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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment with general anesthesia (neuroleptanalgesia) and deep hypothermia was performed on 8 patients suffering from epilepsy. The body temperature was decreased to 29 degrees C and the temperature in the brain ventricles to 16 degrees C. Somatosensory evoked potentials were recorded. Increase in latency of all waves was observed, and it was noted that the more distant the wave, the higher the increase in latency. Statistical values are given for N1, N2 and N3. A parallel decrease in the amplitudes of all components of the somatosensory evoked potential was also present.
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PMID:Somatosensory evoked potentials in deep hypothermia. 746

Spontaneous periodic hypothermia is a rare syndrome of recurrent, centrally mediated hypothermia without an identifiable systemic cause or brain lesion. Most patients defend a temporarily lowered temperature "set point" during episodes of hypothermia, despite manifesting many well-known systemic consequences of core temperature hypothermia. No case of death directly attributable to an episode of spontaneous periodic hypothermia has been reported, although many of the serious systemic effects of hypothermia have been documented in these cases, so it is not unlikely that death may occur. The syndrome's cause, and that of Shapiro syndrome, remains unknown. Pharmacologic trials to date have been only modestly successful. Anticonvulsant agents, clonidine, and cyproheptadine appear the most likely to succeed, with cyproheptadine being a reasonable first choice. Given that the term "spontaneous periodic hypothermia" describes a syndrome, and not a pathophysiologic mechanism, it is likely to encompass a common eventuality, arrived at via several different pathways. One can postulate mechanisms such as structural abnormalities, trauma, infection, irritation, and degeneration involving strategic locations which create a focus for epileptic or other periodic dysfunction whose scope involves the centers for thermoregulation. The existence of 2 distinct, oppositional thermoregulatory centers would allow for speculation of similar mechanisms accounting for cases of both periodic hypo- and hyperthermia (61). Postmortem data regarding the hypothalamic and surrounding areas from future cases of Shapiro syndrome and spontaneous periodic hypothermia would be of great interest. Further, more sensitive in vivo testing methods are clearly needed. The role of PET or single photon emission computed tomography (SPECT) with technetium 99m-labeled hexamethylpropylene amine oxime (Tc 99m HMPAO) performed acutely during an episode remains to be characterized (64, 103, 105). The term "diencephalic epilepsy" may in fact be accurate, given the periodic episodes of the case presented here and similar cases resulting from non-generalized seizure activity, with or without an underlying predisposing lesion. The label diencephalic epilepsy has been merely speculative so far, however, as definitive evidence of seizure activity has not been documented. Further, it is expected that the descriptive terms "spontaneous periodic hypothermia" and "episodic spontaneous hypothermia with hyperhidrosis" will outlive their usefulness as researchers gain greater understanding of this syndrome, and be replaced with a more pathophysiologically meaningful nomenclature.
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PMID:Spontaneous periodic hypothermia. 756 67

The changes in the permeability of the blood-brain barrier during pentylenetetrazol (PTZ)-induced seizures were investigated in normothermic and hypothermic rats. Six groups of rats were studied: (I) normothermic control; (II) hypothermic control; (III) normothermia plus PTZ (80 mg/kg); (IV) normothermia plus PTZ (160 mg/kg); (V) hypothermia plus PTZ (80 mg/kg); (VI) hypothermia plus PTZ (160 mg/kg). The rats were anesthetized with diethyl ether. In the hypothermic animals, colonic temperature was reduced to 20 +/- 1 degree C by submerging the animals in ice water. In normothermic animals, distinct Evans-blue leakage was observed in the occipital cortex, thalamus, hypothalamus, substantia nigra, corpus striatum, and medulla oblongata in both PTZ groups. However, hypothermic animals which received a high dose of PTZ showed the most severe blood-brain barrier breakdown. Mean levels of Evans blue in the brains of low-dose (80 mg/kg) PTZ-treated animals were 8.7 +/- 2.2 micrograms/g and 5.7 +/- 1.4 micrograms/g in the normothermic and hypothermic groups, respectively. This difference was significant (P < 0.01). The levels in the high dose (160 mg/kg) PTZ-treated animals were 10.2 +/- 3.5 micrograms/g and 15.9 +/- 3.6 micrograms/g in the normothermic and hypothermic groups, respectively (P < 0.02). In conclusion, deep hypothermia prevents the blood-brain barrier disruption induced by 80 mg/kg pentylenetetrazol and aggravates the increase in permeability after 160 mg/kg pentylenetetrazol.
Epilepsy Res 1994 Dec
PMID:The effect of profound hypothermia on blood-brain barrier permeability during pentylenetetrazol-induced seizures. 769 98

The clinically established antiepileptic drug phenytoin has long been thought to be ineffective in the kindling model, which is one of the most widely used animal models of epilepsy. More recent studies with acute administration of phenytoin in kindled rats have shown that the drug exerts potent anticonvulsant activity in this model, provided that certain pharmacokinetic and technical factors are dealt with in the experimental protocol used. In the present study, we examined the effects of phenytoin in amygdala-kindled rats during chronic treatment. Before the experiments in kindled rats, various experiments with acute and chronic administration of phenytoin at different doses were done in nonkindled rats in order to develop a treatment protocol by which active and tolerable plasma levels were attained. Based on the saturation kinetics of the drug, i.p. administration of 75 mg/kg, followed by once-daily injection of 50 mg/kg, resulted in plasma levels within the "therapeutic range" known from epileptic patients, whereas more frequent drug injections or once-daily administration of 75 mg/kg resulted in too marked drug accumulation and neurotoxicity. In kindled rats, the anticonvulsant activity of chronic treatment with phenytoin depended on the protocol used for amygdala stimulation. When seizures were induced by currents 20% above the individual seizure threshold, phenytoin was much more effective than in experiments with fixed, suprathreshold currents (500 microA). Depending on the stimulus protocol, phenytoin significantly reduced the severity of seizures or blocked the seizures completely throughout the 2-week period of treatment. In contrast to the anticonvulsant effect, tolerance developed to the adverse effects, i.e., motor impairment and hypothermia, recorded during treatment with phenytoin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anticonvulsant efficacy and adverse effects of phenytoin during chronic treatment in amygdala-kindled rats. 833 59

Hypothermia occurs when the core body temperature falls below 95 degrees F (35 degrees C). Several conditions which can occur in the psychiatric population increase the risk of hypothermia: nocturnal enuresis, seizure disorder, debilitating physical illness, and mental retardation. The risk of hypothermia is further increased by the use of several classes of medications used to treat psychiatric disorders: antipsychotics, beta-adrenergic antagonists, benzodiazepines, and other sedatives. Air-conditioning is also identified as a risk factor for hypothermia. Hypothermia is posited as a possible link between antipsychotic medication and sudden unexplained death. Suggestions for further investigation are made, and clinical recommendations are offered to reduce the risk of hypothermia in the psychiatric patient population.
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PMID:Risk factors for hypothermia in psychiatric patients. 880 34

In this study we investigated the relationship between penicillin-induced hypothermia and petit mal epilepsy induced by this proconvulsant antibiotic. In order to find a possible dose-dependent relationship, we used two doses: 1500.000 and 1000.000 U/kg b.wt., both known as being sufficient to induce absence-like attacks with subsequent spike and wave discharges (SWD) in electrocorticogram (ECoG). Because of experimental data suggesting penicillin binding to benzodiazepine receptor recognition site, we also studied penicillin-induced changes in body temperature after diazepam pretreatment. Results of this study clearly show that penicillin in doses known to induce petit mal-like epilepsy concomitantly induces statistically significant dose-dependent decrease in body temperature. Pretreatment with diazepam completely prevents both penicillin-induced hypothermia and SWDs. On the other hand, both the diazepam and mixed diazepam + penicillin treatments did not significantly alter body temperature. These results suggest, however, that at least some of the penicillin effects described could be assigned to its binding to the benzodiazepine receptor recognition site at GABA(A) ionophore. This may have an important clinical implication because the inhibitory action of penicillin at the benzodiazepine receptor recognition site could account for the mechanism of penicillin-induced unspecific encephalopathies in humans. The relationship between petit mal epilepsy and hypothermia sheds new light on the action mechanisms of penicillin-induced absence seizures.
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PMID:The connection between absence-like seizures and hypothermia induced by penicillin: possible implication on other animal models of petit mal epilepsy. 944 16

The objective of this study was to improve the ability to detect cerebrovascular complications in patients undergoing complicated neurosurgical procedures using on-line monitoring of cerebral pH with in vivo microdialysis. We employed on-line pH monitoring in patients with a variety of neurosurgical procedures including high-flow bypass surgery, aneurysm clipping, and temporal resection in epilepsy treatment. The pH was monitored with a microdialysis probe, usually inserted into the frontal cortex and pH of the dialysate was measured on-line with a pH electrode. We monitored 17 cases: 12 high-flow extracranial-intracranial (EC-IC) bypass procedures, 3 surgeries to clip large basilar tip aneurysms under protection of hypothermic circulatory arrest, and 2 surgeries for intractable seizure disorders. In the patients undergoing high-flow bypass, the pH remained stable in 5 patients and all had an uneventful outcome. In 3 patients, the pH decreased during surgery. One patient had a severe hemiparesis on awaking from anesthesia. The fall in pH in another patient was corrected when the blood pressure was raised during surgery. The pH was also responsive to changes in intraoperative ventilation and probably also to brain edema with elevation of pH values. In the three patients undergoing basilar tip aneurysm clipping under hypothermic circulatory arrest, the pH fell to 6.41 in one patient. This patient awoke with a mild hemiparesis. In the other two patients, the pH was stable during the hypothermia and neither patient had complications. In the patients undergoing temporal lobectomy and hippocampectomy, the pH fell rapidly with the onset of ischemia. We conclude that it is possible to monitor the cerebral extracellular pH with on-line microdialysis. The information obtained may alert the surgeon to the possibility of impending cerebral ischemia or other complications. However, further experience is needed before the technique can be recommended for general use.
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PMID:Intraoperative on-line monitoring of cerebral pH by microdialysis in neurosurgical procedures. 952 50

A patient with Marfan's syndrome was seen at 29 weeks' gestation with acute aortic dissection. She underwent aortic root replacement under deep hypothermia and circulatory arrest. The fetal heart rate was ominous during surgery but recovered later. Serial ultrasonographic examinations showed progressive fetal brain atrophy. The patient was delivered at 38 weeks' gestation of a girl weighing 2305 g, in whom severe spastic tetraplegia, absent psychomotor development, and therapy-resistant epilepsy developed. This is the first case to document progressive fetal brain atrophy after cardiac surgery in pregnancy.
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PMID:Hypoxic-ischemic fetal insult resulting from maternal aortic root replacement, with normal fetal heart rate at term. 975 1

Five patients with acute encephalopathy underwent methylprednisolone pulse (mPSL-P), hypothermia and their combination therapies (3 cases, 1 case and 1 case, respectively), with excellent outcome. Two cases with severe brain edema survived. One had severe brain damage as a sequelae. The remaining one recovered well after the combination therapy with mPSL-p and mild hypothermia, despite complete obstruction of the fourth ventricle on the first CT scan; the sequelae, hemiplegia and intelligent disturbance, was only mild. Four patients who received mPSL-P therapy within 6 hours after the onset of CNS symptoms recovered well though one was left with epilepsy. These results indicate that mPSL-P and/or hypothermia therapy will be chosen as the treatment of acute encephalopathy.
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PMID:[Efficacy of methylprednisolone pulse and mild hypothermia therapies in patients with acute encephalopathy]. 1065 54

Traumatic brain injury is a common neurologic condition that can have a significant emotional and financial burden. Neurologic injury is classified on the basis of initial clinical status by the Glasgow Coma Scale, and also by the type and location of head injury. Complications in the management of these patients are reviewed, ranging from intracranial pressure management and stroke to post-traumatic epilepsy. In addition, predictive prognostic variables that can be used to predict outcome based on a patient's presentation at the time of a head trauma are discussed. Finally, interventions such as induced hypothermia that can be undertaken to try to optimize outcome, are discussed along with current data in support of or against such techniques.
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PMID:Neurologic aspects of traumatic brain injury. 1527 51


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