eMedicine Specialties > Neurology > Seizures and Epilepsy

First Seizure in Adulthood, Diagnosis and Treatment

Author: Eissa Ibrahim AlEissa, MBBS, MD, Fellow in EEG and Epilepsy, Tampa General Hospital
Coauthor(s): Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Contributor Information and Disclosures

Updated: Aug 21, 2009

Introduction

Background

Many diseases can cause paroxysmal clinical events. The correct diagnosis of the paroxysmal event is necessary to provide correct treatment. If the event is an epileptic seizure, the seizure type and associated clinical, electroencephalographic (EEG), and neuroimaging findings assist in determining the risk of seizure recurrence and the possible need to begin anticonvulsant therapy. Yet, the correct diagnosis is often missed.

This article focuses on 2 related questions:

• Is the spell an epileptic seizure?
• If the event is epileptic, is it likely to recur?

Thus, the stepwise approach should be:

• Is it a seizure?
• Is it epilepsy?
• What kind of epilepsy?
• What is the cause?

This article describes the common clinical features of patients with a first seizure, risk factors for seizure recurrence, and a general approach to management.

Pathophysiology

The definitions of the following terms come from the International League Against Epilepsy (ILAE) Guidelines.^3,4,5

An epileptic seizure is a clinical event presumed to result from an abnormal and excessive neuronal discharge. The clinical symptoms are paroxysmal and may include impaired consciousness and motor, sensory, autonomic, or psychic events perceived by the subject or an observer.

Epilepsy occurs when 2 or more epileptic seizures occur unprovoked by any immediately identifiable cause. The seizures must occur more than 24 hours apart. In epidemiologic studies, an episode of status epilepticus is considered a single seizure. Febrile seizures and neonatal seizures are excluded from this category.

Idiopathic epilepsy describes epilepsy syndromes with specific age-related onset, specific clinical and electrographic characteristics, and a presumed genetic mechanism.

Epileptic seizures are classified as cryptogenic or symptomatic. Cryptogenic seizure is a seizure of unknown etiology. This type of seizure is not associated with a prior CNS insult known to increase the risk of developing epilepsy. It does not conform to the criteria for the idiopathic or symptomatic categories. Previous studies use the term idiopathic to describe a seizure of unknown etiology. However, current ILAE guidelines discourage use of the term idiopathic to describe a seizure of unknown etiology.

Symptomatic seizure is a seizure caused by a previously known or suspected disorder of the CNS. This type of seizure is associated with a prior CNS insult known to increase the risk of developing epilepsy.

An acute symptomatic seizure is one that occurs following a recent acute disorder such as a metabolic insult, toxic insult, CNS infection, stroke, brain trauma, cerebral hemorrhage, medication toxicity, alcohol withdrawal, or drug withdrawal. An example of an acute symptomatic seizure is a seizure that occurs within 1 week of a stroke or head injury. Studies have reported that 25-30% of first seizures are acute symptomatic seizures.⁶

A remote symptomatic seizure is a seizure that occurs more than 1 week following a disorder that is known to increase the risk of developing epilepsy. The seizure may occur a long time after the disorder. These disorders may produce static or progressive brain lesions. An example of a remote symptomatic seizure is a seizure that first occurs 6 months following a traumatic brain injury or stroke.

Seizures are also classified as provoked or unprovoked. A provoked seizure is an acute symptomatic seizure. An unprovoked seizure is a cryptogenic or a remote symptomatic seizure.

Compared with an epileptic seizure, a nonepileptic event is a clinical event that can mimic, and be mistaken for, an epileptic seizure. Examples of nonepileptic events that mimic seizures include syncope and psychogenic nonepileptic attacks (PNEAs). Syncope is caused by decreased cerebral perfusion that results mostly from a decrease in the cardiac output, which results in loss of consciousness.

Frequency

United States

In 1997, Moore-Sledge reported that the annual incidence of adult-onset seizures in the United States was 84 cases per 100,000 population and that about 6% of the US population experience a nonfebrile seizure sometime during life.⁷ She estimated that approximately 50 out of 84 patients develop epilepsy.

International

In European studies, the incidence of first unprovoked seizures ranges from 26-70 cases per 100,000 persons. Beghi et al attributed the variability to differences in methodology and definitions.⁸ The rates were similar in different geographic areas despite technical differences in the studies.

Mortality/Morbidity

In a recent study, individuals with a first acute symptomatic seizure were found to be significantly more likely to die in the first 30 days after the seizure compared with those with a first unprovoked seizure; however, the risk of 10-year mortality did not differ.⁹ Also, the risk for subsequent unprovoked seizure was 80% lower in the group with first acute symptomatic seizure compared with those with first unprovoked seizure.

Race

Racial differences have not been studied.

Sex

Most authors report a small-to-moderate preponderance of men in their studies of first seizures in adults.^10,11,12,13

In 1986, Annegers et al found a slight overall preponderance of women.¹⁴ Their etiologic categories were neurologic deficit from birth, remote symptomatic, and no known prior etiology. They identified a preponderance of men in the group with neurologic deficit from birth, no sex preponderance in the group with remote symptomatic seizures, and a slight preponderance of women in the group with no known prior etiology. These authors did not determine if these sexual differences were statistically significant.

Among patients who had an initial generalized tonic-clonic seizure, Bora et al found that only 45.5% were men.¹⁵ Patients with partial seizures and structural lesions proven on CT scan were excluded from this study.

Age

The incidence rate of epilepsy is age-related, with highest incidence in very young and very old groups. The incidence rate in children younger than 1 year is 100-233 per 100,000. The rate decreases in patients aged 20-60 years to 30-40 cases per 100,000. The rate increases to 100-170 cases per 100,000 in patients older than 65 years.¹⁶

Clinical

History

History remains the key in obtaining a correct diagnosis in patients with first seizure in adulthood. The detailed description of the actual episode in question is particularly important. The description should be obtained separately from the patient and from a caregiver who has witnessed the event. The patient may be able to report a warning or aura and the feeling after the seizure. The presence of an aura, by definition, makes the diagnosis of a localization-related epilepsy because auras are “simple partial” seizures with subjective symptoms. However, not every warning symptom is an aura.

Generally speaking, in order to be considered auras, symptoms should be brief (seconds) and followed, at least some of the time, by more definite seizure. Auras widely vary but tend to be stereotyped in a given patient. Some (eg, deja-vu, fear, epigastric sensation, lateralized somatosensory or visual phenomena) are very specific and even localizing; others are not (eg, indescribable sensation, whole body sensations, other vague symptoms like dizziness). The patient may not be able to describe the symptoms during the seizure, which speaks to loss of awareness, but says that the “next thing I know is coming to.” The caregivers or witnesses should then describe what they observe; having the caregivers mimic the types of movements or behaviors they see during the attacks may be helpful. Occasionally, the best witnesses are not present; this may require a telephone call.

The following information should be obtained in the history:

• Patient's age should be recorded.
• If a family history of seizures is noted, the clinical epilepsy syndrome of the affected family member should be determined.
• Ask about a history of any previous provoked seizure.
• Determine if the first seizure was status epilepticus.
• Ask the time of day of the seizure occurrence.
• History of postictal confusion, incontinence, and occurrence out of sleep.
• Consider other paroxysmal neurologic events and identify seizure mimics, such as syncope, transient ischemic attack, transient global amnesia, migraine, sleep disorder, movement disorder, and vertigo.
• In syncope, several historical features can be helpful. When an accurate description is missing (eg, unwitnessed event), the distinction between syncope and seizures can be difficult because it is based on history alone; several symptoms are helpful in aiding the diagnosis.^17,18  These include the circumstances of the attacks, because the most common mechanism for syncope (vasovagal response) is typically triggered by known precipitants (eg, pain such as inflicted by medical procedures, emotions, cough, micturition, hot environment, prolonged standing, exercise).
• Other historical features that favor syncope include “presyncopal” prodromes (eg, vertigo, dizziness, lightheadedness, chest pain, nausea), as well as age and a history of cardiovascular disease. Historical features that favor seizures include tongue biting, head turning, posturing, urinary incontinence, cyanosis, prodromal deja-vu, and postictal confusion.^17,18 A point system using most of these features was designed, with a reported 94% sensitivity and specificity for the diagnosis of seizures.¹⁷
• Psychogenic nonepileptic attacks (PNEAs) are the most common nonepileptic events seen in referral epilepsy centers but should only be considered in the setting of recurrent episodes.¹⁹
• Seek a possible etiology (see Causes).

Physical

• The neurologic examination should be directed at finding clinical evidence of a focal brain lesion.
• A general physical examination should be performed to exclude a nonneurologic cause of the seizure.⁷
• The examiner should pay attention to presence of signs traumatic injuries to any part of the body, especially tongue bite, which is highly specific in epileptic seizures.^20,21

Causes

• Causes of epilepsy
  • Prenatal, perinatal, or postnatal complications of pregnancy and delivery
  • Febrile seizure: Distinguish a complex febrile seizure from a simple febrile seizure.
  • Cerebrovascular disease such as cerebral infarction, cerebral hemorrhage, and venous thrombosis
  • Head trauma: Head trauma is more significant when it occurs with loss of consciousness lasting longer than 30 minutes, posttraumatic amnesia lasting longer than 30 minutes, focal neurologic findings, or neuroimaging findings suggesting a structural brain injury.
  • CNS infections such as meningitis or encephalitis
  • Neurodegenerative diseases
  • Autoimmune disease
  • Brain neoplasm
  • Genetic diseases
  • Drug intoxication, drug withdrawal, or alcohol withdrawal
  • Metabolic medical disorders such as uremia, hypoglycemia, hyponatremia, and hypocalcemia
• The wrong diagnosis of epilepsy is common; 20-30% of cases seen at epilepsy centers are misdiagnosed.^19,22
  • Convulsive syncope: Decreased cardiac output causes reduced cerebral perfusion with loss of consciousness and convulsive motor activity. Scheepers et al reported that cardiovascular disease was the most common diagnosis among patients whose conditions were initially misdiagnosed as epilepsy.¹ Using a comprehensive battery of cardiovascular tests in a population of patients diagnosed with epilepsy, Zaidi et al reported alternative diagnoses in 41%.²³
  • Transient ischemic attack
  • Migraine
  • Sleep disorders, parasomnias, non-REM parasomnias (eg, night terrors, sleepwalking, and confusional arousals), REM behavior disorder, cataplexy (part of the narcolepsy tetrad, consisting of an abrupt loss of tone), hypnic jerks (ie, benign myoclonic jerks)
  • Paroxysmal movement disorders, including acute dystonic reactions, hemifacial spasms, and nonepileptic myoclonus  
  • Transient global amnesia
  • Paroxysmal vertigo
  • Panic attacks
  • PNEAs: These are the most common conditions at epilepsy monitoring units. They comprise more than 90% of misdiagnosed adult cases and comprise more than 50% of cases in chidren.²²
  • Malingering

• Search for CME/CE on This Topic »

• Microarray Technologies in the Diagnosis and Treatment of Head and Neck Cancer (Otolaryngology and Facial Plastic Surgery)
• Lateral Orbital Canthotomy (Clinical Procedures)
• Small-Bowel Obstruction (Pediatrics: General Medicine)
• Rocky Mountain Spotted Fever (Pediatrics: General Medicine)

• Brain and Nervous System Center
• Epilepsy Overview
• Epilepsy Causes
• Epilepsy Symptoms
• Epilepsy Treatment

• FDA Suicide Warnings About Antidepressants Cut Rates of Depression Diagnosis and Treatment
• Discovery of Genetic Mutation May Improve Diagnosis and Treatment of Granulosa-Cell Ovarian Tumors
• New ESC Guidelines on Infective Endocarditis

• Diagnosis and Treatment of Pelvic Inflammatory Disease
• New Guidelines About Diagnosis and Treatment of Children and Infants With Stroke
• Case Detection, Diagnosis, and Treatment of Patients With Primary Aldosteronism: An Endocrine Society Clinical Practice Guideline: F1000 Ranking "Changes Clinical Practice"

• Parkinson's Disease Resource Center
• Secondary Anemia
• Ovarian Cancer