The diagnosis of epilepsy is made on the basis of the clinical history of the seizures taken from the patient and often from a witness. The prototypical seizure, the tonic-clonic seizure (previously called grand mal seizure), often starts with sudden loss of consciousness, with the patient falling stiffly (the tonic phase); this is followed by rhythmic jerking of the limbs and torso (the clonic phase), which slows and then stops abruptly. Such seizures usually last only 60 to 90 seconds. The patient awakens after a period of postictal stupor, which usually lasts less than 15 minutes, but confusion may persist considerably longer. Such seizures coincide with very rapid, abnormal cortical and subcortical neuronal activity, which is recruited so rapidly that it appears synchronously in all brain areas when recorded on an electroencephalogram (EEG).

The physiologic abnormalities that may accompany these attacks include apnea, hypoxemia, acidosis, and autonomic disruptions such as cardiac arrhythmias and hypertension. Pulmonary edema can occur and may play a role in the syndrome of sudden death that occurs occasionally even in young, otherwise healthy patients with epilepsy. Other physical complications may include dislocation of the shoulder, vertebral collapse, and aspiration pneumonia.

Focal or partial seizures begin in a localized cortical area, with the clinical ictal phenomena being determined by the brain region involved. For example, seizures beginning with abnormal neuronal activity in primary motor cortex may cause initial twitching of the face or limb, depending on the exact site of onset. The patient with an occipital ictal focus may report flashing lights or globes, often in the visual field contralateral to the focus. Foci in the temporal lobes often produce autonomic symptoms such as nausea or complex psychic experiences such as intense feelings of familiarity (déjà vu) or feelings of strangeness. Such recalled seizure onsets commonly are called auras; although commonly construed as warnings of seizures they actually reflect the beginnings of the seizures themselves. The duration of focal seizures is generally 30 to 60 seconds.

Focal seizures that end without impairment of consciousness are termed simple partial seizures. Whether they begin with an aura or with sudden loss of awareness, focal seizures that at some time impair consciousness are called complex partial seizures. A witness typically reports that the patient stares and becomes unreactive, and that the patient may carry out simple motor activities such as picking at the clothes, walking about, or most typically smacking the lips. Complex partial seizures also last about a minute and may or may not be followed by postictal confusion. Both simple and partial seizures may spread throughout the brain, developing into a typical tonic-clonic seizure.

There are also less dramatic seizure types, many occurring more commonly in children than in adults. An absence seizure (previously called petit mal seizure) refers to a brief episode of loss of awareness, occuring without warning, lasting for a few seconds, and ending with immediate resumption of consciousness. The patient usually stops what she is doing; the eyes remain open or may blink rapidly, but the patient does not fall. Absences may occur many times per day. Patients often are unaware of them, and they commonly are noted first by family members or teachers.

Another brief seizure type is the myoclonic seizure, which consists of sudden, brief single or repetitive jerks of the limbs without warning. Myoclonic seizures occur without warning and generally last only a few seconds. Consciousness sometimes is impaired, but like the absence seizure, the myoclonic seizure is followed by immediate return to full awareness without a postictal state.

Less common are the brief atonic or akinetic seizures, which consist of sudden falls without warning, usually but not always with loss of consciousness. Although brief, these seizures can be very dangerous, with patients often suffering injuries to the face or skull.

The primary generalized epilepsies are a group of disorders which usually present in childhood, respond well to treatment, and may have high rates of remission. They generally are considered genetic in origin, most having nonspecific inheritance patterns but definite family clustering. The seizure types seen in these syndromes vary and may include generalized tonic-clonic seizures, absence seizures, and myoclonic seizures.

Patients with primary generalized epilepsies usually have normal neurologic examinations,
are of normal intelligence, and give no history suggesting preexisting brain pathology. The EEG shows normal background activity, often interrupted by bursts of generalized spike-andwave discharges. Primary generalized epilepsies make up 30% to 40% of childhood epilepsies.

Virtually all of the primary generalized epilepsies are age related, beginning and often remitting at specific times of life. The most common syndrome is that of febrile seizures, which occur in nearly 5% of children, generally between the ages of 1 and 3 years. Uncomplicated febrile seizures stop by the age of 5 years and are not associated with an increased risk of seizures in later life. On the contrary, when the seizures are prolonged (30 minutes or more), repeated, or followed by postictal hemiparesis (Todd’s paralysis), children do have an increased risk of developing a chronic seizure disorder, which sometimes appears years later in the form of complex partial or other seizure types. Such syndromes are called complicated febrile seizures.

Childhood absence epilepsy usually begins between the ages of 4 and 10 years with the appearance of absence seizures. In 30% to 40% of cases, tonic-clonic seizures appear around the time of puberty. Seizures usually respond easily to medical treatment, and the remission rate by young adulthood may reach 80% to 90%. Before treatment, the EEG usually shows normally developed background activity interrupted by hyperventilation-induced three per second spikeand-wave activity (see Diagnosing Epilepsy), which is characteristic and helpful for diagnosis.

Juvenile myoclonic epilepsy is one of the most common genetically based epilepsies, with onset between the ages of 10 and 20 years. Patients usually present with a tonic-clonic seizure occurring without warning, often in the early morning. If specifically asked, they also give a history of recent involuntary jerks of the limbs or dropping of objects from the hands. These myoclonic seizures also occur most commonly in the morning and often immediately precede the “big” seizure that usually brings them to medical attention. Sleep deprivation or alcohol use commonly triggers seizures. The EEG shows characteristic polyspike-and-wave discharges elicited by strobe lights. The seizures themselves, however, are not sensitive to flashing lights. This type of epilepsy persists for decades or may even be lifelong.

In contrast to the previously mentioned seizure types, almost all adult epilepsies, as well as the majority beginning in childhood, are focal or localization-related epilepsies, with focal or partial seizures. The occurrence of focal seizures implies the existence of focal brain pathology. An almost unlimited variety of clinical seizure phenomena may occur, depending on the site of brain injury.

In the diagnosis of all forms of epilepsy, taking a meticulous history from the patient as well as from witnesses to the seizures is essential. The precise sequence of events making up the attacks reveals the site of seizure onset in the brain and the route and extent of seizure propagation through the brain. For example, a patient with a meningioma growing over the right cerebral hemisphere may present with focal motor seizures of the left leg resulting from irritation of nearby cerebral motor cortex by the tumor. Such an attack may spread down along the precentral (motor) gyrus, sequentially involving the cortex controlling the left arm. If the patient remains conscious throughout the seizure, the episode is called a simple partial seizure. Commonly, however, intrinsic cerebral inhibitory mechanisms fail to keep the seizure localized, and the electrical discharge may spread suddenly into thalamic and other brain structures with strong, widespread cortical projections. In this case, a generalized tonic-clonic seizure ensues. Unless the clinician obtains the history of focal onset of such an attack, a mistaken diagnosis of primary generalized epilepsy may be made, and a search for localized brain disease may be left undone.

A completely different symptom complex may be reported by the patient with temporal lobe injury, such as that following encephalitis, anoxia, or complicated febrile convulsions. A complex partial seizure often begins with a subjective experience such as a sudden feeling of strangeness or an abrupt sensation of nausea moving upward from the epigastrium. If the seizure discharges remain confined to a small area of the temporal lobe, the attack may not proceed further and may end in 30 to 60 seconds. If, however, the seizure spreads throughout both sides of the limbic system, consciousness may be altered or lost. The patient may stare vacantly or may appear to look about, becoming unresponsive and often making simple movements (automatisms) such as lip smacking, grimacing, or hand wringing. He may stand or sit still or may walk about aimlessly. Because of the intimate relationship between limbic cortical structures and the hypothalamus, autonomic signs and symptoms such as piloerection, change in skin color, borborygmus, or an urge to urinate are common in complex partial seizures. If the seizure stops at this point, the altered behavior also stops abruptly, but the patient may remain confused for several minutes or longer. If the seizure has started in the speech-dominant hemisphere, language function may be temporarily impaired postictally. If the ictal activity spreads further, however, a full-fledged tonic-clonic seizure occurs. Patients may be able to describe vividly the onset or aura of such attacks, but many subjects with temporal lobe seizures have no recall of events before loss of consciousness, and the physician must rely on witnesses for a full description of the episodes.

Focal epilepsy, with or without secondary generalization of the attacks, is by far the most common form of seizure disorder seen by the primary care physician and by most neurologists. Within this category, complex partial seizures are the most prevalent type. Many patients with partial seizures find complete relief from attacks with medication, but about 30% continue to have some seizures even with competent medical advice and optimal therapy.

The clinical picture becomes even more complex in the patient with multifocal or diffuse brain injury. Such a person may be subject to two or sometimes three seizure types. Generalized motor convulsions, focal seizures of any type, or absence attacks all may occur chronically. Additional patterns also may be present, often as fragments (tonic seizures) or distinctive types of episodes such as sudden losses of muscle tone with falling (akinetic seizures). Patients with these multiple seizure types nearly always bear other stigmata of serious cerebral injury such as mental retardation or cerebral palsy. In such cases, seizures are often difficult if not impossible to control with drugs, are almost always lifelong, and are best handled with the help of a neurologist or epileptologist.

Epilepsy takes a heavy toll on many aspects of patients’ lives. Although prejudicial attitudes are softening gradually, epilepsy is still a condition often hidden from those outside the family. Social stigmatization is still surprisingly high, often affecting employment, insurability, and self-esteem. When the condition is poorly controlled, it can dominate and define relationships between parents, children, spouses, and siblings. Children may be sheltered excessively by parents and teachers, which may cause social maturation to be delayed or prevented. Depression and anxiety are very common and underdiagnosed in those with epilepsy, and suicide rates are above average. Learning difficulties in children with epilepsy are common and sometimes overlooked.

Details of state regulations vary, but usually the patient with epilepsy who cannot demonstrate complete, long-term control of the attacks is prohibited from driving. Public transportation and car pools are often inadequate solutions for day-to-day autonomy. Because a diagnosis of epilepsy has far-reaching implications for the
life of the patient, it is essential that the diagnosis be neither missed nor misapplied.

Epilepsy is diagnosed through the patient’s history—not by head scans, EEGs, or the neurologic examination. In cases when a seizure disorder is suspected, the physician must spend adequate time with the patient and often with witnesses to the attacks to make a reliable diagnosis.

In most cases, asking the patient for a detailed account of the last episode, or of the last one the patient recalls well, often evokes precise details and a coherent impression. Physicians should ask what the patient was doing when the attack began. They should inquire about the first thing that occurred when the attack started and what happened next. They also should ask how the patient felt after the episode ended and if any focal weakness or speech difficulty was present, details that might reveal the focal nature of the seizure.

The stereotypy of the attacks is an important diagnostic point, because for the individual patient, seizures are highly consistent events. Even when there is more than one seizure type, each type has its own stereotypy. Significant variation in the pattern of attacks argues against epilepsy.

The duration of seizures is generally invariant. Except for brief absence or myoclonic seizures, which generally last 5 to 15 seconds, most focal or tonic-clonic seizures last 30 to 90 seconds. The postictal recovery period depends on the type of seizure, but actual seizurelike episodes that last many minutes to hours are usually not epileptic.

Finally, a brief history from a witness is often crucial. What does the witness see and how does the attack begin? Patients with complex partial seizures sometimes recall the aura that begins the seizure, but are unaware of the subsequent loss of awareness. A witness may provide the crucial description of the blank stare and unresponsiveness typical of this type of seizure. The details of such seizures are crucial in discussing safety issues such as driving.

Discriminating between absence and complex partial seizures sometimes may be a diagnostic hurdle. The latter is much more common than the former, especially in adults. Making the correct diagnosis is important because only complex partial seizures imply the presence of focal brain disease and the therapies for the two types vary somewhat. If a reliable witness can be found, the two seizure types can be distinguished accurately by the duration of the attack. Almost all absence seizures last less than 15 seconds, and many are shorter. However, most complex partial seizures continue for more than 30 seconds, with many lasting 1 to 1.5 minutes. Auras, automatisms, and postictal confusion are common with complex partial seizures but are not characteristic of absence seizures. Postictal language difficulty or other focal neurologic signs may be reported after a complex partial seizure.