Seizures are known to produce many transient physiologic changes, such as apnea and subsequent hypoxia, fever, or hyperglycemia. The patient may also become hypertensive. The physical exam should be focused and attempt to identify these changes when possible. If the patient is actively seizing, the physician should know the type of seizure, presence of posturing, eye deviation, or other signs of focal deficits.

To distinguish a true seizure from a seizure mimic, note the following characteristics:

• Suggestive of seizure: Slow return of baseline mental status, available witnesses able to confirm shaking activity, bowel/bladder incontinence.
• Suggestive of syncope: Rapid return to baseline mental status, EKG with evidence of dysrhythmia or long QT syndrome.

Lab Tests

In general, studies have shown a low yield (only abnormal in approximately 15% of patients) for extensive laboratory testing unless indicated in history or physical exam.³ Leukocytosis and lactic acidosis may be present, but are transient and usually caused by the seizure itself.

ACEP’s clinical policy recommends that emergency physicians obtain serum glucose, sodium level, and pregnancy test in women of childbearing age.⁴

Patients currently on antiepileptic medications can also have the blood levels assessed when available.

Any patient with a history of malignancy should also have serum calcium levels assessed. Lumbar puncture should be considered for patients with immunocompromised states, severe headache, fever, suspicion for AIDS, or status epilepticus.

Of note, prolactin is occasionally used in the diagnosis of seizure.

In one meta-analysis, a prolactin level greater than 3 times normal when taken within 1 hour of the event had a positive likelihood ratio (LR) of 4.6 for generalized tonic-clonic seizure versus nonconvulsive syncope and LR of 8.9 for generalized tonic-clonic seizure versus pseudoseizure.⁵ However, because of the limitations of the study, lack of power, and sensitivity of just 71% (95% confidence interval 49%-87%), it is considered only moderately effective as a screening tool.