What is the appropriate diagnostic and treatment approach for a 19-year-old boy presenting with seizures?

Management of a 19-Year-Old Boy with Seizures

For a 19-year-old presenting with seizures, immediately assess if the seizure is provoked (metabolic, toxic, or acute brain insult) versus unprovoked, as this fundamentally determines whether antiepileptic medication is needed—provoked seizures require treating the underlying cause without initiating antiepileptic drugs, while unprovoked seizures may warrant treatment only if high-risk features are present. 1

Immediate Assessment and Stabilization

Active Seizure Management

• If the patient is actively seizing for >5 minutes, treat as status epilepticus with benzodiazepines first-line (lorazepam 4 mg IV at 2 mg/min) 1, 2
• If seizures persist after benzodiazepines, administer second-line agents: fosphenytoin, levetiracetam, or valproate—all have similar efficacy (45-47% seizure cessation within 60 minutes) 1
• Levetiracetam is preferred due to minimal cardiovascular effects and no hypotension risk, unlike fosphenytoin which causes hypotension in 12% of patients 1, 2

Determine Seizure Classification

The critical first step is distinguishing provoked from unprovoked seizures, as this determines the entire management pathway 1, 3:

Provoked (acute symptomatic) seizures occur within 7 days of:

• Metabolic abnormalities (hypoglycemia, hyponatremia, hypocalcemia, hypomagnesemia) 3, 4
• Alcohol or drug withdrawal 3, 5
• Acute brain injury, infection, or stroke 1, 5
• Drug toxicity 3

Unprovoked seizures occur without acute precipitating factors and include:

• Remote symptomatic seizures (>7 days after CNS injury like prior stroke or trauma) 1, 3
• Idiopathic/cryptogenic seizures with no identifiable cause 1

Essential Laboratory Workup

Obtain serum glucose and sodium immediately—these are the only laboratory tests that consistently alter acute management 6:

• Check glucose, sodium, calcium, and magnesium as these are the most frequent correctable abnormalities 3, 6
• Pregnancy test if applicable 6
• Consider toxicology screen if substance exposure suspected 6
• Additional labs (CBC, comprehensive metabolic panel) only if clinically indicated by specific findings 6

Neuroimaging Decision Algorithm

Perform emergent non-contrast head CT if ANY of these high-risk features are present 6:

• Age >40 years 6
• History of malignancy or immunocompromised state 6
• Fever or persistent headache 6
• Focal seizure onset before generalization 6
• Recent head trauma 6
• Persistent altered mental status or new focal neurological deficits 6
• Anticoagulation use 6
• Patient has not returned to baseline 6

For low-risk patients (young, returned to baseline, normal neurologic exam, reliable follow-up), defer to outpatient MRI 6:

• MRI is superior to CT, detecting abnormalities in 28-29% of cases missed by CT 1
• MRI should use dedicated epilepsy protocol with thin-cut coronal slices 1

Antiepileptic Drug Initiation Decision

For Provoked Seizures

Do NOT initiate antiepileptic medication in the ED—identify and treat the underlying precipitating condition 1, 3:

• Correct metabolic abnormalities (hypoglycemia, electrolyte disturbances) 3, 4
• Treat infections, manage withdrawal syndromes 1, 4
• Use short-acting anticonvulsants only for temporary seizure control if needed 3

For First Unprovoked Seizure

Emergency physicians need NOT initiate antiepileptic medication in the ED for patients with a first unprovoked seizure who have returned to baseline and have no evidence of brain disease or injury 1:

• Approximately one-third to one-half will have recurrence within 5 years, but starting treatment after a single seizure does not improve long-term outcomes at 5 years 1
• Number needed to treat is 14 to prevent one seizure recurrence in the first 2 years 1
• The strategy of waiting until a second seizure before initiating medication is appropriate 1

Consider initiating or deferring antiepileptic medication (in coordination with neurology) if the patient has 1:

• Remote history of brain disease or injury (stroke, trauma, tumor) 1
• Structural lesion on imaging 1
• These patients have higher recurrence rates and treatment after one seizure is considered appropriate 1

Specific Drug Selection (If Treatment Indicated)

For partial onset seizures: Levetiracetam is effective as initial monotherapy, starting at 500-1500 mg twice daily orally 7, 8

For generalized tonic-clonic seizures: Valproate, levetiracetam, or lamotrigine are preferred 8

Avoid valproate in patients with liver disease or hyperthyroidism due to hepatotoxicity concerns 2

Disposition Decisions

Emergency physicians need NOT admit patients with a first unprovoked seizure who have returned to their clinical baseline in the ED 1, 6:

Consider admission only if 6:

• Persistent abnormal neurologic examination
• Abnormal investigation results requiring inpatient management
• Patient has not returned to baseline
• Immunocompromised status requiring lumbar puncture after CT 6

Seizure Recurrence Risk in First 24 Hours

• Overall 24-hour recurrence rate is 19%, decreasing to 9% when alcohol-related events and focal CT lesions are excluded 6
• Mean time to first recurrence is 121 minutes (median 90 minutes), with >85% occurring within 6 hours 6
• Nonalcoholic patients with new-onset seizures have the lowest recurrence rate (9.4%) 6

Critical Pitfalls to Avoid

• Do not miss metabolic causes: Hypoglycemia and hyponatremia require immediate correction 6, 4
• Do not assume alcohol withdrawal: This should be a diagnosis of exclusion, especially in first-time seizures—always search for symptomatic causes first 6
• Do not overlook alternative diagnoses: 28-48% of suspected first seizures are actually syncope, nonepileptic seizures, or panic attacks 6
• Do not start antiepileptic drugs for provoked seizures: This exposes patients to medication adverse effects without benefit 1, 3
• Do not perform routine lumbar puncture: Only indicated when meningitis/encephalitis suspected or patient is immunocompromised 6

Outpatient Follow-Up Arrangements

All patients require 6, 9:

• Neurology referral for EEG (abnormal EEG predicts increased recurrence risk) 6
• Outpatient MRI if not performed emergently 6
• Counseling about driving restrictions and safety precautions 9
• Clear return precautions if seizure recurs 6