What is the initial workup and treatment for a patient presenting with a seizure?

Initial Workup and Treatment for Seizure Presentation

For patients presenting with a first-time seizure, perform neuroimaging in the ED when feasible, obtain serum glucose and sodium levels, and discharge patients who have returned to baseline with reliable outpatient follow-up rather than routinely admitting or starting antiepileptic drugs. 1

Immediate Stabilization and Assessment

Time the seizure duration immediately - status epilepticus is defined as seizure lasting >5 minutes or multiple seizures without return to baseline, requiring emergent benzodiazepine administration. 2

Keep the patient NPO until swallowing ability is formally assessed to prevent aspiration, as seizures can temporarily impair swallowing function. 3, 2

Laboratory Workup

The laboratory evaluation should be targeted rather than routine:

• Obtain serum glucose and sodium levels - these are the most frequent metabolic abnormalities identified in new-onset seizures and directly guide management. 1

• Obtain pregnancy test if the patient has reached menarche, as this fundamentally changes management decisions. 1

• Consider toxicology screening only if there is clinical suspicion of drug exposure or substance abuse based on history or examination findings. 1

• Additional laboratory tests (CBC, comprehensive metabolic panel, calcium) should be obtained only when suggested by specific clinical findings such as vomiting, diarrhea, dehydration, or fever - not routinely. 1, 4

The evidence shows that while 23% of patients have abnormal physical examinations and various percentages have laboratory abnormalities, only glucose and sodium abnormalities consistently alter acute management. 4

Neuroimaging Strategy

Perform CT head without contrast emergently when any of these high-risk features are present: 4, 1

• New focal neurological deficits
• Persistent altered mental status
• Fever
• Recent head trauma
• Persistent headache
• History of malignancy or immunocompromised state
• Anticoagulation use
• Age >40 years
• Partial-onset (focal) seizure before generalization

MRI is the preferred imaging modality for non-emergent evaluation when the patient has returned to baseline, as it provides superior detection of structural abnormalities. 1

Deferred outpatient neuroimaging is acceptable for patients who have returned to baseline, have normal neurologic examination, and have reliable follow-up arrangements. 4

The evidence demonstrates that 41% of first-time seizure patients have abnormal CT findings, and 22% with normal neurologic examinations still have abnormal imaging, but immediate ED imaging primarily impacts disposition rather than mortality. 4

Lumbar Puncture Indications

Perform lumbar puncture only when there is specific concern for: 1

• Meningitis or encephalitis (fever, persistent altered mental status, meningeal signs)
• Immunocompromised patients (after CT to rule out mass effect)

Routine lumbar puncture is not indicated for uncomplicated first-time seizures. 4

EEG Timing

EEG should be obtained as part of the neurodiagnostic evaluation but does not need to be performed emergently in the ED. 1 Abnormal EEG findings predict increased seizure recurrence risk but do not change acute ED management. 1

Disposition Decisions

Emergency physicians need not admit patients with a first unprovoked seizure who have returned to their clinical baseline in the ED. 1

Consider admission only if any of the following persist: 1

• Abnormal neurologic examination
• Abnormal investigation results requiring inpatient management
• Patient has not returned to baseline

The recurrence risk data shows that 19% of patients have seizure recurrence within 24 hours, decreasing to 9% when alcohol-related events and focal CT lesions are excluded. 4 However, the mean time to first recurrence is 121 minutes (median 90 minutes) with 85% occurring within 6 hours. 1, 3

Antiepileptic Drug Initiation

Do not routinely initiate antiepileptic drugs in the ED for patients with a first unprovoked seizure who have returned to baseline. 2

The evidence demonstrates that antiepileptic drug treatment reduces 1-2 year recurrence risk but does not affect long-term recurrence rates or remission rates. 4 Starting treatment for a single seizure exposes patients to medication adverse effects without proven mortality or morbidity benefit.

For status epilepticus or ongoing seizures, the treatment algorithm is: 2

1. First-line: Benzodiazepines (lorazepam or diazepam)
2. Second-line: Phenytoin/fosphenytoin, valproate, or levetiracetam
3. Refractory: Consider propofol or barbiturates

Valproate (30 mg/kg) is as effective as phenytoin with potentially fewer adverse effects like hypotension. 1

Common Pitfalls to Avoid

• Failing to identify hypoglycemia or hyponatremia - these reversible causes must be checked and corrected immediately. 1

• Allowing oral intake before swallowing assessment - this can lead to aspiration pneumonia, particularly after multiple seizures. 3

• Missing structural lesions by omitting neuroimaging in high-risk patients (age >40, focal features, trauma, immunocompromised). 1

• Delaying benzodiazepines in status epilepticus - treatment should begin immediately when seizure duration exceeds 5 minutes. 2

• Routinely admitting or starting antiepileptic drugs for uncomplicated first seizures - this exposes patients to unnecessary hospitalization costs and medication side effects without proven benefit. 1, 2