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<< Seizures and Status Epilepticus: Diagnosis and Management in the Emergency Department
Psychogenic Nonepileptic Seizures
Psychogenic nonepileptic seizures (pseudoseizures) are characterized by episodes of behavior and/or motor activity that are not the result of abnormal cortical discharges. It is important to note that psychogenic seizures are different from malingering and are grouped with psychoneurological illness (e.g., conversion disorders, somatoform disorders).
Psychogenic seizures can be extremely difficult to differentiate from epileptic seizures and, when inappropriately labeled, can result in mismanagement.175, 176, 177 One review cites a mean time to diagnosis as 7.2 years. 178 Several historical, clinical, and laboratory characteristics of convulsive psychogenic seizures can help the emergency physician make the correct diagnosis. 179
Epidemiology of psychogenic seizures: The prevalence of psychogenic seizures ranges from 2 to 33 cases in 100,000 persons in the general population.180 Five to ten percent of the outpatient epileptic population has PNES, compared to 20 to 40% of the inpatient epilepsy population.181, 182, 183 Confounding the diagnosis is the concurrence of psychogenic seizures with true seizures. Early studies reported that up to 60% of patients with psychogenic seizures had a coexistent neurogenic seizure disorder,184 although more recent studies using a strict definition of epilepsy report a co-existence rate of approximately 10%.188, 185 Authors have reported epileptic seizures evolving into nonepileptic events.186
Clinical characteristics: Care should be taken when using clinical characteristics to distinguish neurogenic from psychogenic seizures. In a cohort of patients referred by experienced epilepsy neurologists for video-EEG monitoring, misdiagnoses occurred in 24% of cases. 187 Characteristics that are suggestive, but not diagnostic of psychogenic seizures are listed in Table 6. Head, extremity, and pelvic thrusting movements are useful in identifying psychogenic seizures, especially if observed in conjunction with each other.187 Neurogenic seizures tend to have in-phase, synchronous tonic-clonic movement of the extremities. Asynchronous and/or thrashing movements of the extremities are more characteristic of psychogenic seizures. This is not an absolute observation and care must be used in applying these features. In particular, complex motor automatisms, such as thrashing and kicking, without an associated change in mental status or post-ictal period may be seen in supplementary motor seizures of the frontal lobe.188 Interestingly, both self-injury and urinary incontinence occur in psychogenic seizures and are not helpful in differentiating them
from neurogenic events.189
Maneuvers: While some cases of psychogenic seizures may be nearly impossible to diagnose in the ED, other cases may be uncovered with simple maneuvers. The simplest involves non-noxious sensory stimulation, such as placing a cotton swab in the nose, passive eye opening, dropping the patient’s arm over their face, or corneal stimulation. These simple tests may result in avoidance (the patient’s hand never hitting their face) or resistance (forceful eye closing) from a patient having a psychogenic seizure. In one study, 18 out of 18 patients with confirmed psychogenic seizures tested positive to avoidance maneuvers.190 The geotrophic eye test is performed by turning the patient’s head from side to side and observing the eyes: the patient will look away from the examiner, regardless of which way the head is turned.191 Noxious stimulation, such as a sternal rub, firm pressure on a digit, or an anhydrous ammonia capsule under the patient’s nose, may also terminate psychogenic seizures.192 Patients with psychogenic seizures may terminate in response to verbal suggestion.193 Many cases do not reveal themselves even with maneuvers, and ultimately require video-EEG monitoring to confirm the diagnosis. The treatment of psychogenic seizures is based on behavioral therapy aimed at identifying stressors, precipitants, and underlying psychiatric disease.194
Psychogenic seizures can be extremely difficult to differentiate from epileptic seizures and, when inappropriately labeled, can result in mismanagement.175, 176, 177 One review cites a mean time to diagnosis as 7.2 years. 178 Several historical, clinical, and laboratory characteristics of convulsive psychogenic seizures can help the emergency physician make the correct diagnosis. 179
Epidemiology of psychogenic seizures: The prevalence of psychogenic seizures ranges from 2 to 33 cases in 100,000 persons in the general population.180 Five to ten percent of the outpatient epileptic population has PNES, compared to 20 to 40% of the inpatient epilepsy population.181, 182, 183 Confounding the diagnosis is the concurrence of psychogenic seizures with true seizures. Early studies reported that up to 60% of patients with psychogenic seizures had a coexistent neurogenic seizure disorder,184 although more recent studies using a strict definition of epilepsy report a co-existence rate of approximately 10%.188, 185 Authors have reported epileptic seizures evolving into nonepileptic events.186
Clinical characteristics: Care should be taken when using clinical characteristics to distinguish neurogenic from psychogenic seizures. In a cohort of patients referred by experienced epilepsy neurologists for video-EEG monitoring, misdiagnoses occurred in 24% of cases. 187 Characteristics that are suggestive, but not diagnostic of psychogenic seizures are listed in Table 6. Head, extremity, and pelvic thrusting movements are useful in identifying psychogenic seizures, especially if observed in conjunction with each other.187 Neurogenic seizures tend to have in-phase, synchronous tonic-clonic movement of the extremities. Asynchronous and/or thrashing movements of the extremities are more characteristic of psychogenic seizures. This is not an absolute observation and care must be used in applying these features. In particular, complex motor automatisms, such as thrashing and kicking, without an associated change in mental status or post-ictal period may be seen in supplementary motor seizures of the frontal lobe.188 Interestingly, both self-injury and urinary incontinence occur in psychogenic seizures and are not helpful in differentiating them
from neurogenic events.189
Maneuvers: While some cases of psychogenic seizures may be nearly impossible to diagnose in the ED, other cases may be uncovered with simple maneuvers. The simplest involves non-noxious sensory stimulation, such as placing a cotton swab in the nose, passive eye opening, dropping the patient’s arm over their face, or corneal stimulation. These simple tests may result in avoidance (the patient’s hand never hitting their face) or resistance (forceful eye closing) from a patient having a psychogenic seizure. In one study, 18 out of 18 patients with confirmed psychogenic seizures tested positive to avoidance maneuvers.190 The geotrophic eye test is performed by turning the patient’s head from side to side and observing the eyes: the patient will look away from the examiner, regardless of which way the head is turned.191 Noxious stimulation, such as a sternal rub, firm pressure on a digit, or an anhydrous ammonia capsule under the patient’s nose, may also terminate psychogenic seizures.192 Patients with psychogenic seizures may terminate in response to verbal suggestion.193 Many cases do not reveal themselves even with maneuvers, and ultimately require video-EEG monitoring to confirm the diagnosis. The treatment of psychogenic seizures is based on behavioral therapy aimed at identifying stressors, precipitants, and underlying psychiatric disease.194
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