Limbic Self-sustaining Status Epilepticus in Rats Is Not Associated with Hyperthermia

Hypothermia as a treatment in status epilepticus: A narrative review

Status epilepticus (SE) is associated with high mortality and morbidity rates, notably in its refractory and super-refractory forms. This narrative review discusses recent data on the potential benefits of targeted temperature management. In studies of patients with cerebral injury due to various factors, therapeutic hypothermia had variable effects on survival and functional outcomes. Sources of this variability may include the underlying etiology, whether hypothermia was used for prophylaxis or treatment, the degree and duration of hypothermia, and the hypothermia application modalities. Data from animal studies strongly suggest benefits from therapeutic hypothermia in SE. In humans, beneficial effects have been described in anecdotal case reports and small case series, but the level of evidence is low. A randomized controlled trial found no evidence that moderate hypothermia (32-34 °C) was neuroprotective in critically ill patients with convulsive SE. Nevertheless, some promising effects were noted, suggesting that therapeutic hypothermia might have a role as an adjuvant to anticonvulsant drug therapy in patients with refractory or super-refractory SE. This article is part of a Special Issue entitled "Status Epilepticus". This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".

A companion to the preclinical common data elements for physiologic data in rodent epilepsy models. A report of the TASK3 Physiology Working Group of the ILAE/AES Joint Translational Task Force

The International League Against Epilepsy/American Epilepsy Society (ILAE/AES) Joint Translational Task Force created the TASK3 working groups to create common data elements (CDEs) for various aspects of preclinical epilepsy research studies, which could help improve standardization of experimental designs. This article concerns the parameters that can be measured to assess the physiologic condition of the animals that are used to study rodent models of epilepsy. Here we discuss CDEs for physiologic parameters measured in adult rats and mice such as general health status, temperature, cardiac and respiratory function, and blood constituents. We provide detailed CDE tables and case report forms (CRFs), and with this companion manuscript we discuss the monitoring of different aspects of physiology of the animals. The CDEs, CRFs, and companion paper are available to all researchers, and their use will benefit the harmonization and comparability of translational preclinical epilepsy research. The ultimate hope is to facilitate the development of biomarkers and new treatments for epilepsy.

Hypothermia did not prevent epilepsy following experimental status epilepticus

In epilepsy research, one of the major challenges is to prevent or at least mitigate development of epilepsy following acquired brain insult by early therapeutic interventions. So far, all pharmacological antiepileptogenic treatment approaches were largely unsuccessful in clinical trials and in experimental animal studies. In a well-established rat model of chronic epilepsy following self-sustaining status epilepticus (SSSE), we assessed the antiepileptogenic properties of 3-h-cooling induced directly after the end of SSSE. Occurrence of spontaneous seizures and seizure severity up to 8 weeks after SSSE were compared with normothermic SSSE controls. Furthermore, electrophysiological parameters assessing inhibition and excitation in the dentate gyrus were assessed at multiple time points. Post SSSE hypothermia did not prevent the occurrence of seizures in any animal. Eight weeks after SSSE, Racine motor seizures trended to be less severe following cooling (4.0±0.6) compared with normothermic controls (4.8±0.2) but the difference was not significant when testing for multiple comparisons. Early loss of inhibition that is typically seen following SSSE was somewhat attenuated in cooled animals 3h after SSSE as expressed by smaller paired-pulse ratios (PPR; 0.16±0.21) compared with normothermic controls (0.54±0.21) but difference was not significant either. Latency between stimulus artefact and excitatory post-synaptic potential 3h after SSSE, reciprocally reflecting neuronal excitation, was higher in animals that underwent hypothermia (8.29±2.45 ms) compared with controls (4.82±0.66 ms), difference was not significant after correction for multiple comparisons. In summary, the current experiments were not able to demonstrate prevention or mitigation of epileptogenesis with immediate short-term cooling following SSSE.

Deep hypothermia terminates status epilepticus--an experimental study

In search for novel treatment approaches in status epilepticus, the anticonvulsant effect of moderate and deep hypothermia was assessed in a rodent model. Self-sustaining status epilepticus (SSSE) characterized by spontaneous high-amplitude discharges recorded from the dentate gyrus was induced in male adult rats by electrical stimulation of the perforant path. After the end of stimulation, rats underwent cooling to 30 °C (n=7) and 20 °C (n=10) for 120 min and rewarming to 37 °C for another 60 min. Control SSSE animals (n=6) remained untreated for 180 min. Frequency of epileptiform discharges was assessed every 10 min. At the target temperature of 20 °C, SSSE was completely suppressed in four rats, this effect was not observed in any animal of the other two groups (p=0.043). On rewarming, seizure activity did not reoccur. Discharge frequency was significantly lower in the 20 °C group at most time points after 60 min of cooling. Following deep hypothermia, eight animals were rewarmed, all survived and moved spontaneously at 37 °C. These experimental data indicate the strong and enduring anticonvulsant and obviously safe properties of cooling down to 20 °C. Patients with status epilepticus refractory to first- and second-line anticonvulsants may benefit from deep cooling as an effective non-pharmacological adjunct to anesthetic anticonvulsants.

Hypothermia reduces brain edema, spontaneous recurrent seizure attack, and learning memory deficits in the kainic acid treated rats

AIMS

It is unknown whether hypothermia can disrupt the progress of epileptogenesis. The present study aimed to determine the effect of hypothermia on brain edema and epileptogenesis and to establish whether brain edema is associated with epileptogenesis after severe status epilepticus (SE).

METHODOLOGY

Rats were injected with a single dose of Kainic acid (KA) to produce either chronic epileptic rats (rats with spontaneous recurrent seizure, SRS) or rats without spontaneous recurrent seizure (no-SRS rats). A second KA injection was used to induce SE in SRS rats and in no-SRS rats. The number of SRS was counted and the brain edema induced by SE was assessed by brain water content measurement. The cognitive function was assessed by the radial-arm maze (RAM) test.

RESULTS

A second KA injection resulted in brain edema that was more severe in SRS rats than in no-SRS rats. After second injection of KA, hypothermia treatment attenuated the KA induced brain edema and reduced the SRS attack in SRS rats. Additionally cognitive function was better in hypothermia-treated SRS rats than in nomothermia treated SRS rats 1 month after the second KA injection.

CONCLUSIONS

Hypothermia treatment immediately after SE not only exhibited protective effects against the chronic spontaneous recurrent convulsant seizures but also improved cognitive function. These antiepileptogenic properties of hypothermia may be related to its attenuating effect on brain edema induced by SE. They therefore suggest that brain edema may be involved in the progress of epileptogenesis.

Klinische Jugendpsychologie

Zusammenfassung: Klinische Jugendpsychologie beschäftigt sich mit auffälligen Entwicklungsverläufen im Übergang zum Erwachsenenalter. Problematische Entwicklungen stellen Rauchen und Alkoholgebrauch/-missbrauch dar. Besondere Anforderungen und Belastungen ergeben sich aus körperlich-chronischen Erkrankungen. Psychische Reaktionen auf Anforderungen und Belastungen äußern sich vielfach geschlechtsspezifisch.

Temperature regulation is compromised in experimental limbic status epilepticus

Temperature dysregulation is well known in generalized convulsive status epilepticus but so far has not been reported in non-convulsive forms. In order to detect possible subtle alterations, we have analyzed the capability to compensate for external cooling in an animal model of limbic status epilepticus. Rats with electrically induced self-sustaining status epilepticus (SSSE) (n=6) as well as rats without electrical stimulation (n=6) were cooled for 3 h and then rewarmed for another hour. The time course of changes in epidural temperature in animals of both groups that underwent cooling and in control rats that were not cooled and not stimulated (n=6) was compared. In animals with limbic SSSE, temperature fell continuously and was significantly lower at all time points under cooling as compared with each of the two other groups. In animals that were not stimulated, temperature under cooling fell by 1 to 2 degrees C only and was not significantly different at any time point as compared with controls. The effect of cooling was reversible in both groups. The current data indicate that temperature homeostasis in limbic status epilepticus is markedly disturbed. This finding may suggest ictal involvement of primary thermoregulatory neurons in the anterior hypothalamus probably by spread of epileptic activity from temporo-mesial structures.

Trends und Anwendungsgebiete der Klinischen Kinderpsychologie

Zusammenfassung: Die noch junge Disziplin der Klinischen Kinderpsychologie zeigt in verschiedenen Anwendungsgebieten erhebliche Fortschritte auf. Im Detail werden ausgeführt: Entwicklungs- und Intelligenzdiagnostik, Betreuung chronisch kranker Kinder und Jugendlicher, Essstörungen und Adipositas, ADHS, Lernstörungen, familienorientierte Diagnostik und Therapie sowie Qualitätssicherung in der psychotherapeutischen Versorgung. Einige Konzepte (z. B. ADHS) besitzen eine immer größere Bedeutung in der Psychiatrie und Klinischen Psychologie des Erwachsenenalters. Die entwicklungsorientierte Denkweise kann als zukunftsweisend für die Psychotherapie und Psychiatrie angesehen werden.

Epilepsien im Jugendalter

Zusammenfassung: Der Beitrag stellt die Bedeutung chronischer Erkrankungen des Jugendalters im Hinblick auf die Interaktion mit allgemeinen normativen Entwicklungsaufgaben der Adoleszenz dar und spezifiziert dann die besonderen psychosozialen Charakteristika der Epilepsie als häufigste neurologische Erkrankung des Jugendalters. Die besondere Bedeutung der Compliance und Aspekte der Krankheitsbewältigung für Jugendliche mit Epilepsie werden im Hinblick auf wichtige entwicklungspsychologische Themen des Jugendalters diskutiert. Bedeutung und Ziele von Patientenschulung als zentraler Behandlungsbaustein bei chronischen Erkrankungen werden erläutert.

Anticonvulsant properties of hypothermia in experimental status epilepticus

Status epilepticus in patients often does not respond to first-line anticonvulsants, and subsequent treatment escalation with continuous intravenous anesthetics may be associated with significant side-effects. Therefore, alternative treatment regimens are urgently needed. Hypothermia has been shown to reduce excitatory transmission and may thus serve as an interesting adjunct in the management of status epilepticus. In the current experiments, three treatment groups were compared. Animals with self-sustaining status epilepticus were treated with external cooling for 3 h, with low-dose diazepam, or with a combination of both. The effect of these regimens on epileptic activity was compared with untreated controls. Animals that underwent cooling were rewarmed, and all animals were monitored for 5 h to assess occurrence and severity of motor seizures and frequency and amplitude of spontaneous epileptic discharges. Cooling alone significantly reduced number and severity of motor seizures but did not alter epileptic discharges. Cooling in addition to low-dose diazepam significantly diminished amplitudes and frequencies of epileptic discharges, while diazepam alone had only a minor reducing effect on discharge amplitudes. However, at later stages of status epilepticus, diazepam significantly reduced motor seizures. Following rewarming, the discharge frequency tended to increase again, suggesting partial reversibility. The current experiments show that in status epilepticus hypothermia exhibits anticonvulsant effects which are most pronounced if co-administered with low-dose diazepam. The results still require confirmation in other animal models and also clinical studies are urgently needed. However, our data indicate that cooling could well become a future adjunct in the treatment of status epilepticus in patients.