New Onset Seizure in Inpatients: Diagnostic Approach and Management
For inpatients with new onset seizures, perform immediate neuroimaging with non-contrast CT (or MRI when feasible) to identify life-threatening intracranial pathology, treat active seizures with IV lorazepam if non-self-limiting, but do not initiate long-term anticonvulsants for a single self-limited seizure. 1
Immediate Stabilization and Assessment
Acute Management of Active Seizures
- Stabilize airway, breathing, and circulation first before any other intervention 1
- For active, non-self-limiting seizures, administer IV lorazepam 0.1 mg/kg (typically 4 mg for adults) given slowly at 2 mg/min 2, 3
- Equipment for airway management must be immediately available before administering benzodiazepines 2
- If seizures persist after 10-15 minutes, repeat lorazepam 4 mg IV 2
- Monitor for respiratory depression and hypotension, which are the most common adverse effects of lorazepam 2
Initial Clinical Evaluation
- Perform rapid neurological examination using a standardized scale (NIHSS) to assess stroke severity and focal deficits 1
- Monitor vital signs including heart rate/rhythm, blood pressure, temperature, oxygen saturation, and hydration status 1
- Obtain immediate blood work: electrolytes, glucose, complete blood count, coagulation studies (INR, aPTT), and creatinine 1
- Do not delay neuroimaging for laboratory results 1
Neuroimaging: Critical Decision Point
Indications for Emergent CT Imaging
Perform brain CT immediately when any of the following are present: 1
- Age >40 years
- History of acute head trauma
- Known malignancy
- Immunocompromised state (including HIV)
- Fever or persistent headache
- Anticoagulation therapy
- New focal neurological findings
- Focal seizure onset before generalization
- Altered mental status not returning to baseline
Key Imaging Findings and Their Implications
- Approximately 23% of new-onset seizure patients have acute stroke or tumor on CT 1
- In immunocompromised patients (e.g., HIV-positive), acute lesions are found in a substantial proportion, sometimes without clinical suspicion 1
- If hemorrhagic stroke is identified, management shifts entirely to hemorrhagic stroke protocols 1
Hospital Admission Criteria
High-Risk Features Requiring Admission
Admit patients with any of the following: 1
- Seizure recurrence within 24 hours (occurs in 19% overall, 9% excluding alcohol-related or focal lesions) 1
- Abnormal neuroimaging showing acute pathology
- Persistent altered mental status
- Inability to ensure reliable outpatient follow-up
- Underlying life-threatening etiology suspected
- Alcohol-related seizures requiring monitoring
Patients Who May Be Discharged
- Alert patients who have returned to baseline neurological status
- Single, self-limited seizure with normal or stable imaging
- Only when reliable outpatient follow-up is confirmed 1
Long-Term Anticonvulsant Decision: The Critical Rule
Do NOT Start Long-Term Anticonvulsants When:
A single, self-limiting seizure occurring at onset or within 24 hours of acute stroke should NOT be treated with long-term anticonvulsant medications 1, 4
Rationale: 1
- No evidence supports prophylactic anticonvulsants
- Possible harm with negative effects on neural recovery
- These "immediate" post-stroke seizures have different implications than epilepsy
DO Start Anticonvulsants When:
- Recurrent seizures occur (≥2 seizures) 1, 4
- Status epilepticus develops
- Brain tumor is identified (most patients require at least transient therapy) 1
- High risk for recurrence: prior brain insult, epileptiform EEG abnormalities, or structural lesion on imaging 5
Preferred Long-Term Agent Selection
Levetiracetam is the first-choice agent for most inpatients because: 1, 6
- No drug interactions with steroids or chemotherapy agents
- Can be administered IV when oral route unavailable 6
- Fewer cardiac and respiratory complications than phenytoin
- Caution: Psychiatric side effects can occur 1
Alternative agents: 1
- Valproic acid: effective but contraindicated in women of childbearing potential; requires monitoring for drug interactions
- Avoid phenytoin, phenobarbital, carbamazepine as first-line due to side effects and drug interactions 1
Special Considerations for Stroke-Related Seizures
Monitoring Requirements
- Monitor for seizure recurrence during routine vital sign checks 1, 4
- Consider EEG monitoring in patients with unexplained reduced consciousness, as nonconvulsive seizures occur in up to 28% of ICH patients 1, 4
- Temperature monitoring is critical—fever worsens outcomes and may indicate infection 1, 4
Blood Pressure Management
- Avoid aggressive blood pressure lowering in watershed territory ischemia to maintain cerebral perfusion 4
- Balance seizure control with maintaining adequate cerebral perfusion pressure
Refractory or Recurrent Seizures
Second-Line Treatment
If seizures recur despite initial lorazepam: 7, 8, 9
- Levetiracetam 20 mg/kg IV over 15 minutes is equally effective as lorazepam and may be preferred in patients with respiratory compromise or hypotension 7
- Fosphenytoin remains an option but has higher risk of cardiac arrhythmias and hypotension 8
- Valproic acid IV is another alternative 8, 9
Status Epilepticus Protocol
If seizures continue >5 minutes or recur without recovery: 9, 3
- This constitutes status epilepticus requiring aggressive management
- Lorazepam remains first-line (64.9% success rate) 3
- Phenobarbital is second-line (58.2% success rate) 3
- Ensure ICU-level monitoring with ventilatory support available 2, 9
Common Pitfalls to Avoid
Do not delay imaging for seizure activity—imaging identifies life-threatening pathology in nearly 1 in 4 patients 1
Do not start prophylactic anticonvulsants for single seizures—this may harm neural recovery without proven benefit 1, 4
Do not use phenytoin as first-line—cardiac toxicity and tissue injury make fosphenytoin or levetiracetam preferable 1, 8
Do not assume seizure cessation means adequate treatment—19% recur within 24 hours, requiring continued monitoring 1
Do not overlook correctable causes—hypoglycemia, hyponatremia, and other metabolic derangements must be identified and corrected immediately 2