The radiology of nontraumatic coma

This article describes a logical approach to the neuroimaging evaluation of patients with coma. The decision tree analysis provides an efficient method and attempts to convey the logical sequential concepts of analysis of CCT findings in patients presenting in stupor or coma. The sequential approach tabulated serves as a good mnemonic for clinicians faced daily with decisions to be made in the evaluation and management of comatose patients. The approach also provides a framework for subsequent statistical (Bayesian or other) analysis of efficacy, cost effectiveness, and impact on clinical practice and health care delivery.     

"Theta pattern coma" occurring in younger adults

Since our previous report, where "theta pattern coma" was described in 2 elderly patients as an EEG pattern with a grave prognosis, we have had the opportunity to see another 9 affected patients. In this article, 3 men with a mean age of 36 years who died after cardiorespiratory arrest presented a "theta coma pattern." The EEG activity was initially reactive to and attenuated by external stimulation in 2, but prior to death the pattern became arreactive. This article shows that "theta pattern coma" is not an age related phenomenon as previously considered. So far, 11 patients with this type of EEG abnormality have been seen in our department; all have died, and all were over 30 years of age. An expanded definition of "theta pattern coma" is given in the discussion. The pathophysiological mechanisms involved in generation of this abnormality are not known. This abnormality, when seen in the unconscious patient, should be classified as a grade 4 abnormality on the EEG coma scale and should be differentiated from rather diffuse theta activity in coma. The prognostic significance of "theta pattern coma" appears to be similar to that of "alpha pattern coma."     

The effect of intense multi-sensory stimulation on coma arousal and recovery

Abstract

The purpose of this study was to evaluate the possible therapeutic benefits of intense multi-sensory stimulation (IMS) in the management of profound coma. Two hundred hospitalised patients with Glasgow Coma Scale (GCS) scores of 6 or less recorded on admission and 1 week later, were included in the IMS treatment programme. Twenty-seven patients were seen within the first month following injury and the onset of coma. The remaining 173 patients were first seen on average 6 months post-onset, with the longest period of coma extending to 2 years prior to IMS. All had a “hopeless” prognosis recorded on their charts and all were reported as being in a persistent vegetative state (PVS). Outcome results are compared with 33 patients (controls) of similar age, sex, and aetiological and GCS distribution who did not receive IMS; 34.5% of the IMS group made a moderate to good recovery based on Glasgow Outcome Scores (GOS), 9% have remained in PVS, 56.5% are still severely disabled with marked psychomotor deficits, but are out of coma and some are continuing to show progress. A total of 91% are out of coma; 33 patients in the control group (100%) remain in coma. The results of this study support earlier observations that the worst prognostic criteria do not apply uniformly to the patient in either acute or chronic coma, and that the outcome in both conditions can be markedly influenced by IMS.     

最小意识状态的定义、诊断标准及临床鉴别

最小意识状态可由急性脑损伤后昏迷或植物状态、变性或先天性神经系统疾病发展而来，有严重意识障碍，但病人既不符合昏迷也不符合植物状态的诊断，存存部分意识鉴别最小意识状态、昏迷及植物状态对于预后的判定有重要的意义。本文主要综述最小意识状念的定义、诊断标准、鉴别诊断及有关临床意义。     

The minimally conscious state: definition and diagnostic criteria

OBJECTIVE: To establish consensus recommendations among health care specialties for defining and establishing diagnostic criteria for the minimally conscious state (MCS). BACKGROUND: There is a subgroup of patients with severe alteration in consciousness who do not meet diagnostic criteria for coma or the vegetative state (VS). These patients demonstrate inconsistent but discernible evidence of consciousness. It is important to distinguish patients in MCS from those in coma and VS because preliminary findings suggest that there are meaningful differences in outcome. METHODS: An evidence-based literature review of disorders of consciousness was completed to define MCS, develop diagnostic criteria for entry into MCS, and identify markers for emergence to higher levels of cognitive function. RESULTS: There were insufficient data to establish evidence-based guidelines for diagnosis, prognosis, and management of MCS. Therefore, a consensus-based case definition with behaviorally referenced diagnostic criteria was formulated to facilitate future empirical investigation. CONCLUSIONS: MCS is characterized by inconsistent but clearly discernible behavioral evidence of consciousness and can be distinguished from coma and VS by documenting the presence of specific behavioral features not found in either of these conditions. Patients may evolve to MCS from coma or VS after acute brain injury. MCS may also result from degenerative or congenital nervous system disorders. This condition is often transient but may also exist as a permanent outcome. Defining MCS should promote further research on its epidemiology, neuropathology, natural history, and management.     

可逆性长期昏迷六例临床报告

目的探讨长期但可逆性非外伤性昏迷患者的临床特点、诊断及治疗方法。方法首都医科大学宣武医院神经内科重症监护病房2005年7月～2008年9月期间入院的745例患者中满足下列条件者入组:(1)入院时昏迷,GCS评分小于或等于8分;(2)非脑外伤、非脑血管病;(3)昏迷,GCS评分小于或等于8分持续时间超过一个月;(4)治疗后意识清醒GCS评分15分,GOS评分大于或等于3分。分析入组患者的临床表现、包括年龄、性别、昏迷持续时间、诊断、高峰时临床表现、实验室、影像学、脑电图检查,治疗及预后。结果入组6例,男性2例,女性4例,年龄16～45岁,平均年龄中位值24.5±10.5岁。3例为单纯疱疹病毒性脑炎、1例巨细胞病毒性脑炎、1例急性缺血缺氧性脑病和1例甲状腺危象性脑病。结论长期可逆性昏迷可能是一种特殊的临床综合征,影响其发生的因素有四:首先是病因及对病因的积极治疗。其次是对非抽搐性惊厥持续状态的及时处理,最好立即脑电图监测,证实后即刻开始抗癫持续状态治疗。三是患者本身对损害因素的易感性,反映出不同的病理生理学过程。最后,神经重症监护病房监测和护理起到关键的作用。     

The management of .22 caliber gunshot wounds of the brain: a review of 49 cases

We analyzed the charts and CT scans of 49 cases of civilian .22 caliber gunshot wounds of the brain admitted to the University of Alberta and Royal Alexandra Hospitals between 1975 and 1985. The average age of the patients was 30 years, 88% were males, 88% were suicide attempts. There were no deaths among patients with an initial coma score above 12 whereas the mortality rate was 85% for those admitted with a score of 7 or less. All those with fixed pupils on admission died. The overall mortality rate of 61% is comparable to that of other series of civilian gunshot wounds including those in which more aggressive surgical management was undertaken. We recommend that no treatment be given those cases with an admission coma score of 3 and/or fixed pupils and that simple scalp wound debridement be employed with those having a coma score of 7 or less. Tract exploration and retrieval of bullet fragments is not indicated, as retained fragments carry a very low incidence of complications (e.g. abscess formation). In patients in good condition (GCS greater than or equal to 12) the management of intracranial hematomas should be independent of their etiology and approached aggressively.     

Use of an anesthesia cerebral monitor bispectral index to assess burst-suppression in pentobarbital coma

A seven-year-old child with generalized status epilepticus who was placed in a barbiturate coma was monitored with the bispectral index monitor in addition to the standard full channel electroencephalogram. This child had a low bispectral index number and high suppression ratio on the bispectral index monitor when the desired level of pentobarbital coma was induced. There was excellent correlation of the bispectral index monitor to the suppression ratio. The burst rate also correlated well to the bispectral index number and to the suppression ratio. Therefore the bispectral index monitor could allow the patient in barbiturate coma to leave the intensive care unit for diagnostic or therapeutic procedures and may one day replace the full-channel electroencephalogram in the management of patients in barbiturate coma.     

Assessment and detection of pain in noncommunicative severely brain-injured patients

Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their feelings and potential perception of pain. However, recent studies suggest that patients in a minimally conscious state can experience pain to some extent. Pain monitoring in these patients is hence of medical and ethical importance. In this article, we will focus on the possible use of behavioral scales for the assessment and detection of pain in noncommunicative patients.     

Prognosis of patients in coma after acute subdural hematoma due to ruptured intracranial aneurysm

Acute subdural hematomas (aSDH) secondary to intracranial aneurysm rupture are rare. Most patients present with coma and their functional prognosis has been classically considered to be very poor. Previous studies mixed good-grade and poor-grade patients and reported variable outcomes. We reviewed our experience by focusing on patients in coma only and hypothesized that aSDH might worsen initial mortality but not long-term functional outcome. Between 2005 and 2013, 440 subarachnoid hemorrhage (SAH) patients were admitted to our center. Nineteen (4.3%) were found to have an associated aSDH and 13 (2.9%) of these presented with coma. Their prospectively collected clinical and outcome data were reviewed and compared with that of 104 SAH patients without aSDH who presented with coma during the same period. Median aSDH thickness was 10 mm. Four patients presented with an associated aneurysmal cortical laceration and only one had good recovery. Overall, we observed good long-term outcomes in both SAH patients in coma with aSDH and those without aSDH (38.5% versus 26.4%). Associated aSDH does not appear to indicate a poorer long-term functional prognosis in SAH patients presenting with coma. Anisocoria and brain herniation are observed in patients with aSDH thicknesses that are smaller than those observed in trauma patients. Despite a high initial mortality, early surgery to remove the aSDH results in a good outcome in over 60% of survivors. Aneurysmal cortical laceration appears to be an independent entity which shows a poorer prognosis than other types of aneurysmal aSDH.     

Post-traumatic amnesia: still a valuable yardstick.

Records of coma and post-traumatic amnesia (PTA) were collected for a group of 38 patients with closed head injury. The results confirmed earlier studies indicating that patients may have short or negligible coma but report prolonged PTA. Comparison of eight patients with prolonged PTA (> 7 days) and short coma (< 6 hours) with the rest of the group on MRI in the acute stage showed that these patients had significantly more extensive hemispheric damage. In the group as a whole both coma and PTA were related to the number of areas in central brain structures in which lesions were detected, but only PTA was significantly related to the number of hemispheric areas in which lesions were found. It is concluded that although both coma and PTA are related to brain damage they reflect disparate patterns of lesions. Assessment of PTA can thus provide additional information concerning severity of injury.     

Which EEG patterns in coma are nonconvulsive status epilepticus?

Nonconvulsive status epilepticus (NCSE) is common in patients with coma with a prevalence between 5% and 48%. Patients in deep coma may exhibit epileptiform EEG patterns, such as generalized periodic spikes, and there is an ongoing debate about the relationship of these patterns and NCSE. The purposes of this review are (i) to discuss the various EEG patterns found in coma, its fluctuations, and transitions and (ii) to propose modified criteria for NCSE in coma.Classical coma patterns such as diffuse polymorphic delta activity, spindle coma, alpha/theta coma, low output voltage, or burst suppression do not reflect NCSE. Any ictal patterns with a typical spatiotemporal evolution or epileptiform discharges faster than 2.5 Hz in a comatose patient reflect nonconvulsive seizures or NCSE and should be treated. Generalized periodic diacharges or lateralized periodic discharges (GPDs/LPDs) with a frequency of less than 2.5 Hz or rhythmic discharges (RDs) faster than 0.5 Hz are the borderland of NCSE in coma. In these cases, at least one of the additional criteria is needed to diagnose NCSE (a) subtle clinical ictal phenomena, (b) typical spatiotemporal evolution, or (c) response to antiepileptic drug treatment. There is currently no consensus about how long these patterns must be present to qualify for NCSE, and the distinction from nonconvulsive seizures in patients with critical illness or in comatose patients seems arbitrary.The Salzburg Consensus Criteria for NCSE [1] have been modified according to the Standardized Terminology of the American Clinical Neurophysiology Society [2] and validated in three different cohorts, with a sensitivity of 97.2%, a specificity of 95.9%, and a diagnostic accuracy of 96.3% in patients with clinical signs of NCSE. Their diagnostic utility in different cohorts with patients in deep coma has to be studied in the future.This article is part of a Special Issue entitled “Status Epilepticus”.     

Nonconvulsive status epilepticus following cardiac arrest—are we missing the beginning?

Background

Status epilepticus (SE) is a common complication in patients surviving a cardiac arrest, but little is known about the frequency of nonconvulsive status epilepticus (NCSE).

Objectives

To compile the first the evidence from the literature of the overall frequency of NCSE in adults with persistent coma following cardiac arrest. Secondarily, to assess the emergence of NCSE in comatose resuscitated patients within the first hours of the return of spontaneous circulation (ROSC) and before inducing target temperature management.

Material and methods

The medical search engine PubMed was screened to identify prospective and retrospective studies in English reporting on the frequency of NCSE in comatose post-resuscitated patients. Study design, time of EEG performance, detection of SE and NCSE, outcomes, and targeted temperature management were assessed.

Results

Only three cohort studies (one prospective and two retrospective) reported on the EEG evaluation describing NCSE during ongoing sedation and target temperature management. Overall, we identified 213 patients with SE in 18–38% and NCSE in 5–12%. Our review found no study reporting NCSE in resuscitated adult patients remaining in coma within the first hours of ROSC and prior to targeted temperature management and sedation.

Conclusion

Studies of NCSE after ROSC in adults are rare and mostly nonsystematic. This and the low proportion of patients reported having NCSE following ROSC suggest that NCSE before target temperature management and sedation is often overlooked. The limited quality of the data does not allow firm conclusions to be drawn regarding the effects of NCSE on outcome calling for further investigations. Clinicians should suspect NCSE in patients with persistent coma before starting sedation and targeted temperature management.

     

Inadequate benzodiazepine dosing may result in progression to refractory and non‐convulsive status epilepticus

Aims. Status epilepticus (SE) is defined as ongoing seizures lasting longer than five minutes or multiple seizures without recovery. Benzodiazepines (BZDs) are first‐line agents for the management of SE. Our objective was to evaluate BZD dosing in SE patients and its effects on clinical/electrographic outcomes. Methods. A retrospective analysis was conducted from a prospective database of SE patients admitted to a university‐based neurocritical care unit. The initial presentation and progression to refractory SE (RSE) and non‐convulsive SE (NCSE) with coma was evaluated. Outcome measures included length of stay (LOS), rates of intubation, ventilator‐dependent days, and Glasgow outcome scale (GOS). The lorazepam equivalent (LE) dosage of BZDs administered was calculated and we analysed variations in progression if 4 mg or more of LE (adequate BZDs) was administered. Results. Among 100 patients, the median dose of LE was 3 mg (IQR: 2–5 mg). Only 31% of patients received adequate BZDs. Only 18.9% of patients with NCSE without coma received adequate BZDs (p=0.04). Among patients progressing to RSE, 75.4% had not received adequate BZDs (p=0.04) and among patients developing NCSE with coma, 80.6% did not receive adequate BZDs (p=0.07). Escalating doses of BZDs were associated with a decrease in cumulative incidences of RSE (correlation coefficient r=‐0.6; p=0.04) and NCSE with coma (correlation coefficient r=‐0.7; p=0.003). Outcome measures were not influenced by BZD dosing. Conclusion. The majority of our patients were not adequately dosed with BZDs. Inadequate BZD dosing progressed to RSE and had a tendency to lead to NCSE with coma. Our study demonstrates the need to develop a hospital‐wide protocol to guide first responders in the management of SE.     

Metabolic encephalopathies

Kinnier Wilson coined the term metabolic encephalopathy to describe a clinical state of global cerebral dysfunction induced by systemic stress that can vary in clinical presentation from mild executive dysfunction to deep coma with decerebrate posturing; the causes are numerous. Some mechanisms by which cerebral dysfunction occurs in metabolic encephalopathies include focal or global cerebral edema, alterations in transmitter function, the accumulation of uncleared toxic metabolites, postcapillary venule vasogenic edema, and energy failure. This article focuses on common causes of metabolic encephalopathy, and reviews common causes, clinical presentations and, where relevant, management.     

Les troubles de l’éveil de coma : déficit ou défense ?

The different troubles in the coma awakening are generally described as deficit or regression movements following external causes. This article shows that depression or delirium can be better explained through a dynamic point of view wich underlines the conflicts existing by post-comatose patients.     

CNS tryptamine metabolism in hepatic coma

Summary Lumbar CSF indoleacetic acid (IAA) was higher in patients with cirrhosis of the liver than in controls. It was also higher in CSF of patients in coma than in those with hepatic cirrhosis but not in coma. There was a strong correlation (r=0.89, p<0.01) between the grade of hepatic coma and CSF IAA. These data indicate that there is an association between elevated CNS tryptamine metabolism and hepatic coma. How far changes in the metabolism of tryptamine and other trace amines are relevant to the induction of hepatic coma or are simply a reflection of advanced liver dysfunction is unclear.     

Routine early CT-scan is cost saving after minor head injury

Significant hospital resources are invested in early detection of intracranial complications after minor head injuries (MHI). This study focuses on economic aspects of MHI management. 88 MHI patients underwent routine early CT-scan and at least 24 h in-hospital observation. The cost of this management was calculated, and compared to estimated costs of three alternative management protocols. CT-scans demonstrated intracranial lesions in eight (9%) patients, but none required neurosurgical intervention. The expense of our management was Norwegian kroner (NOK) 576136. An alternative management protocol including routine early CT-scan and discharge of patients with normal CT-findings, Glasgow coma score 2 14 and no neurological deficits, was found to be safe, and estimated to reduce costs with 43% to NOK 326669. It is concluded that routine early CT-scan is the most reliable and cost saving management procedure after MHI.     

EEG abnormality grades and subdivisions of prognostic importance in traumatic and anoxic coma in adults

The EEG has long been established as an important laboratory test when assessing cerebral function in comatose states. During the last three decades, several grading scales regarding severity of the EEG abnormality in coma have been suggested to increase the prognostic power of the EEG for survival. Their main limitation was, that the majority of EEG abnormalities in coma fell in the middle of the five point scaling systems, i.e. Grade 3 abnormality on the five grade abnormality scales. In addition, it was considered that non-reactivity of EEG pattern in coma is confined only to the most advanced grades. The purpose of the present article is to define precisely the main five abnormality grades and their subdivisions, and to allocate them in five principal categories regarding their significance for survival. The five categories are: 1 = optimal, 2 = benign if persistent, 3 = uncertain, 4 = malignant if persistent, and 5 = fatal unless caused by drug effect or hypothermia. After the inclusion of more recently described coma patterns, it was possible to outline prognostic significance for survival in eleven types of abnormalities with assurance. Only four remain of uncertain prognostic significance. The EEG abnormalities as discussed in this article are generally applicable only to coma after diffuse brain trauma and cerebral hypoxia. However, they may also be found in some other diffuse encephalopathies associated with coma.