Characteristics of bone metabolism in postmenopausal female patients with different types of idiopathic benign paroxysmal positional vertigo: A single-centre retrospective study.

OBJECTIVE: The association between benign paroxysmal positional vertigo (BPPV) and impaired calcium metabolism has attracted widespread interest. Several studies have suggested that decreased bone mineral density (BMD) and serum 25-hydroxyvitamin D (25(OH)D) level are related to the occurrence and/or recurrence of BPPV; however, the characteristics of bone metabolism in patients with BPPV subtypes have not been fully investigated, and conclusions have been controversial. This study aimed to evaluate BMD and serum levels of 25(OH)D and bone turnover markers to clarify the characteristics of bone metabolism in patients with different types of BPPV. METHOD: We retrospectively analysed the data of new-onset idiopathic postmenopausal female patients with BPPV at our institution from January 2016 to January 2020. The patients' demographic data including age, medication history, concomitant diseases, onset time, clinical form, laboratory indicators, such as serum levels of 25(OH)D, bone formation markers, namely, amino-terminal propeptide of type I procollagen (PINP) and osteocalcin (OC), bone resorption marker, namely, ß-isomerized carboxy-terminal telopeptide of type I collagen (ß-CTX), and BMD were collected and analysed. RESULTS: This study included 201 consecutive postmenopausal female patients with BPPV. Among them, 138 were diagnosed with posterior semicircular canal BPPV, 42 were diagnosed with lateral semicircular canal canalolithiasis, and 21 were diagnosed with lateral semicircular canal cupulolithiasis. There were no significant differences in age distribution, body mass index, clinical history, levels of albumin, globulin, uric acid, creatinine, or blood urea nitrogen, lipid profiles (except high-density lipoprotein cholesterol) and routine blood parameters among these groups (P > 0.05). There were no significant differences in the mean T-score and BMD values of different sites or in the serum levels of 25(OH)D and bone turnover markers (PINP, OC and ß-CTX) among the subgroups (P > 0.05). The proportion of reduction in BMD (T-score < -1 SD) and decreased serum vitamin D level (< 20 ng/ml) were not significantly different between the subgroups (P > 0.05). CONCLUSION: There were no significant differences in bone metabolism in postmenopausal female patients with different types of idiopathic BPPV.

The evolutionary hypothesis of benign paroxysmal positional vertigo.

Human otoliths, primarily formed from salts of calcium and carbonate, are different from bones of the skeleton, which are composed of calcium phosphate. The echinoderms, which share the earliest common ancestor with us, began to protect the body by making an endoskeleton out of calcium and carbon dioxide dissolved in the sea. In subsequent vertebrates, aerobic respiration supported strong muscle activity, but an occasional shortage of oxygen led to low pH due to the accumulation of lactate produced by anaerobic respiration, increasing the risk of melting bones composed of calcium carbonate. So, all vertebrates used calcium phosphate to increase bone strength, having a stronger ionic bonding than calcium carbonate. But otoliths, which are in the inner ear and thereby not connected to muscles, still use calcium carbonate. Benign paroxysmal positional vertigo (BPPV) is a disorder in which otoliths detached from the utricle enter the semicircular canals and cause a sense of rotation. Otoliths, the calcium carbonate ear bones retaining a long evolutionary history, can be easily broken at low pH. During sleep, shallow breathing produces mild respiratory acidosis and low pH in the blood. Since otoliths are corroded at low pH during nighttime, BPPV occurs frequently in the morning. In addition, diabetes mellitus or gout often decreases pH in the blood and increases the occurrence of BPPV.

Impaired Calcium Metabolism in Benign Paroxysmal Positional Vertigo: A Topical Review.

BACKGROUND AND PURPOSE: Although acute attacks of benign paroxysmal positional vertigo (BPPV) may be treated with canalith repositioning maneuvers, there have been no well-designed prospective trials to prevent this highly prevalent and recurrent disorder. This topical review explores the evidence related to the association between deficient calcium metabolism and BPPV. We also describe the development of therapeutic options to prevent recurrences of BPPV and introduce results from a recent randomized controlled trial on the effect of vitamin D and calcium supplementation in preventing BPPV recurrences. SUMMARY OF KEY POINTS: The literature describes 3 lines of evidence on association of impaired calcium metabolism and development of BPPV: (1) decreased bone mineral density was more frequently observed in persons with BPPV than in healthy controls; (2) estrogen plays a vital role in maintenance of otoconia, and estrogen deficiency appears to precipitate degeneration of otoconia and development of BPPV; and (3) lower serum vitamin D level is associated with development of BPPV, and supplementation of vitamin D and calcium carbonate may reduce further attacks of BPPV in persons with BPPV and subnormal serum vitamin D level. RECOMMENDATIONS FOR CLINICAL PRACTICE: Restoration of impaired calcium metabolism with supplementation of vitamin D or estrogen should be considered in the treatment of individuals with frequent recurrences of BPPV. Future randomized controlled trials are mandatory to validate these supplementation therapies in individuals with recurrent BPPV.

Salivary α-amylase levels in vertigo: Can it be an autonomic dysfunction?

We aim to demonstrate possible autonomic dysfunction based on salivary α-amylase measurements during and after the vertigo attacks associated with Ménière disease (MD) and benign paroxysmal positional vertigo (BPPV). Patients admitted to the emergency room with a diagnosis of vertigo attacks caused by either MD (n = 15) or BPPV (n = 9) constituted the study groups. The control group (n = 10) consisted of volunteer patients admitted to the emergency department with minor soft-tissue trauma. The first saliva samples were obtained immediately during the attacks and the second and third samples were obtained on the third and fifteenth days of the attack, respectively. In the controls, the first sample was obtained after admission to the hospital and the second sample was obtained on the third day. Salivary α-amylase levels were evaluated. The difference between salivary α-amylase levels in patients with MD and BPPV was not significant. The amylase value measured early after the BPPV attack was significantly lower than that of the controls (p = 0.008). Although not significant, an undulating pattern of salivary α-amylase levels was observed with both diseases. An autonomic imbalance could be partly demonstrated by salivary α-amylase measurement early after the attack in patients with BPPV. Therefore, amylase may be a promising marker that is worth further investigation.

Oxidative Status in Patients with Benign Paroxysmal Positional Vertigo.

OBJECTIVE: Benign paroxysmal positional vertigo (BPPV) is the most frequent peripheral vestibular disorder and is particularly seen among older patients suffering from vertigo. The brief vertigo attacks in and imbalance symptoms of BPPV are caused by freely floating otoconia within the semicircular canals. The aim of this prospective study was to evaluate the role of oxidative stress, using native thiol/disulfide (SH/SS) homeostasis as a novel indicator, in the etiology of BPPV. MATERIALS AND METHODS: The 62 participants in the study included 31 patients with BPPV and, as the control group, 31 healthy individuals without any cochleovestibular disorders. RESULTS: Patients with BPPV initially had significantly lower native SH levels and significantly lower SH/total thiol (TT) ratios, as well as significantly higher SS/SH and SS/TT ratios, than the healthy controls. After successful treatment of their vertigo, which was confirmed based on the results obtained from the second blood sample, patients with BPPV still had lower SH levels and SH/TT ratios and significantly higher SS/SH and SS/TT ratios than the healthy controls. CONCLUSION: Our results suggest a role of oxidative stress in the development of BPPV, through both calcium metabolism and the direct toxic effects of free oxygen radicals, including the triggering of apoptosis.

[Benign paroxysmal positional vertigo: modern concepts of its etiology and pathogenesis]. / Dobrokachestvennoe paroksizmal'noe pozitsionnoe golovokruzhenie: sovremennye predstavleniia ob étiologii i patogeneze.

The objective of the present review of the literature is the analysis of the currently available data concerning etiology and pathogenesis of benign paroxysmal positional vertigo (BPPV). The special emphasis is placed on the modern hypotheses of BPPV formation that collectively account for not more than 15% of all known cases of this condition. The best explored are the following causes of benign paroxysmal positional vertigo: vestibular neuronitis, head injuries, and disorders in the middle ear. During the recent years, much attention has been given to the role of disturbances of calcium metabolism and osteoporosis in etiology of benign paroxysmal positional vertigo. It is supposed that pathogenesis of vertiginous attacks can be explained in terms of the canalolithiasis and cupulolithiasis theories.

Biochemical markers of bone turnover in benign paroxysmal positional vertigo.

OBJECTIVE: Several studies have suggested a possible relationship between recurrent benign paroxysmal positional vertigo (BPPV) and altered calcium homeostasis in the endolymph of the inner ear. The present study aimed to evaluate the association between Ca2+ and vitamin D status and BPPV occurrence as well as the status of bone biochemical markers in osteoporotic patients who were diagnosed with idiopathic BPPV. METHODS: The study included total 132 patients who were referred to our clinic between August 2008 and October 2013. Based on the bone mineral density (BMD) results, the subjects were divided into three groups: normal BMD (n = 34), osteopenia (n = 40) and osteoporosis (n = 58). The biochemical markers of bone turnover including serum Carboxy-terminal telopeptide of type I collagen (s-CTX), osteocalcin, alkaline phosphatase (ALP) and urinary free deoxypyridinoline (u-DPD), were analyzed, along with the serum Ca2+ and vitamin D levels. RESULTS: The mean serum calcium, phosphate and creatinine clearance levels were within the standard laboratory reference range. The incidence of vitamin D deficiency was 11.8% (4/34) in the normal BMD group, 15% (6/40) in the osteopenia group and 43.1% (25/58) in the osteoporosis group. There was a positive correlation between the 25(OH)D and BMD results in the patients with BPPV. Among the bone turnover markers, the osteocalcin and u-DPD levels were significantly elevated in the osteoporotic patients with BPPV. Multiple logistic regression analyses showed that osteoporosis and vitamin D deficiency were associated with BPPV. CONCLUSION: Our findings suggest that the prevalence of BPPV in osteoporotic patients is associated with vitamin D deficiency and high bone turnover rates at systemic level, which could disturb local Ca2+ homeostasis in the inner ear.