Causes of brain dysfunction in acute coma: a cohort study of 1027 patients in the emergency department

BACKGROUND: Coma of unknown etiology (CUE) is a major challenge in emergency medicine. CUE is caused by a wide variety of pathologies that require immediate and targeted treatment. However, there is little empirical data guiding rational and efficient management of CUE. We present a detailed investigation on the causes of CUE in patients presenting to the ED of a university hospital. METHODS: One thousand twenty-seven consecutive ED patients with CUE were enrolled. Applying a retrospective observational study design, we analyzed all clinical, laboratory and imaging findings resulting from a standardized emergency work-up of each patient. Following a predefined protocol, we identified main and accessory coma-explaining pathologies and related these with (i.a.) GCS and in-hospital mortality. RESULTS: On admission, 854 of the 1027 patients presented with persistent CUE. Their main diagnoses were classified into acute primary brain lesions (39%), primary brain pathologies without acute lesions (25%) and pathologies that affected the brain secondarily (36%). In-hospital mortality associated with persistent CUE amounted to 25%. 33% of patients with persistent CUE presented with more than one coma-explaining pathology. In 173 of the 1027 patients, CUE had already resolved on admission. However, these patients showed a spectrum of main diagnoses similar to persistent CUE and a significant in-hospital mortality of 5%. CONCLUSION: The data from our cohort show that the spectrum of conditions underlying CUE is broad and may include a surprisingly high number of coincidences of multiple coma-explaining pathologies. This finding has not been reported so far. Thus, significant pathologies may be masked by initial findings and only appear at the end of the diagnostic work-up. Furthermore, even transient CUE showed a significant mortality, thus rendering GCS cutoffs for selection of high- and low-risk patients questionable. Taken together, our data advocate for a standardized diagnostic work-up that should be triggered by the emergency symptom CUE and not by any suspected diagnosis. This standardized routine should always be completed - even when initial coma-explaining diagnoses may seem evident

Serial measurement of neuron specific enolase improves prognostication in cardiac arrest patients treated with hypothermia: A prospective study

<p>Abstract</p> <p>Background</p> <p>Neuron specific enolase (NSE) has repeatedly been evaluated for neurological prognostication in patients after cardiac arrest. However, it is unclear whether current guidelines for NSE cutoff levels also apply to cardiac arrest patients treated with hypothermia. Thus, we investigated the prognostic significance of absolute NSE levels and NSE kinetics in cardiac arrest patients treated with hypothermia.</p> <p>Methods</p> <p>In a prospective study of 35 patients resuscitated from cardiac arrest, NSE was measured daily for four days following admission. Outcome was assessed at ICU discharge using the CPC score. All patients received hypothermia treatment for 24 hours at 33°C with a surface cooling device according to current guidelines.</p> <p>Results</p> <p>The cutoff for absolute NSE levels in patients with unfavourable outcome (CPC 3-5) 72 hours after cardiac arrest was 57 μg/l with an area under the curve (AUC) of 0.82 (sensitivity 47%, specificity 100%). The cutoff level for NSE kinetics in patients with unfavourable outcome (CPC 3-5) was an absolute increase of 7.9 μg/l (AUC 0.78, sensitivity 63%, specificity 100%) and a relative increase of 33.1% (AUC 0.803, sensitivity 67%, specificity 100%) at 48 hours compared to admission.</p> <p>Conclusion</p> <p>In cardiac arrest patients treated with hypothermia, prognostication of unfavourable outcome by NSE kinetics between admission and 48 hours after resuscitation may be superior to prognostication by absolute NSE levels.</p

The diagnostic value of the neurological examination in coma of unknown etiology

Background: Identifying the cause of non-traumatic coma in the emergency department is challenging. The clinical neurological examination is the most readily available tool to detect focal neurological deficits as indicators for cerebral causes of coma. Previously proposed clinical pathways have granted the interpretation of clinical findings a pivotal role in the diagnostic work-up. We aimed to identify the actual diagnostic reliability of the neurological examination with regard to identifying acute brain damage. Methods: Eight hundred and fifty-three patients with coma of unknown etiology (CUE) were examined neurologically in the emergency department following a predefined routine. Coma-explaining pathologies were identified retrospectively and grouped into primary brain pathology with proof of acute brain damage and other causes without proof of acute structural pathology. Sensitivity, specificity and percentage of correct predictions of different examination protocols were calculated using contingency tables and binary logistic regression models. Results: The full neurological examination was 74% sensitive and 60% specific to detect acute structural brain damage underlying CUE. Sensitivity and specificity were higher in non-sedated patients (87/61%) compared to sedated patients (64%/59%). A shortened four-item examination protocol focusing on pupils, gaze and pyramidal tract signs was only slightly less sensitive (67%) and more specific (65%). Conclusions: Due to limited diagnostic reliability of the physical examination, the absence of focal neurological signs in acutely comatose patients should not defer from a complete work-up including brain imaging. In an emergency, a concise neurological examination should thus serve as one part of a multimodal diagnostic approach to CUE

implementation of an in-house management routine

Background Coma of unknown origin is an emergency caused by a variety of possibly life-threatening pathologies. Although lethality is high, there are currently no generally accepted management guidelines. Methods We implemented a new interdisciplinary standard operating procedure (SOP) for patients presenting with non-traumatic coma of unknown origin. It includes a new in- house triage process, a new alert call, a new composition of the clinical response team and a new management algorithm (altogether termed “coma alarm”). It is triggered by two simple criteria to be checked with out-of-hospital emergency response teams before the patient arrives. A neurologist in collaboration with an internal specialist leads the in-hospital team. Collaboration with anaesthesiology, trauma surgery and neurosurgery is organised along structured pathways that include standardised laboratory tests and imaging. Patients were prospectively enrolled. We calculated response times as well as sensitivity and false positive rates, thus proportions of over- and undertriaged patients, as quality measures for the implementation in the SOP. Results During 24 months after implementation, we identified 325 eligible patients. Sensitivity was 60 % initially (months 1–4), then fluctuated between 84 and 94 % (months 5–24). Overtriage never exceeded 15 % and undertriage could be kept low at a maximum of 11 % after a learning period. We achieved a median door-to-CT time of 20 minutes. 85 % of patients needed subsequent ICU treatment, 40 % of which required specialised neuro- ICUs. Discussion Our results indicate that our new simple in-house triage criteria may be sufficient to identify eligible patients before arrival. We aimed at ensuring the fastest possible proceedings given high portions of underlying time-sensitive neurological and medical pathologies while using all available resources as purposefully as possible. Conclusions Our SOP may provide an appropriate tool for efficient management of patients with non- traumatic coma. Our results justify the assignment of the initial diagnostic workup to neurologists and internal specialists in collaboration with anaesthesiologists

Long‐Term Cognitive Outcome in Anti–N‐Methyl‐D‐Aspartate Receptor Encephalitis

Objective: Cognitive dysfunction is a core symptom of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, but detailed studies on prevalence, characteristics of cognitive deficits, and the potential for recovery are missing. Here, we performed a prospective longitudinal study to assess cognitive long-term outcome and identify clinical predictors. Methods: Standardized comprehensive neuropsychological assessments were performed in 43 patients with NMDAR encephalitis 2.3 years and 4.9 years (median) after disease onset. Cognitive assessments covered executive function, working memory, verbal/visual episodic memory, attention, subjective complaints, and depression and anxiety levels. Cognitive performance of patients was compared to that of 30 healthy participants matched for age, sex, and education. Results: All patients had persistent cognitive deficits 2.3 years after onset, with moderate or severe impairment in >80% of patients. Core deficits included memory and executive function. After 4.9 years, significant improvement of cognitive function was observed, but moderate to severe deficits persisted in two thirds of patients, despite favorable functional neurological outcomes (median modified Rankin Scale = 1). Delayed treatment, higher disease severity, and longer duration of the acute phase were predictors for impaired cognitive outcome. The recovery process was time dependent, with greater gains earlier after the acute phase, although improvements were possible for several years after disease onset. Interpretation: Cognitive deficits are the main contributor to long-term morbidity in NMDAR encephalitis and persist beyond functional neurological recovery. Nonetheless, cognitive improvement is possible for several years after the acute phase and should be supported by continued cognitive rehabilitation. Cognition should be included as an outcome measure in future clinical studies

The accuracy of initial diagnoses in coma: an observational study in 835 patients with non-traumatic disorder of consciousness

Background: Management of patients with coma of unknown etiology (CUE) is a major challenge in most emergency departments (EDs). CUE is associated with a high mortality and a wide variety of pathologies that require differential therapies. A suspected diagnosis issued by pre-hospital emergency care providers often drives the first approach to these patients. We aim to determine the accuracy and value of the initial diagnostic hypothesis in patients with CUE. Methods: Consecutive ED patients presenting with CUE were prospectively enrolled. We obtained the suspected diagnoses or working hypotheses from standardized reports given by prehospital emergency care providers, both paramedics and emergency physicians. Suspected and final diagnoses were classified into I) acute primary brain lesions, II) primary brain pathologies without acute lesions and III) pathologies that affected the brain secondarily. We compared suspected and final diagnosis with percent agreement and Cohen's Kappa including sub-group analyses for paramedics and physicians. Furthermore, we tested the value of suspected and final diagnoses as predictors for mortality with binary logistic regression models. Results: Overall, suspected and final diagnoses matched in 62% of 835 enrolled patients. Cohen's Kappa showed a value of kappa = .415 (95% CI .361-.469, p < .005). There was no relevant difference in diagnostic accuracy between paramedics and physicians. Suspected diagnoses did not significantly interact with in-hospital mortality (e.g., suspected class I: OR .982, 95% CI .518-1.836) while final diagnoses interacted strongly (e.g., final class I: OR 5.425, 95% CI 3.409-8.633). Conclusion: In cases of CUE, the suspected diagnosis is unreliable, regardless of different pre-hospital care providers' qualifications. It is not an appropriate decision-making tool as it neither sufficiently predicts the final diagnosis nor detects the especially critical comatose patient. To avoid the risk of mistriage and unnecessarily delayed therapy, we advocate for a standardized diagnostic work-up for all CUE patients that should be triggered by the emergency symptom alone and not by any suspected diagnosis

Neurological Emergencies in Refugees

Objective: Health care personnel in Europe is increasingly involved in care of displaced persons from non-European countries; we investigated the spectrum of neurological disorders and medical management in refugees presenting to the emergency room (ER) of a German university hospital.Methods: We retrospectively studied ER-patients with refugee status (R-patients) during the peak of the European refugee crisis between July 2015 and February 2016 (N = 100). Complaints on admission, medical management and diagnoses at discharge were compared to matched groups of German residents with migrational background (M-patients; N = 96) and to native Germans (N-patients; N = 95).Results: R-patients were mostly male young adults (75% male; mean age 33.2 years). Headache was the most frequent complaint in all groups (R-patients 38%; M-patients 43%; N-patients 24%). R-patients, however, presented much more often with possible or definite seizures (R-patients 27%; M-patients 9%; N-patients 15%). Initial triage, length of medical history and examination records, utilization of laboratory tests and cranial imaging did not differ between groups. However, time to diagnosis was considerably longer in R-patients (220 min; M-patients 151 min, N-patients 123 min). While strokes and other life-threatening emergencies were rare final diagnoses in R-patients, a substantial proportion was discharged with a diagnosis of non-epileptic seizures or a psychiatric disorder (20%; M-patients 6%; N-patients 7%).Conclusions: Refugee patients present with a spectrum of neurological disorders that not solely results from cultural differences but rather reflects the consequences of forced displacement. ER management of refugees requires more time, language skills and critically depends on psychosomatic/psychiatric expertise

Early volumetric changes of hippocampus and medial prefrontal cortex following medial temporal lobe resection

Previous studies have shown that cognitive demands and physical exercise stimulate adult neurogenesis in the dentate gyrus and hippocampus. Recent observations in healthy humans and patients with mild cognitive impairment moreover suggest that training-induced increases in hippocampal volume may be associated with improved memory performance. The corresponding plasticity processes in hippocampal volume may occur on timescales of months to years. For patients with focal lesions in this region, previous functional imaging studies suggest that increased recruitment of the contralateral hippocampus and extratemporal regions may be an important part of the reorganization of episodic memory. However, it is currently unclear whether focal damage to the medial temporal lobe (MTL) induces gray matter (GM) volume changes in the intact contralateral hippocampus and in connected network regions on a shorter timescale. We therefore investigated whether unilateral resection of the MTL, including the hippocampus, induces measurable volumetric changes in the contralateral hippocampus and in the default mode network (DMN). We recruited 31 patients with unilateral left (N = 19) or right (N = 12) hippocampal sclerosis undergoing MTL resection for treatment of drug-resistant epilepsy. Structural MRI was acquired immediately before and 3 months after surgery. Longitudinal voxel-based morphometry (VBM) analysis revealed a significant increase of right hippocampal volume following resection of the left anterior MTL. Furthermore, this patient group showed GM volume increases in the DMN. These results demonstrate significant structural plasticity of the contralateral hippocampus, even in patients with a long-standing unilateral hippocampal dysfunction and structural reorganization processes extending to distant, but functionally connected brain regions

Impaired Representation of Geometric Relationships in Humans with Damage to the Hippocampal Formation

The pivotal role of the hippocampus for spatial memory is well-established. However, while neurophysiological and imaging studies suggest a specialization of the hippocampus for viewpoint-independent or allocentric memory, results from human lesion studies have been less conclusive. It is currently unclear whether disproportionate impairment in allocentric memory tasks reflects impairment of cognitive functions that are not sufficiently supported by regions outside the medial temporal lobe or whether the deficits observed in some studies are due to experimental factors. Here, we have investigated whether hippocampal contributions to spatial memory depend on the spatial references that are available in a certain behavioral context. Patients with medial temporal lobe lesions affecting systematically the right hippocampal formation performed a series of three oculomotor tasks that required memory of a spatial cue either in retinal coordinates or relative to a single environmental reference across a delay of 5000 ms. Stimulus displays varied the availability of spatial references and contained no complex visuo-spatial associations. Patients showed a selective impairment in a condition that critically depended on memory of the geometric relationship between spatial cue and environmental reference. We infer that regions of the medial temporal lobe, most likely the hippocampal formation, contribute to behavior in conditions that exceed the potential of viewpoint-dependent or egocentric representations. Apparently, this already applies to short-term memory of simple geometric relationships and does not necessarily depend on task difficulty or integration of landmarks into more complex representations. Deficient memory of basic geometric relationships may represent a core deficit that contributes to impaired performance in allocentric spatial memory tasks