Seizure Precipitants

Pierre Jallon

Benjamin G. Zifkin

Introduction

Seizures occur in patients with and without epilepsy. In patients without epilepsy, provoked seizures may arise from an underlying systemic disorder or be caused by direct cerebral insult. These provoked seizures, called acute symptomatic seizures (Commission) or situation-related seizures, are considered extensively in Chapter 8. Although epilepsy is defined as a condition characterized by recurrent, unprovoked seizures, it has long been recognized that even if most seizures appear to occur spontaneously, they may be provoked or the occurrence modulated by a variety of endogenous and environmental phenomena. Seizure precipitants are “those circumstances that precede the onset of an epileptic attack and are considered by both patient and neurologist to be a possible explanation for why the seizure happened when it did, and not earlier or later.”⁴ These precipitants include both seizure-inducing and seizure-triggering factors. Seizure-inducing factors are of environmental or endogenous origin and produce transient lowering of the seizure threshold.¹ More than 40 precipitating factors have been reported in the literature.¹ Seizures may be triggered by specific stimuli. The terms reflex seizures and reflex epilepsies have been proposed and this nosographic group will be developed in Chapter 257.

Knowledge of seizure precipitants has practical implications in patient treatment and counseling. Some 53% to 92% of patients reported one or more seizure precipitants.⁶^,¹⁹^,²⁴^,²⁶ Precipitants are much more frequent in patients with active and/or intractable epilepsy and in some epileptic syndromes such as idiopathic generalized epilepsies with myoclonic seizures.³^,⁶^,¹⁰ Patients often mention several factors. It is often difficult for a patient and/or the doctor to determine exactly which specific precipitant may have facilitated or triggered a seizure or to discern the relative importance of the individual factors.

Common Reported Seizure Precipitants

Emotional Stress

Although difficult to quantify, emotional stress is the most common factor (30% to 66%) identified by patients, mostly by women.⁶^,¹⁹^,²⁴^,²⁷ Since the time of Hughlings Jackson and Gowers, attention has been paid to the role of the emotions in the precipitation of epileptic seizures. Many reports provide evidence of an association between stressful life events or tension states and seizures.⁷^,¹⁰^,¹⁸^,¹⁹^,²⁶ In one study,¹⁸ 58% of patients reported emotional stress, such as worry, anxiety, frustration, and anger, as the second most frequent precipitating or modulating factor for seizures. Another study⁷ examined the psychologic factors confronting psychiatric patients with epilepsy before the onset of epilepsy. No fewer than 20 of 51 patients had experienced a severe emotional disturbance shortly before the first attack, caused, for example, by a mother-in-law’s serious illness, the death of a mother, arrest by the Gestapo, a husband’s heart attack, retirement after 45 years with the same firm, severe financial difficulties, and frequent unemployment. In patients subjected to a stress interview with electroencephalogram (EEG) recordings, neuronal instability increases during procedures, as evidenced by a seizure or emergence or increase in epileptiform activity. The mechanisms whereby emotional factors may elicit seizures have yet to be determined. An activation of specific networks has been involved. Patients with generalized seizures and those with partial seizures seemed to be equally sensitive to emotional stress.¹⁹ However, patients with temporal lobe epilepsy would be expected to be more vulnerable to emotional activation of seizures than patients with complex partial seizures because the anatomic structures involved during complex partial seizures are those that handle normal emotional responses. In one study,¹⁰ stress represented 30% of seizure precipitants. Patients with temporal lobe epilepsy were the most likely to identify stress (46%) and patients with cryptogenic epilepsies were the least (15%). However, multiple factors may converge. Emotional disturbance may lead to sleep deprivation, noncompliance, excessive drinking, and even hyperventilation. Stress may be present during a period of time ranging from minutes to days, weeks, or years. Relaxation was the most commonly used technique for aborting seizures by 53.7% of the patients, which is consistent with the fact that 53% of the patients who could identify seizure precipitants reported that stress or tension could trigger their seizures.²⁵

Sleep and Sleep Deprivation

Many patients have seizures only at night. In the 1950s, some neurologists erroneously considered sleep (“morpheic”) epilepsy as an entity. In several epileptic syndromes, such as idiopathic epilepsies, benign partial epilepsy of childhood with centrotemporal sharp waves, and symptomatic or cryptogenic frontal and temporal lobe epilepsies, seizures appear preferentially during sleep. Sleep deprivation is the second most often reported seizure precipitant in four studies.³^,⁶^,¹⁰^,¹⁹^,²²^,²⁶ As sleep deprivation usually occurs during periods of overactivity or tension often associated with the use of stimulants and overhydration, its role is not always clinically clear.¹ Patients with idiopathic epilepsies frequently reported sleep deprivation as a significant precipitant.¹⁰ There is no gender distribution. Sleep deprivation is a common precipitant of seizures in juvenile myoclonic epilepsy (JME).⁶ In the adolescent and young adult population affected by JME, late nights of studying or socializing frequently result in myoclonic jerks and generalized tonic–clonic seizures (GTCSs). Sleep deprivation as an activator of EEG epileptiform discharges is commonly used as a diagnostic aid in epilepsy⁹ but has been recently reported as not affecting seizure frequency during video EEG monitoring¹⁷ (see Chapter 188). Sudden awakening is a major precipitant of JME. Provoked awakenings are more dangerous than spontaneous ones.
The effect is more noticeable when sleep is interrupted during unstable phases, such as rapid eye movement (REM) sleep during the early part of the night and phase 2 sleep at the end of the night.

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