Author:
DaewonKim
John A.Guisto
Description
- Generalized seizures:
- Abnormal neuronal activity in both cerebral hemispheres
- Classically tonic-clonic (grand mal) seizures: Impaired awareness, muscle rigidity (tonic), rhythmic jerking movements (clonic)
- Absence (petit mal) seizures: Altered consciousness but no postural tone change; can have brief twitches (myoclonus)
- Focal (partial) seizures:
- Usually involves one cerebral hemisphere preserving consciousness, may spread to involve both hemispheres and cause altered sensorium
- More likely to be secondary to localized structural lesion
- No longer classified as simple partial (i.e., Jacksonian) and complex partial (consciousness or mentation affected)
- Status epilepticus:
- Seizure lasting longer than 5 min (classically defined as at least 30 min) or recurrent seizures without return to baseline mental status between events
- Nonconvulsive status epilepticus may present in >9% of hospitalized patients with prolonged decreased mental status
- Life-threatening emergency, mortality approaching 30% if seizure lasts >1 hr
- At least one-half of patients presenting to ED in status do not have a history of seizures
- Special populations:
- HIV: Mass lesions, encephalopathy, herpes zoster, toxoplasmosis, Cryptococcus, neurosyphilis, meningitis
- Neurocysticercosis: CNS infection of tapeworm Taenia solium, MCC of provoked seizures in developing world
- Pregnancy beyond 20 wk of gestation: Eclampsia (hypertension, edema, proteinuria, seizures)
- Alcohol withdrawal seizures: Peak within 24 hr of last drink, rarely progress to status epilepticus
- 8-10% lifetime risk of symptomatic seizure
- Patients with a single seizure have a 35% risk of recurrent seizure within 5 yr
- In 2011:
- 1.6 million ED visits for seizures
- 400,000 with new-onset seizures
Pediatric Considerations |
Simple febrile seizures (self-limited and benign)- Age 6 mo-6 yr
- Generalized convulsions
- Typically lasts <15 min
- Do not recur within 24 hr
- No CNS infection or other neurologic disease
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Etiology
- Hypoxia
- Hypertensive encephalopathy
- Eclampsia
- Infection:
- Meningitis
- Abscess
- Encephalitis
- Vascular:
- Ischemic stroke
- Hemorrhagic stroke
- Subdural hematoma
- Epidural hematoma
- Subarachnoid hemorrhage
- Arteriovenous malformation
- Structural:
- Primary or metastatic neoplasm
- Degenerative disease (e.g., multiple sclerosis)
- Lesion from previous trauma
- Metabolic:
- Electrolytes
- Hypernatremia
- Hyponatremia
- Hypocalcemia
- Hypo/hyperglycemia
- Uremia
- Toxins/drugs:
- Lidocaine
- Tricyclic antidepressants
- Salicylates
- Isoniazid
- Cocaine
- Alcohol withdrawal
- Benzodiazepine withdrawal
- Congenital abnormalities
- Idiopathic
- Trauma
Signs and Symptoms
- Altered level of consciousness
- Involuntary repetitive movements:
- Tonic posturing or clonic jerking
- Seizures of abrupt onset:
- Aura may precede a focal seizure
- Duration usually 90-120 s:
- Impaired memory of the event
- Postictal state is a brief period of confusion and somnolence following a seizure
- Evidence of recent seizure activity:
- Confusion or somnolence
- Acute intraoral injury
- Urinary incontinence
- Posterior shoulder dislocation
- Todd paralysis (transient paralysis following a seizure, usually subsides within 48 hr)
- Other findings may suggest etiology of seizure:
- Fever and nuchal rigidity (CNS infection)
- Needle tracks, stigmata of liver disease (drugs or alcohol)
- Any toxidromes
- Head trauma:
- Papilledema (increased intracranial pressure)
- Lateralized weakness, sensory loss, or asymmetric reflexes
History
- History of seizures:
- Recent illness
- Head trauma
- Headaches
- Anticoagulation therapy
- Fever
- Neck stiffness
Physical Exam
- Complete neurologic exam:
- Complete secondary and tertiary survey to evaluate for any trauma secondary to seizure or potential cause for seizure
Essential Workup
- Thorough history is the most valuable part of the workup:
- Witness accounts
- History of prior seizures
- Presence of acute illness
- Past medical problems
- History of substance use
- Patients with chronic seizure disorder and typical seizure pattern may need to have only serum glucose and anticonvulsant levels checked
- New-onset seizure mand ates workup:
- Electrolytes including calcium, phosphorus
- Head CT
- Toxicology screen
- Pregnancy test if woman is of childbearing age
- Lumbar puncture indicated if:
- New-onset seizure with fever
- Severe headache (i.e., “thunderclap” headache)
- Immunocompromised state
- Persistently altered mental state:
- Search for specific underlying cause
- Patient's condition and resources for follow-up determine whether all these tests must be done in ED
Pediatric Considerations |
- A child with a febrile seizure should receive fever workup as dictated by clinical condition; however, full seizure work up may not be necessary for simple febrile seizures
- Inquire about family history of febrile seizures
- Lumbar puncture for febrile seizure:
- Consider if age <1 yr
- Ill appearing (lethargy or poor feeding)
- Hib/PCV vaccines not up-to-date
- Meningeal signs or difficult exam
- Unreliable follow-up
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Diagnostic Tests & Interpretation
Lab
- Serum anticonvulsant levels
- Consider blood alcohol level, toxicology screen
- CBC:
- Chemistry panel:
- Lactate and prolactin may be elevated
- CSF:
- May have transient increase in WBC to 20/μL
Imaging
- Noncontrast head CT:
- Persistent or progressive alteration of mental status
- Focal neurologic deficits
- Seizure associated with trauma
- CT scan with IV contrast should be obtained in HIV-positive patients to rule out toxoplasmosis
- MRI sensitive for low-grade tumors, small vascular lesions, early inflammation, early cerebral infarcts:
- Consider electively in new-onset seizures
Diagnostic Procedures/Surgery
- EEG may be arranged with neurology on an outpatient basis
- Bedside EEG may be performed in ED if there is suspicion of nonconvulsive status epilepticus or psychogenic seizures
- Consider ECG if syncope, ACS, arrhythmias, toxins are on differential diagnosis
Differential Diagnosis
- Syncope (may have incontinence, myoclonic jerks)
- TIA, CVA, ICH, global transitory amnesia
- Intracranial mass
- Meningitis, encephalitis, intracranial abscess
- Movement disorders
- Migraine
- Posterior reversible encephalopathy syndrome
- Sleep disorders
- Metabolic derangement
- Psychogenic nonepileptic seizures (PNES)
- Panic attacks or other psychiatric disorders
- Delirium tremens
- Tetanus
- Thyrotoxicosis
- Medications or toxins (e.g., extrapyramidal symptoms of antipsychotics)
- Intoxication or withdrawal
Prehospital
Anticonvulsant as per local protocol
Initial Stabilization/Therapy
- Airway management as indicated
- Strongly consider rapid-sequence intubation with status epilepticus, cyanosis, hypoxia
- Pulse oximetry, oxygen, suction, IV access:
- C-spine precautions
- Rapid-sequence intubation if patient cannot protect airway or with hypoxia or major head trauma
- Rapid determination of serum glucose:
- Lorazepam, diazepam, midazolam for active seizures
- Naloxone if concern for narcotic overdose
ED Treatment/Procedures
- First-time seizure:
- Structural lesion on CT or MRI:
- Start antiepileptic drug (AED) in consultation with PCP and /or neurologist
- Recurrent seizure not on AED:
- Start AED in consultation with PCP and /or neurologist
- Recurrent seizure with subtherapeutic AED level:
- IV and /or PO load current AED
- Recurrent seizure with therapeutic AED level:
- Need careful evaluation for cause of seizures, new lesions, etc.:
- Adjust and /or add AED in consultation with neurologist
- Seizure in a pregnant patient:
- Evaluate as other seizure patients
- Strongly consider eclampsia between 20 wk gestation and 6 wk postpartum
- OB consultation, arrange for C-section
- Magnesium sulfate first line
- Seizures related to alcohol:
- Determine if seizure is caused by withdrawal (6-48 hr after last drink) or another cause
- Benzodiazepines first line
Pediatric Considerations |
- Fever control with acetaminophen and ibuprofen
- Anticonvulsants not needed for febrile seizures
- Anticonvulsants should be prescribed in conjunction with neurologist
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Medication
First Line
- Diazepam: 10 mg IV or 10-20 mg PR; 0.15-0.2 mg/kg IV (up to 10 mg); 0.2-0.5 mg/kg PR (up to 20 mg); may repeat in 5 min
- Lorazepam: 4 mg IV over 2 min; 0.1 mg/kg IV/IM (up to 2 mg if <40 kg, otherwise max 4 mg); may repeat in 10 min
- Midazolam: 10 mg IV/IM/IN/buccal; 0.2 mg/kg IV/IM/IN (up to 5 mg if <40 kg, otherwise max 10 mg); 0.5 mg/kg buccal; may repeat in 10 min
Second Line
- Fosphenytoin: 20 mg phenytoin sodium equivalents (PE)/kg IV/IM (infusion <150 mg PE/min)
- Pentobarbital: 5-15 mg/kg IV bolus then 0.5-5 mg/kg/hr infusion; intubation required
- Phenobarbital: 15-20 mg/kg IV infusion; intubation likely required
- Phenytoin: 20 mg/kg IV infusion at 1 mg/kg/min (max 50 mg/min)
- Propofol: 1-2 mg/kg IV bolus then 20-200 mcg/kg/min infusion; intubation required
- Valproate sodium: 20-40 mg/kg IV infusion (up to 60 mg/kg/d) at 5 mg/kg/min
Special Populations
- Dextrose: 25 g IV D50W (0-1 mo: 2 mL/kg IV D10W; 1 mo-2 yr: 2 mL/kg IV D25W; >2 yr: 2 mL/kg D25W); if adult max 50 mL D50W
- Magnesium sulfate: 6 g IV over 15 min, then 2 g/hr; first line for eclampsia
- Naloxone: 0.4-2 mg IV/IM/SQ/IN (peds: 0.1 mg/kg IV/IM/SQ)
- Pyridoxine: Equal dose of isoniazid ingestion (max 5 g) at 0.5 g/min IV until seizure control; if isoniazid ingestion
Disposition
Admission Criteria
- Patients with status epilepticus should be admitted to the ICU
- Patients with seizures secondary to underlying disease (e.g., meningitis, intracranial lesion) must be admitted for appropriate treatment and monitoring
- Patients with poorly controlled repetitive seizures should be admitted for monitoring
- Delirium tremens
Discharge Criteria
- Patient with normal workup, return to baseline mental status, normal neuro exam, and appropriate neurology follow-up
- Uncomplicated seizure in patient with chronic seizure disorder
- Seizure secondary to reversible cause:
- Hypoglycemia if blood sugar has stabilized
- Alcohol withdrawal if baseline mental status and no further seizures
- Simple febrile seizure
Issues for Referral
- Consider early neurology follow-up
- Anticonvulsant drug level monitoring
Follow-up Recommendations
No driving, swimming, or other potentially dangerous activities until seizures are under control
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