Sensation Of Nausea Research Articles

Insular cortex involvement in migraine patients with chronic pain: A volumetric radiological and clinical study

BackgroundThis study aimed to assess abnormalities in the insular cortex of individuals suffering from migraines and examine their associations with pain duration, medication usage, and clinical symptoms. MethodsWe analyzed radiological data from 38 migraine patients who had undergone 3D iso T1-weighted brain MRI at our university hospital between 2019 and 2023. Structured questionnaires were used to collect information on participants' age, migraine type, disease duration, clinical symptoms, and medication use. Volumetric analysis was performed on the insular regions using Volbrain and 3DSlicer. The results were statistically analyzed. ResultsComparing groups with chronic pain to normal groups revealed significant differences in several insular regions, including the posterior insula (p = 0.034), parietal operculum (p = 0.04), and the entire insular cortex (p = 0.023). Further group comparisons (Group 1, 2, and 3) showed significant differences in specific insular regions. For instance, the anterior insula (p = 0.032) was associated with taste changes, the posterior insula (p = 0.010) with smell-related changes, and the central operculum (p = 0.046) with sensations of nausea. Additionally, significant changes were observed in the parietal operculum concerning nausea, photophobia, phonophobia, and changes in smell. ConclusionTo the best of our knowledge, there have been no studies investigating the relationship between clinical manifestations and volumetric correlation. This study provides insights into abnormalities in the insular cortex among migraine patients and their potential relevance to pain duration, severity, and migraine type. The results suggest that understanding alterations in insular regions possibly linked to pain could contribute to the development of innovative approaches to managing chronic pain.

Top-down control of vestibular inputs by the dorsolateral prefrontal cortex.

The vestibular apparatus provides spatial information on the position of the head in space and with respect to gravity. Low-frequency sinusoidal galvanic vestibular stimulation (sGVS), a means of selectively changing the firing of vestibular afferents, induces a frequency-dependent perception of sway and, in some individuals, induces nausea. Given that vestibular afferents project to the insular cortex-which forms part of the vestibular cortex-and that the insula receives inputs from the dorsolateral prefrontal cortex (dlPFC), we tested the hypothesis that electrical stimulation of the dlPFC can modulate vestibular inputs. Sinusoidal electrical stimulation (± 2mA, 0.08Hz, 100 cycles) was delivered via surface electrodes over (1) the mastoid processes alone (sGVS), (2) electroencephalogram (EEG) site F4 (right dlPFC) and the nasion or (3) to each site concurrently (sGVS + dlPFC) in 23 participants. The same stimulation protocol was used in a separate study to investigate EEG site F3 (left dlPFC) instead of F4 in 13 participants. During sGVS, all participants reported perceptions of sway and 13 participants also reported nausea, neither sensation of which occurred as a result of dlPFC stimulation. Interestingly, when sGVS and dlPFC stimulations were delivered concurrently, vestibular perceptions and sensations of nausea were almost completely abolished. We conclude that the dlPFC provides top-down control of vestibular inputs and further suggests that dlPFC stimulation may provide a novel means of controlling nausea.

A Young Man With Epigastric Abdominal Pain

A Young Man With Epigastric Abdominal Pain

Psychometric evaluation of the Lebanese Arabic version of the Dental Fear Survey: a cross-sectional study

BackgroundDental fear is a prevalent problem that can lead to poor dental health. The Kleinknecht’s Dental Fear Survey (DFS) is one of the used scales to assess dental fear. The present study aims to evaluate the psychometric properties of the Lebanese Arabic version of the DFS (DFS-A) and to determine the optimal cut-off to identify dental fear as well as the correlates of dental fear in a group of Lebanese adults dental patients.MethodsA cross-sectional study was conducted among a group of 442 dental patients (18–65 years) recruited at 29 dental clinics from March to June 2019. Patients completed a questionnaire including questions about demographic characteristics, previous bad dental experience, trauma’s experience period, the sensation of nausea during dental treatment, the DFS-A scale, the Lebanese Arabic version of the Modified Dental Anxiety Scale (MDAS-A), and a general question about dental fear.ResultsDFS-A revealed evidence of adequate psychometric properties. DFS-A scale demonstrated high internal consistency (cronbach’s alpha = 0.93). Test–retest reliability assessment demonstrated strong reproducibility of the DFS-A scale score (ICC = 0.92 with 95% CI (0.83–0.96), p value < 0.0001 (N = 30). Confirmatory factor analysis revealed a three-factor structure of the DFS-A reflecting fear associated with specific dental stimuli and procedures, patterns of dental avoidance and anticipatory anxiety, and physiologic arousal during dental treatment. A significant correlation was found between DFS-A and the MDAS-A indicating a good convergent validity. The optimal cut-off point to identify patients with and without dental fear is 41. Considering this cut-off score, the prevalence of dental fear in our sample was reported at 33.8%. Multivariable analysis showed that having previous scary and painful dental experiences, a sensation of nausea during treatment, and having dental anxiety were identified as predictors of dental fear.ConclusionThe adapted Arabic version of the DFS (DFS-A) is a valid tool to evaluate dental fear among Lebanese adult patients.

Assessment of dental anxiety and dental phobia among adults in Lebanon

BackgroundDental anxiety continues to be a widespread problem affecting adult populations. The primary aim of our study was to evaluate the psychometric properties of the Lebanese Arabic version of the Modified Dental Anxiety Scale (MDAS-A) and to identify the optimal cut-off for assessing dental anxiety and dental phobia among adults in Lebanon. In addition, we sought to assess dental anxiety and phobia as well as their correlates among Lebanese adult patients.MethodsA cross-sectional study was carried out on a sample of 451 dental adult patients aged between 18 and 65 years old. Information about demographic characteristics, previous bad dental experience, trauma’s experience period, perception of a periodontal problem, sensation of nausea during dental treatment, the MDAS-A scale, and the Visual Analogue Scale for anxiety (VAS-A) were collected.ResultsMDAS-A exhibited evidence of adequate psychometric properties. The optimal cut-off was 12 for dental anxiety and 14 for dental phobia. Out of the total sample, 31.5% suffered from dental anxiety while 22.4% had a dental phobia. Multivariable analysis showed that the odds of dental anxiety and phobia were higher among females compared to males. Also, patients suffering from periodontal problem perceptions, bad dental experiences during childhood and adolescence, and the sensation of nausea during dental treatment were at a higher risk of developing dental anxiety and phobia compared to their counterparts. However, a higher level of education was found to be a protective factor against dental phobia among Lebanese adult patients.ConclusionThe MDAS-A scale is a suitable tool for the routine assessment of dental anxiety and phobia among Lebanese adult patients. Identifying patients with dental anxiety at the earliest opportunity is of utmost importance for delivering successful dental care.

Surgical Therapy of Esophagus Reflux Disease

Abstract Introduction: Fundoplication is the most frequently used action in the surgical treatment of gastroesophageal reflux disease (GERD). There are several types of fundoplication. The objective of our study was to identify complications after surgical treatment of GERD. Material and Methods: We determined several parameters of the monitored and we recorded complications related to surgery: occurrence of surgical, early and late post-surgical complications. Results: 52 patients (24 men and 28 women) with an average age of 53.3 years were included. The most frequently chosen type of fundoplication was Nissen-Rossetti. The most frequently occurring subjective post-surgery difficulties were temporal dysphagia (11.5%), sensation of nausea and vomiting after eating (3.8 %), pain in the surgical wound, and dyspnoea occurring in all patients after thoracotomy. Early post-surgery complication developed in 6 patients (11.5 %) Conclusion: Occurrence of complications in the group monitored by us was up to 11.5 % and perioperative mortality was 0 %. Hiatal hernia is frequently found in patients with GERD and it is considered to be one of the major causes for the development of this disease.

Patient and Operator Centered Outcomes in Implant Dentistry: Comparison between Fully Digital and Conventional Workflow for Single Crown and Three-Unit Fixed-Bridge.

Background: Scientific information about the effects of implant therapy following a precise workflow and patient and operators’ preferences should be considered to choose which implant treatment protocol to use, and to achieve patient’s satisfaction and functional results. The aim of this study was to analyze implant rehabilitations with a fully digital workflow and compare this approach with a conventional one. Methods: This study comprises 64 patients treated with a fully digital approach and 58 patients treated using a conventional protocol. Patient and operator centered outcomes were assessed through two visual analogue scale (VAS) questionnaires. Results: The VAS questionnaire demonstrated better results for the digital workflow concerning anxiety, convenience, taste, nausea sensation, pain and breathing difficulties (p < 0.0001). The VAS questionnaire administered to the operators showed better scores for the digital approach in relation to anxiety, convenience, difficulties of the impression procedure and the workflow (p < 0.0001). A significant reduced mean time for the digital workflow as well as a reduced number of required visits were recorded. Conclusion: The analysis of a fully digital and a conventional protocol showed better results according to patient and operators’ preferences when a fully digital approach was used.

Progress in treatment on substance use disorders with virtual reality technologies

Substance use disorder (SUD) is a chronic brain disease with a high rate of relapse that results from the complex interaction amongst physical, psychological, and social factors. To deal with this intractable brain disease, it is necessary to utilize a variety of treatment methods for comprehensive intervention under the guidance of integrative physical-social-psychological treatment model. Currently, the virtual reality (VR) technologies has been successfully used to investigate the effects of specific and context cue on the emotional, cognitive and behavioral response and craving in the persons with SUD, and new treatment methods on SUD with VR have been well developing. This technique synthesizes the immersive, interactive, and constructive technological advantages of VR to provide a complex changeable multi-factor interactive virtual environment. With the aid of VR technique, it is hoped that the quality and effects of cue-exposure therapy and behavioral therapy will make a new breakthrough. This article summarizes the research advances in this field within the last decade. It includes: To improve the validity of craving assessment by providing the drug-related cues and contexts more similar with the real life environments, combined with multiple levels of craving assessment methods like subjective report, eye movement tracking, heart rate, galvanic skin response and electroencephalograph; To improve the ecological validity of cue exposure therapy by extinguishing the cue response with multiple drug-related cues and contexts, and the trans-context extinction training will reduce the spontaneous recovery, which is the big challenge in regular cue exposure therapy; To improve the coping skill on how to deal with high relapse risk environments by training the coping skills in the virtual environments with social pressure context associated with drug-related cues; To improve the therapeutic effect of regular psychological and behavioral therapy, like cognitive behavioral therapy. In sum, the virtual reality procedures have some advantages in the subjective and objective assessment of craving, and improvement of therapeutic effect by providing a flexible and controllable platform to integrate different psychological and behavioral therapies under the virtual environments with specific complex drug-related cues, contexts and social interaction. The specificity created by virtual reality techniques holds the great promise to the development of individualized care and treatment in SUD. The future researches will focus on how to increase the sense of presence and reduce the sensations of nausea, and then to elevate the individual involvement to the virtual environments.

Nausea: a review of pathophysiology and therapeutics

The sensation of nausea is a common occurrence with diverse causes and a significant disease burden. Nausea is considered to function as a protective mechanism, warning the organism to avoid potential toxic ingestion. Less adaptive circumstances are also associated with nausea, including post-operative nausea, chemotherapy-induced nausea, and motion sickness. A common definition of nausea identifies the symptom as a precursor to the act of vomiting. The interaction, though present, does not appear to be a simple relationship. Nausea is unfortunately the 'neglected symptom', with current accepted therapy generally directed at improving gastrointestinal motility or acting to relieve emesis. Improved understanding of the pathophysiological basis of nausea has important implications for exploiting novel mechanisms or developing novel therapies for nausea relief.

Cannabinoids suppress acute and anticipatory nausea in preclinical rat models of conditioned gaping.

The sensation of nausea is one of the most debilitating human experiences. Current antiemetic therapies are effective in reducing vomiting, but are less effective in reducing acute and delayed nausea and are completely ineffective in reducing anticipatory nausea. Recent preclinical evidence using a selective rat model of nausea (conditioned gaping reactions) has revealed that cannabinoids have great promise as treatments for nausea and that their antinausea effects may be mediated by the interoceptive insular cortex.

The Nose Knows: An Unusual Presentation of a Cerebral Aneurysm

BackgroundCerebral aneurysms most commonly present with subarachnoid hemorrhage (SAH), a catastrophic event. However, 11–15% of unruptured aneurysms are symptomatic, with presentations including seizures, unilateral cranial nerve deficits, visual loss, headache, and ischemia. Of patients presenting with seizures, the semiology described includes speech arrest, “feelings of dread,” localized pins and needles, and tonic clonic episodes. We report the case of a patient who presented to the emergency department (ED) with complex partial seizures secondary to a cerebral aneurysm. Case ReportA 54-year-old woman presented to the ED after an episode where she had noticed a “bad smell” and sensations of nausea and dizziness. This was the third episode she had experienced in 2 weeks, and other than migraine, she had no significant medical or family history. Physical examination was normal, but a computed tomography (CT) scan of the brain revealed a 15-mm aneurysm of the right middle cerebral artery. The patient was subsequently transferred for urgent neurosurgical intervention. Why Should an Emergency Physician Be Aware of This?The emergency physician should strongly consider the use of head CT in the evaluation of adults presenting with a first unprovoked seizure, as rarely they can be caused by urgent pathologies including cerebral aneurysms. If a patient is found to have a possible symptomatic unruptured aneurysm, they should be referred for urgent neurosurgical consultation, as these lesions have an increased risk of rupture.

1034 The Dual Action of the KAMPO MEDICINE Rikkunshito Offers a Promising New Approach for the Treatment of Ghrelin Resistance in Cancer Anorexia-Cachexia

G A A b st ra ct s using HRM. Methods: Studies were performed in 12 healthy volunteers (5 males, median age 23 years). Nausea was induced by a motion video of a rotating and tilted view of a landscape and rated on a VAS scale ranging from 1-4 (no/mild/moderate/severe nausea) every minute until complete recovery. GEP and anatomical changes were assessed with HRM. FP was measured from the five pressure channels positioned below the LES. Reflux was assessed by impedance-pH (MII-pH). After intubation, a baseline (BL) recording of 15min was obtained. This was followed by the motion video (until the volunteer perceived nausea VAS≥3 (at least 10min, max 20min)) followed by 30min recovery recording. Results correspond to measurements at peak nausea, early recovery (first 5 min after the end of the motion video) and late recovery (last 5min of the 30min recovery period). Results: 10/12 subjects showed a drop in FP during peak nausea compared to BL (-4.0±0.8mmHg; p= 0.005) with 8/10 subjects showing a partial or complete FP return during late recovery. 8/ 10 subjects who showed FP drop also showed a drop of LES pressure during peak nausea (-8.8±2.5mmHg; p=0.04) with 9/10 subjects showing a partial or complete return of LES pressure during late recovery. Peak nausea preceded peak fundus and LES relaxation. 8/10 subjects showed increase in length of the oesophageal body during peak nausea and early recovery (+0.8±0.2cm and +0.7±0.1cm; p,0.05) whereas a shortening of the oesophagus was observed during late recovery (-0.6±0.2cm; p,0.05). There was a significant decrease in LES thickness during peak nausea (-0.8±0.3cm; p,0.05). The number of swallows was comparable during BL/nausea/recovery. MII-pH showed normal acid exposure and 0-2 reflux episodes during total recording times. The number of TLESRs was significantly greater during the recovery period compared to the nausea period (p=0.01). Conclusion: Fundus and GEJ changes during nausea are different from those observed during meals, TLESRs and vomiting. Peak nausea is followed by a drop in fundus and LES pressure, oesophageal lengthening and a decrease in LES thickness. LES relaxation during nausea is incomplete and not accompanied by reflux. Whether anatomical changes provoke the sensation of nausea or vice versa is unknown, however the time sequence in our experiment suggests the latter.

1035 Subpopulation Analysis Based on Background Responds to Rabeprazole Dose in Patients With Functional Dyspepsia in a Multicenter, Double-Blind, Randomized, Placebo-Controlled Clinical Trial; the Samurai Study

G A A b st ra ct s using HRM. Methods: Studies were performed in 12 healthy volunteers (5 males, median age 23 years). Nausea was induced by a motion video of a rotating and tilted view of a landscape and rated on a VAS scale ranging from 1-4 (no/mild/moderate/severe nausea) every minute until complete recovery. GEP and anatomical changes were assessed with HRM. FP was measured from the five pressure channels positioned below the LES. Reflux was assessed by impedance-pH (MII-pH). After intubation, a baseline (BL) recording of 15min was obtained. This was followed by the motion video (until the volunteer perceived nausea VAS≥3 (at least 10min, max 20min)) followed by 30min recovery recording. Results correspond to measurements at peak nausea, early recovery (first 5 min after the end of the motion video) and late recovery (last 5min of the 30min recovery period). Results: 10/12 subjects showed a drop in FP during peak nausea compared to BL (-4.0±0.8mmHg; p= 0.005) with 8/10 subjects showing a partial or complete FP return during late recovery. 8/ 10 subjects who showed FP drop also showed a drop of LES pressure during peak nausea (-8.8±2.5mmHg; p=0.04) with 9/10 subjects showing a partial or complete return of LES pressure during late recovery. Peak nausea preceded peak fundus and LES relaxation. 8/10 subjects showed increase in length of the oesophageal body during peak nausea and early recovery (+0.8±0.2cm and +0.7±0.1cm; p,0.05) whereas a shortening of the oesophagus was observed during late recovery (-0.6±0.2cm; p,0.05). There was a significant decrease in LES thickness during peak nausea (-0.8±0.3cm; p,0.05). The number of swallows was comparable during BL/nausea/recovery. MII-pH showed normal acid exposure and 0-2 reflux episodes during total recording times. The number of TLESRs was significantly greater during the recovery period compared to the nausea period (p=0.01). Conclusion: Fundus and GEJ changes during nausea are different from those observed during meals, TLESRs and vomiting. Peak nausea is followed by a drop in fundus and LES pressure, oesophageal lengthening and a decrease in LES thickness. LES relaxation during nausea is incomplete and not accompanied by reflux. Whether anatomical changes provoke the sensation of nausea or vice versa is unknown, however the time sequence in our experiment suggests the latter.

Preventing Postoperative Nausea and Vomiting: Is the Answer in your Hands?

Nausea and vomiting are unpleasant and frequent side effect of anesthesia. One complimentary therapy that has minimal side effects and good outcomes is acupressure stimulation therapy to P6 (Neiguan point). P6 is located near the wrist. The precise anatomical site is along the median nerve pathway, two finger widths below the wrist crease. Acupressure stimulation can be created by needle acupuncture, transcutaneous electrical stimulus, acupressure by manual pressure, and acupuncture stimulation device such as wristbands. A Cochrane collaborative report reviewed forty research reports relevant to P6 stimulation (Fan, 2009). Statistical analysis of the studies demonstrated that P6 stimulation worked as well as current pharmacological antiemetic therapies. The method of stimulation of the acupressure point and the duration of time of the intervention varied with each study. There were no recommendations from this report on the best method of acupressure for optimal results (Fan, 2009). A recent study of a patient undergoing cardiac surgery found that one preoperative treatment with acupuncture at this site significantly diminished the sensation of nausea on postoperative day one and day two (Korinenko, Y, Vincent, A, Cutshall, S, Li, Z & Sundt,TM, 2009). There are many ways to take these findings from the literature and apply them to clinical practice. The first application would be to read the above documents and lead a discussion with the anesthesia care providers and surgical staff in your care facility. The discussion should focus on the improved patient outcomes associated with decreased PONV. The second application would be to develop a teaching protocol that would incorporate teaching the staff and patients the methods of the technique. The protocol would also strengthen the portion of informed consent for anesthesia which discusses risks, benefits, and alternatives. As a workgroup the healthcare providers would need to choose the procedural aspects such as method of acupressure stimulation, timing of treatments, and duration. What are your clinical experiences with complimentary therapies?

Dexamethasone Combined with Morphine Does Not Decrease Postoperative Nausea and Vomiting in Patients Undergoing Thyroidectomy or Parathyroidectomy

Objective: A prospective, randomized, double-blind study was conducted to investigate the efficacy of dexamethasone in the prevention of postoperative nausea and vomiting (PONV) in patients who underwent thyroid or parathyroid surgery, when combined with morphine injection at the end of general anesthesia. Methods: One hundred and twenty-two patients between 14 and 79 years old were included in this study. Group Ⅰ(N=80) consisted of patients who received dexamethasone (10 mg) before induction, and Group Ⅱ (N=42) consisted of those who received placebo (normal saline, 10 ml) before induction. Thirty-nine patients in group Ⅰ were given morphine (5 mg) by the anesthetists, before the end of general anesthesia. At 4 hr and 24 hr after surgery, the sensation of nausea and the incidence of vomiting were assessed. Results: At 4 hr after surgery, the sensation of nausea and incidence of vomiting were significantly higher in Group Ⅱ than in Group Ⅰ without morphine injection (P=0.009 and P=0.010, respectively) and significantly higher in patients receiving morphine than in patients without morphine of Group Ⅰ (P=0.026 and P=0.008, respectively). Conclusions: Preinduction with dexamethasone (10 mg) infusion can decrease PONV at 4 hr after surgery if morphine is not used, but dexamethasone infusion in conjunction with morphine injection before the end of general anesthesia does not decrease PONV.

Papyriferic Acid, An Antifeedant Triterpene From Birch Trees, Inhibits Succinate Dehydrogenase From Liver Mitochondria

Papyriferic acid (PA) is a triterpene that is secreted by glands on twigs of the juvenile ontogenetic phase of resin producing tree birches (e.g., Betula neoalaskana, B. pendula) and that deters browsing by mammals such as the snowshoe hare (Lepus americanus). We investigated the pharmacology of PA as a first step in understanding its antifeedant effect. After oral administration to rats, PA and several metabolites were found in feces but not urine, indicating that little was absorbed systemically. Metabolism involved various combinations of hydrolysis of its acetyl and malonyl ester groups, and hydroxylation of the terpene moiety. The presence of a malonyl group suggested a possible interaction with succinate dehydrogenase (SDH), a mitochondrial enzyme known to be competitively inhibited by malonic acid. The effect of PA on the oxidation of succinate by SDH was examined in mitochondrial preparations from livers of ox, rabbit, and rat. In all three species, PA was a potent inhibitor of SDH. Kinetic analysis indicated that, unlike malonate, PA acted by an uncompetitive mechanism, meaning that it binds to the enzyme-substrate complex. The hydrolysis product of PA, betulafolienetriol oxide, was inactive on SDH. Overall, the evidence suggests that PA acts as the intact molecule and interacts at a site other than the succinate binding site, possibly binding to the ubiquinone sites on complex II. Papyriferic acid was potent (K(iEIS) ranged from 25 to 45 microM in the three species) and selective, as malate dehydrogenase was unaffected. Although rigorous proof will require further experiments, we have a plausible mechanism for the antifeedant effect of PA: inhibition of SDH in gastrointestinal cells decreases mitochondrial energy production resulting in a noxious stimulus, 5-HT release, and sensations of nausea and discomfort. There is evidence that the co-evolution of birches and hares over a large and geographically-diverse area in Northern Europe and America has produced marked differences in the formation of PA by birches, and the tolerance of hares to dietary PA. The present findings on the metabolic fate and biochemical effects of PA provide a rational basis for investigating the mechanisms underlying differences among populations of hares in their tolerance of a PA-rich diet.

Antiemetics: uses, mode of action and prescribing rationale

Vomiting, and the associated sensation of nausea, are very distressing symptoms that may be experienced by patients as the result of a disease process or its treatment. The specific causes of episodes of nausea and vomiting can be many and varied but fortunately there are a wide range of potential therapies available that may help. This article focuses on the different pharmacological groups of antiemetic medications that may be tried and provides information on their mechanisms, side-effects and uses.

Differences in autonomic responses between subjects with and without nausea while watching an irregularly oscillating video

Prodromal signs such as cardiac rhythm disturbance and changes in gastric motility are generally induced before and during nausea in humans. These autonomic reactions were compared in subjects who were or were not experiencing nausea. Nausea was induced by having the subjects view a movie of oscillating pictures. Seventeen healthy volunteers were asked to relax their muscles and watch the movie. Electrogastrogram (EGG), electrocardiogram (ECG), palmar and metopic perspiration, digital blood flow and thoracic movement related to respiration were simultaneously measured while the subjects viewed the movie. A total of 11 of 17 subjects complained of nausea after watching the movie. The characteristic changes in their autonomic responses during exposure to the movie were as follows. The power of the EGG, heart rate and metopic perspiration significantly increased compared to those before watching the movie. The respiratory cycle gradually increased during and even after watching the movie. In contrast, no significant changes in the power of the EGG, heart rate and metopic perspiration were observed in the remaining six subjects who did not experience nausea. The role of the autonomic nervous system in nausea is discussed. These results suggest that these symptoms regarding the sympathetic nervous system could actually be defensive reactions against the sensation of nausea.

Intravenous lorazepam versus dimenhydrinate for treatment of vertigo in the emergency department: A randomized clinical trial

Study Objective: To determine whether lorazepam is more effective than dimenhydrinate in relieving the symptom of vertigo in the emergency department setting. Methods: A prospective, randomized, double-blind trial of intravenous lorazepam versus dimenhydrinate therapy was conducted in the ED of a county-owned, university-affiliated hospital. All adult patients who presented between January 24, 1998, and May 23, 1999, with the symptom of vertigo were eligible for inclusion. The intervention was varying the intravenous treatment between lorazepam, 2 mg, and dimenhydrinate, 50 mg. All patients received intravenous infusion of Ringer’s lactate solution at a rate of 100 mL/h. Adequacy of randomization to the 2 treatment groups was assessed by comparing the patients’ relevant baseline history, physical examination, and symptoms. The predetermined primary outcome measurement was the patient’s sensation of “vertigo with ambulation” 1 and 2 hours after treatment. Secondary outcome measurements included vertigo while lying, sitting, and turning the head, ability to ambulate as judged by the enrolling physician, and sensation of nausea and drowsiness 1 and 2 hours after treatment, and whether the patient was “ready to go home” per patient report or physician assessment 2 hours after treatment. All patient symptoms were reported on 10-point scales. Outcome measurements were compared between the 2 treatment groups with a 2-way repeated-measures analysis of variance, Student’s t test, Mann-Whitney U, and χ2 test as appropriate. Results: Ten patients refused entry into the study, 16 were excluded, and 74 were enrolled, treated, and included in the analysis. One enrolled patient had evidence of vertigo of central origin. The pretreatment values of vertigo with ambulation were strongly correlated with the patient’s ability to ambulate (P <.001), suggesting good internal validity. The patients randomly assigned to the lorazepam group were sicker based on their pretreatment symptoms and ability to ambulate, and this may have biased the study results. The patients’ symptom of “vertigo with ambulation” decreased 1.5 units more (95% confidence interval [CI] 0 to 3.0) on average on a 10-point scale 2 hours after treatment in the dimenhydrinate group. All other measures of vertigo also decreased more in the dimenhydrinate group, although the differences were not statistically significant. At 2 hours after treatment, the patients’ ability to ambulate was better in the dimenhydrinate group (P <.001), and 17% (95% CI –2 to 36) more patients in this group were “ready to go home.” Patients in the lorazepam group experienced a 1.8-unit (95% CI 0.2 to 3.4) greater increase in drowsiness 2 hours after treatment. Conclusion: Our results suggest that dimenhydrinate was more effective in relieving vertigo and less sedating than lorazepam at the intravenous doses administered in this study. Dimenhydrinate appears to be the preferred medicine for patients who present to the ED with vertigo likely to be of peripheral origin. [Marill KA, Walsh MJ, Nelson BK. Intravenous lorazepam versus dimenhydrinate for treatment of vertigo in the emergency department: a randomized clinical trial. Ann Emerg Med. October 2000;36:310-319.]

Nausea and Vomiting: Underlying Mechanisms and Upcoming Treatments.

Nausea and vomiting (emesis) occur under a variety of conditions in response to activation of one or more emetic triggers, such as abdominal visceral, cardiac and vestibular nerve afferents, the area postrema chemoreceptor trigger zone in the caudal brainstem, and higher brain centers. The act of vomiting is coordinated by neuronal circuitry located in the brainstem and extending from the nucleus of the solitary tract through the lateral tegmental field of the reticular formation to the ventrolateral medulla. The sensation of nausea is thought to involve the cerebral cortex. The motor act of vomiting is produced primarily by complicated changes in the activity of the respiratory muscles. There are also complex changes in the activity of the gastrointestinal tract, which are mediated by the vagus nerve but are not essential for vomiting. The recently introduced serotonin type 3 receptor antagonists are very effective in combating nausea and vomiting induced by cancer chemotherapy and radiation therapy. More broad based anti-emetic action has been achieved in animal models by using serotonin type 1A receptor agonists and neurokinin type 1 receptor antagonists. Stimulation of the P6 acupuncture point is reported to be effective against motion and pregnancy sickness, and postoperative and cancer chemotherapy-induced nausea and vomiting. Greater understanding of the mechanisms underlying nausea and vomiting and more effective treatments are still required, especially in conditions such as pregnancy sickness, postoperative nausea and vomiting, the delayed phase of vomiting following cisplatin therapy, and cyclical vomiting.