Toxic-metabolic encephalopathy in adults: Critical discussion and pragmatical diagnostic approach

Screening of toxic-metabolic encephalopathy with and without epileptic seizure with density spectral array

OBJECTIVE

Although toxic metabolic encephalopathy (TME) is clinically common, distinguishing between TME with/without epileptic findings remains challenging. We examined the efficacy of density spectral array (DSA), a form of power-spectrum electroencephalography (EEG) screening tool, for clinicians not specializing in EEG interpretation to make this distinction.

METHODS

Among 346 patients with suspected TME who underwent EEG for acute impaired consciousness (2012-2023), 149 were ultimately diagnosed with TME (mean age 68.9 ± 13.3 years) were enrolled. Using EEG data, we operationally classified DSAs based on frequency changes, as follows: 1) flame or cyclic (presence of temporal frequency change), 2) band (presence of continuous alpha-range activity), 3) gradation (alpha to delta-range activity), and 4) other patterns. The inter-rater agreement rate for DSA pattern assignment was evaluated in a double-blind manner to confirm the reasonableness of the classification. Additionally, we evaluated the sensitivity and specificity of each DSA pattern at determining the ultimate diagnostic outcomes (TME alone or TME with epileptic findings).

RESULTS

TME alone and TME with epileptic findings were 136 and 13, respectively. The inter-rater agreement for DSA classification was high among clinicians (κ = 0.72-0.92). The flame or cyclic pattern exhibited high specificity (97.1 %), but low sensitivity (23.1 %) for the diagnosis of TME with epileptic findings. Conversely, the band and gradation patterns showed a high specificity (76.9-84.6 %) for the diagnosis of TME alone.

CONCLUSIONS

Overall, our DSA classification demonstrated a high inter-rater agreement rate, indicating utility as a simple yet specific tool for distinguishing TME with and without epileptic findings.

Hashimoto's Encephalopathy: Clinical Features, Therapeutic Strategies, and Rehabilitation Approaches

Hashimoto's encephalopathy (HE), also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), is an autoimmune disorder with heterogeneous presentation that poses diagnostic challenges. This review synthesizes the current literature to clarify the clinical, laboratory, and radiological features of SREAT/HE, including the diagnostic utility of thyroid peroxidase (TPO) antibodies, cerebrospinal fluid (CSF) abnormalities, and neuroimaging findings. Cognitive impairment and behavioral changes are common in HE, but specific manifestations vary widely, which can lead to misdiagnosis. While elevated TPO antibodies are frequently observed, a direct causal relationship with HE is unlikely, and their presence may indicate a general state of autoimmunity. Corticosteroids remain the cornerstone of treatment, although responses vary, and alternative immunosuppressive agents or intravenous immunoglobulin may be needed in some cases. Evidence regarding rehabilitation for people affected by HE is limited, but neurorehabilitation strategies adapted from other neurological conditions, including cognitive re-education (CR), physical therapy, and psychosocial support, may be beneficial. Further research is needed to elucidate the underlying mechanisms of SREAT, refine the diagnostic criteria, and develop more targeted and effective therapies, including rehabilitation strategies, for this debilitating neurological disorder.

Cyclic Alternating Patterns of Encephalopathy (CAPE) in Acute Brain Injury Through a Quantitative Electroencephalogram (QEEG) Perspective: A Case Series

Continuous EEG (cEEG) is a non-invasive bedside tool used to detect causative or contributory conditions of the encephalopathic state. By continuously recording electrical brain activity, it provides insights into background patterns, seizures, and dynamic cerebral activity, thereby aiding in the management of critically ill patients with acute brain injury. The term 'cyclic alternating pattern of encephalopathy' (CAPE) was recently introduced to describe alternating changes in brain electrical activity observed on EEG in critically ill patients. CAPE is characterized by electrocerebral background pattern shifts lasting at least ten seconds and repeating regularly for a minimum of six cycles. Quantitative EEG (QEEG) facilitates the interpretation of extensive cEEG datasets by applying mathematical algorithms to transform raw EEG data into time-compressed, frequency- or amplitude-based visualizations. Through Fourier analysis, QEEG decomposes the EEG signals, plotting the amplitude of different frequency bands over time, enabling easier identification of state changes such as CAPE across extended periods. This case series highlights four critically ill patients exhibiting CAPE on cEEG, with corresponding findings illustrated via QEEG. These cases demonstrate that QEEG effectively identifies CAPE by detecting changes in spectral power density and rhythmicity across distinct states. Adjusting the temporal resolution on QEEG enhances the visibility of CAPE patterns, facilitating their recognition.

Toxic-metabolic encephalopathy induced by metronidazole and disulfiram: classics never die

A 53-year-old male with recovering alcohol dependency, diagnosed with bipolar disorder and recurrent episodes of diverticulitis, came to the emergency department with disorientation and confusion after 3 days of treatment with metronidazole 250 mg/12 hours and ciprofloxacin 500 mg/12 hours for acute diverticulitis. In the hospital emergency department, he presented moments of agitation, fluctuations of attitude, increased basal tremor, with rhythmic movement of the left arm and leg, as well as generalised rigidity with an episode of tonic-clonic seizure of 1.5-2 min duration. After performing different diagnostic tests, significant brain findings were ruled out. The pharmacy department recommended the discontinuation of one of the two drugs. As a result, the on-call doctor adjusted the patient's treatment: disulfiram and previous antibiotic therapy (metronidazole and ciprofloxacin) were discontinued, and amoxicillin/clavulanic acid 2 g/8 hour was prescribed instead. The patient progressed well and fully recovered.

The Approach to Altered Mental Status in the Intensive Care Unit

Altered mental status (AMS) is a syndrome posing substantial burden to patients in the intensive care unit (ICU) in both prevalence and intensity. Unfortunately, ICU patients are often diagnosed merely with syndromic labels, particularly the duo of toxic-metabolic encephalopathy (TME) and delirium. Before applying a nonspecific diagnostic label, every patient with AMS should be evaluated for specific, treatable diseases affecting the central nervous system. This review offers a structured approach to increase the probability of identifying specific causal etiologies of AMS in the critically ill. We provide tips for bedside assessment in the challenging ICU environment and review the role and yield of common neurodiagnostic procedures, including specialized bedside modalities of diagnostic utility in unstable patients. We briefly review two common etiologies of TME (uremic and septic encephalopathies), and then review a selection of high-yield toxicologic, neurologic, and infectious causes of AMS in the ICU, with an emphasis on those that require deliberate consideration as they elude routine screening. The final section lays out an approach to the various etiologies of AMS in the critically ill.

Clinical and Radiological Differences between Patients Diagnosed with Acute Ischemic Stroke and Chameleons at the Emergency Room: Insights from a Single-Center Observational Study

INTRODUCTION

Scarce data exist about clinical/radiological differences between acute ischemic strokes diagnosed in the emergency room (AISER) and stroke chameleons (SCs). We aimed at describing the differences observed in a comprehensive stroke center in Chile.

METHODS

Prospective observational study of patients with ischemic stroke syndromes admitted to the emergency room (ER) of Clínica Alemana between December 2014 and October 2023.

RESULTS

1,197 patients were included; of these 63 (5.2%, 95% CI: 4.1-6.6) were SC; these were younger (p < 0.001), less frequently hypertensive (p = 0.03), and they also had lower systolic (SBP) (p < 0.001), diastolic blood pressures (DBP) (p = 0.011), and NIHSS (p < 0.001). Clinically, they presented less frequently gaze (p = 0.008) and campimetry alterations (p = 0.03), facial (p < 0.001) and limb weakness (left arm [p = 0.004], right arm (p = 0.041), left leg (p = 0.001), right leg p = 0.0029), sensory abnormalities (p < 0.001), and dysarthria (p < 0.001). Neuroradiological evaluations included less frequently large vessel occlusions (p = 0.01) and other stroke locations (p = 0.005); they also differed in their etiologies (p < 0.001). Brainstem strokes (p < 0.001) and extinction/inattention symptoms (p < 0.001) were only seen in AISER. In multivariate analysis, younger age (OR: 0.945; 95% CI: 0.93-0.96), DBP (OR: 0.97; 95% CI, 0.95-0.99), facial weakness (OR: 0.39; 95% CI: 0.19-0.78), sensory abnormities (OR: 0.16.18; 95% CI, 0.05-0.4), infratentorial location (OR: 0.36; 95% CI, 0.15-0.78), posterior circulation involvement (OR: 3.02; 95% CI, 1.45-6.3), cardioembolic (OR: 3.5; 95% CI, 1.56-7.99), and undetermined (OR: 2.42; 95% CI, 1.22-4.7; 95%) etiologies, remained statistically significant. A stepwise analysis including only clinical elements present on the patient's arrival to the ER, demonstrates that age (OR: 0.95; 95% CI: 0.94-0.97), DBP (OR: 0.97; 95% CI, 0.95-0.99), the presence of atrial fibrillation (OR: 2.22; 95% CI, 1.04-4.75, NIHSS (OR: 0.88; 95% CI, 0.71-0.89) and the presence in NIHSS of 1a level of consciousness (OR: 5.66; CI: 95% 1.8-16.9), 1b level of consciousness questions (OR: 3.023; 95% CI, 1.35-6.8), facial weakness (OR: 0.3; CI: 95% 0.17-0.8), and sensory abnormalities (OR: 0.27; 95% CI, 0.1-0.72) remained statistically significant.

CONCLUSION

SC had clinical and radiological differences compared to AISER. An additional relevant finding is that neurological symptoms in a patient with atrial fibrillation, even with a negative diffusion-weighted imaging, should be carefully evaluated as a potential stroke until other causes are satisfactorily ruled out.

Review of the Brain's Behaviour after Injury and Disease for Its Application in an Agent-Based Model (ABM)

The brain is the most complex organ in the human body and, as such, its study entails great challenges (methodological, theoretical, etc.). Nonetheless, there is a remarkable amount of studies about the consequences of pathological conditions on its development and functioning. This bibliographic review aims to cover mostly findings related to changes in the physical distribution of neurons and their connections-the connectome-both structural and functional, as well as their modelling approaches. It does not intend to offer an extensive description of all conditions affecting the brain; rather, it presents the most common ones. Thus, here, we highlight the need for accurate brain modelling that can subsequently be used to understand brain function and be applied to diagnose, track, and simulate treatments for the most prevalent pathologies affecting the brain.

Evidentiary Significance of Routine EEG in Refractory Cases: A Paradigm Shift in Psychiatry

Over the past decade, the Diagnostic and Statistical Manual's method of prescribing medications based on presenting symptoms has been challenged. The shift toward precision medicine began with the National Institute of Mental Health and culminated with the World Psychiatric Association's posit that a paradigm shift is needed. This study supports that shift by providing evidence explaining the high rate of psychiatric medication failure and suggests a possible first step toward precision medicine. A large psychiatric practice began collecting electroencephalograms (EEGs) for this study in 2012. The EEGs were analyzed by the same neurophysiologist (board certified in electroencephalography) on 1,233 patients. This study identified 4 EEG biomarkers accounting for medication failure in refractory patients: focal slowing, spindling excessive beta, encephalopathy, and isolated epileptiform discharges. Each EEG biomarker suggests underlying brain dysregulation, which may explain why prior medication attempts have failed. The EEG biomarkers cannot be identified based on current psychiatric assessment methods, and depending upon the localization, intensity, and duration, can all present as complex behavioral or psychiatric issues. The study highlights that the EEG biomarker identification approach can be a positive step toward personalized medicine in psychiatry, furthering the clinical thinking of "testing the organ we are trying to treat."

Tagging EEG features within exam reports to quickly generate databases for research purposes

OBJECTIVE

assess the effectiveness of a new method for classifying EEG recording features through the use of tags within reports. We present feature prevalence in a sample of patients with toxic-metabolic encephalopathy and discuss the advantages of this approach over existing classification systems.

METHODS

during EEG report creation, tags reflecting background activity, epileptiform features and periodic discharges were selected according to the findings of each recording. Reports including the tags have been collected and processed by the EEG report parser script written in PHP language. The resulting spreadsheet was analysed to calculate the prevalence and type of EEG features in a sample group of patients with toxic-metabolic encephalopathy.

RESULTS

tag checking and extraction were very little time-consuming processes. Considering 5784 EEG recordings performed either in inpatients or outpatients over 2 years, toxic-metabolic aetiology was tagged in 218 (3.8 %). The most frequent background feature was severe slowing (5-6 Hz frequency), occurring in 79 (36.2 %). Epileptiform abnormalities were rare, reaching a maximum of 10 (4.6 %). Triphasic waves were tagged in 43 (19.7 %) recordings.

CONCLUSIONS

tagging and parsing processes are very fast and integrated into the daily routine. Sample analysis in patients with toxic-metabolic encephalopathies showed EEG slowing as the prevalent feature, while triphasic waves occurred in a minority of recordings. Existing software such as "SCORE" (Holberg EEG) requires the replacement of the currently used software for EEG reporting, minimizing additional costs and training. EEG Report Parser is free and open-source software, so it can be freely adopted, modified and redistributed, allowing further improvement and adaptability.

Blood-brain barrier dysfunction in intensive care unit

The central nervous system is characterized by a peculiar vascularization termed blood-brain barrier (BBB), which regulates the exchange of cells and molecules between the cerebral tissue and the whole body. BBB dysfunction is a life-threatening condition since its presence corresponds to a marker of severity in most diseases encountered in the intensive care unit (ICU). During critical illness, inflammatory response, cytokine release, and other phenomena activating the brain endothelium contribute to alterations in the BBB and increase its permeability to solutes, cells, nutrients, and xenobiotics. Moreover, patients in the ICU are often old, with underlying acute or chronic diseases, and overly medicated due to their critical condition; these factors could also contribute to the development of BBB dysfunction. An accurate diagnostic approach is critical for the identification of the mechanisms underlying BBB alterations, which should be rapidly managed by intensivists. Several methods were developed to investigate the BBB and assess its permeability. Nevertheless, in humans, exploration of the BBB requires the use of indirect methods. Imaging and biochemical methods can be used to study the abnormal passage of molecules through the BBB. In this review, we describe the structural and functional characteristics of the BBB, present tools and methods for probing this interface, and provide examples of the main diseases managed in the ICU that are related to BBB dysfunction.