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17SEIZURESKent N. Hall, MD

1. Whatisaseizure?A seizure is an episode of abnormal brain function caused by excessive and aberrant electrical discharge in the brain. This electrical discharge may, or may not, result in characteristic muscle activity that is recognized as seizure activity. In addition to tonic-clonic muscle activity, generalized seizures may also manifest as staring episodes, lip smacking or other minor motor activity, or complete disruption of muscle tone (drop attacks). Generalized seizures are often followed by a postictal phase characterized by confusion and/or lethargy. This phase usually lasts for 5 to 15 minutes, although it may last longer.

The recognition and appropriate management of seizures are critically important to the patient and the emergency physician because they are a common ED presenting problem. Prolonged excessive electrical activity in the brain causes neuronal destruction. This destruction is not due to build-up of metabolic by-products but is actually directly related to the electrical activity itself. For an unknown reason, the hippocampus is particularly sensitive to the damage from this electrical activity.

2. Howareseizuresclassified?Seizures are classified according to the amount of brain involved in the abnormal electrical activity, its resulting physical manifestation, and its underlying cause. In general, seizures are divided into two groups, generalized and focal (Table 17-1). Generalized seizures affect a large volume of brain tissue in the abnormal electrical activity, whereas focal seizures involve a specific brain area. Because of this, the manifestations of focal seizures, whether simple or complex, may lead to bizarre manifestations including hallucinations, memory disturbance, visceral symptoms (abdominal symptoms), and perceptual distortions. This has often resulted in the patient with partial seizures being misdiagnosed as having a psychiatric problem.

Often the emergency physician is presented with a patient who is not actively seizing but has had a seizure. In this case, it is important to evaluate for secondary signs of seizure activity. These include bowel or bladder incontinence, biting of the tongue or buccal mucosa, and postictal confusion.

3. Whatarethecausesofseizures?Seizures are abnormal electrical activity in the brain. Primary seizures are recurrent episodes without an underlying cause. This is classically referred to as epilepsy. Secondary seizures (also called reactive seizures) have a (usually non-neurologic) underlying condition. Table 17-2 lists the most common etiologies for secondary seizures.

4. Whatisincludedinthedifferentialdiagnosisofseizure?Anything that can cause a sudden disturbance of neurologic function may be mistaken for a seizure. Common processes that fall into this category include syncope, hyperventilation syndrome, migraines, movement disorders, and narcolepsy. Pseudoseizure is a special category and is discussed later.

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5. Whatshouldmyprioritiesbeinmanagingapatientwhoisactivelyseizing?Clinical priorities are the ABCs. Attention is always directed to the airway first. It is rare that a seizure patient needs to be intubated. Supplemental oxygen, usually via nasal cannula, should be given because of the increased oxygen demand caused by the generalized muscle activity. Supplemental ventilation (bag-valve-mask) is rarely needed. Evaluation of the circulatory status can be readily accomplished by noting blood pressure, pulse, and capillary refill. Check the temperature and administer antipyretics in appropriate doses when needed.

Airway protection can usually be accomplished by positioning the patient on his or her side. Suctioning of the patient’s oral secretions will also help decrease the chance of aspiration. However, nothing should be put into the patient’s mouth that might be bitten off

TABLE 17-1. CLASSIFICATION OF SEIZURES

Type Manifestations

Generalized

Tonic-clonic (grand mal) Loss of consciousness followed immediately by tonic contractions of muscles, then clonic contractions of muscles (jerking) that may last for several minutes. A period of disorientation (postictal period) occurs after the tonic-clonic activity.

Absence (petit mal) Sudden loss of awareness with cessation of activity or body position control. The period usually lasts for seconds to minutes and is followed by a relatively short postictal phase.

Atonic (drop attacks) Complete loss of postural control with falling to the ground, sometimes causing injury. It usually occurs in children.

Myoclonic Brief, vigorous, spasmodic muscle contractions. These may affect the entire body or only specific areas.

Tonic Prolonged muscle contraction. It occurs usually with associated deviation of the head and eyes in a particular direction.

Clonic Repetitive jerking motions occur without any associated tonic muscle contraction.

Partial or focal

Simple partial Multiple patterns are possible depending on the area of the brain affected. If the motor cortex is involved, the patient will have contraction of the corresponding body area. If nonmotor areas of the brain are involved, the sensation may be paresthesias, hallucinations, or déjà vu.

Complex partial Usually there is loss of ongoing volitional major motor activity with repetitive minor motor activity, such as lip smacking and walking aimlessly.

Partial with secondary generalization

Initial manifestations are the same as partial. However, the activity progresses to involve the entire body, with loss of postural control and possibly tonic-clonic muscle activity.

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TABLE 17-2. ETIOLOGIES OF SECONDARY SEIZURES

Metabolic

Hypoglycemia, hyperglycemia

Hyponatremia, hypernatremia

Hypocalcemia

Hypomagnesemia

Uremia

Hypothyroidism

Hepatic encephalopathy

High anion gap acidosis

Fever (“febrile seizures”)

Infectious diseases

Meningitis

Encephalitis

Cerebral abscess

Cerebral parasitosis

HIV

Drugs/toxins (multiple)

Subtherapeutic antiepileptic drug levels

Cocaine, lidocaine

Antidepressants

Theophylline

Alcohol withdrawal

Drug withdrawal

Structural

Trauma (recent and remote)

Intracranial hemorrhage

Vascular lesions

Mass lesions

Eclampsia

Hypertensive encephalopathy

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6. WhatdoIdoifthepatientdoesn’tstopseizing?Most seizures last for less than 2 minutes. When a seizure lasts longer, pharmacologic intervention is generally indicated. Benzodiazepines are the accepted first-line therapy. The intravenous (IV) route is the preferred route of administration. Lorazepam (2–4 mg intravenously) is the conventional first choice because of theoretical issues related to duration of action. However, diazepam (5–10 mg intravenously) may also be used. Diazepam may be administered intravenously, rectally, or intraosseously but is not recommended for intramuscular use because of uneven uptake.

Once the seizure has ceased, anticonvulsants are used to keep it from recurring. Phenytoin is considered the first-line therapy. Table 17-3 shows the medications in this class along with their dosage and route of administration.

7. Whatisstatusepilepticus?Howisitmanaged?When seizures last longer than 5 minutes despite acute pharmacologic intervention or recur so frequently that normal mentation does not resume between the seizures, it is called status epilepticus. In this case, immediate pharmacologic intervention is indicated. Table 17-4 gives an algorithm that can be used to manage the patient with status epilepticus.

8. Isthehistoryimportant?The history if vitally important! The mnemonic COLD can be used to ensure you have covered the aspects of the seizure activity itself.n Character: What type of seizure activity occurred?n Onset: When did it start? What was the patient doing?n Location: Where did the activity start?n Duration: How long did it last?In general, seizures start abruptly, are stereotyped (similar seizure activity recurs from attack to attack in an individual patient), are not provoked by environmental stimuli, are manifested by purposeless or inappropriate motor activity, and except for petit mal seizures, are followed by a period of confusion or lethargy (the postictal phase). Other important historical aspects include the patient’s past medical history (especially previous seizure history), alcohol use,

(including fingers) and thus become an obstructing foreign body. Gently restraining the patient so he or she is not harmed is also important.

Diagnostic priorities should focus on likely secondary causes of seizures that are reversible. Hypoglycemia is a common cause of secondary seizures that is treatable with rapid results. Similarly, immediate evaluation of significant electrolyte abnormalities (i.e., sodium, calcium, magnesium) in a patient with prolonged seizure activity is warranted.

TABLE 17-3. ANTICONVULSANTS

Drug Adult dose

Phenytoin 15–20 mg/kg IV at ,50 mg/min

Fosphenytoin 15–20 mg PE/kg at 100–150 mg PE/min; may be given IM

Phenobarbital 20 mg/kg IV at 60–100 mg/min. May be given as IM loading dose

Valproate 15–30 mg/kg IV should be given over one hour

Pentobarbital 5 mg/kg IV at 25 mg/min, then titrate to EEG. Intubation required

Isoflurane Via general endotracheal anesthesia

EEG, electroencephalogram; IM, intramuscularly; IV, intravenously; PE, phenytoin sodium equiva-lents; PR, per rectum.

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toxic ingestions, current medications, any history of central nervous system (CNS) neoplasms, and history of recent or remote trauma.

9. Inadditiontotheneurologicexamination,whatotherpartsofthephysicalexaminationareimportant?A complete head-to-toe examination is important. In addition to looking for causes of the seizure, the physician should look for trauma caused by the seizure. The examination is often normal but occasionally may give clues to an underlying problem. Specifically, examination of the skin might reveal lesions from meningococcemia, other infectious problems, or stigmata of liver failure. Examine the head for trauma. If nuchal rigidity is found, meningitis or subarachnoid hemorrhage should be suspected.

The neurologic examination is most important. Focal neurologic findings, such as focal paresis after the seizure (Todd’s paralysis), may indicate a focal cerebral lesion (i.e., tumor, abscess, or cerebral contusion) as the cause of the seizure. Evaluation of the cranial nerves and the fundi can point to increased intracranial pressure.

10. WhatancillarytestingshouldIdointhepatientwithahistoryofseizures?Extensive ancillary testing is reserved for the patient with new onset seizure. For patients with a prior history of seizures who have an unprovoked attack, measurement of appropriate serum anticonvulsant levels is all that is required. The decision to proceed with further testing depends on the patient’s history and physical findings at the time of presentation. If there is a question whether the patient had a major motor seizure, then measurement of the anion gap within 1 hour of the seizure might be of benefit.

TABLE 17-4. PROPOSED GUIDELINES FOR MANAGEMENT OF THE PATIENT WITH STATUS EPILEPTICUS

Time Frame Measures

Establish/maintain airway

IV/oxygen/monitor

0–5 min Dextrose, 0.5 gm/kg IV, if indicated

Consider thiamine, 100 mg IV, and magnesium 1–2 gm IV for alcoholic or malnourished patients

Lorazepam, 1 mg per min IV up to 0.1 mg/kg (or diazepam, 5 mg IV every 5 min up to 20 mg)

10–20 min Phenytoin, 20 mg/kg IV at 50 mg/min, or fosphenytoin, 20 mg/kg PE IV at 150 mg/min

Phenobarbital up to 20 mg/kg IV at 50–75 mg/min IV

Valproate up to 30 mg/kg IV over 1 hour

30 min And/or

General anesthesia with midazolam, 0.2 mg/kg slow IVP, then 0.75–10 mg/kg/min

Or propofol, 1–2 mg/kg IV, then 1–15 mg/kg/hr

Or pentobarbital, 10–15 mg/kg IV over 1 hour, then 0.5–1.0 mg/kg/hr

IV, intravenous; IVP, intravenous push; PE, phenytoin sodium equivalents. Adapted from Lowenstein DH, Aldredge BK: Status epilepticus. N Engl J Med 338:970, 1998.

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A transiently (,1 hour) raised anion gap is good evidence that a grand mal seizure has occurred. This is determined by blood samples drawn as close to the time of seizure as possible. Field blood samples are ideal for this study. If there is no anion gap acidosis, one may presume that the patient did not have a major motor seizure.

KEY POINTS: ANCILLARY LABORATORY TESTING IN PATIENTS WITH SEIZURES

1. Usually not indicated for patients with recurrent seizures unchanged from prior episodes.

2. Should be limited to those tests designed to find underlying causes of seizures.

3. Include blood chemistries (i.e., sodium, calcium, magnesium), blood sugar, appropriate drug screen, kidney function, and liver function.

11. Andifthepatientdoesnothaveahistoryofseizures?Routine screening laboratory tests in a patient with new onset seizure who has returned to baseline have low yield. In general, it is recommended that these patients have a blood sugar and blood sodium determination. If the patient is a woman of child-bearing years, a pregnancy test can be useful because it may affect choice of antiepileptic therapy and/or disposition. The routine use of lumbar puncture in new onset seizure patients is not supported by the literature. Additional testing (i.e., calcium, magnesium, drug screening, and kidney and liver function testing) should be obtained if clinically indicated.

12. Whataboutimagingstudies?In the patient with a first-time seizure, emergent noncontrast head CT is recommended for patients in whom a structural lesion is suspected. This includes patients with new focal deficits, persistent altered mental status, fever, recent head trauma, persistent headache, history of cancer, or presence of a coagulopathy or platelet disorder; patients who are on anticoagulation therapy; and patients who are HIV positive or otherwise immunosuppressed. Emergent neuroimaging should also be considered in the patient with first-time seizure who is older than 40 years or who has a partial seizure.

13. Whatshouldbethedispositionofthepatientwhopresentswithaseizure?Patients who present with any of the following should be considered for emergent admission to the hospital for inpatient evaluation and therapy: persistent altered mental status, CNS infection, new focal abnormality, new intracranial lesion, underlying correctable medical problem (e.g., significant hypoxia, hypoglycemia, hyponatremia, dysrhythmia, and significant alcohol withdrawal), acute head trauma, status epilepticus, and eclampsia. If the patient has a history of seizure and has a simple seizure and a subtherapeutic anticonvulsant level, then this should be addressed prior to discharge.

Patients with new onset seizures who have normal work-ups in the ED and are medically stable may be considered for discharge. In this case, follow up with the patient’s primary care physician or a consulting neurologist must be arranged. The patient should be informed via ED discharge instructions on the possibility of another seizure and be advised to avoid working with hazardous machines, driving an automobile, and doing any other activities that can result in serious injury if the patient has another seizure. Also, most states have laws that require reporting a patient with seizures, if the patient has a driver’s license.

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KEY POINTS: EMERGENT NEUROIMAGING RECOMMENDATIONS FOR PATIENTS WITH SEIZURES

1. Seizure with focal neurological deficits, persistent altered mental status, fever, recent trauma, persistent headache, history of cancer, history of anticoagulation, HIV positive (AIDS), and when timely follow-up cannot be ensured.

2. Urgent imaging for patients who have completely recovered from their seizure and for whom no clear-cut cause has been identified to help identify a possible structural cause.

3. Patients with first-time seizures who are older than 40 years or have partial onset seizure.

4. Patients with prior history of seizures who have a new or different seizure pattern.

WEBSITES

American College of Emergency Physicians: http://www.acep.org

BIBLIOGRAPHY

1. Duvivier E, Pollack C: Seizures. In Marx JA, Hockberger RS, Walls RM, et al, editors: Rosen’s emergency medicine: concepts and clinical practice, ed 7, New York, 2009, Mosby.

2. Lowenstein DH, Aldredge BK: Status epilepticus. N Engl J Med 338:970, 1998.

3. Millikan D, Rice B, Silbergleit R: Emergency treatment of status epilepticus: current thinking. Emerg Med Clin North Am 27:101–110, 2009.

4. Schachter SC: Seizure disorders. Med Clin North Am 93(2) 343–351, 2009.

5. St. Louis EK, Granner MA: Seizures and epilepsy in adolescents and adults. In Rakel RE, Bope ET: Conn’s Current Therapy 2009, Philadelphia, 2008, Saunders.

6. Trescher WH, Lesser RP: The epilepsies. In Bradley WG, Daroff RB, Fenichel GM, et al, editors: Neurology in clinical practice, ed 5, Philadelphia, 2008, Butterworth Heinemann.

14. ShouldIstartthepatientwithanewseizureonantiepilepticmedicationpriortodischarge?This decision is best made in consultation with the patient’s primary care physician or neurologist. Most patients with a single new onset seizure who can be discharged do not need to be started on anticonvulsants until seen in follow-up and further testing (i.e., electroencephalogram [EEG]) is completed.

15. Whatisapseudoseizure?Pseudoseizures are functional events that may mimic seizures in their motor activity or behavior. They are not caused by abnormal electrical discharges in the brain. In general, patients with pseudoseizures have underlying anxiety or hysterical/histrionic personality disorders. Pseudoseizures are sometimes difficult to diagnose in the ED. Some maneuvers that may be of benefit include suggesting to the patient that the seizure will stop soon or attempting to distract the patient with loud noises or bright lights during the seizure activity. Patients who show asynchronous extremity movements, forward thrusting movement of the pelvis, and eyes deviated toward the ground no matter what the head position are more likely to be having pseudoseizures. Simultaneous video and EEG monitoring can help to differentiate true seizures from pseudoseizures. In addition, a serum prolactin level drawn within 20 minutes of seizure activity should be elevated in the patient with true seizure. A normal anion gap on serum electrolytes drawn immediately after the grand mal seizure supports the diagnosis of a pseudoseizure.