Worsening of Dizziness Impairment Is Associated with Bone Marrow Kinase on Chromosome X Level in Patients after Mild Traumatic Brain Injury.

Over 2 million people suffer from mild traumatic brain injury (mTBI) each year. Predicting symptoms of mTBI and the characterization of those symptoms has been challenging. Biomarkers that correlate clinical symptoms to disease outcome are desired to improve understanding of the disease and optimize patient care. Bone marrow kinase on chromosome X (BMX), a member of the TEC family of nonreceptor tyrosine kinases, is up-regulated after traumatic neural injury in a rat model of mTBI. The aim of this investigation was to determine whether BMX serum concentrations can effectively be used to predict outcomes after mTBI in a clinical setting. A total of 63 patients with mTBI (Glasgow Coma Score [GCS] between 13 and 15) were included. Blood samples taken at the time of hospital admission were analyzed for BMX. Data collected included demographic and clinical variables. Outcomes were assessed using the Dizziness Handicap Inventory (DHI) questionnaire at baseline and 6 weeks postinjury. The participant was asssigned to the case group if the subject's complaints of dizziness became worse at the sixth week assessment; otherwise, the participant was assigned to the control group. A receiver operating characteristic curve was constructed to explore BMX level. Significant associations were found between serum levels of BMX and dizziness. Areas under the curve for prediction of change in DHI postinjury were 0.76 for total score, 0.69 for physical score, 0.65 for emotional score, and 0.66 for functional score. Specificities were between 0.69 and 0.77 for total score and emotional score, respectively. Therefore, BMX demonstrates potential as a candidate serum biomarker of exacerbating dizziness post-mTBI.

Biomarkers of Oxidative Stress and Endogenous Antioxidants for Patients with Chronic Subjective Dizziness.

As a neurotologic disorder of persistent non-vertiginous dizziness, chronic subjective dizziness (CSD) arises unsteadily by psychological and physiological imbalance. The CSD is hypersensitivity reaction due to exposure to complex motions visual stimuli. However, the pathophysiological features and mechanism of the CSD still remains unclearly. The present study was purposed to establish possible endogenous contributors of the CSD using serum samples from patients with the CSD. A total 199 participants were gathered and divided into two groups; healthy (n = 152, male for 61, and female for 91) and CSD (n = 47, male for 5, female for 42), respectively. Oxidative stress parameters such as, hydrogen peroxide and reactive substances were significantly elevated (p < 0.01 or p < 0.001), whereas endogenous antioxidant components including total glutathione contents, and activities of catalase and superoxide dismutase were significantly deteriorated in the CSD group (p < 0.01 or p < 0.001) as comparing to the healthy group, respectively. Serum levels of tumor necrosis factor -α and interferon-γ were significantly increased in the CSD participants (p < 0.001). Additionally, emotional stress related hormones including cortisol, adrenaline, and serotonin were abnormally observed in the serum levels of the CSD group (p < 0.01 or p < 0.001). Our results confirmed that oxidative stress and antioxidants are a critical contributor of pathophysiology of the CSD, and that is first explored to establish features of redox system in the CSD subjects compared to a healthy population.

Value of copeptin and the S-100b protein assay in ruling out the diagnosis of stroke-induced dizziness pattern in emergency departments.

BACKGROUND: Dizziness is a frequent reason for visiting emergency departments (EDs). Differentiating stroke from other causes is challenging for physicians. The role of biomarkers has been poorly assessed. We evaluated whether copeptin and S100b protein (PS100b) assessment, alone or in combination, could rule out stroke in patients visiting EDs for dizziness. METHODS: We included patients 18 years of age or older, visiting the adult ED of a French university hospital for a new episode of dizziness evolving for less than 72 h. All patients underwent standardized physical examination (HINT [Head Impulse test, Nystagmus, test of skew deviation] maneuvers), copeptin and S-100b protein (PS100) measurement and injected brain imaging. Stroke diagnosis involved diffusion-weighted magnetic resonance imaging or, if not available, neurological examination and contrast brain CT scan compatible with the diagnosis. RESULTS: Of the 135 patients participating in the study, 13 (10%) had stroke. The sensitivity, specificity and positive and negative predictive values of copeptin/PS100 combination were 100% (95%CI, 77-100%), 48% (40-57%), 14% (11-27%) and 100% (94-100%), respectively. Values for copeptin alone were 77% (CI95% 0.50-0.91), 50% (CI95% 0.49-0.58), 14% (CI95% 0.08-0.24), 93% (CI95% 0.87-0.98), and for PS100 alone were 54% (CI95% 0.29-0.77), 97% (CI95% 0.92-0.99), 64% (CI95% 0.35-0.84), 95% (CI95% 0.90-0.98). CONCLUSIONS: Absence of copeptin and PS100 elevation seems to ruling out the diagnosis of stroke in patients visiting the ED for a new episode of dizziness. These results need to be confirmed in a large-scale study.

You're The Flight Surgeon.

Beauvais A, Tate J, Kluesner JK. You're the flight surgeon: hypoglycemia. Aerosp Med Hum Perform. 2019; 90(9):826-829.

Ménière's disease with unremitting floating sensation is associated with canal paresis, gravity-sensitive dysfunction, mental illness, and bilaterality.

OBJECTIVE: The aim of the present study was to evaluate the association of neuro-otological examination, blood tests, and scoring questionnaire data with treatment-resistant intractability of persistent dizziness in Ménière's disease. METHODS: We managed 1520 successive vertigo/dizziness patients at the Vertigo/Dizziness Center in Nara Medical University from May 2014 to April 2018. Five hundred and twenty-two patients were diagnosed with Ménière's disease (522/1520; 34.3%) according to the 2015 diagnostic guideline of the International Classification of Vestibular Disorders. Among the patients with Ménière's disease there were 102 with intractable rotatory vertigo attacks for more than 3-6 months (102/522; 19.5%), including 20 bilateral cases (20/102; 19.6%), and 88 with intractable unremitting floating sensation rather than rotatory vertigo attacks for more than 3-6 months (88/522; 16.9%), including 28 bilateral cases (28/88; 31.8%). Sixty out of 88 cases with intractable unremitting floating sensation were unilateral and were enrolled for hospitalization to undergo neuro-otological examinations including pure-tone audiometry (PTA), the caloric test (C-test), vestibular evoked cervical myogenic potentials (cVEMP), subjective visual vertical (SVV) test, glycerol test (G-test), electrocochleogram (ECoG), inner ear magnetic resonance imaging (ieMRI), blood tests including anti-diuretic hormone (ADH) and bone alkaline phosphatase (BAP), and self-rating questionnaires of depression score (SDS). Data are presented as positive (+) ratios of the number of patients with examination and questionnaire data outside of the normal range. RESULTS: The ratios (+) were as follows: C-test=33.3% (20/60), cVEMP=25.0% (15/60), SVV=50.0% (30/60), G-test=55.0% (33/60), ECoG=63.3% (38/60), ieMRI=86.7% (52/60), ADH=35.0% (21/60), BAP=11.7% (7/60), and SDS=40.0% (24/60). Multivariate regression analysis revealed that the periods of persistent dizziness were significantly longer in unilateral Ménière's patients with C-test(+), SVV(+), and SDS(+) compared with those with negative findings. Additionally, the periods in bilateral cases were significantly longer than those in unilateral ones. CONCLUSIONS: Although approximately 70% of patients with Ménière's disease are usually treatable through the appropriate conservative medical therapy, the presence of canal paresis, gravity-sensitive dysfunction, neurosis/depression, and bilaterality may make the persistent dizziness intractable and may thus require additional treatments.

Clinical and laboratory factors related to acute isolated vertigo or dizziness and cerebral infarction.

OBJECTIVE: To clarify the relationship of clinical factors with isolated vertigo or dizziness of cerebrovascular origin. METHODS: Clinical data of patients admitted in East Hospital from Jan. 2015 to Apr. 2016, whose complaint were acute vertigo or dizziness were retrospectively collected. All patients arrived at the emergency department within 24 hr of symptom onset, had no acute ischemic lesion first CT and NIHSS score of 0. Patients were divided into cerebral infarction group and noncerebral infarction group according to subsequent cerebral imaging results and clinical and laboratory factors related to cerebral infarction were analyzed. RESULT: 51.6% of patients were female (n = 141). 46 patients (16.8%) were diagnosed with acute cerebral infarction. Baseline demographic data of the two groups was not significantly different. Univariate analysis found that history of smoking (p = 0.009), headache (p = 0.028), unsteadiness (p = 0.009), neuron specific enolase (p = 0.001), and vertebral artery abnormalities found on imaging (p = 0.009) were the significant difference between two groups. Increased neuron specific enolase (p = 0.005) and an abnormal vertebral artery (p = 0.044) were significant on multivariate analysis. CONCLUSIONS: 16.8% of acute isolated vertigo or dizziness presentations were diagnosed with acute cerebral infarction. Increased serum neuron specific enolase and vertebral artery abnormalities were the strongest indicators of acute cerebral infarction.

Autonomic Nervous System Response to Stressors in Newly Diagnosed Patients with Multiple Sclerosis.

Autonomic dysfunction is commonly detected in patients with multiple sclerosis (MS). However, data evaluating autonomic nervous system function in early MS are limited. Present study investigates response to two different stressors in newly diagnosed MS patients, looking for the signs of autonomic dysfunction at the beginning of the disease. We examined 19 MS patients and 19 age, sex, and body mass index matched healthy controls. MS patients were newly diagnosed, untreated, and with low expanded disability status scale (EDSS) values [median 1.0 (interquartile range 1.0-1.5)]. Two stressors were used to evaluate the response of autonomic nervous system: Stroop word-color interference mental stress test and orthostasis. Plasma levels of epinephrine and norepinephrine, blood pressure (BP), and heart rate variability (HRV) parameters were evaluated. At the end of Stroop test MS patients had lower systolic BP (121 ± 15 vs. 132 ± 17 mmHg, p = 0.044), lower heart rate (79 ± 9 vs. 88 ± 16 1/min, p = 0.041), and lower epinephrine increment (10 ± 22 vs. 30 ± 38 pg/ml; p = 0.049) compared to healthy controls. Norepinephrine response was unaffected in MS, however, with lower norepinephrine levels during the test (p = 0.036). HRV parameters were similar in both groups. No differences in BP, heart rate, catecholamines, and HRV parameters between groups during orthostatic testing were found. We found slightly diminished sympathetic response to mental stress test, but unchanged response to orthostasis, in newly diagnosed untreated MS patients. The results suggest that autonomic dysfunction in MS is connected with more developed disease.

Adrenomedullin and galanin responses to orthostasis in older persons.

BACKGROUND: Neuroendocrine responses to orthostasis may be critical in the maintenance of mean arterial pressure in healthy individuals. A greater reduction in orthostatic tolerance with age may relate to modulation of hormonal responses such as adrenomedullin and galanin. Thus, we investigated (i) whether adrenomedullin and galanin concentrations increase during orthostatic challenge in older subjects, (ii) whether adrenomedullin and galanin concentrations are higher in older females compared with older males when seated and during orthostatic challenge, and (iii) whether postural changes in plasma concentrations of galanin are correlated with levels of adrenomedullin in either older females or males. MATERIALS AND METHODS: Subjects (n = 18; 12 ♀; 55-80 years old) performed a sit-to-stand test in a 25°C sensory-minimised environment, with blood samples collected after 4 min of being seated and then when standing. Plasma adrenomedullin and galanin concentrations were determined. RESULTS: Baseline plasma concentration of adrenomedullin (5·35 ± 0·74 (n = 12, females) vs. 7·40 ± 1·06 pg/mL (n = 5, males)) and galanin (64·07 ± 9·05 vs. 98·99 ± 16·90 pg/mL, respectively) did not significantly differ between genders. Furthermore, plasma adrenomedullin and galanin concentrations were not significantly affected by adoption of the upright posture in either gender and were not correlated in females or males. CONCLUSIONS: Adrenomedullin and galanin concentrations were similar between genders and did not change following adoption of the standing posture. To further clarify the roles, these hormones play in orthostatic intolerance, adrenomedullin and galanin concentrations should be assessed in participants who show presyncopal symptoms during an orthostatic challenge.

From dizziness to severe ataxia and dysarthria: New cases of anti-Ca/ARHGAP26 autoantibody-associated cerebellar ataxia suggest a broad clinical spectrum.

In 2010, a novel anti-neuronal autoantibody, termed anti-Ca, was described in a patient with subacute cerebellar ataxia, and Rho GTPase-activating protein 26 (ARHGAP26) was identified as the target antigen. Recently, three additional cases of anti-Ca-positive cerebellar ataxia have been published. In addition to ataxia, cognitive decline and depression have been observed in some patients. Here, we report two new cases of anti-Ca-associated autoimmune cerebellar ataxia. Patient 1 presented with dizziness and acute yet mild limb and gait ataxia. Symptoms stabilized with long-term oral corticosteroid therapy but transiently worsened when steroids were tapered. Interestingly, both initial occurrence and worsening of the patient's neurological symptoms after steroid withdrawal were accompanied by spontaneous cutaneous hematomas. Patient 2 initially presented with an increased startle response and myoclonic jerks, and subsequently developed severe limb and gait ataxia, dysarthria, oculomotor disturbances, head and voice tremor, dysphagia, cognitive symptoms and depression. Steroid treatment was started five years after disease onset. The symptoms then responded only poorly to corticosteroids. At most recent follow-up, 19 years after disease onset, the patient was wheelchair-bound. These cases extend the clinical spectrum associated with anti-ARHGAP26 autoimmunity and suggest that early treatment may be important in patients with this rare syndrome.

Unexplained spikes in lamotrigine serum concentration: nonlinear elimination?

OBJECTIVES: The objective of this study was to evaluate possible nonlinear lamotrigine (LTG) pharmacokinetics at elevated concentration. LTG is reported to have linear kinetics, so that elimination rate is linearly proportional to blood concentration and a change in dose is accompanied by a proportionate change in serum concentration. We encountered patients in whom LTG serum concentration increased dramatically in response to minor or no change in LTG dose. We studied this phenomenon in patients with LTG toxicity in one clinic. MATERIALS AND METHODS: Using electronic medical records from 1997 to 2014, we identified patients who developed clinical LTG toxicity with LTG serum concentrations >20 mg/l, after tolerating lamotrigine at lower serum concentrations. We reviewed LTG dose change and other changes that preceded the episode of toxicity. RESULTS: Twenty-two patients had at least one episode of LTG toxicity with levels higher than 20 mg/l (of 922 patients with available levels). The peak serum concentration varied from 21.1 to 40.3 mg/l (mean 28.7). The increase in level was explained in three patients (post-delivery in one, addition of valproate in two). In the 18 others, the increase was not explained or it was disproportionate to an increase in LTG dose. CONCLUSIONS: Spikes in LTG levels and associated clinical toxicity may occur unexpectedly, suggesting that elimination kinetics may be nonlinear in some individuals at serum concentrations in the upper range. Measurement and close monitoring of LTG levels is warranted for new symptoms that could be consistent with lamotrigine toxicity, particularly when the baseline serum concentration has been >10 mg/l.

N-Terminal Pro-Brain Natriuretic Peptide (NT-proBNP) Levels are Increased in Patients With Transient Ischemic Attack Accompanied by Nonfocal Symptoms.

BACKGROUND: Transient nonfocal neurological symptoms may serve as markers of cardiac dysfunction. We assessed whether serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, a biomarker of cardiac disease, are increased in patients with transient ischemic attack (TIA) accompanied by nonfocal symptoms and in patients with attacks of nonfocal symptoms (transient neurological attack [TNA]). METHODS AND RESULTS: We included 15 patients with TNA, 69 with TIA accompanied by nonfocal symptoms, 58 with large-vessel TIA, 32 with cardioembolic TIA, and 46 age- and sex-matched healthy control participants. Serum NT-proBNP levels were determined within 1 week after the attack. We compared log-transformed NT-proBNP levels of patients with cardioembolic TIAs and mixed or nonfocal TNAs, with those of patients with noncardioembolic TIAs as a reference group. Adjustments for age, sex, atrial fibrillation, and a history of nonischemic heart disease were made with a multiple linear regression model. Compared with large-vessel TIA (mean 14.2 pmol/L), mean NT-proBNP levels were significantly higher in patients with TIA accompanied by nonfocal symptoms (40.5 pmol/L, P=0.049) and with cardioembolic TIA (123.5 pmol/L; P=0.004) after adjustments for age, sex, atrial fibrillation, and a history of nonischemic heart disease. Patients with TNA also had higher mean NT-proBNP levels (20.8 pmol/L, P=0.38) than those with large-vessel TIA, but this difference was not statistically significant. CONCLUSION: NT-proBNP levels are increased in patients with TIA accompanied by nonfocal symptoms.

The role of thyroid and parathyroid metabolism disorders in the etiology of sudden onset dizziness.

BACKGROUND: The aim of this study was to evaluate thyroid and parathyroid functions as a cause of sudden onset dizziness (SOD) in patients who were admitted to the Emergency Department (ED). MATERIAL AND METHODS: This study was conducted prospectively in 100 patients with sudden onset dizziness (SOD) admitted to the ED. Neurologic, ear-nose-throat, detailed neck examinations, serum calcium levels, thyroid function tests (TFT), and parathormone and thyroid ultrasounds were performed on all patients in our study. RESULTS: Thirty-seven (37%) females and 63 (63%) males were included in this study. Four patients (4%) had elevated serum TSH levels, 6 (6%) had decreased serum fT3 levels, 10 (10%) had decreased serum fT4 levels, 2 (2%) had elevated serum fT4 levels, and 2 (2%) had elevated serum parathormone levels. In 4 (4%) patients, the serum calcium levels were lower than normal, and 2 (50%) of these patients had symptomatic hypocalcemia. Thyroid ultrasound examinations showed multinodular goiter in 28 (28%) patients, 2 (2%) patients had thyroiditis, 12 (12%) had an isolated unilateral nodule, and 58 (58%) had normal thyroid tissues. CONCLUSIONS: We suggest that detailed neck examination, TFT, and thyroid ultrasound examination should be considered in the diagnostic algorithms of SOD to provide rapid diagnosis and proper treatment for a patient in the ED.

Aldosterone to active Renin ratio as screening test for primary aldosteronism: reproducibility and influence of orthostasis and salt loading.

Measurement of the aldosterone to active renin ratio (AARR) is the recommended screening test for primary aldosteronism (PA), but several sampling conditions impact on the AARR. We aimed to evaluate the reproducibility and the influence of orthostasis and salt loading on the AARR. The Graz Endocrine Causes of Hypertension (GECOH) study is a diagnostic accuracy study among hypertensive patients at a tertiary care centre in Graz, Austria. With a median interval of 4 weeks we determined the AARR under standardized sampling conditions twice in the sitting position, after 1h in the supine position, and after a salt infusion test (SIT). We identified 9 patients with PA and 151 patients with essential hypertension (EH). The Pearson correlation coefficient between both AARR measurements in the sitting position was 0.79 (p<0.001). In EH, recumbency was associated with a significant decrease of aldosterone and, to a lesser extent, of renin, thus lowering the AARR as compared to the sitting position (p<0.001 for all). In PA, recumbency had only minor effects, but it increased the rate of false negative AARR. SIT suppressed the AARR and its components in EH, whereas in PA only renin was slightly decreased. AARR has a good intra-individual reproducibility and decreases during recumbency. These results suggest that a single AARR determination in the sitting position is a reliable screening tool for PA.

Effects of orthostasis on endocrine responses to psychosocial stress.

Standardized psychological procedures have been designed to induce physiological stress responses. However, the impact of standing (orthostasis) on the physiological reaction after psychological stress remains unclear. The purpose of the current analysis was to examine and quantify the relative contribution of orthostasis to the physiological stress response by comparing a "standing with stress" to a "standing without stress" condition. We investigated the effect of standing with and without stress on responses of the sympathetic-adrenomedullary (SAM) system and the hypothalamic-pituitary-adrenal (HPA) axis using a standardized psychosocial stress protocol (Trier Social Stress Test) and a non-stress condition in a repeated measures design. Subjects (N=30) were exposed to both conditions in randomized order and had to maintain a standing, upright position for 10minutes. In the "standing with stress" condition, significant increases in repeatedly assessed plasma norepinephrine (NE) and epinephrine (EP), as well as in saliva cortisol were found, while in the "standing without stress" condition, no significant changes in plasma epinephrine and saliva cortisol were observed. Calculations of the relative contribution of orthostasis to physiological stress responses revealed that 25.61% of the NE increase, 82.94% of the EP increase, and 68.91% of the cortisol increase, could be attributed to psychosocial stress adjusted for the effects of orthostasis and basal endocrine output. Although these results are indicative for a marked endocrine reaction that is caused by psychosocial stress alone, our findings show that the contribution of orthostasis must be taken into account when interpreting endocrine data collected in a psychosocial stress test.

Hydration does not prevent orthostatic hypercoagulability.

Prolonged standing activates the coagulation cascade by the activation of endothelial cells, and probably the haemoconcentration effect contributes to this "orthostatic hypercoagulability". It was the objective of this study to assess whether rehydration (haemodilution) prevents or attenuates orthostatic induced thrombin formation. Twelve healthy young subjects were studied during two separate visits. Haematocrit (Hct), total plasma protein, coagulation profile tests, including endothelial activation related factors, and protein C global pathway were studied at rest supine, and while standing at 15 and 30 minutes (min). During the second visit the study was repeated after intravenous 1.5 liter 0.9% saline. While in supine posture, intravenous rehydration resulted in Hct reduction of 14.2 +/- 2% (haemodilution), a decrease of 11.5 +/- 1.3% in total protein, as well as a significant dilutional effect on most of the coagulation parameters. Still standing for 30 min, with and without rehydration caused a comparable increase in tissue factor by 49.83 +/- 13.6%, and 35.34 +/- 8.55% (p>0.05), respectively and in von Willebrand factor (vWF) 9.5 +/- 2.4% and 13.59 +/- 2.17% (p>0.05), respectively. At 30 min standing, after intravenous rehydration, factor V and VIII activities, and fibrinogen rose by 22 +/- 1.9%, 31.2 +/- 6.2%, 9.15 +/- 2.64%, (p<0.002 for all), respectively. Prothrombin fragments 1+2 elevated by 84.84 +/- 15.3% (p<0.001). Comparable results were obtained with and without the rehydration. Additionally, protein C assay results decreased by 19.4 +/-1.7% and 17.5 +/- 2.6%, with and without fluids (p<0.05 for both). In healthy subjects, intravenous prophylactic rehydration with normal saline resulted in a haemodilution of all the coagulation parameters, but did neither attenuate nor prevent the orthostatic hypercoagulability.

Blood glucose and insulin levels in patients with peripheral vestibular disease.

UNLABELLED: Metabolic disorders can cause dizziness. AIM: to study the prevalence of glucose and glucose-insulin alterations in patients with peripheral vestibular disorders by studying the four-hour glucose-insulin curve; to check at what time there was the highest prevalence of altered cases and whether the glucose and insulin curves together are better than the isolate glucose curve and fasting glucose curve. MATERIALS AND METHODS: retrospective study, analyzing 81 four-hour glucose-insulin curves in patients with peripheral vestibular dizziness. RESULTS: Four-hour glucose-insulin curve alterations happened in 87.7% of the patients. Hypoglycemia was seen in 61.7% of the cases, hyperinsulinemia in 55.5%, hyperglycemia in 27.2%, glucose intolerance in 12.3% and hypoinsulinemia in 1.2%. Normal tests were seen in 12.3 % of the cases and altered fasting glucose in 23.5%. CONCLUSIONS: The four-hour glucose-insulin curve analysis showed that 87.7% of the patients with dizziness and suspicion of peripheral vestibular disorder had glucose or insulin metabolism disorders. The highest number of alterations was seen up to the third and fourth hour of the glucose-insulin curve. The glucose and insulin curves together overcame the glucose curve alone and fasting glucose curve in regards of the prevalence of altered cases.

Blood glucose and insulin levels in patients with peripheral vestibular disease / Avaliação da curva glicoinsulinêmica nos pacientes com vestibulopatia periférica

Metabolic disorders can cause dizziness. AIM: to study the prevalence of glucose and glucose-insulin alterations in patients with peripheral vestibular disorders by studying the four-hour glucose-insulin curve; to check at what time there was the highest prevalence of altered cases and whether the glucose and insulin curves together are better than the isolate glucose curve and fasting glucose curve. MATERIALS AND METHODS: retrospective study, analyzing 81 four-hour glucose-insulin curves in patients with peripheral vestibular dizziness. RESULTS: Four-hour glucose-insulin curve alterations happened in 87.7 percent of the patients. Hypoglycemia was seen in 61.7 percent of the cases, hyperinsulinemia in 55.5 percent, hyperglycemia in 27.2 percent, glucose intolerance in 12.3 percent and hypoinsulinemia in 1.2 percent. Normal tests were seen in 12.3 percent of the cases and altered fasting glucose in 23.5 percent. CONCLUSIONS: The four-hour glucose-insulin curve analysis showed that 87.7 percent of the patients with dizziness and suspicion of peripheral vestibular disorder had glucose or insulin metabolism disorders. The highest number of alterations was seen up to the third and fourth hour of the glucose-insulin curve. The glucose and insulin curves together overcame the glucose curve alone and fasting glucose curve in regards of the prevalence of altered cases.

Alterações metabólicas podem causar tontura. OBJETIVOS: Identificar a prevalência das alterações glicêmicas e glicoinsulinêmicas em pacientes com vestibulopatia periférica por meio da curva glicoinsulinêmica de 4 horas; verificar em que momento do exame foi encontrada a maior prevalência de casos alterados e se as curvas glicêmica e insulinêmica em conjunto superam a curva glicêmica isolada e glicemia de jejum. MATERIAL E MÉTODO: Estudo retrospectivo, com análise de 81 curvas glicoinsulinêmicas de quatro horas em pacientes com queixa de tontura de origem vestibular periférica. RESULTADOS: Alterações na curva glicoinsulinêmica de 4 horas ocorreram em 87,7 por cento dos pacientes. Hipoglicemia ocorreu em 61,7 por cento dos casos, hiperinsulinemia em 55,5 por cento, hiperglicemia em 27,2 por cento, intolerância à glicose em 12,3 por cento e hipoinsulinemia em 1,2 por cento. Exame normal em 12,3 por cento dos casos e glicemia de jejum alterada em 23,5 por cento. CONCLUSÕES: A análise da curva glicoinsulinêmica de 4 horas evidenciou que 87,7 por cento dos pacientes com tontura e hipótese de disfunção vestibular periférica apresentaram alterações do metabolismo da glicose ou insulina. O maior número de alterações foi encontrado até a terceira e quarta horas da curva glicoinsulinêmica. As curvas glicêmicas e insulinêmicas em conjunto superaram a curva glicêmica isolada e glicemia de jejum quanto à prevalência de casos alterados.

Circulating endocannabinoid concentrations during orthostatic stress.

BACKGROUND: In animals, the endocannabinoid system is activated during hemodynamic insults and restrains blood pressure in part through sympathetic inhibition. MATERIALS AND METHODS: We tested the hypothesis that hemodynamic stress elicited by head-up tilt testing increases systemic endocannabinoid concentrations in humans and that excessive endocannabinoid availability predisposes to presyncope. RESULTS: With head-up tilt, 2-arachidonoylglycerol increased, whereas anandamide remained unchanged. CONCLUSIONS: In contrast to our expectations, anandamide plasma concentration at rest was directly correlated with orthostatic tolerance, rather than intolerance.