Biases related to periostin levels in chronic rhinosinusitis with nasal polyposis: a systematic review.

BACKGROUND: The role of periostin in the pathophysiology of chronic rhinosinusitis with nasal polyposis (CRSwNP) has been debated in the literature, with several authors proposing periostin as a potential biomarker or theurapeutical target. However, the mechanisms regulating the systematic or local periostin production in both CRSwNP patients and controls remain elusive. METHODOLOGY: Any factors reported to affect periostin expression in polyp tissue samples, nasal mucosa samples, serum and nasal secretions were considered as primary outcomes in this systematic review. Interactions or synergistic effects between bias factors were considered as secondary outcomes. RESULTS: Eosinophilic CRSwNP, large polyp size and radiological severity were found to be high-risk, positive bias factors for periostin levels in polyp tissue samples, while the role of atopy and asthma has been debated. Immunotherapy and eosinophilic endotype were identified as biases for serum periostin measurements, while steroids and non-steroidal anti-inflammatory drug exacerbated respiratory disease remain of unclear risk. Bronchal asthma, eosinophilic endotype and immunotherapy have been reported to bias periostin measurements in nasal secretions. CONCLUSIONS: The relevant literature is extremely limited and little is actually known about the intrinsic or extrinsic factors affecting periostin measurements. The synthesis of the existing literature should be done with cautiousness.

Sleep position and laterality of benign paroxysmal positional vertigo.

OBJECTIVE: The aim of this study was to investigate the frequency of posterior semicircular canal benign paroxysmal positional vertigo in each ear, and to assess the association between the ear affected by benign paroxysmal positional vertigo and the head-lying side during sleep onset. Based on a previous study which used objective methods to prove the preference of the elderly for the right head-lying side during sleep, we hypothesised that a predominance of the same head-lying side in benign paroxysmal positional vertigo patients may affect the pathophysiology of otoconia displacement. STUDY DESIGN: We conducted a prospective study of out-patients with posterior semicircular canal benign paroxysmal positional vertigo, confirmed by a positive Dix-Hallpike test. METHODS: One hundred and forty-two patients with posterior semicircular canal benign paroxysmal positional vertigo were interviewed about their past medical history, focusing on factors predisposing to benign paroxysmal positional vertigo. All patients included in the study were able to define a predominant, favourite head-lying side, right or left, during sleep onset. RESULTS: The Dix-Hallpike test was found to be positive on the right side in 82 patients and positive on the left side in 54; six patients were found to be positive bilaterally. During sleep onset, 97 patients habitually laid their head on the right side and the remaining 45 laid their head on the left. The association between the affected ear and the head-lying side during sleep onset was statistically significant (p < 0.001). CONCLUSIONS: Our study found a predominance of right-sided benign paroxysmal positional vertigo, a subjective preference amongst patients for a right head-lying position during sleep onset, and an association between the ear affected by benign paroxysmal positional vertigo and the preferred head-lying side during sleep onset. The clinical and therapeutical implications of this observation are discussed.