Characteristics of epileptic seizures after ischemic stroke

BACKGROUND: Anesthesia gas delivery equipment is a potentially important source of patient injury. To better define the contribution of gas delivery equipment to professional liability in anesthesia, the authors conducted an in-depth analysis of cases from the database of the American Society of Anesthesiologists Closed Claims Project. METHODS: The database of the Closed Claims Project is composed of closed US malpractice claims that have been collected in a standardized manner. All claims resulting from the use of gas delivery equipment were reviewed for recurrent patterns of injury. RESULTS: Gas delivery equipment was associated with 72 (2%) of 3,791 claims in the database. Death and permanent brain damage accounted for almost all adverse outcomes (n = 55, 76%). Equipment misuse was defined as fault or human error associated with the preparation, maintenance, or deployment of a medical device. Equipment failure was defined as unexpected malfunction of a medical device, despite routine maintenance and previous uneventful use. Misuse of equipment (n = 54, 75%) was three times more common than equipment failure (n = 17, 24%). Misconnects and disconnects of the breathing circuit made the largest contribution to injury (n = 25, 35%). Reviewers judged that 38 of 72 claims (53%) could have been prevented by pulse oximetry, capnography, or a combination of these two monitors. Overall, 56 of 72 gas delivery claims (78%) were deemed preventable with the use or better use of monitors. The year of occurrence for claims involving gas delivery equipment ranged from 1962 to 1991 and did not differ significantly from claims involving other adverse respiratory events. CONCLUSIONS: Claims associated with gas delivery equipment are infrequent but severe and continue to occur in the 1990s. Educational and preventive strategies that focus on equipment misuse and breathing circuit configuration may have the greatest potential for enhancing the safety of anesthesia gas delivery equipment.     

Time dependencies in the occurrences of epileptic seizures

A new method of analysis, developed within the framework of nonlinear dynamics, is applied to patient recorded time series of the occurrence of epileptic seizures. These data exhibit broad band spectra and generally have no obvious structure. The goal is to detect hidden internal dependencies in the data without making any restrictive assumptions, such as linearity, about the structure of the underlying system. The basis of our approach is a conditional probabilistic analysis in a phase space reconstructed from the original data. The data, recorded from patients with intractable epilepsy over a period of 1-3 years, consist of the times of occurrences of hundreds of partial complex seizures. Although the epileptic events appear to occur independently, we show that the epileptic process is not consistent with the rules of a homogeneous Poisson process or generally with a random (IID) process. More specifically, our analysis reveals dependencies of the occurrence of seizures on the occurrence of preceding seizures. These dependencies can be detected in the interseizure interval data sets as well as in the rate of seizures per time period. We modeled patient's inaccuracy in recording seizure events by the addition of uniform white noise and found that the detected dependencies are persistent after addition of noise with standard deviation as great as 1/3 of the standard deviation of the original data set. A linear autoregressive analysis fails to capture these dependencies or produces spurious ones in most of the cases.     

Maintained hypersexuality between male rats following chronically induced limbic seizures: implications for bisexuality in complex partial epileptic seizures

Adult male albino rats were given a treatment that produced hypothermia after the induction of limbic seizures by a single subcutaneous injection of lithium and pilocarpine. When housed in groups, these rats exhibited marked hypersexuality (for at least two months), defined as repeated mounting of another male, pelvic thrusting, and persistent genital licking; while the male was mounted, female postures were assumed. There were also periods of physical submission. During active periods three of the four rats were mounted and thrusting in tandem. Possible relevance to the Klüver-Bucy syndrome and to bisexuality and homosexuality in males who report elevated complex partial epileptic-like signs is discussed.     

Gene therapy: a primer for radiologists

Gene therapy is one of the most rapidly evolving areas in medicine. Radiologists should have an understanding of basic techniques used to identify and clone a gene and insert it into a vector capable of directing expression in mammalian tissues. DNA delivery systems include retroviral vectors (RNA viruses), adenoviral vectors (DNA viruses), and cationic liposomes, along with strategies that involve ultrasound-directed gene transfer, computed tomography-guided gene transfer, and transcatheter gene delivery, in particular via the hepatic artery. Genes being evaluated in preclinical and clinical trials include oncogenes, antioncogenes (tumor suppressor genes), suicide genes, conventional antimetabolites, antiangiogenesis factors, secreted immunostimulatory cytokines such as interleukins and interferons, and immunomodulatory cell surface proteins, including foreign HLA proteins and costimulatory molecules. A foundation in molecular biology is needed for the practicing radiologist interested in but unfamiliar with current gene therapy terminology and experimental strategies. Such a foundation will encourage the dissemination of basic biologic, diagnostic imaging, and interventional oncoradiologic developments and should facilitate integration of the radiologist into the gene therapy team.     

Chiropractic management of a patient with subluxations, low back pain and epileptic seizures

OBJECTIVE: To describe the chiropractic management of a patient presenting with complaints of low back pain and epileptic seizures. The discussion also addresses epilepsy and the current concepts of this disorder; possible mechanisms for the neurological effects of the chiropractic adjustment at sites of subluxation and its therapeutic implications are proposed. CLINICAL FEATURES: A 21-year-old woman with low back pain reported that she had fainted during the night and hit her head. She had been diagnosed since childhood with grand mal (tonicclonic) seizures as well as petit mal seizures. She had a seizure approximately every 3 hr, with a duration between 10 sec and 30 min for each episode. Examination indicated signs of subluxation/dysfunction at the L5-S1, C6-C7 and C3-C4 spinal levels. There was no evidence of cranial nerve involvement or any upper motor neuron lesion. Radiographic analysis revealed retrolisthesis of L5, hypolordosis of the cervical spine and hyperextension of the C6-C7 motion segment. INTERVENTION AND OUTCOME: Chiropractic adjustments using a specific-contact, short-lever arm, high-velocity, low-amplitude maneuver (i.e., Gonstead) were applied to the subluxations at the cervical, thoracic and lumbopelvic region. The patient's reported low back pain and neck complaints improved and her seizure frequency decreased. At 1.5-yr follow-up, the patient reported her low back complaints had resolved and her seizures had decreased (period between seizures as great as 2 months). CONCLUSION: Results encourage further investigation of possible neurological sequalae, such as epileptic seizures, from spinal dysfunction identified as vertebral subluxation complexes by chiropractors and treated by specific spinal adjustments.     

Apnoea and bradycardia during epileptic seizures: relation to sudden death in epilepsy

OBJECTIVE: To record non-invasively ictal cardiorespiratory variables. METHODS: Techniques employed in polysomnography were used in patients with epilepsy undergoing EEG-video recording at a telemetry unit. RESULTS: Apnoea (> 10, range > 10-63, mean 24 s) was seen in 20 of 47 clinical seizures (three secondary generalised, 16 complex partial, and one tonic) and 10 of 17 patients. Apnoea was central in 10 patients, but obstructive apnoea was also recorded in three of 10. Oxyhaemoglobin saturation (SpO2) dropped to less than 85% in 10 seizures (six patients). An increase in heart rate was common (91% of seizures). Bradycardia/sinus arrest was documented in four patients (mean maximum RR interval 5.36, range 2.8-8.6 s) but always in the context of a change in respiratory pattern. CONCLUSION: Ictal apnoea was often seen. The occurrence of bradycardia in association with apnoea suggests the involvement of cardiorespiratory reflexes. Similar mechanisms may operate in cases of sudden death in epilepsy.     

Nonlinear dynamics of epileptic seizures on basis of intracranial EEG recordings

PURPOSE: An understanding of the principles governing the behavior of complex neuronal networks, in particular their capability of generating epileptic seizures implies the characterization of the conditions under which a transition from the interictal to the ictal state takes place. Signal analysis methods derived from the theory of nonlinear dynamics provide new tools to characterize the behavior of such networks, and are particularly relevant for the analysis of epileptiform activity. METHODS: We calculated the correlation dimension, tested for irreversibility, and made recurrence plots of EEG signals recorded intracranially both during interictal and ictal states in temporal lobe epilepsy patients who were surgical candidates. RESULTS: Epileptic seizure activity often, but not always, emerges as a low-dimensional oscillation. In general, the seizure behaves as a nonstationary phenomenon during which both phases of low and high complexity may occur. Nevertheless a low dimension may be found mainly in the zone of ictal onset and nearby structures. Both the zone of ictal onset and the pattern of propagation of seizure activity in the brain could be identified using this type of analysis. Furthermore, the results obtained were in close agreement with visual inspection of the EEG records. CONCLUSIONS: Application of these mathematical tools provides novel insights into the spatio-temporal dynamics of "epileptic brain states". In this way it may be of practical use in the localization of an epileptogenic region in the brain, and thus be of assistance in the presurgical evaluation of patients with localization-related epilepsy.     

Periocular capillary hemangioma: a review for pediatricians and family physicians

We retrospectively evaluated the incidence of late accumulation of 99Tcm-HMPAO leukocytes (99Tcm-WBC) in the right lower quadrant of a large population of children and characterized some predictive patterns that would enable differentiation of active inflammation from this late occasional accumulation of 99Tcm-WBC. We reviewed the charts of 211 children. The first group evaluated consisted of 79 controls: 30 normal children with no gastrointestinal disease, but who underwent 99Tcm-WBC scanning for other medical problems, and 49 children who had non-specific gastrointestinal (GI) complaints, but had no demonstrable inflammatory bowel disease by conventional diagnostic methods. The second group consisted of 132 children with inflammatory bowel disease: 80 children with Crohn's disease (CD), 34 with ulcerative colitis (UC) and 18 with indeterminate colitis (IC). Children were imaged at 30 min and 3 h. Fifteen (19%) of the 79 controls scanned showed accumulation of 99Tcm-WBC in the right lower quadrant at 3 h and none at 30 min. Of those 15, 8 were from the control population and 7 from the group with non-specific GI complaints and negative work-ups. There was no uptake in other segments of the bowel. The accumulation was faint, of lesser intensity than in the iliac wing, and diffuse, such that identification of a specific loop of involved bowel was not possible. Migration of the 99Tcm-WBC distal to the terminal ileum was demonstrated. The other 64 children in the control group showed no accumulation of 99Tcm-WBC at any time during their scans. All 79 scans were blindly interpreted as normal studies. There were no false-positive readings encountered in the 132 children with inflammatory bowel disease (80 CD, 34 UC, 18 IC) when the aforementioned characteristics of the late accumulation of 99Tcm were used to differentiate inflammation from this physiological excretion. In conclusion, the late accumulation of 99Tcm-WBC in the right lower quadrant is characterized by (1) accumulation at no less that 3 h, (2) no accumulation in other segments of the bowel, (3) faint accumulation of lesser intensity than in the iliac wing, (4) a diffuse accumulation pattern and (5) migration of the 99Tcm-WBC into the caecum and ascending colon over time. Recognition of this excretion pattern enables differentiation of active Crohn's disease of the small bowel from migration and accumulation of 99Tcm-WBC in the right lower quadrant of the abdomen.     

Biologically-generated primer for PCR: PCR primer of unknown sequence

We describe a method for producing specific PCR primers directly from PCR product, bypassing the usual need to know the primer sequence. Lack of abundance of primers derived from a PCR product is compensated for by the incorporation of an arbitrary 5'TAG sequence which acts as a surrogate template target for the bulk amplification phase. We use the technique to amplify clonospecific rearranged immunoglobulin genes, which have applications as markers of lymphoid neoplasms for tracing the success of therapy. The principle may have wider application wherever conserved and variable regions of DNA are juxtaposed.     

The pathophysiology of the blood-brain barrier dysfunction induced by severe hypercapnia and by epileptic brain activity

Antiserum to fentanyl was obtained in rabbits repeatedly injected with carboxyfentanyl conjugated to bovine serum albumin. Using the antiserum, a highly sensitive radioimmunoassay has been developed, based on the dextran-coated charcoal method. It proved possible to assay the drug directly in plasma, in amounts as small as 30 picogram in 0.5 ml. The antibody was highly specific for fentanyl and no cross-reaction was observed with its major metabolites. This sensitive and specific radioimmunoassay method was employed to determine fentanyl in plasma from six volunteers after an intravenous bolus of 0.2 mg, and in plasma from dogs treated both intravenously and subcutaneously with 0.02 mg/kg. The plasma level of fentanyl could be followed for up to 6 h after a therapeutic dose in dogs and man.     

A stereoelectroencephalographic (SEEG) study of light-induced mesiotemporal epileptic seizures

PURPOSE: This study explored the mechanism of light-induced complex partial seizures by using ictal intracerebral recordings in a patient with refractory epilepsy of the right temporal lobe. METHODS: Presurgical evaluation of this patient was realized by means of video-EEG recordings, WADA test, magnetic resonance imaging (MRI), F18-deoxyglucose and C11-flumazenil positron emission tomography (PET) interictal neuroimaging data, and stereoelectroencephalographic (SEEG) ictal recordings. RESULTS: SEEG investigations demonstrated the right mesiotemporal origin of all the patient's seizures. This result was confirmed by a successful right temporal lobectomy. Moreover, SEEG recordings revealed a frequent interictal spiking activity in the right occipital visual cortex that was undetectable on scalp recordings. However, the occipital cortex was not involved at the onset of mesiotemporal ictal discharges and was not hyperresponsive to focal electrical stimulation. CONCLUSIONS: This study shows that, in spite of interictal occipital spiking, the photosensitivity of mesiotemporal seizures can be observed in both the absence of occipital cortex involvement during ictal discharges and demonstrable hyperexcitability of the occipital cortex to light or direct electrical stimulation.     

Reducing the incidence of epileptic seizures in the Belgian Tervuren through selection

There is growing evidence that idiopathic epilepsy in the Belgium Tervuren has a genetic foundation. Reducing the incidence of this disorder, which may afflict as much as 17% of the breed, will rely upon the wise selection of parents. Seizure data on 997 dogs from the American Belgian Tervuren Club were collected through questionnaires in which animals were classified into one of four mutually exclusive categories: 1) no seizures observed, 2) one seizure observed, 3) two to five seizures, and 4) more than five seizures. The analysis of this ordered data made use of a threshold model of Bayesian inference. Integration of posterior densities was accomplished through Gibbs sampling. Through this analysis we are able to predict that the offspring of the mating of two non-epileptic dogs has a probability of 0.99 of never suffering from a seizure. The offspring of the mating of two dogs who have each had 1 seizure has a predicted probability 0.58 of never suffering from a seizure. Prevention of this disease is best prescribed through the selection of non-epileptic dogs as parents of future generations.     

Paroxysmal and bizarre motor agitation as manifestation of partial frontal lobe epileptic seizures

Three patients, two men of 21 and 38 years and a woman of 20 years old, showed atypical seizures with motor agitation without tongue bite, incontinence or postictal confusion. After extensive video-EEG registration frontal lobe epilepsia was diagnosed. This is a relatively recently recognized disease entity.