Christian Henke

Quick Discrimination of Adelta and C Fiber Mediated Pain Based on Three Verbal Descriptors

Background Aδ and C fibers are the major pain-conducting nerve fibers, activate only partly the same brain areas, and are differently involved in pain syndromes. Whether a stimulus excites predominantly Aδ or C fibers is a commonly asked question in basic pain research but a quick test was lacking so far. Methodology/Principal Findings Of 77 verbal descriptors of pain sensations, “pricking”, “dull” and “pressing” distinguished best (95% cases correctly) between Aδ fiber mediated (punctate pressure produced by means of von Frey hairs) and C fiber mediated (blunt pressure) pain, applied to healthy volunteers in experiment 1. The sensation was assigned to Aδ fibers when “pricking” but neither “dull” nor “pressing” were chosen, and to C fibers when the sum of the selections of “dull” or “pressing” was greater than that of the selection of “pricking”. In experiment 2, with an independent cohort, the three-descriptor questionnaire achieved sensitivity and specificity above 0.95 for distinguishing fiber preferential non-mechanical induced pain (laser heat, exciting Aδ fibers, and 5-Hz electric stimulation, exciting C fibers). Conclusion A three-item verbal rating test using the words “pricking”, “dull”, and “pressing” may provide sufficient information to characterize a pain sensation evoked by a physical stimulus as transmitted via Aδ or via C fibers. It meets the criteria of a screening test by being easy to administer, taking little time, being comfortable in handling, and inexpensive while providing high specificity for relevant information.

Acupuncture--deep pain with an autonomic dimension?

Stimulation of acupuncture point Pc6, located above the median nerve, has been shown to be effective in treating nausea and vomiting. It has also frequently been reported to cause a heart rate reduction. The mechanism behind this autonomic reaction has not been clarified, so far. We combined brainstem-sensitive functional magnetic resonance imaging with heart rate recording and time-resolved rating of the needling sensation to measure neuronal correlates of sensations and autonomic reactions during acupuncture. On the cortical level, needling sensation activated typical pain-related areas, of which the ventromedial and dorsolateral prefrontal cortex and perigenual anterior cingulate cortex were further involved in mediating the heart rate response. In the brainstem, needling sensation activated nuclei of the descending pain control system, in which a network of hypothalamus, periaqueductal gray, rostral ventromedial medulla, and ventrolateral medulla was identified as the source of the heart rate changes. Our findings indicate that acupuncture may be a special pain stimulus, whose autonomic concomitants could explain its non-analgesic effects and in some cases even have a therapeutic potential.

Anthropometric approximation of body weight in unresponsive stroke patients

Background and purpose: Thrombolysis of acute ischaemic stroke is based strictly on body weight to ensure efficacy and to prevent bleeding complications. Many candidate stroke patients are unable to communicate their body weight, and there is often neither the means nor the time to weigh the patient. Instead, weight is estimated visually by the attending physician, but this is known to be inaccurate. Methods: Based on a large general population sample of nearly 7000 subjects, we constructed approximation formulae for estimating body weight from simple anthropometric measurements (body height, and waist and hip circumference). These formulae were validated in a sample of 178 consecutive inpatients admitted to our stroke unit, and their accuracy was compared with the best visual estimation of two experienced physicians. Results: The simplest formula gave the most accurate approximation (mean absolute difference 3.1 (2.6) kg), which was considerably better than the best visual estimation (physician 1: 6.5 (5.2) kg; physician 2: 7.4 (5.7) kg). It reduced the proportion of weight approximations mismatched by >10% from 31.5% and 40.4% (physicians 1 and 2, respectively) to 6.2% (anthropometric approximation). Only the patient’s own estimation was more accurate (mean absolute difference 2.7 (2.4) kg). Conclusions: By using an approximation formula based on simple anthropometric measurements (body height, and waist and hip circumference), it is possible to obtain a quick and accurate approximation of body weight. In situations where the exact weight of unresponsive patients cannot be ascertained quickly, we recommend using this approximation method rather than visual estimation.

Dysphagia Risk Assessment in Acute Left-Hemispheric Middle Cerebral Artery Stroke

Background and Purpose: Bedside evaluation of dysphagia may be challenging in left middle cerebral artery (MCA) stroke due to frequently existing aphasia. Here we analyse the predictive value of common bedside screening tests and of two items of cortical dysfunction, aphasia and buccofacial apraxia (BFA), for the detection of dysphagia. Methods: We prospectively examined 67 consecutive patients with clinical and imaging evidence of acute (<72 h) left MCA stroke. Dysphonia, dysarthria, abnormal volitional cough and abnormal gag reflex were assessed followed by a standardized 50-ml water-swallowing test determining the symptoms cough and voice change after swallow. Aphasia and BFA were assessed according to defined criteria. Fibre-optic endoscopic evaluation of swallowing (FEES) was performed for validation of dysphagia. Results: 41 (61%) patients had FEES-proven dysphagia. Abnormal gag reflex, abnormal volitional cough, cough after swallow, aphasia and BFA were significantly more frequent in dysphagic as compared to non-dysphagic patients, while dysphonia, dysarthria and voice change after swallow were not. Aphasia and BFA had the highest sensitivity (97 and 78%, respectively) and high negative predictive values (89 and 68%, respectively) for dysphagia. Multivariate regression analysis did not identify an independent predictor of dysphagia. Conclusions: In left MCA stroke, the sensitivity and specificity of common bedside dysphagia screening methods are low. In contrast, aphasia and BFA have a high sensitivity and high negative predictive power, presumably due to the neuro-anatomical overlap between cortical regions involved in swallowing, speech production, imitation and voluntary movement control.

Forgotten Features of Head Zones and Their Relation to Diagnostically Relevant Acupuncture Points

In the 1890s Sir Henry Head discovered certain areas of the skin that develop tenderness (allodynia) in the course of visceral disease. These areas were later termed “Head zones”. In addition, he also emphasized the existence of specific points within these zones, that he called “maximum points”, a finding that seems to be almost forgotten today. We hypothesized that two important groups of acupuncture points, the diagnostically relevant Mu and Shu points, spatially and functionally coincide with these maximum points to a large extent. A comparison of Heads papers with the Huang Di Neijing (Yellow Thearchs Inner Classic) and the Zhen Jiu Jia Yi Jing (Systematic Classic of Acupuncture and Moxibustion), two of the oldest still extant Chinese sources on acupuncture, revealed astonishing parallels between the two concepts regarding both point locations and functional aspects. These findings suggest that the Chinese discovery of viscerocutaneous reflexes preceded the discovery in the West by more than 2000 years. Furthermore, the fact that Chinese medicine uses Mu and Shu points not only diagnostically but also therapeutically may give us new insights into the underlying mechanisms of acupuncture.

Paraneoplastic cerebellar degeneration associated with lymphoepithelial carcinoma of the tonsil

BackgroundParaneoplastic cerebellar degeneration (PCD) is a classical tumor-associated, immune-mediated disease typically associated with gynecological malignancies, small-cell lung-cancer or lymphoma.Case presentationHere we present the case of a 38-year old male with an over 12 months rapidly progressive cerebellar syndrome. Extensive diagnostic workup revealed selective hypermetabolism of the right tonsil in whole-body PET. Histological examination after tonsillectomy demonstrated a lymphoepithelial carcinoma of the tonsil and the tongue base strongly suggesting a paraneoplastic cause of the cerebellar syndrome. To the best of our knowledge this is the first case of an association of a lymphoepithelial carcinoma, a rare pharyngeal tumor, with PCD.ConclusionsIn cases of classical paraneoplastic syndromes an extensive search for neoplasms should be performed including whole-body PET to detect tumors early in the course of the disease.

A Network-Wide Stroke Team Program Reduces Time to Treatment for Endovascular Stroke Therapy in a Regional Stroke-Network

Background and Purpose: Driven by the positive results of randomized, controlled trials of endovascular stroke therapies (EVT) in stroke patients with large vessel occlusion, different approaches to speed up the workflow for EVT candidates are currently being implemented worldwide. We aimed to assess the effect of a simple stroke network-wide workflow improvement project, primarily focusing on i.v. thrombolysis, on process times for patients undergoing EVT. Methods: In 2015, we conducted a network-wide, peer-to-peer acute stroke workflow improvement program for i.v. thrombolysis with the main components of implementing a binding team-based algorithm at every stroke unit of the regional network, educating all stroke teams about non-technical skills and providing a stroke-specific simulation training. Before and after the intervention we recorded periprocedural process times, including patients undergoing EVT at the 3 EVT-capable centers (January – June 2015, n = 80 vs. July 2015 – June 2016, n = 184). Results: In this multi-centric evaluation of 268 patients receiving EVT, we observed a relevant shortening of the median time from symptom onset to EVT specifically in patients requiring secondary transfer by almost an hour (300 min, 25–75% interquartile range [IQR] 231–381 min to 254 min, IQR 215.25–341 min; p = 0.117), including a reduction of the median door-to-groin time at the EVT-capable center in this patient group by 15.5 min (59 min, IQR 35–102 min to 43.5 min, IQR 27.75–81.25 min; p = 0.063). In patients directly admitted to an EVT-capable center, the median door-to-groin interval was reduced by 10.5 min (125 min, IQR 83.5–170.5 min to 114.5 min, IQR 66.5–151 min; p = 0.167), but a considerable heterogeneity between the centers was observed (p < 0.001). Conclusions: We show that a simple network-wide workflow improvement program primarily directed at fast i.v. thrombolysis also accelerates process times for EVT candidates and is a promising measure to improve the performance of an entire stroke network.

Predictors of Dysphagia in Acute Pontine Infarction

Background and Purpose— Little is known about the frequency and the clinical characteristics of neurogenic dysphagia in pontine strokes. In this study, we sought to identify predictors for dysphagia in a cohort of patients with isolated pontine infarctions. Methods— We included all patients admitted to our department between 2008 and 2014 having an acute (<48 hours after symptom onset) ischemic stroke in the pons, as documented by means of diffusion-weighted magnetic resonance imaging. Precise infarct localization was stratified according to established vascular territories. The presence of dysphagia was the primary end point of the study and was assessed by a Speech-Language Pathologist according to defined criteria. Results— The study recruited 59 patients, 14 with and 45 without dysphagia. Median (interquartile range) stroke severity (in terms of National Institutes of Health Stroke Scale values) was higher in the dysphagic group as compared with patients without dysphagia (8.5 [6–12] versus 2 [1–5]; P<0.001). Infarct localization in the upper part of the pons (78.6% versus 33.3%; P=0.004) and in the anterolateral vascular territory (78.6% versus 31.1%; P=0.002) occurred more often in the dysphagic group. In a multivariate model, age, infarct volume, and National Institutes of Health Stroke Scale value were independent predictors of dysphagia. Conclusions— Dysphagia occurs frequently in patients with isolated pontine infarctions. Clinical and imaging predictors of dysphagia may help to provide optimal screening, to prevent complications and to improve long-term prognosis.

Implementation of stroke teams and simulation training shortened process times in a regional stroke network—A network-wide prospective trial

Background To meet the requirements imposed by the time-dependency of acute stroke therapies, it is necessary 1) to initiate structural and cultural changes in the breadth of stroke-ready hospitals and 2) to find new ways to train the personnel treating patients with acute stroke. We aimed to implement and validate a composite intervention of a stroke team algorithm and simulation-based stroke team training as an effective quality initiative in our regional interdisciplinary neurovascular network consisting of 7 stroke units. Methods We recorded door-to-needle times of all consecutive stroke patients receiving thrombolysis at seven stroke units for 3 months before and after a 2 month intervention which included setting up a team-based stroke workflow at each stroke unit, a train-the-trainer seminar for stroke team simulation training and a stroke team simulation training session at each hospital as well as a recommendation to take up regular stroke team trainings. Results The intervention reduced the network-wide median door-to-needle time by 12 minutes from 43,0 (IQR 29,8–60,0, n = 122) to 31,0 (IQR 24,0–42,0, n = 112) minutes (p < 0.001) and substantially increased the share of patients receiving thrombolysis within 30 minutes of hospital arrival from 41.5% to 59.6% (p < 0.001). Stroke team training participants stated a significant increase in knowledge on the topic of acute stroke care and in the perception of patient safety. The overall course concept was regarded as highly useful by most participants from different professional backgrounds. Conclusions The composite intervention of a binding team-based algorithm and stroke team simulation training showed to be well-transferable in our regional stroke network. We provide suggestions and materials for similar campaigns in other stroke networks.

Early Screening Parameters for Dysphagia in Acute Ischemic Stroke

Background: Dysphagia is a frequent symptom in patients with acute stroke. It is associated with malnutrition, aspiration and mortality. The identification of early screening parameters for dysphagia promptly leading to a professional swallowing examination is therefore of utmost importance. This study aimed to detect early and easily assessable predictors of dysphagia in a large cohort of patients with acute ischemic stroke. Methods: Our analysis was based on data from a prospective in-hospital registry. Patients with ischemic stroke were included over the course of 3 years. Patients were scheduled to undergo a clinical swallowing investigation within the first 24 h after hospital admission. Step-wise multivariate logistic regression was used to identify independent predictors of dysphagia in general and of pneumonia in particular. Results: 1,646 patients with ischemic stroke were included. Stroke severity in terms of higher National Institute of Health Stroke Scale (NIHSS) values (p < 0.001), male gender (p = 0.006) and higher age (p < 0.001) independently predicted dysphagia. A receiver operating characteristics analysis revealed an NIHSS cut-off value of 4.5 for optimal differentiation between patients with and without dysphagia (sensitivity 0.77; specificity 0.77). Dysphagia (p < 0.001), male gender (p = 0.002), higher NIHSS scores (p < 0.001) and higher age (p = 0.002) were factors that were independently associated with pneumonia. The NIHSS cut-off value for differentiating between patients with and without pneumonia was 5.5 (sensitivity 0.91; specificity 0.67). Conclusions: Stroke severity in terms of NIHSS is a simple and reliable predictor of dysphagia. Patients with NIHSS values ≥5 should be quickly directed towards a professional swallowing examination. Dysphagia was confirmed to be a strong predictor of pneumonia.