What laboratory tests and initial management are recommended for a patient presenting with a seizure?

Laboratory Tests and Initial Management for Seizure Patients

For patients presenting with a seizure, essential laboratory tests include serum glucose, sodium, complete blood count, coagulation status (INR, aPTT), and creatinine, along with immediate neuroimaging with non-contrast CT or MRI to rule out structural causes. 1

Initial Assessment and Stabilization

• Rapid assessment of airway, breathing, and circulation 1
• Neurological examination to determine focal deficits and assess seizure severity using a standardized scale (e.g., NIHSS) 1
• Vital signs monitoring: heart rate and rhythm, blood pressure, temperature, oxygen saturation, hydration status 1
• Seizure activity assessment: duration, type, and post-ictal state 1

Laboratory Investigations

Essential Tests for All Patients:

• Serum glucose 1, 2
• Serum sodium 1, 2
• Complete blood count 1
• Coagulation status (INR, aPTT) 1
• Creatinine 1
• Pregnancy test for women of childbearing age 1, 2

Additional Tests Based on Clinical Presentation:

• Complete metabolic panel for altered mental status 2
• Toxicology screen if substance use is suspected 1, 2
• Blood cultures if fever is present 2
• Antiepileptic drug levels in patients on seizure medications 2
• CK levels after generalized tonic-clonic seizures 2
• Troponin levels in older patients with generalized seizures 2

Neuroimaging

• All patients with suspected acute stroke or seizure should undergo immediate brain imaging with non-contrast CT (NCCT) or MRI 1
• Emergent neuroimaging indications:
  • Focal neurologic deficit
  • Persistent altered mental status
  • History of trauma
  • History of malignancy
  • Immunocompromised state
  • Fever
  • Persistent headache
  • Age over 40 years
  • Focal onset seizure 1

Lumbar Puncture

• Perform lumbar puncture (after neuroimaging) if:
  • Patient is immunocompromised 1
  • Clinical signs of meningitis are present 2
  • Fever is present with no clear source 2
  • Patient is unduly drowsy, irritable, or systemically ill 2

Seizure Management

• New-onset seizures that are self-limited (lasting <5 minutes) typically do not require emergency medication 2

• For ongoing seizures (>5 minutes) or status epilepticus:

  • Administer benzodiazepines (e.g., lorazepam IV) if seizures are not self-limited 1
  • Consider levetiracetam loading dose (1500 mg orally or up to 60 mg/kg IV) for patients with subtherapeutic levels 2

• Do not administer prophylactic anticonvulsants in patients with acute seizure 1

• Single, self-limiting seizures occurring at onset or within 24 hours of stroke should not be treated with long-term anticonvulsant medications 1

Disposition Considerations

Discharge Criteria:

• Return to baseline mental status
• Single self-limited seizure with no recurrence
• Normal or non-acute findings on neuroimaging
• Reliable follow-up available
• Responsible adult to observe the patient 2

Admission Criteria:

• Status epilepticus or recurrent seizures
• Persistent altered mental status
• Acute symptomatic seizure
• Significant abnormality on neuroimaging requiring urgent intervention
• Inability to complete outpatient workup 2

Common Pitfalls to Avoid

1. Delaying neuroimaging or treatment for laboratory results - these should not delay imaging or treatment decisions 1

2. Routine use of extensive laboratory testing without clinical indication - studies show that clinical examination can accurately predict the need for most laboratory studies 3

3. Prophylactic use of anticonvulsants - not recommended in patients with acute stroke and may have negative effects on neural recovery 1

4. Missing non-epileptic causes of seizures - factors that may provoke seizures include organ failure, electrolyte imbalance, medication effects, and hypertensive encephalopathy 4

5. Failure to monitor for recurrent seizures - patients should be monitored for recurrent seizure activity during routine monitoring of vital signs and neurological status 1