Which laboratory tests are commonly ordered after a seizure to assess metabolic causes?

• A. Complete blood count, lipid panel, thyroid function.
• B. Serum glucose, electrolytes (sodium, potassium, calcium, magnesium), renal and liver function, toxicology screen, and pregnancy test if applicable.
• C. CT head and MRI.
• D. Urinalysis only.

Answer: (B)

After a seizure, the first priority is to look for metabolic factors that could provoke or worsen the event and affect treatment. A focused metabolic panel does this efficiently: measuring serum glucose to catch hypo- or hyperglycemia, and checking electrolytes such as sodium, potassium, calcium, and magnesium to identify imbalances like hyponatremia, hypernatremia, hypocalcemia, or hypomagnesemia that can trigger seizures or interfere with recovery. Assessing renal and liver function helps reveal issues that could alter toxin clearance, acid-base balance, or overall brain homeostasis, which are important for both diagnosis and management.

Including a toxicology screen is important because exposure to certain substances or drug interactions can cause seizures, altered consciousness, or mimic seizure activity. For women of reproductive age, a pregnancy test is essential because pregnancy-related seizures due to conditions like preeclampsia/eclampsia require specific management and have safety implications for both patient and fetus.

Imaging tests and other labs have valuable roles, but they address different aspects—structural brain pathology or broader health screening—rather than the immediate metabolic contributors to seizures.