Nonepileptic disorders imitating generalized idiopathic epilepsies

The Orexin System: A Potential Player in the Pathophysiology of Absence Epilepsy

BACKGROUND

Absence epilepsy is characterized by the presence of spike-and-wave discharges (SWDs) at the EEG generated within the cortico-thalamo-cortical circuit. The molecular mechanisms involved in the pathophysiology of absence epilepsy are only partially known. WAG/Rij rats older than 2-3 months develop spontaneous SWDs, and they are sensitive to anti- absence medications. Hence, WAG/Rij rats are extensively used as a model for absence epilepsy with predictive validity.

OBJECTIVE

The aim of the study was to examine the possibility that the orexin system, which supports the wake status in experimental animals and humans, plays a role in the pathophysiology of absence seizures.

METHODS

The perspective grounds its method from recent literature along with measurements of orexin receptor type-1 (OX1) protein levels in the thalamus and somatosensory cortex of WAG/Rij rats and non-epileptic Wistar control rats at two ages (25 days and 6-7 months). OX1 protein levels were measured by immunoblotting.

RESULTS

The analysis of the current literature suggests that the orexin system might be involved in the pathophysiology of absence epilepsy and might be targeted by therapeutic intervention. Experimental data are in line with this hypothesis, showing that OX1 protein levels were reduced in the thalamus and somatosensory cortex of symptomatic WAG/Rij rats (6-7 months of age) with respect to non-epileptic controls, whereas these differences were not seen in pre-symptomatic, 25 days-old WAG/Rij rats.

CONCLUSION

This perspective might pave the way for future studies on the involvement of the orexinergic system in the pathophysiology of SWDs associated with absence epilepsy and its comorbidities.

Is it really a seizure? The challenge of paroxysmal nonepileptic events in young infants

Paroxysmal nonepileptic events (PNE) comprise of a variety of nonepileptic behaviors and are divided into various types. A more accurate diagnosis is possible by examining the video clip provided by the caregiver. In infants, physiologic PNE accounts for the majority of the PNE. It is important to exclude epilepsy, for which blood tests, electroencephalography, and imaging tests can facilitate differential diagnosis. Since most PNE have a benign progress, symptoms often improve with age and without special treatment. Therefore, it is important to reassure the caregivers after making an accurate diagnosis.

Reflex anoxic seizures (RAS) in an adult patient: a separate entity from epilepsy

Reflex anoxic seizures (RAS) are essential in the differential diagnosis of non-epileptic paroxysmal seizures. They are precipitated by vagally mediated brief cardiac asystole, which in turn leads to transient cerebral ischaemia. RAS are usually seen in infants and preschool children, but in this case happened in a middle-aged man. Our patient is a 61-year-old man who presented with sudden, repeated contractions of his left upper arm and urine incontinence, followed by loss of consciousness for about 30 s. He reported a similar episode occurred 2 years earlier. He did indicate episodic confusion pointing towards possibility of more occurrences. In the emergency department, he developed a similar seizure, during which telemetry revealed sinus arrest lasted for 4-6 s that was followed by junctional escape. Implantation of a pacemaker resulted in total cessation of sinus arrest and seizure activity during the admission. On 1-year follow-up, patient and family members did not report episodic confusion or any seizure-like activity. RAS constitute a particular entity of seizures and need careful interpretation and management. They have a similar pathophysiology to cardiac syncope. Successful prevention of cerebral hypoperfusion with a cardiac pacemaker usually leads to complete resolution of symptoms in patients with RAS as demonstrated in this case.

Narcolepsy Type 1 and Idiopathic Generalized Epilepsy: Diagnostic and Therapeutic Challenges in Dual Cases

STUDY OBJECTIVES

The aim of this study is to describe the possible co-occurrence of narcolepsy type 1 and generalized epilepsy, focusing on diagnostic challenge and safety of dual treatments.

METHODS AND RESULTS

Four patients with comorbidity for narcolepsy type 1 and idiopathic generalized epilepsy are reported: in three cases the onset of epilepsy preceded narcolepsy type 1 appearance, whereas in one case epileptic spells onset was subsequent. Patients presented with absences, myoclonic and tonic-clonic seizure type: in the patient with tonic-clonic seizures the dual pathology was easily recognized, in the other cases the first diagnosis caused the comorbid disease to be overlooked, independent of the time-course sequence. All four patients underwent neurological examination, video-electroencephalogram during which ictal and interictal epileptic discharges were recorded, and sleep polysomnographic studies. Repeated sleep onset rapid eye movement periods (SOREMPs) were documented with the multiple sleep latency test (MLST) in all the four cases. All patients had unremarkable brain magnetic resonance imaging studies and cerebrospinal hypocretin-1 was assessed in two patients, revealing undetectable levels. The association of antiepileptic drugs and substances currently used to treat narcolepsy type 1, including sodium oxybate, was effective in improving seizures, sleep disturbance, and cataplexy.

CONCLUSIONS

Narcolepsy type 1 may occur in association with idiopathic generalized epilepsy, leading to remarkable diagnostic and therapeutic challenges. Electrophysiological studies as well as a comprehensive somnologic interview can help confirm the diagnosis in patients with ambiguous neurological history. Sodium oxybate in combination with antiepileptic drugs is safe and effective in treating cataplexy and excessive daytime sleepiness.

Improved quality of life after treatment of prolonged asystole during breath holding spells with a cardiac pacemaker

Objectives:

To validate the physical and psychological effectiveness of cardiac pacing in pediatric patients with breath-holding spells (BHS) and prolonged asystole.

Materials and Methods:

The records and clinical data of all the patients with BHS who presented to our center in the period of 2001–2013 were reviewed. All patients who received cardiac pacemaker implantation for prolonged asystole during BHS were included. In addition, the parents were asked to fill out a standardized quality of life (QOL) questionnaire.

Results:

Seven patients were identified. The mean onset of symptoms was 7 month (1–12 months) of age, documented asystole was 12–21 seconds, and a permanent cardiac pacemaker device was implanted at a mean age of 23 months (8 months–3.9 years). No pacemaker related adverse events were recorded. Follow up showed immediate resolution from spells in four cases (4/7). Two patients (2/7) showed significant reduction of frequency and severity of spells, with complete elimination of loss of consciousness (LOC). One patient (1/7) with an additional neurologic disorder continued to have minor pallid BHS and eventually switched from pallid to cyanotic spells without further detection of bradycardia or asystole in holter examination. QOL questionnaire revealed significant reduction in subjective stress levels of patients (P = 0.012) and parents (P = 0.007) after pacemaker implantation.

Conclusion:

Cardiac pacing using appropriate pacemaker settings seems effective in the prevention of LOC and reduction of the frequency of BHS. Our results imply a reduction of subjective stress levels of patients and parents as well as an increased quality of everyday life. After all, randomized controlled trials of the influence of cardiac pacemaker implantation on subjective stress levels in patients with BHS are needed.

Simultaneous recording of EEG and electromyographic polygraphy increases the diagnostic yield of video-EEG monitoring

PURPOSE

To investigate the usefulness of adjunctive electromyographic (EMG) polygraphy in the diagnosis of clinical events captured during long-term video-EEG monitoring.

METHODS

A total of 40 patients (21 women, 19 men) aged between 19 and 72 years (mean 43) investigated using video-EEG monitoring were studied. Electromyographic activity was simultaneously recorded with EEG in four patients selected on clinical grounds. In these patients, surface EMG electrodes were placed over muscles suspected to be activated during a typical clinical event.

RESULTS

Of the 40 patients investigated, 24 (60%) were given a diagnosis, whereas 16 (40%) remained undiagnosed. All four patients receiving adjunctive EMG polygraphy obtained a diagnosis, with three of these diagnoses being exclusively reliant on the EMG recordings. Specifically, one patient was diagnosed with propriospinal myoclonus, another patient was diagnosed with facio-mandibular myoclonus, and a third patient was found to have bruxism and periodic leg movements of sleep.

CONCLUSIONS

The information obtained from surface EMG recordings aided the diagnosis of clinical events captured during video-EEG monitoring in 7.5% of the total cohort. This study suggests that EEG-EMG polygraphy may be used as a technique of improving the diagnostic yield of video-EEG monitoring in selected cases.

Comparing standard medical care for nonepileptic seizures in Chile and the United States

OBJECTIVE

We sought to compare the diagnostic and treatment practices for psychogenic nonepileptic seizures (PNES) in the United States (US) to Chile.

METHODS

A survey on the diagnostic and treatment practices for PNES was administered to practicing clinicians in Chile. Results from 96 Chilean respondents were compared to results from 307 US clinicians. Type I error (alpha) was set to 0.005 for multiple comparisons.

DIAGNOSIS

The diagnosis of PNES is made by inpatient video-EEG/LTM in 89% of the US respondents compared to 25% of the Chilean respondents (p<0.0001). The diagnosis of PNES is made by history and exam alone at twice the rate in Chile (38%) than in the US (16%; p<0.0001).

TREATMENT

A higher proportion of the Chilean respondents (65%) endorsed psychopharmacotherapy as potentially beneficial compared to the US respondents (31%; p<0.0001).

DISCUSSION

This cross-cultural multi-site survey reveals some differences in PNES evaluation and management between neurologists and other clinicians in the US and in Chile. Access to video EEG may improve PNES diagnosis and treatment.

Patients with psychogenic non-epileptic seizures referred to a tertiary epilepsy centre: patient characteristics in relation to diagnostic delay

OBJECTIVE

This clinical study examines patient and seizure characteristics of patients with psychogenic non-epileptic seizures (PNES) in a tertiary epilepsy centre. The main focus was whether a new subgroup of PNES patients emerged with a relatively short referral time and possible specific characteristics.

METHODS

All PNES patients referred to a specialist program in our centre between mid 2007 and mid 2009 were consecutively included. This yielded a study cohort of 90 patients.

RESULTS

The majority of the patients have a patient history with many medical symptoms and they were or had been in treatment by a medical specialist. Furthermore diffuse psychological/psychiatric symptoms and subsequent treatments are also remarkably common, in general without a clear psychological diagnosis. The average time between seizure onset and referral to an epilepsy centre is remarkably low (4.29 years). About 50% of the patients were referred within 2 years of seizure onset. This 'active high speed referral group' had significantly more previous psychological complaints, significantly more previous psychological/psychiatric treatments and a trend towards more previous medical investigations.

CONCLUSION

There seems to be a new subgroup of PNES patients with a short referral time, characterized by a more active attitude towards examination of the symptoms in combination with an active attitude to apply for treatment. However, the PNES cohort as a whole is characterized by having somatoform symptoms based on a process of somatization.

Narcolepsy: a review

Narcolepsy is a lifelong sleep disorder characterized by a classic tetrad of excessive daytime sleepiness with irresistible sleep attacks, cataplexy (sudden bilateral loss of muscle tone), hypnagogic hallucination, and sleep paralysis. There are two distinct groups of patients, ie, those having narcolepsy with cataplexy and those having narcolepsy without cataplexy. Narcolepsy affects 0.05% of the population. It has a negative effect on the quality of life of its sufferers and can restrict them from certain careers and activities. There have been advances in the understanding of the pathogenesis of narcolepsy. It is thought that narcolepsy with cataplexy is secondary to loss of hypothalamic hypocretin neurons in those genetically predisposed to the disorder by possession of human leukocyte antigen DQB1*0602. The diagnostic criteria for narcolepsy are based on symptoms, laboratory sleep tests, and serum levels of hypocretin. There is no cure for narcolepsy, and the present mainstay of treatment is pharmacological treatment along with lifestyle changes. Some novel treatments are also being developed and tried. This article critically appraises the evidence for diagnosis and treatment of narcolepsy.

Seizure-like activities during head-up tilt test-induced syncope

PURPOSE

Some patients with neurally mediated reflex syncope may be misdiagnosed as epilepsy because myoclonic jerky movements are observed during syncope. The seizure-like activities during the head-up tilt test (HUT) have been rarely reported. The purpose of this study was to assess the characteristics of these seizure-like activities and evaluate whether there are differences in the clinical characteristics and hemodynamic parameters of patients with neurally mediated reflex syncope with and without seizure-like activities during HUT-induced syncope.

MATERIALS AND METHODS

The medical records of 1,383 consecutive patients with a positive HUT were retrospectively reviewed, and 226 patients were included in this study.

RESULTS

Of 226 patients, 13 (5.75%) showed seizure-like activities, with 5 of these (2.21%) having multifocal myoclonic jerky movements, 5 (2.21%) having focal seizure-like activity involving one extremity, and 3 (1.33%) having upward deviation of eye ball. Comparison of patients with and without seizure-like activities revealed no significant differences in terms of clinical variables and hemodynamic parameters during HUT.

CONCLUSION

Seizure-like activities occurred occasionally during HUT-induced syncope in patients with neurally mediated reflex syncope. The seizure-like activities during HUT might not be related to the severity of the syncopal episodes or hemodynamic changes during HUT.

Familial benign neonatal sleep myoclonus

Benign neonatal sleep myoclonus is a nonepileptic syndrome characterized by myoclonic jerks during sleep. It occurs in the first weeks of life and disappears, in most cases, within 3 months. There are no sequelae, and psychomotor and cognitive development are normal. The syndrome is usually sporadic; only a few familial cases have been reported in the literature. This case report describes three members of a single family with benign neonatal sleep myoclonus and discusses its differentiation from other types of myoclonus.

Delayed post-ictal event-related potentials do not differentiate between generalized tonic-clonic seizures and syncope

BACKGROUND

The differentiation between generalized tonic-clonic seizure (GTCS) and syncope is an important clinical problem. Corroborative investigations, which are requested when history is unclear or insufficient, have limited diagnostic value. The aim of our study was to determine whether auditory event-related potentials (ERPs) can be utilized in post-event differentiation between GTCS and syncope.

MATERIALS AND METHODS

ERPs were recorded in 18 patients with a single seizure and in 21 patients following syncope, either on one or two occasions. ERP latencies and amplitudes were compared between groups and sessions.

RESULTS

No significant differences of P3, N2, P2 and N1 latencies and P3, N2 and P2 amplitudes were found between patients following a single GTCS as compared to patients following syncope on either session.

CONCLUSION

Post-event ERPs are insufficient to differentiate between GTCS and syncope. Further investigations are needed to evaluate the influence of different post-event intervals and ERP paradigms on ERP parameters in patients with GTCS.