What labs do you check for a patient in status epilepticus?

Laboratory Tests for Status Epilepticus Patients

For patients in status epilepticus, comprehensive laboratory testing is essential to identify underlying causes, guide treatment, and prevent complications, including glucose and electrolyte abnormalities which are the most common treatable metabolic causes. 1

Essential Laboratory Tests

• Blood glucose: Hypoglycemia is one of the most common treatable causes of seizures and should be checked immediately, even before other laboratory tests 1, 2
• Serum sodium: Hyponatremia is a frequent abnormality identified in seizure patients and can both cause and result from prolonged seizure activity 1, 2
• Complete blood count: To evaluate for infection, anemia, or other hematologic abnormalities that may trigger or complicate status epilepticus 3, 4
• Basic metabolic panel: To assess electrolyte disturbances (potassium, calcium, magnesium), renal function, and acid-base status 3, 4
• Liver function tests: Particularly important for patients on antiepileptic medications or with suspected hepatic encephalopathy 2
• Toxicology screening: For suspected substance use, withdrawal, or medication overdose as potential causes 3, 4
• Antiepileptic drug levels: In patients with known epilepsy to assess for medication non-compliance or subtherapeutic levels 1, 2

Additional Tests Based on Clinical Presentation

• Arterial blood gas: For patients with respiratory compromise or suspected metabolic acidosis 1
• Pregnancy test: For women of childbearing age 4
• Lumbar puncture: Consider when infection (meningitis/encephalitis) is suspected, especially in febrile patients 4, 5
• Ammonia level: Particularly in patients with known liver disease or suspected hepatic encephalopathy 2
• Inflammatory markers (ESR, CRP): When autoimmune or inflammatory causes are suspected 5

Neurological Testing

• Emergent EEG: Consider in patients with:
  • Persistent altered consciousness despite apparent clinical seizure cessation 1
  • Suspected nonconvulsive status epilepticus 1
  • Patients receiving long-acting paralytics or in drug-induced coma 1
  • Refractory status epilepticus to guide treatment efficacy 1

Common Pitfalls to Avoid

• Delayed glucose assessment: Hypoglycemia can cause seizures and should be checked immediately 1, 2
• Overlooking alcohol withdrawal: Diagnosis of alcohol withdrawal seizure should be a diagnosis of exclusion, especially in first-time seizures 1
• Missing subtle status epilepticus: EEG may be necessary to detect ongoing electrical seizure activity despite absence of motor manifestations 1
• Incomplete toxicology screening: Many substances can lower seizure threshold or directly cause seizures 3, 4

Special Considerations

• Therapeutic drug monitoring: For patients on antiepileptic medications, levels should be checked to guide dosing adjustments 2
• Glucose control: Maintain moderate glucose control (108-144 mg/dL) rather than tight control, as hypoglycemia can trigger seizures 1
• Electrolyte replacement: Correct electrolyte abnormalities promptly but cautiously, especially sodium imbalances 1, 2

Laboratory testing in status epilepticus should be performed promptly to identify treatable causes and guide management decisions. The history and physical examination will predict many laboratory abnormalities, but comprehensive testing is warranted given the high morbidity and mortality associated with status epilepticus 1, 6.