• Occurrence of an aura.
  
• Alteration in or impaired consciousness or behavior.
  
• Abnormal movement.
  
• Interictal trauma or incontinence.
  
• Eyewitness account.
  
• Presence of fever.
  
• Postictal confusion, lethargy, or sleepiness.
  
• Diagnostic electroencephalogram.
  
• Abnormality on neuroimaging.

Despite an alarming appearance, a single seizure rarely causes injury or permanent sequelae or signals the onset of epilepsy. The lifetime risk for seizure is 10% but only 2% of the population develops epilepsy, defined as usually unprovoked, recurrent seizures. The annual number of new seizures in children and adolescents is 50,000-150,000, only 10,000-30,000 of which constitute epileptic seizures.

Epilepsy has an annual incidence of 50 and a prevalence of 500-1000 per 100,000 population. The incidence is high in childhood, decreases in midlife, and then peaks in the elderly. Generally, epilepsy presents as repetitive seizures, but even a single seizure coupled with a significant abnormality on neuroimaging or a diagnostic electroencephalogram (EEG) can signify epilepsy. During childhood the incidence of partial seizures is 20 per 100,000; generalized tonic-clonic seizures, 15 per 100,000; and absence seizures, 11 per 100,000.

Only about 30% of children get a medical evaluation after a single seizure. In contradistinction, more than 80% of children with a second seizure obtain medical assistance. Recognizable, treatable seizure etiologies; negative family histories; normal physical examinations; lack of head trauma; normal EEG findings; and normal neuroimaging results indicate low risk for seizure recurrence. Each year about 3% of 6-month-old to 6-year-old children have a febrile seizure, the most common seizure entity. The likelihood of these children developing epilepsy is extremely low.

A seizure results from an abnormal, transient outburst of involuntary neuronal activity. Anoxic degeneration, focal neuron loss, hippocampal sclerosis (common in temporal lobe epilepsy), and neoplasia are examples of pathologic central nervous system (CNS) changes that can produce seizures. Why a seizure spontaneously erupts is unclear, but abnormal ion flow in damaged neurons initiates the event.

Seizures are either generalized (a simultaneous discharge from the entire cortex) or partial (focal, a discharge from a focal point within the brain). Generalized seizures impair consciousness and, with the exception of some petite mal (absence) spells, cause abnormal movement, usually intense muscle contractions termed convulsions. Because generalized convulsions occur most commonly in the absence of a focal defect, the initiating mechanism of a generalized seizure is less well understood than that of a partial seizure from a focal CNS lesion. Partial seizures may either impair consciousness (complex) or not (simple) and can start with almost any neurologic complaint, the aura, including abnormal smells, visions, movements, feelings, or behaviors. Partial seizures can progress to and thus mimic generalized seizures, a fact that sometimes obscures the true nature of the problem because the commotion of the convulsion dominates recall of events.

The etiology of epilepsy in childhood is 68% idiopathic, 20% congenital, 5% traumatic, and 4% postinfectious, but only 1% each vascular, neoplastic, and degenerative. The latter three are much more common in adulthood: 16% vascular, 11% neoplastic, and 3% degenerative. Complex partial seizures, the most difficult type to control, afflict 21% of children; generalized tonic-clonic seizures, the easiest to control, 19%; absence seizures, rare in adults, 12%; simple partial seizures 11%; other generalized seizures 11%; simultaneous multiple types, often syndrome associated, 7%; myoclonic seizures, often difficult to recognize because of limited motor activity, 14%; and other types 5%. In adults, 39% of epilepsy cases are complex partial seizures, 25% generalized, 21% simple partial, and 15% other types.

The majority of convulsions are due to an inciting event such as head trauma, CNS infection, drug ingestion, or metabolic abnormalities such as hypoglycemia, hyponatremia, or alcohol withdrawal, but the cause of many reactive seizures remains unknown. Nonspecific etiologies such as stress or sleep deprivation are often blamed for lowering the seizure threshold. Impact seizures are common after head trauma, but the 5-year risk for epilepsy is only 2%. On the other hand, 15%-30% of children with depressed skull fractures develop epilepsy. Syncopal episodes with diminished CNS perfusion often result in minor twitching or even major tonic-clonic seizures that do not portend epilepsy.

Unprovoked seizures are more likely to be epilepsy. The majority of epileptic seizures have no known cause so are termed cryptogenic. Those with identifiable causes like prior head trauma are called symptomatic. If genetic inheritance is at fault, the epilepsy is idiopathic. Genetic predisposition to epilepsy has been clearly defined for many entities, including tuberous sclerosis and juvenile myoclonic epilepsy which affects 1-3 per 1000 persons and is linked to chromosome 6. A genetic predisposition to seize is probably distributed throughout the population.

Table 9-1 presents a scheme of seizure description to guide treatment and predict outcome. Some forms of epilepsy are specially categorized as epilepsy syndromes (eg, infantile spasms [West syndrome] or benign childhood epilepsy with centrotemporal spikes [rolandic epilepsy or BECTS]). Table 9-2 lists a general classification of epilepsy syndromes.

Primary prevention includes advice to pregnant mothers to avoid addictive drug use (alcohol, cocaine, benzodiazepines), trauma (automobile safety), and infection (young kittens with toxoplasmosis). Obstetric techniques minimize birth trauma and cerebral anoxia, the leading cause of cerebral palsy, an unfortunately persistent disorder despite efforts to reduce its incidence. Family history may reveal significant errors of metabolism (Gaucher disease) or chromosomes, some of which are amenable to treatment. Strict attention to childhood immunization to prevent especially pneumococcal or Haemophilus influenzae type b infection; and to safety during childhood activities (using car seats, wearing bicycle helmets, supervision when swimming or in the bathtub) and for adolescents (wearing seatbelts); and avoidance of addictive drugs (alcohol, cocaine, phencyclidine) are examples of appropriate, primary seizure prevention strategies. Annual influenza vaccination decreases the potential for febrile illness and secondary seizures. A full night’s sleep, regular exercise, and a well-rounded diet are extremely important in the primary prevention of seizures.

Secondary prevention requires attention to the triggers, such as drugs that lower seizure threshold or cause seizures de novo (Table 9-3). Some children seize after prolonged fasting, possibly from hypoglycemia: for example, the unfed infant who seizes on Sunday morning when the parents oversleep, the “Saturday night seizure.” Stimulation from light or noise, startle responses, faints, metabolic derangements, or certain video games, television shows, or computer programs can cause repetitive seizures. Avoidance of any known precipitant is required to reduce future likelihood of another event. Individuals with epilepsy should not drive until seizure free for 6 months, swim or take baths alone, or engage in potentially dangerous activities. Patient education and referral to sources such as the Epilepsy Foundation play important roles in keeping patients healthy and active.

Symptoms and Signs

The clinician must decide whether a neurologic event could be a seizure, and if so, what evaluations are necessary (Table 9-4), and whether treatment is required to prevent recurrence. The consequences of diagnosing a seizure including the effects on the family, school, driving, and work must be considered as well as special circumstances such as risks during pregnancy. The primary tool for seizure assessment is the history including (1) age at onset; (2) family history; (3) developmental status; (4) behavior profile; (5) intercurrent distress including fever, vomiting, diarrhea, or illness exposure; (6) precipitating events, including exposure to flashing lights, toxins, or trauma; (7) sleep pattern; (8) dietary pattern; and (9) drug use. Whether an aura occurred is a critical feature pointing to a partial seizure, although a brief aura can also accompany a generalized seizure. Any symptom can constitute an aura. An aura usually requires more extensive evaluation for a focal CNS lesion. Because 20% of childhood seizures occur only at night, a description of early morning behavior, including transient neurologic dysfunction or disorientation, is especially important. Reports of preictal, ictal, and postictal events from both the patient and witnesses help to clarify the seizure type and therapy.

Mental retardation and cerebral palsy are among the most common conditions associated with epilepsy. Other cognitive disorders linked to epilepsy include attention deficit hyperactivity disorder, learning disorders, and dementia. Associated psychological difficulties such as depression, psychoses, anxiety disorders including panic attacks, eating disorders like anorexia nervosa, or personality disorders are common in epilepsy and often make recognition or control of seizures difficult. In adults sleep apnea can cause recurrent seizures. The myriad causes of seizures (Table 9-5) require diligence to elucidate.

Generalized Seizures

Tonic-clonic (grand mal) seizures are both the most common and the most readily recognized. A short cry just before the seizure, apnea, and cyanosis are usual. The majority of these seizures are reactive, do not recur, last less than 3 minutes (usual maximum 15 minutes), and have no major sequelae. Following a convulsion, Todd postictal paralysis can persist for up to 24 hours even without an underlying structural lesion. When myoclonic or tonic-clonic epilepsy begins between ages 8 and 18 years, prospects for permanent remission are poor: about 90% relapse when antiepileptic drug (AED) treatment is stopped.

More difficult to identify, typical absence spells (petit mal) are 10-30 second losses of consciousness, unresponsive stare, and occasional chewing or lip smacking without collapse. Common from ages 3 to 20 years, these spells, often precipitated by photic stimulation or hyperventilation, interrupt normal activity only briefly. Up to 50% of petit mal seizures evolve into tonic-clonic seizures, especially if the onset was during adolescence. About 10% of epileptic children have atypical absence spells with some motor activity of the extremities, duration greater than 30 seconds, and postictal confusion. Many of these children are mentally handicapped. Both types of absence spells can occur up to hundreds of times per day, creating havoc with school performance and recreational activities.