Diagnostic Workup of Seizures in the Inpatient Setting
All adult inpatients with seizures require immediate serum glucose and sodium testing, with additional workup guided by clinical presentation rather than routine comprehensive metabolic panels. 1
Immediate Initial Assessment
Vital Signs and Clinical Monitoring
- Assess airway, breathing, and circulation immediately upon presentation 2
- Monitor heart rate and rhythm, blood pressure, temperature, oxygen saturation, and hydration status 2
- Perform neurological examination to identify focal deficits and assess severity using a standardized scale like NIHSS 2
Core Laboratory Tests (All Patients)
- Serum glucose and sodium are the only universally recommended tests, as these represent the most common metabolic abnormalities causing seizures 1, 3
- Pregnancy test for all women of childbearing age, as this affects testing decisions, disposition, and antiepileptic drug selection 1, 3
- Complete blood count if infection is suspected 3
Risk-Stratified Additional Testing
Patients with Known Medical Conditions
- Extended electrolyte panel (calcium, magnesium, phosphate) for patients with:
High-Risk Clinical Presentations Requiring Expanded Workup
- Immunocompromised patients: Complete metabolic panel, head CT, and lumbar puncture after imaging 1, 3
- Fever or meningeal signs: Lumbar puncture after head CT 1, 3
- Altered mental status not returning to baseline: Complete metabolic panel and toxicology screen 1
- First-time seizure with substance use concern: Drug of abuse screen (though routine use has limited evidence) 1
Neuroimaging
CT Imaging Indications
- All older adults with new-onset seizures require head CT to evaluate for structural lesions 3
- Emergent head CT for patients with:
MRI Considerations
- MRI is the preferred imaging modality for new-onset seizures when available and when CT is negative but clinical suspicion for structural abnormality remains high 1, 3
Electroencephalography (EEG)
- EEG is essential for proper classification of epileptic seizures and syndromes, though it neither proves nor excludes seizure diagnosis 6, 7
- Enhanced or prolonged EEG should be considered for neonates, children with stroke, and adults with unexplained reduced level of consciousness 2
- EEG timing can be non-emergent in stable patients who have returned to baseline 8, 6
Anticonvulsant Drug Levels
- Check anticonvulsant levels only in patients with known seizure disorder on chronic therapy 9
- Subtherapeutic levels are the most common laboratory abnormality found in seizure patients (96 of 104 significant abnormalities in one study) 9
Critical Clinical Pitfalls to Avoid
Low-Yield Testing
- Routine comprehensive metabolic panels have extremely low yield in patients who have returned to baseline neurological status, with most abnormalities predictable by history and physical examination 1, 9
- One prospective study found only 1 unexpected case of hypoglycemia in 163 patients when clinical examination was used to guide testing 1, 9
Diagnostic Errors
- Do not assume alcohol withdrawal as the cause of first-time seizures without excluding other etiologies 1, 3
- Do not overlook subtle focal features that may indicate structural brain abnormalities 5
- Do not confuse seizure-like events (syncope, psychogenic non-epileptic seizures) with true epileptic seizures 5
Seizure Management Considerations
Acute Treatment
- Treat active seizures with short-acting medications (e.g., lorazepam IV) if not self-limited 2
- Do not initiate long-term anticonvulsants for a single, self-limiting seizure occurring at onset or within 24 hours of acute stroke 2
- Monitor for recurrent seizure activity during routine vital sign checks 2
Prophylaxis
- Prophylactic anticonvulsants are not recommended in acute stroke patients, as there is no supporting evidence and possible harm with negative effects on neural recovery 2