Epilepsy
- Investigation

Laboratory tests

Patient should have a wide anion gap metabolic acidosis (lactic acid) following a major seizure, which should correct spontaenously within 1 hour.

Routine tests:

• Glucose level
• FBC (seizure can induce brief increase in WBC)
• U&E, creatinine, Ca2+, Mg2+
• Pregnancy test
• Toxicology screen
• Anticonvulsant drug level
• Prolactin
     * May be elevated briefly (15min to 60min)
     * Normal prolactin does not exclude seizure

Radiographic studies

CT scan of the head

Immediately if:

• New focal deficit
• Persistent altered mental status
• Recent head trauma
• Fever
• Anticoagulation therapy
• Known or suspected HIV-positive
• History of cancer
• Persistent or severe headache
• Change in seizure pattern

Xray of the chest if cancer is suspected

Xray of the cervical spine if there has been head trauma.

 

Electroencephalography (EEG)

In emergency, can be used in patient with persistent, unexplained, altered mental status to rule out nonconvulsive status epilepticus

Also distinguishes generalised from focal seizures

 

Absence seizure's characteristic EEG finding

   -> 3 Hz spike wave activity