What is the immediate management for a patient with new onset generalized tonic-clonic (GTC) seizures?

Immediate Management of New-Onset Generalized Tonic-Clonic Seizures

For an otherwise healthy adult who has returned to baseline neurological status after a first GTC seizure, obtain serum glucose and sodium levels, perform a pregnancy test if female of childbearing age, and arrange neuroimaging (preferably when feasible in the ED), but do not routinely start antiepileptic medications or admit to hospital. 1, 2

Initial Assessment and History

The first priority is distinguishing between provoked and unprovoked seizures, as this determines both immediate management and long-term prognosis 1, 2:

Provoked seizures occur in close temporal relationship to:

• Systemic disorders (hypoglycemia, hyponatremia, hypocalcemia)
• Acute brain insults (stroke, head trauma, CNS infection)
• Alcohol withdrawal
• Medications or drug intoxication 1, 2

Unprovoked seizures occur without acute precipitants but may have remote symptomatic causes or genetic predisposition 1, 2.

Critical History Elements to Obtain

From the patient and witnesses, document 1, 2:

• Pre-ictal phase: prolonged standing, pain, medical procedures, aura, unusual smells, or no clear trigger
• During seizure: duration of tonic-clonic movements, hemilateral clonic movements, automatisms (chewing, lip-smacking), tongue biting, cyanosis, incontinence
• Post-ictal phase: duration of confusion, muscle aching, time to return to baseline
• Past medical history: stroke, traumatic brain injury, CNS disease, recent illness, fever, head trauma, sleep deprivation, alcohol use or withdrawal, drug use

Mandatory Laboratory Testing

All patients require 3, 1, 2, 4:

• Serum glucose - hypoglycemia is a common reversible cause
• Serum sodium - hyponatremia is a common reversible cause
• Pregnancy test for all women of childbearing age - affects testing, disposition, and antiepileptic drug selection

Additional testing based on clinical context 1, 2:

• Ionized calcium if history suggests hypocalcemia (parathyroid disease, recent surgery, malnutrition) 3
• Complete blood count and basic metabolic panel if signs of infection or renal insufficiency
• Drug screen if intoxication suspected (though routine use not supported by evidence) 3

Do NOT routinely order 1, 2, 4:

• Calcium, magnesium, or phosphate in otherwise healthy patients without specific clinical indicators
• Extensive electrolyte panels beyond glucose and sodium

Neuroimaging

Head CT scan should be performed in the ED when feasible 3, 1:

• 22% of patients with normal neurologic examination have abnormal CT findings 3, 4
• 23% of new-onset seizure patients have acute stroke or tumor on CT 3, 4

Emergent CT is mandatory for 1, 2:

• Post-ictal focal deficits that do not quickly resolve
• Altered mental status persisting beyond expected post-ictal period
• Age >40 years (high risk of structural lesions) 3
• History of head trauma, malignancy, or anticoagulation 3
• Immunocompromised patients 3
• Fever or signs of meningeal irritation 3

MRI is preferred when 3, 1:

• Patient is stable and MRI is available
• CT is negative but clinical suspicion for structural abnormality remains high
• MRI detects abnormalities not seen on CT in 28-47% of cases 3

Deferred outpatient neuroimaging is acceptable 3, 1 when:

• Patient has returned to baseline
• No high-risk features present
• Reliable follow-up is ensured

Lumbar Puncture Indications

Perform lumbar puncture (after CT scan) for 3, 1, 4:

• Immunocompromised patients
• Fever or signs of meningeal irritation
• Persistent altered mental status suggesting CNS infection

Do NOT perform lumbar puncture 3, 1 on alert, oriented, afebrile, immunocompetent patients who have returned to baseline.

Antiepileptic Drug Decision

For provoked seizures 1, 2:

• Do NOT initiate antiepileptic medications in the ED
• Instead, identify and treat the precipitating medical condition (correct hypoglycemia, hyponatremia, hypocalcemia, treat infection, etc.)

For unprovoked seizures 1, 2:

• Do NOT routinely start antiepileptic medications after first seizure
• Treatment within days to weeks after first seizure prolongs time to subsequent event but does not affect outcomes at 5 years 2
• Approximately one-third to one-half of patients will have recurrence within 5 years 3

Exceptions where treatment after first seizure is appropriate 2:

• History of CNS injury
• Remote symptomatic seizures
• Certain structural brain lesions identified on imaging

If antiepileptic medication is indicated (after neurology consultation), options include 5, 6:

• Levetiracetam: start 500 mg twice daily, may increase by 1000 mg/day every 2 weeks to maximum 3000 mg/day 5
• Valproic acid: first choice in males or menopausal women without weight concerns 6
• Lamotrigine or levetiracetam: viable alternatives, especially in women of childbearing age 6

Disposition Decisions

Discharge is appropriate when 1, 2:

• Patient has returned to clinical baseline
• No persistent focal deficits or altered mental status
• No high-risk features for recurrence
• Reliable follow-up arranged

Consider admission or extended observation for 1, 2:

• Persistent altered mental status or focal deficits
• Immunocompromised status
• Fever or signs of infection
• Age ≥40 years with concerning imaging findings
• Alcoholism (though most early recurrences occur within 6 hours, mean 121 minutes) 2

Critical Pitfalls to Avoid

• Do NOT assume alcohol withdrawal seizures without thorough evaluation - this should be a diagnosis of exclusion, especially in first-time seizures 1, 2, 4
• Do NOT confuse brief myoclonic jerking after syncope with true epileptic seizures - syncope does not require neurologic investigation 3, 1
• Do NOT defer neuroimaging in elderly patients - delayed imaging is potentially dangerous due to high rate of serious structural lesions 4
• Do NOT discharge patients with persistent altered mental status or focal deficits - these require admission and further workup 1, 2
• Do NOT routinely start antiepileptic medications after first unprovoked seizure - this does not affect long-term outcomes 1, 2