Acute seizures after intracerebral hemorrhage: a factor in progressive midline shift and outcome

In nonconvulsive status epilepticus (NCSE), treat to burst-suppression: pro and con

Dr. Jordan (PRO) argues that when refractory NCSE is combined with acute brain injury, it produces synergistically compounded brain damage that is time dependent. Treating to EEG burst-suppression is the most rapid and effective method for stopping NCSE. The risks of burst-suppression are common to many intensive care interventions and can be minimized with expert management. Dr. Hirsch (CON) argues that treating with coma-inducing medication is highly risky and has a high mortality rate, often due to iatrogenic complications. It remains unclear if nonconvulsive seizures cause permanent neuronal injury. Nonconvulsive seizures should be diagnosed and treated as quickly as possible,but with non-coma-inducing treatments in most cases [corrected]

Advances in the management of spontaneous intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is associated with the highest mortality of all cerebrovascular events, and most survivors never regain functional independence. Many clinicians believe that effective therapies are lacking for patients who have ICH; however, this perception is changing in light of new data on the pathophysiology and treatment of this disorder, in particular, research establishing the role of medical therapies to promote hematoma stabilization. This article discusses the basic principles of management of ICH, including initial stabilization, the prevention of hematoma growth, treatment of complications, and identification of the underlying etiology. In addition, minimally invasive surgery to reduce clot size is discussed, with the goal of preserving neurologic function through reduction in parenchymal damage from edema formation.

[Recommendations of the European Stroke Initiative for the diagnosis and treatment of spontaneous intracerebral haemorrhage]

This article summarises the recommendations for the management of managing patients with intracerebral haemorrhage published in 2006 by the European Stroke Initiative (EUSI) on behalf of the European Stroke Council (ESC), the European Neurological Society (ENS), and the European Federation of Neurological Societies (EFNS).

Seizure development after stroke

Although there have been many studies on seizures following stroke, there is still much we do not know about them. In this study, we evaluated the characteristics of seizures in stroke patients. There were 2267 patients with a first-ever stroke, and after excluding 387 patients, 1880 were available for analysis. Of these 1880 patients, we evaluated 200 patients with seizures and 400 patients without seizures. We investigated the seizures according to age, gender, stroke type, the aetiology of ischaemic stroke and the localisation of the lesion. The seizures were classified as early onset and late onset and the seizure type as partial, generalised or secondarily generalised. Seizures occurred in 200 (10.6%) of 1880 strokes. The number of patients with seizures were 138 (10.6%) in ischaemic stroke group and 62 (10.7%) in haemorrhagic stroke group. Patients with ischaemic strokes had 41 embolic (29.7%) and 97 thrombotic (70.3%) origin, and these were not statistically significant in comparison with controls. Cortical involvement for the development of seizures was the most important risk factor (odds ratios = 4.25, p < 0.01). It was concluded that embolic strokes, being younger than 65 years old, and cortical localisation of stroke were important risks for developing seizures.

Primary intracerebral hemorrhage

This article reviews the epidemiology, pathophysiology and management of primary intracerebral hemorrhage. In North American and European populations, 15% of strokes are due to intracerebral hemorrhage. Pathologically in hypertension, early arteriolar proliferation of smooth muscle is followed later by smooth muscle cell death and collagen deposition. This eventually leads to occlusion or ectasia of arterioles. The latter leads to Charcôt-Bouchard aneurysm formation and possible intracerebral hemorrhage. Amyloid deposition in the tunica media causes similar brittle arterioles. Fibrin globes in concentric spheres attempt to seal off the site of bleeding. But vasculopathy (either amyloid or hypertensive) inhibits the contractile capability of arterioles. The size of the final sphere of blood at cessation of bleeding determines the clinical spectrum, from asymptomatic to fatal. Since arteriolar bleeding is slower than arterial bleeding, several hours exist where intervention may be useful. While medical intervention is controversial, guidelines for blood pressure, intracranial pressure, glucose and seizure management exist. Surgical trials have tended to show no benefit. Recombinant factor VIIa is undergoing investigation as hemostatic therapy for intracerebral hemorrhage, to limit clot expansion and possibly also as a hemostatic adjunct to surgery.

Evaluation of gabapentin and ethosuximide for treatment of acute nonconvulsive seizures following ischemic brain injury in rats

Acute seizures following brain injury have been associated with a worsening of patient outcome, but they are often undiagnosed and untreated when they occur without motor convulsions. Here, we sought to compare the antiseizure profile of ethosuximide (EXM; 125-312.5 mg/kg i.v.) and gabapentin (GBP; 0.3-50 mg/kg. i.v.) in a rat model of nonconvulsive seizures (NCS) induced by brain ischemia. Seizures were detected by continuous electroencephalographic monitoring for 24 h following permanent middle cerebral artery occlusion (MCAo). Both "preseizure" and "postseizure" treatment effects were evaluated. Control rats experienced a 91% incidence of NCS (averaging 10-11 NCS/rat), which was significantly reduced following preseizure treatment (delivered 20 min post-MCAo) with either EXM (ED(50) = 161 mg/kg) or GBP (ED(50) = 10.5 mg/kg). In contrast to preseizure treatment effects, only GBP reduced NCS when given after the first seizure event. A further, albeit nonsignificant, 20% reduction in NCS incidence was measured when given in combination postseizure. Drug treatment also reduced infarct volume, which was positively correlated to the number of NCS events (r = 0.475; P < 0.001). EXM and GBP treatment of cultured neurons exposed to neurotoxic or ischemic insults showed no neuroprotective effects, suggesting that in vivo neuroprotection can be attributed to anti-seizure effects. We conclude that EXM and GBP significantly attenuate NCS in a dose-related manner and may help to improve patient outcome from brain ischemia-induced seizure activity.

Nonconvulsive Seizures in the Pediatric Intensive Care Unit: Etiology, EEG, and Brain Imaging Findings

PURPOSES

To determine the occurrence of nonconvulsive seizures (NCS) in the Pediatric Intensive Care Unit (PICU); to ascertain the relationship of NCS to past medical history, etiology, EEG, and brain imaging; and to determine the concordance between abnormal EEG findings and neuroimaging abnormalities.

METHODS

A retrospective review was conducted of all pediatric patients who were admitted or transferred to the PICU from January 2000 to December 2003 with an unexplained decrease in level of consciousness, no overt clinical seizures, and EEG recordings performed within the 24 h of onset of an altered state of consciousness.

RESULTS

Twenty-three of 141 patients who met criteria for inclusion in the study (16.3%) were found to have NCS. The male to female ratio was 1.9:1. The largest group of patients (43%) had no preexisting neurological condition prior to the onset of NCS. In the remainder, the etiology of NCS included: acute structural brain lesion (48%), acute nonstructural brain lesion (22%), epilepsy-related seizure (13%), and others (17%). Epileptic foci were lateralized to the right side in 39.2%, the left side in 30.4%, and were bilateral in 30.4%. Of 23 patients with NCS, 18 (78.3%) demonstrated abnormal neuroimaging. In 10 of 18 of these patients (55.6%), the findings on neuroimaging were concordant with the lateralization found on EEG (p < 0.05, Fisher's exact test).

CONCLUSIONS

NCS are not uncommon in pediatric patients with an altered state of consciousness. Almost half of the patients were previously healthy especially if they were under 6 months of age. This report highlights the importance of clinical awareness of NCS in the PICU.

Risk and predictors of early epileptic seizures in acute cerebral venous and sinus thrombosis

We assessed the risk and determined predictors of early epileptic seizures (ES) in patients with acute cerebral venous and sinus thrombosis (CVST). A prospective series of 194 consecutive patients with acute CVST admitted to neurological wards in two German university hospitals was analysed for frequency of ES and in-hospital mortality. Demographic, clinical and radiological characteristics during the acute stage were retrospectively analysed for significant association with ES in univariate and multivariate analyses. During the acute stage, 19 patients (9.8%) died. Early symptomatic seizures were found in 86 patients (44.3%). Status epilepticus occurred in 11 patients (12.8%) of whom four died. Amongst patients with epileptic seizures, mortality was three times higher in those with status than in those without (36.4% and 12%, respectively). In multivariate logistic regression analysis, motor deficit [odds ratio (OR) 5.8; 95% CI 2.98-11.42; P < 0.001], intracranial haemorrhage (OR 2.8; 95% CI 1.46-5.56; P = 0.002) and cortical vein thrombosis (OR 2.9; 95% CI 1.43-5.96; P = 0.003) were independent predictors of early epileptic seizures. Status epilepticus was an important source of morbidity and early mortality in patients with CVST in this study. Patients with focal motor deficits, cortical vein thrombosis and intracranial haemorrhage carried the highest risk for ES. Prophylactic antiepileptic treatment may be an option for these patients.

Recommendations for the Management of Intracranial Haemorrhage – Part I: Spontaneous Intracerebral Haemorrhage

This article represents the recommendations for the management of spontaneous intracerebral haemorrhage of the European Stroke Initiative (EUSI). These recommendations are endorsed by the 3 European societies which are represented in the EUSI: the European Stroke Council, the European Neurological Society and the European Federation of Neurological Societies.

Prognostic significance of continuous EEG monitoring in patients with poor-grade subarachnoid hemorrhage

INTRODUCTION

Predicting outcome in patients with poor-grade subarachnoid hemorrhage (SAH) may help guide therapy and assist in family discussions. The objective of this study was to determine if continuous electroencephalogram (cEEG) monitoring results are predictive of 3-month outcome in critically ill patients with SAH.

METHODS

We prospectively studied 756 patients with SAH over a 7-year period. Functional outcome was assessed at 3 months with the modified Rankin Scale (mRS). Patients that underwent cEEG monitoring were retrospectively identified and EEG findings were collected. Multivariate logistic regression analysis was performed to identify EEG findings associated with poor outcome, defined as mRS 4 to 6 (dead or moderately to severely disabled).

RESULTS

In 116 patients with SAH, cEEG monitoring and 3-month mRS were available. Of these patients, 88% had a Hunt & Hess grade of 3 or worse on admission. After controlling for age, Hunt & Hess grade, and presence of intraventricular hemorrhage on admission CT scan, poor outcome was associated with the absence of sleep architecture (80 versus 47%; odds ratio [OR] 4.3, 95%-confidence interval [CI] 1.1-17.2) and the presence of periodic lateralized epileptiform discharges (PLEDS) (91 versus 66% OR 18.8, 95%-CI 1.6-214.6). In addition, outcome was poor in all patients with absent EEG reactivity (n = 8), generalized periodic epileptiform discharges (n = 12), or bilateral independent PLEDs (n = 5), and in 92% (11 of 12) of patients with nonconvulsive status epilepticus.

CONCLUSIONS

cEEG monitoring provides independent prognostic information in patients with poor-grade SAH, even after controlling for clinical and radiological findings. Unfavorable findings include periodic epileptiform discharges, electrographic status epilepticus, and the absence of sleep architecture.

Early poststroke seizures

We define as early seizure (ES) those occurring within 7 days after stroke and late seizures those developing beyond 1 week after stroke. Seizures are well known to occur at the onset of intracerebral hemorrhage and serve as a clinical marker. Onset seizures may be focal or generalized, are usually brief and are associated with loss of consciousness in the setting of hemorrhage. A similar concept of immediate seizure occurs in traumatic brain injury. Predictive factors of ES can be classified of general and neurologic origin. An important question is whether ES per se worsen prognosis and outcome. The viability of the penumbral region in animal models of focal ischemia is influenced by the peri-infarct depolarization waves. If this also is true in humans, seizures in the immediate poststroke period might worsen outcome. Recently, hypercholesterolemia has been associated with better functional outcome at 1 month after a first-ever stroke, and multivariate analysis studies have shown that mean cholesterol values were lower in patients with ES compared with controls.

Future of brain support: multimodality monitoring

Multimodality monitoring of cerebral physiology encompasses the application of different monitoring techniques and integration of several measured physiological and biochemical variables into the assessment of brain metabolism, structure, perfusion and oxygenation status, in addition to clinical evaluation. Novel monitoring techniques include transcranial Doppler ultrasonography, neuroimaging, intracranial pressure, cerebral perfusion and cerebral blood flow monitors, brain tissue oxygen tension monitoring, microdialysis, evoked potentials and continuous electroencephalography. Multimodality monitoring enables the immediate detection and prevention of acute neurological events, as well as appropriate intervention based on a patient’s individual disease state in the neurocritical care unit. Simultaneous real-time analysis of cerebral physiological, metabolic and cardiovascular parameters has broadened knowledge regarding complex brain pathophysiology and cerebral hemodynamics. Integration of this information allows for a more precise diagnosis and optimization of management of patients with brain injury.

Treatment of cerebral edema

BACKGROUND

Cerebral edema is a potentially devastating complication of various acute neurologic disorders. Its successful treatment may save lives and preserve neurologic function.

REVIEW SUMMARY

Different pathophysiological mechanisms are responsible for the formation of cytotoxic and vasogenic edema. Yet, these 2 types of edema often coexist and their treatment tends to overlap, with the exception of corticosteroids, which should be only used to ameliorate vasogenic edema. Currently available to control brain swelling include osmotic agents (with emphasis on mannitol and hypertonic saline solutions), corticosteroids, hyperventilation, sedation (propofol, barbiturates), neuromuscular paralysis, hypothermia, and surgical interventions. This article discusses the indications, advantages, and limitations of each treatment modality following an evidence-based approach.

CONCLUSIONS

The therapy for brain edema remains largely empirical. More research aimed at enhancing our understanding of the pathophysiology of cerebral edema is needed to identify new and more effective forms of treatment.

Update on intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is a common and serious disease. About 1 to 2 out of 10 patients with stroke have an ICH. The mortality of ICH is higher than that of ischaemic stroke. Only 31% are functionally independent at 3 months. Only 38% of the patients survive the 1(st) year. The cost of ICH is high. Hypertension is the major risk factor, increasing the risk of ICH about 4x. Up to half of hypertensive patients who suffer a ICH are either unaware of their hypertension, non-compliant with the medication or fail to control periodically their blood pressure levels Microbleeds and white matter changes are MRI markers of the risk of ICH. ICH has 3 main pathophysiological phases: arterial rupture and haematoma formation, haematoma enlargement and peri-haematoma oedema. Up to 40% of the haematomas grow in the first hours post-rupture. ICH growth is associated with early clinical deterioration. Two randomised clinical trials (RCTs) demonstrated that treatment with rFVIIa limited haematoma growth and improved outcome, but was associated with a increase in thromboembolic complications. Ventricular drainage with thrombolytics might improve outcome for patients with intraventricular bleeding. A large RCT and meta-analysis failed to show a benefit of surgery over conservative treatment in acute ICH.

AC electrocorticographic correlates of peri-infarct depolarizations during transient focal ischemia and reperfusion

Several studies have highlighted a delayed secondary pathology developing after reperfusion in animals subjected to prolonged cerebral ischemia, and recently we have shown that peri-infarct depolarizations (PIDs) occur not only during ischemia, but also in this delayed period of infarct maturation. Here we study the electrocorticographic (ECoG) manifestations of PIDs as signatures of developing secondary pathology. DC- and traditional AC-ECoG signals were recorded continuously from epidural, nonpolarizable electrodes during 2 h of middle cerebral artery occlusion (MCAo) and 22 h of reperfusion in freely behaving rats. During MCAo, seizures and PIDs recurred frequently and their incidence was significantly correlated. After reperfusion, seizures and PIDs ceased, and for the next several hours delta wave abnormalities dominated the ECoG with progressively increasing amplitude. After a variable period (5 to 15 h), the ECoG amplitude decremented with the onset of a prolonged repetitive series of PIDs. Initial PIDs in this delayed phase produced transient depressions of the high amplitude ECoG signal, but thereafter the ECoG was persistently attenuated, with no transient depressions during subsequent PIDs. The time of onset of postreperfusion PIDs, and hence measures of ECoG attenuation, correlated with 24 h infarct volumes. PIDs could always be detected in baseline shifts of the AC-ECoG signal with a low high-pass cutoff setting. These results suggest that delayed PIDs after reperfusion contribute to a complex secondary pathology involving delayed edema, intracranial hypertension, and hypoperfusion. The manifestation of PIDs in ECoG/electroencephalography recordings may enable continuous real-time monitoring of infarct progression.

Management of Seizures in the Critically Ill

Seizures in a critically ill patient are not infrequent phenomena. Physicians are perplexed by the wide range of possible cranial or extracranial etiologies, alerted by the risk for further crucial organ compromise if seizures recur, and confused about the treatment options in an environment rich in complex drug interactions and multiple organ dysfunction. The advent of an armamentarium containing multiple new antiepileptic medications complicates the situation further, since several of them have less known mechanisms of action, side effects, or interactions with other intensive care unit (ICU) medications. This review contains useful information regarding the most common etiologies and treatment options for intensivists, consulting neurologists, neurosurgeons, or other specialized physicians treating ICU patients with seizures.

Treatment of intracerebral haemorrhage

Apart from management in a specialised stroke or neurological intensive care unit, until very recently no specific therapies improved outcome after intracerebral haemorrhage (ICH). In a recent phase II trial, recombinant activated factor VII (eptacog alfa) reduced haematoma expansion, mortality, and disability when given within 4 h of ICH onset; a phase III trial (the FAST trial) is now in progress. Ventilatory support, blood-pressure reduction, intracranial-pressure monitoring, osmotherapy, fever control, seizure prophylaxis, and nutritional supplementation are the cornerstones of supportive care in intensive care units. Ventricular drainage should be considered in all stuporous or comatose patients with intraventricular haemorrhage and acute hydrocephalus. Given the lack of benefit seen in a the recent STICH trial, emergency surgical evacuation within 72 h of onset should be reserved for patients with large (>3 cm) cerebellar haemorrhages, or those with large lobar haemorrhages, substantial mass effect, and rapidly deteriorating condition.

Brain metabolism of exogenous pyruvate

Pyruvate given in large doses may be neuroprotective in stroke, but it is not known to what degree the brain metabolizes pyruvate. Intravenous injection of [3-13C]pyruvate led to dose-dependent labelling of cerebral metabolites so that at 5 min after injection of 18 mmoles [3-13C]pyruvate/kg (2 g sodium pyruvate/kg), approximately 20% of brain glutamate and GABA were labelled, as could be detected by 13C nuclear magnetic resonance spectrometry ex vivo. Pyruvate, 9 mmoles/kg, was equivalent to glucose, 9 mmoles/kg, as a substrate for cerebral tricarboxylic acid (TCA) cycle activity. Inhibition of the glial TCA cycle with fluoroacetate did not affect formation of [4-13C]glutamate or [2-13C]GABA from [3-13C]pyruvate, but reduced formation of [4-13C]glutamine by 50%, indicating predominantly neuronal metabolism of exogenous pyruvate. Extensive formation of [3-13C]lactate from [2-13C]pyruvate demonstrated reversible carboxylation of pyruvate to malate and equilibration with fumarate, presumably in neurones, but anaplerotic formation of TCA cycle intermediates from exogenous pyruvate could not be detected. Too rapid injection of large amounts of pyruvate led to seizure activity, respiratory arrest and death. We conclude that exogenous pyruvate is an excellent energy substrate for neurones in vivo, but that care must be taken to avoid the seizure-inducing effect of pyruvate given in large doses.

Intracerebral Hemorrhage

INTRODUCTION

Intracerebral hemorrhage (ICH) occurs from the rupture of small vessels into the brain parenchyma and accounts for approximately 10% of all strokes in the United States, and carries with it a significantly high morbidity and mortality.

SUMMARY

This article reviews the course and management of ICH. The most common chronic vascular diseases that lead to ICH are chronic hypertension and cerebral amyloid angiopathy. Additional factors that predispose to ICH include vascular malformations, chronic alcohol use, hypocholesterolemia, and use of anticoagulant medications. The understanding of mechanisms leading to ICH has advanced significantly, but questions regarding site predilection and timing of spontaneous hemorrhage still remain. Management in the acute setting is first focused on reducing hematoma expansion. Although no specific therapy has yet been proven effective, promising agents, particularly recombinant Factor VIIa, are on the horizon. Subsequent care is focused on controlling hemostasis, hemodynamics, and intracranial pressure in efforts to minimize secondary brain injury.

CONCLUSION

The morbidity and mortality associated with ICH remain high despite recent advances in our understanding of the clinical course of ICH. Novel preventive and acute treatment therapies are needed and may be on the horizon.

Continuous electroencephalogram monitoring in critically ill patients

The past few years have witnessed remarkable advances in continuous EEG monitoring (cEEG). The indications and applications for cEEG are broadening, including detection of nonconvulsive seizures, spell characterization, and prognostication. Seizures are common in the critically ill, are usually nonconvulsive, and can easily be missed without cEEG. Interpretation and clinical management of the complex periodic and rhythmic EEG patterns commonly identified in these patients require further study. With the use of quantitative analysis techniques, cEEG can detect cerebral ischemia very early, before permanent neuronal injury occurs. This article reviews the indications and recent advances in cEEG in critically ill patients. Continuous brain monitoring with cEEG is rapidly becoming the standard of care in critically ill patients with neurologic impairment.

Multimodality monitoring and telemonitoring in neurocritical care: from microdialysis to robotic telepresence

PURPOSE OF REVIEW

This review will highlight the state-of-the-art in brain monitoring in neurointensive care and define methods of integrating this technology into patient care using telemedicine methods.

RECENT FINDINGS

Several new methods of brain monitoring have been established over the last several years including continuous EEG monitoring, brain tissue oxygenation, jugular venous oxygenation, and cerebral microdialysis. Observational research using these monitors has documented that the brain metabolism, blood flow and function are dynamic after a primary insult. The dynamic nature of the brain can predispose the brain to secondary insults that can occur in the setting of intensive care. Several variables of brain metabolism and function can be monitored and directly impact treatment decisions as well as provide diagnostic and prognostic information. General treatment guidelines for brain injury and brain hemorrhage were developed, in part, prior to implementation of use of these monitors, and there is a trend away from adoption of a one-size-fits-all approach and a trend towards monitor-guided therapy. Dealing with the data provided by multimodality monitoring can be overwhelming. Efficient use of such information requires methods to integrate diverse sets of information, and methods to access the online monitoring information remotely and at any time, day or night. Such remote access integration methods will be reviewed.

SUMMARY

Multimodality and telemedicine techniques have advanced the state of knowledge about brain function in critically ill patients, and are presently being implemented to direct therapy. Increasing complexity of care will become commonplace, but will be facilitated by computer-enhanced tools that permit the intensivist to integrate this information into an improved treatment regimen.

Treatment of convulsive and nonconvulsive status epilepticus

Status epilepticus (SE) should be treated as quickly as possible with full doses of medications as detailed in a written hospital protocol. Lorazepam is the drug of choice for initial treatment. If intravenous access is not immediately available, then rectal diazepam or nasal or buccal midazolam should be given. Prehospital treatment of seizures by emergency personnel is effective and safe, and may prevent cases of refractory SE. Home treatment of prolonged seizures or clusters with buccal, nasal, or rectal benzodiazepines should be considered for all at-risk patients. Nonconvulsive SE is underdiagnosed. An electroencephalogram should be obtained immediately in anyone with unexplained alteration of behavior or mental status and after convulsive SE if the patient does not rapidly awaken. Delay in diagnosis of SE is associated with a worse outcome and a higher likelihood of poor response to treatment. For refractory SE, continuous intravenous midazolam and propofol (alone or in combination) are rapidly effective. Randomized trials are needed to determine the best treatment for SE after lorazepam.

Continuous EEG monitoring for the detection of seizures in traumatic brain injury, infarction, and intracerebral hemorrhage: "to detect and protect"

Brain injury results in a primary pathophysiologic response that enables the brain to have seizures. Seizures occur frequently after traumatic and nontraumatic intracerebral bleeding. These seizures can be nonconvulsive, and if one does not monitor for seizures, one will not know they are occurring. The use of continuous EEG monitoring (cEEG) to detect brain arrhythmias after a primary insult, much in way that cardiac arrhythmias are detected after myocardial infarction, can influence treatment decisions and mitigate some of the pathophysiologic natural history of brain injuries. Seizures after brain injury worsen clinical outcome and need to be treated. In summary, cEEG is a valuable clinical instrument "to detect and protect," i.e., to detect seizures and protect the brain from seizure-related injury in critically ill patients, whose brains are often in a particularly vulnerable state.

Which EEG Patterns Warrant Treatment in the Critically Ill? Reviewing the Evidence for Treatment of Periodic Epileptiform Discharges and Related Patterns

Continuous electroencephalographic monitoring in critically ill patients has improved detection of nonconvulsive seizures and periodic discharges, but when and how aggressively to treat these electrographic patterns is unclear. A review of the literature was conducted to understand the nature of periodic discharges and the strength of the data on which management recommendations have been based. Periodic discharges are seen from a wide variety of etiologies, and the discharges themselves are electrographically heterogeneous. This spectrum suggests a need to consider these phenomena along a continuum between interictal and ictal, but more important clinically is the need to consider the likelihood of neuronal injury from each type of discharge in a given clinical setting. Recommendations for treatment are given, and a modification to current criteria for the diagnosis of nonconvulsive seizures is suggested.

Priorities for clinical research in intracerebral hemorrhage: report from a National Institute of Neurological Disorders and Stroke workshop

BACKGROUND AND PURPOSE

Spontaneous intracerebral hemorrhage (ICH) is one of the most lethal stroke types. In December 2003, a National Institute of Neurological Disorders and Stroke (NINDS) workshop was convened to develop a consensus for ICH research priorities. The focus was clinical research aimed at acute ICH in patients.

METHODS

Workshop participants were divided into 6 groups: (1) current state of ICH research; (2) basic science; and (3) imaging, (4) medical, (5) surgical, and (6) clinical methodology. Each group formulated research priorities before the workshop. At the workshop, these were discussed and refined.

RESULTS

Recent progress in management of hemorrhage growth, intraventricular hemorrhage, and limitations in the benefit of open craniotomy were noted. The workshop identified the importance of developing animal models to reflect human ICH, as well as the phenomena of rebleeding. More human ICH pathology is needed. Real-time, high-field magnets and 3-dimensional imaging, as well as high-resolution tissue probes, are ICH imaging priorities. Trials of acute blood pressure-lowering in ICH and coagulopathy reversal are medical priorities. The exact role of edema in human ICH pathology and its treatment requires intensive study. Trials of minimally invasive surgical techniques including mechanical and chemical surgical adjuncts are critically important. The methodologic challenges include establishing research networks and a multi-specialty approach. Waiver of consent issues and standardizing care in trials are important issues. Encouragement of young investigators from varied backgrounds to enter the ICH research field is critical.

CONCLUSIONS

Increasing ICH research is crucial. A collaborative approach is likely to yield therapies for this devastating form of brain injury.

Continuous electroencephalogram monitoring in the critically ill

The use of continuous electroencephalogram (cEEG) monitoring in the intensive care unit is becoming more widespread, with improvements in data storage capability and networking and the increasing awareness of nonconvulsive seizures. Current and potential uses for this technology include seizure detection, ischemia detection, and prognostication. Nonconvulsive seizures are common in the critically ill, particularly those with acute brain injury and those who are comatose. The implications of some of the electrographical patterns observed in critically ill patients are not yet clear. This article discusses findings with cEEG to date, pitfalls in performing and interpreting these studies, and where we should turn our attention with this underutilized brain monitoring technique.

Management of seizures in critically ill patients

For many neurologists, seizures in critically ill patients represent a difficult problem. Etiology can be elusive because of the complexity of the environment, and treatment decisions can be compromised by the paucity of evidence-based guidelines. Emerging data support a higher than previously thought incidence of nonconvulsive epileptic activity in this patient population, which is another important consideration. Although a seizure in the intensive care unit should be treated aggressively, prophylactic antiepileptic drug administration is dependent on the specific etiology, time of onset, and ensuing complications. After ischemic stroke, prophylactic treatment is not generally recommended, and after intracerebral hemorrhage treatment is recommended only after a few weeks. After subarachnoid hemorrhage, prophylactic treatment beyond discharge is also not recommended. Although there is no reason to believe that late seizures after severe head trauma cannot be prevented with prophylactic treatment, such an approach may be useful during the first week after the injury. Physicians, however, have to individualize the treatment to the critical patient after stroke or trauma based on the presence of additional factors that increase the risk for seizures, including structural cortical injuries and medications used in critical illness with epileptogenic potential. A general therapeutic scheme for seizures in the intensive care unit and the role newer antiepileptic drugs can play are also presented in this review.

Antiepileptic drug treatment of nonconvulsive seizures induced by experimental focal brain ischemia

Nonconvulsive seizures (NCSs) after traumatic and ischemic brain injury are often refractory to antiepileptic drug therapy and are associated with a decline in patient outcome. We recently characterized an in vivo rat model of focal brain ischemia-induced NCS and here sought to evaluate potential pharmacological treatments. Electroencephalographic activity was recorded continuously for 24 h in freely behaving rats subjected to permanent middle cerebral artery occlusion (MCAo). Rats were treated with an antiepileptic drug from one of seven different drug classes at ED(50) and 2x ED(50) doses (as reported in other rat seizure models), delivered as a single i.v. injection 20 min post-MCAo. Vehicle-treated rats (n = 9) had an 89% incidence of NCS with an average number of NCS of 8.6 +/- 1.9. The latency to onset of NCS was 32.5 +/- 3.4 min post-MCAo with an average duration of 49.1 +/- 8.2 s/event. The high doses of ethosuximide, gabapentin, fos-phenytoin, and valproate significantly reduced the incidence of NCS (11, 14, 14, and 38%, respectively), whereas midazolam, phenobarbital, and dextromethorphan had no significant effect at either dose. Across treatment groups, there was a low but significant correlation between the number of NCS events per animal and volume of brain infarction (r = 0.352). Antiepileptic drug therapy that prevented the occurrence of NCS also reduced mortality from 26 to 7%. Based on combined effects on NCS, infarction, neurological recovery, and mortality, ethosuximide and gabapentin were identified as having the best therapeutic profile.

Novel therapies for intracerebral hemorrhage

PURPOSE OF REVIEW

To summarize new pathophysiologic insights and recent advances in the treatment of intracerebral hemorrhage.

RECENT FINDINGS

Emerging information of the physiopathologic mechanisms of injury that occur after intracerebral hemorrhage is available from current animal models and human studies. The effects of chronic vascular changes are fundamental to the genesis of the hematoma. Novel proposed mechanisms in the pathophysiology of hematoma expansion and worsening edema include harmful accumulation of excitotoxins and osmotically active electrolytes, followed by activation of leukocytes and platelets with production of inflammatory mediators such as interleukin-1, interleukin-6, intercellular adhesion molecule, tumor necrosis factor alpha, and vascular endothelial growth factor. Expression of metalloproteinases and the toxic effects of the complement, thrombin, and blood degradation products may play a role in late edema formation after intracerebral hemorrhage. Despite recent attempts to discern the pathophysiology of ICH, evidence-based therapies for intracerebral hemorrhage are not yet available. Treatment is primarily supportive, and outcomes remain poor. Blood pressure lowering, intracranial pressure monitoring, osmotherapy with adequate fluid balance, fever control, and seizure prophylaxis are usually done in the acute setting. Novel approaches currently under study include ultra early hemostatic therapy and thrombolytic therapy for intraventricular hemorrhage. Although the value of surgical treatment remains unclear, the results of a large, randomized study (the STITCH Trial) are forthcoming.

SUMMARY

Prospective controlled studies are needed to develop novel medical and surgical therapies for ICH.

Poststroke Epilepsy

Seizures and status epilepticus can be a presenting feature of acute stroke. They may occur in its early (<7 days) clinical course or be a remote (>7 days) complication. Most seizures are single, either partial or generalised. Early and remote seizures seem to have different predictors and pathogenesis. Seizures are more frequent in severe and disabling strokes, haemorrhagic strokes and those with cortical involvement. The risk of epilepsy is higher for patients with early seizures, cortical infarctions and lobar haemorrhages and in dependent patients. Early or remote seizures do not have a significant influence on dependency or mortality, although seizures and status epilepticus can be a direct cause of death. Treatment can be started after a first or a recurrent seizure. Treatment options include phenytoin, carbamazepine, valproic acid (valproate sodium) and the new antiepileptic drugs (AEDs). New AEDs can be used to decrease the likelihood of drug interactions and adverse effects in patients who do not tolerate the classic AEDs and in treatment failures with classic AEDs. Large observational studies to define prognostic factors for poststroke seizures in specific stroke subtypes are needed. Randomised controlled trials of AED prophylaxis for acute and remote seizures are essential to improve the evidence level of current guidelines and recommendations.