etiologies including CNS toxoplasmosis, lymphoma, and cryptococcal meningitis. 7

Patients with 22q11.2 deletion syndrome have 4-fold increased epilepsy risk and require monitoring for hypocalcemia and hypomagnesemia. 6

Common Pitfalls to Avoid

• Never dismiss adult "febrile seizure" as benign—unlike the pediatric condition, this represents serious pathology until proven otherwise 5
• Do not delay lumbar puncture in patients with fever and seizure without clear alternative explanation 5
• Avoid labeling as "alcohol withdrawal seizure" without excluding other symptomatic causes, especially in first-time seizures 5
• Do not start chronic antiepileptic drugs for provoked seizures—treat the underlying cause 6

Disposition Considerations

Patients with seizure and fever typically require hospital admission for:

• Completion of infectious workup and antimicrobial therapy 5
• Monitoring for recurrent seizures or status epilepticus 5
• Correction of metabolic abnormalities 6
• Neuroimaging if not yet obtained or if clinical deterioration occurs 7