Neurology of allergic inflammation and rhinitis

Sphenopalatine ganglion stimulation: a comprehensive evaluation across diseases in randomized controlled trials

Background

Current literature extensively covers the use of sphenopalatine ganglion stimulation (SPGs) in treating a broad spectrum of medical conditions, such as allergic rhinitis, cluster headaches, and strokes. Nevertheless, a discernible gap in the systematic organization and analysis of these studies is evident. This paper aims to bridge this gap by conducting a comprehensive review and analysis of existing literature on SPGs across various medical conditions.

Methods

This study meticulously constructed a comprehensive database through systematic computerized searches conducted on PubMed, Embase, CNKI, Wanfang, VIP, and CBM up to May 2022. The inclusion criteria encompassed randomized controlled trials (RCTs) published in either Chinese or English, focusing on the therapeutic applications of SPGs for various medical conditions. Both qualitative and quantitative outcome indicators were considered eligible for inclusion.

Results

This comprehensive study reviewed 36 publications, comprising 10 high-quality, 23 medium-quality, and three low-quality articles. The study investigated various diseases, including allergic rhinitis (AR), ischemic strokes (IS), cluster headache (CH), primary trigeminal neuralgia (PTN), pediatric chronic secretory otitis (PCSO), refractory facial paralysis (RFP), chronic tension-type headache (CTTH), as well as the analysis of low-frequency sphenopalatine ganglion stimulation (LF-SPGs) in chronic cluster headache (CCH) and the impact of SPGs on Normal nasal cavity function (NNCF). SPGs demonstrate efficacy in the treatment of AR. Regarding the improvement of rhinoconjunctivitis quality of life questionnaire (RQLQ) scores, SPGs are considered the optimal intervention according to the SUCRA ranking. Concerning the improvement in Total Nasal Symptom Score (TNSS), Conventional Acupuncture Combined with Tradiational Chinese Medicine (CA-TCM) holds a significant advantage in the SUCRA ranking and is deemed the best intervention. In terms of increasing Effective Rate (ER), SPGs outperformed both conventional acupuncture (CA) and Western Medicine (WM; P < 0.05). In the context of SPGs treatment for IS, the results indicate a significant improvement in the 3-month outcomes, as evaluated by the modified Rankin Scale (mRS) in the context of Cerebral Cortical Infarction (CCI; P < 0.05). In the treatment of CH with SPGs, the treatment has been shown to have a statistically significant effect on the relief and disappearance of headaches (P < 0.05). The impact of SPGs on NNCF reveals statistically significant improvements (P < 0.05) in nasal airway resistance (NAR), nasal cavity volume (NCV), exhaled nitric oxide (eNO), substance P (SP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY). SPGs treatments for PCSO, RFP, and CTTH, when compared to control groups, yielded statistically significant results (P < 0.05).

Conclusion

SPGs demonstrate significant effectiveness in the treatment of AR, IS, and CH. Effective management of CCH may require addressing both autonomic dysregulation and deeper neural pathways. However, additional high-quality research is essential to clarify its effects on NNCF, PTN, PCSO, RFP, and CTTH.

Systematic Review Registration

PROSPERO, identifier CRD42021252073, https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=312429.

Tic disorder in allergic rhinitis children and adolescents: a case-control study

BACKGROUND

Allergic rhinitis is the most common allergic disease. It can accompany psychological disorders such as tic disorders due to the prolonged course of the symptoms of allergic rhinitis. This pioneer case-control study aims to investigate tic disorders in children and adolescents under 18 years of age diagnosed with allergic rhinitis.

METHOD

The case group in this study consisted of patients who had both allergic rhinitis and tic disorders. Patients with allergic rhinitis without tic disorders were also enrolled as the control group with matched gender and age. Demographic characteristics, tic classifications, and contributing factors for allergic rhinitis and tic disorders were studied among the cases. Tic disorders were evaluated using DSM-5 criteria for the classification of tic disorders.

RESULTS

47 patients in the case group and 47 patients in the control group were included in this study. 53.2% and 46.8% were males and females in the case group, respectively. The mean age of the patients was 10.46 ± 3.97 years old. Sound tics were more common among the patients compared to motor tics. Patients with concomitant AR and tic disorders had more days per week with AR symptoms (P-value ≤ 0.001; OR (every day vs. three days a week = 11.02(2.98, 40.76))). Most patients with sound tick were women (p: 0.026), and most patients with motion tic were in the Provisional tic disorder group (p: 0.001). The history of infantile eczema was seen more in patients without sound tic (p: 0.025), and otitis media was significantly less common among patients with sound tics (p: 0.026). Provisional tic disorder was the most common class among the patients. In the case group (coexistence between allergic rhinitis and tic) compared to the control group, patients had significantly more days with AR symptoms per week.

CONCLUSION

This preliminary study indicates that Provisional tic disorder was the most common classification of tic among patients with allergic rhinitis, especially in patients with motor tics. Asthma in motor tics, a history of food allergy in infancy, and a history of infantile eczema were also common among patients with vocal tics. Also, patients with allergic rhinitis and tic had more severe disease (more symptoms per week) than those with rhinitis alone. These findings emphasize the association of tic disorders with immunological pathways.

Can Sex Improve Nasal Function?-An Exploration of the Link Between Sex and Nasal Function

OBJECTIVES

This study was conducted to examine the impact of sexual activity on nasal breathing and compare such effect to that of a nasal decongestant.

METHODS

We evaluated nasal breathing at 5 different times: (1) before sexual activity (baseline), (2) immediately after sexual activity, (3) 30 minutes, (4) 1 hour (5), and 3 hours after sexual climax. Same measurements were taken on the second day following application of nasal decongestant spray. For evaluation of nasal breathing, we used a visual analogue scale (VAS). Additionally, we used a portable rhinometric device to measure resistance and nasal flow.

RESULTS

Nasal breathing improved significantly after sexual intercourse with climax to the same degree as after application of nasal decongestant for up to 60 minutes, as measured subjectively with the VAS (sex -3.6, P < .001; spray -3.2, P < .001). This was confirmed in the objective rhinometric data as mean nasal flow (mL/s) increased while resistance decreased immediately (flow sex +214, P < .001; flow spray +235, P < .001), 30 (flow sex +249, P < .001; flow spray +287, P < .001), and 60 minutes (flow sex +180, P < .001; flow spray +287, P < .001) post-intervention. Nasal breathing was back to the baseline level after 3 hours following sexual intercourse, while it continued to be improved for longer after application of nasal decongestant. Only participants having nasal obstruction (Nasal Obstruction Symptom Evaluation score >30) showed nasal function improvement after sex.

CONCLUSIONS

Sexual intercourse with climax can improve nasal breathing to the same degree as application of nasal decongestant for up to 60 minutes in patients having nasal obstruction.

In healthy subjects nasal nitric oxide does not correlate with olfactory sensitivity, trigeminal sensitivity, and nasal airflow

OBJECTIVE

The aim of the study was to determine the relationship between nasal nitric oxide (nNO) and olfactory sensitivity, trigeminal sensitivity and nasal airflow in healthy subjects.

STUDY DESIGN

This is a correlational study.

SETTING

This study was carried out in a tertiary referral centre.

PARTICIPANTS

Forty healthy participants were recruited.

MAIN OUTCOME MEASURES

nNO was measured using a chemiluminescence analyser (Niox Vero^® , Circassia AB, Uppsala, Sweden), olfactory sensitivity was determined using phenyl ethyl alcohol odour thresholds using the 'Sniffin' Sticks', trigeminal sensitivity was assessed with carbon dioxide delivered by an automated device, and nasal airflow was measured using the peak nasal inspiratory flow (PNIF).

RESULTS

The median nNO was 518 ppb (IQR =333) in the right nostril, and it was 567 ppb (IQR = 314) in the left nostril. The median odour threshold was 7.1 (IQR = 4.4), the median CO₂ threshold was 919 ms (IQR = 1297) and the mean PNIF was 108 L/min (SEM = 4.9). nNO did not correlate significantly with odour threshold, CO₂ threshold or PNIF (Spearman's |ρ|  <0.15, p > .18).

CONCLUSION

In healthy subjects, nNO does not appear to be associated with olfactory sensitivity, trigeminal sensitivity and PNIF.

A pharmacological interactome between COVID-19 patient samples and human sensory neurons reveals potential drivers of neurogenic pulmonary dysfunction

The SARS-CoV-2 virus infects cells of the airway and lungs in humans causing the disease COVID-19. This disease is characterized by cough, shortness of breath, and in severe cases causes pneumonia and acute respiratory distress syndrome (ARDS) which can be fatal. Bronchial alveolar lavage fluid (BALF) and plasma from mild and severe cases of COVID-19 have been profiled using protein measurements and bulk and single cell RNA sequencing. Onset of pneumonia and ARDS can be rapid in COVID-19, suggesting a potential neuronal involvement in pathology and mortality. We hypothesized that SARS-CoV-2 infection drives changes in immune cell-derived factors that then interact with receptors expressed by the sensory neuronal innervation of the lung to further promote important aspects of disease severity, including ARDS. We sought to quantify how immune cells might interact with sensory innervation of the lung in COVID-19 using published data from patients, existing RNA sequencing datasets from human dorsal root ganglion neurons and other sources, and a genome-wide ligand-receptor pair database curated for pharmacological interactions relevant for neuro-immune interactions. Our findings reveal a landscape of ligand-receptor interactions in the lung caused by SARS-CoV-2 viral infection and point to potential interventions to reduce the burden of neurogenic inflammation in COVID-19 pulmonary disease. In particular, our work highlights opportunities for clinical trials with existing or under development rheumatoid arthritis and other (e.g. CCL2, CCR5 or EGFR inhibitors) drugs to treat high risk or severe COVID-19 cases.

A pharmacological interactome between COVID-19 patient samples and human sensory neurons reveals potential drivers of neurogenic pulmonary dysfunction

The SARS-CoV-2 virus infects cells of the airway and lungs in humans causing the disease COVID-19. This disease is characterized by cough, shortness of breath, and in severe cases causes pneumonia and acute respiratory distress syndrome (ARDS) which can be fatal. Bronchial alveolar lavage fluid (BALF) and plasma from mild and severe cases of COVID-19 have been profiled using protein measurements and bulk and single cell RNA sequencing. Onset of pneumonia and ARDS can be rapid in COVID-19, suggesting a potential neuronal involvement in pathology and mortality. We sought to quantify how immune cells might interact with sensory innervation of the lung in COVID-19 using published data from patients, existing RNA sequencing datasets from human dorsal root ganglion neurons and other sources, and a genome-wide ligand-receptor pair database curated for pharmacological interactions relevant for neuro-immune interactions. Our findings reveal a landscape of ligand-receptor interactions in the lung caused by SARS-CoV-2 viral infection and point to potential interventions to reduce the burden of neurogenic inflammation in COVID-19 disease. In particular, our work highlights opportunities for clinical trials with existing or under development rheumatoid arthritis and other (e.g. CCL2, CCR5 or EGFR inhibitors) drugs to treat high risk or severe COVID-19 cases.

Rhinitis and sleep disorders: The trigeminocardiac reflex link?

Rhinitis, allergic or non-allergic, is an inflammatory condition of the nose. It is associated with a wide range of sleep disorders that are generally attributed to nasal congestion and presence of inflammatory mediators like cytokines and interleukins. However, the pathophysiological mechanisms behind these sleep disorders remain unclear. On the other hand, the trigeminocardiac reflex (TCR) has recently been linked to various sleep disorders like obstructive sleep apnea, sleep bruxism and rapid eye movement (REM) sleep apnea. TCR can be incited by stimulation of the trigeminal nerve or the area innervated by its branches including the nasal mucosa. Trigeminal nasal afferents can be activated on exposure to noxious stimuli (mechanical or chemical) like ammonia vapors, carbon-dioxide, nicotine, hypertonic saline, air-puffs and smoke. In rhinitis, there is associated neuronal hyper-responsiveness of sensory nasal afferents due to inflammation (which can be suppressed by steroids). This may further lead to increased occurrence of TCR in rhinitis. Moreover, there is involvement of autonomic nervous system both in rhinitis and TCR. In TCR, parasympathetic over activity and sympathetic inhibition leads to sudden onset bradycardia, hypotension, apnea and gastric motility. Also, the autonomic imbalance reportedly plays a significant role in the pathophysiology of rhinitis. Thus, considering these facts we hypothesize that the TCR could be the link between rhinitis and sleep disorders and we believe that further research in this direction may yield significant development in our understanding of sleep disorders in rhinitis.

Sleep Disorders: Is the Trigemino-Cardiac Reflex a Missing Link?

Trigeminal innervated areas in face, nasolacrimal, and nasal mucosa can produce a wide array of cardiorespiratory manifestations that include apnea, bradypnea, bradycardia, hypotension, and arrhythmias. This reflex is a well-known entity called "trigemino-cardiac reflex" (TCR). The role of TCR is investigated in various pathophysiological conditions especially in neurosurgical, but also skull base surgery procedures. Additionally, its significance in various sleep-related disorders has also been highlighted recently. Though, the role of diving reflex, a subtype of TCR, has been extensively investigated in sudden infant death syndrome. The data related to other sleep disorders including obstructive sleep apnea, bruxism is very limited and thus, this mini review aims to investigate the possible role and correlation of TCR in causing such sleep abnormalities.

A study of the role of different forms of chronic rhinitis in the development of otitis media with effusion in children affected by adenoid hypertrophy

OBJECTIVE

The aim of the present study was to evaluate the role of the different forms of chronic rhinitis in the pathogenesis of otitis media with effusion in children affected by obstructive adenoid hypertrophy.

METHODS

81 patients, aged between 4 and 15 years (mean age of 6.9 years), affected by obstructive adenoid hypertrophy were evaluated. All patients underwent accurate history taking, physical examination with endoscopy of the nasopharynx, skin prick test, nasal cytology and hearing evaluation.

RESULTS

Nasal citology showed that 21% of patients had a non-allergic rhinitis (NAR) subtype, 17.4% NAR overlapping with infectious rhinitis (IR), 29.6% IR, 4.9% allergic rhinitis (AR), 2.5% AR overlapping with IR and the remaining 24.6% a negative cytology. The presence of OME was positively correlated with neutrophils (p = 0.01) and mast cells (p = 0.022), while it was negatively correlated with the presence of eosinophils (p = 0.02) and bacteria (p = 0.02).

CONCLUSIONS

A chronic rhinitis was present in more than 70% of children with AH and 60% of them showed OME. Nasal cytology together with SPT showed that AR was rarely present in this group of children, while the mast-cells and neutrophils positively correlated with OME.

Heart rate variability analysis in patients with allergic rhinitis

BACKGROUND

Very few studies investigate the role of the autonomic nervous system in allergic rhinitis. In this study, we evaluated the autonomic nervous system in allergic rhinitis patients using heart rate variability (HRV) analysis.

METHODS

Eleven patients with allergic rhinitis and 13 healthy controls, aged between 19 and 40 years old, were enrolled in the study. Diagnosis of allergic rhinitis was based on clinical history, symptoms, and positive Phadiatop test. Electrocardiographic recordings on the sitting and supine positions were obtained for HRV analysis.

RESULTS

In the supine position, there were no significant statistical differences in very-low-frequency power (VLF, ≤0.04 Hz), low-frequency power (LF, 0.04-0.15 Hz), high-frequency power (HF, 0.15-0.40 Hz), and the ratio of LF to HF (LF/HF) between the patient and control groups. The mean RR intervals significantly increased, while LF% and LF/HF significantly decreased in the patient group in the sitting position. Moreover, mean RR intervals, LF, and LF/HF, which were significantly different between the two positions in the control group, did not show a significant change with the posture change in the patient group.

CONCLUSION

These suggest that patients with allergic rhinitis may have poor sympathetic modulation in the sitting position. Autonomic dysfunction may therefore play a role in the pathophysiology of allergic rhinitis.

Pupillometric assessment of autonomic nervous system in children with allergic rhinitis

OBJECTIVE

The purpose of this study was to investigate autonomic nervous system dysfunction by measuring pupil sizes in pediatric patients with allergic rhinitis.

SUBJECTS AND METHODS

The study group consisted of 60 children (28 girls and 32 boys) who were age and gender matched with the control group, which also consisted of 60 children (26 girls and 34 boys). The diagnosis of allergic rhinitis was based on the history, physical examination and skin prick test performed by an allergologist. Pupil diameter measurements were performed using the pupillometer incorporated in the NİDEK OPD-Scan.

RESULTS

In the allergic rhinitis group, mean photopic and mesopic pupil diameters were 3.52 ± 0.07 and 5.98 ± 0.21, respectively, while in the control group, corresponding measurements were 4.03 ± 0.18 and 6.55 ± 0.16. There was a significant difference for photopic and mesopic pupil diameter between the groups (p < 0.001).

CONCLUSION

This study showed that the pupil size in response to a light stimulus in children with allergic rhinitis was smaller than that of the control group and may indicate parasympathetic hyperactivity and sympathetic hypoactivity.

Autonomic neural control of the airways

The airways and lungs are innervated by both sympathetic and parasympathetic nerves. Cholinergic parasympathetic innervation is well conserved in the airways while the distribution of noncholinergic parasympathetic and adrenergic sympathetic nerves varies considerably amongst species. Autonomic nerve function is regulated primarily through reflexes initiated upon bronchopulmonary vagal afferent nerves. Central regulation of autonomic tone is poorly described but some key elements have been defined.

Autonomic dysfunction and clinical severity of disease in children with allergic rhinitis

OBJECTIVES

The involvement of autonomic imbalance has been reported in the pathogenesis of allergic diseases.

PURPOSE

To investigate the association between the clinical severity of childhood allergic rhinitis and autonomic nervous system (ANS) dysfunction, to define whether the severity of disease correlates with ANS activity.

METHODS

In this cross-sectional, case-control study, we evaluated the ANS testing by measuring sympathetic skin response (SRR) and heart rate (R-R) interval variation (RRIV) in 55 children with perennial allergic rhinitis (PAR), aged 7-12 yrs without any chronic co-morbidity, and the results were compared with 40 sex- and age-matched control subjects. The patients were divided into two groups according to the severity of allergic rhinitis.

RESULTS

There were significant increase in calculated RRIV variables during at rest and deep breathing in children with PAR compared to controls, which reflect parasympathetic nervous system (PNS) activity (p<0.005). The mean amplitude of SSR in patients, which reflect sympathetic nervous system (SNS) activity was smaller compared with the controls, but this difference was not significant (0.61±0.35 μV vs controls 0.94±0.46, p>0.05). Lower RRIV and the prolonged SSR latencies in children with AR were closely correlated with disease severity (r=-0.65, p<0.05, and r=-0.59, p<0.05 respectively).

CONCLUSION

Combined use of these two tests, allows separate testing of PNS and SNS function, and are very sensitive methods in assessing of severity of disease in children with PAR.

Mouth breathing and forward head posture: effects on respiratory biomechanics and exercise capacity in children

OBJECTIVE

To evaluate submaximal exercise tolerance and respiratory muscle strength in relation to forward head posture (FHP) and respiratory mode in children, comparing mouth-breathing (MB) children with nasal-breathing (NB) children.

METHODS

This was a controlled, analytical cross-sectional study involving children in the 8-12 year age bracket with a clinical otorhinolaryngology diagnosis of MB, recruited between October of 2010 and January of 2011 from the Mouth Breather Clinic at the State University of Campinas Hospital de Clínicas, located in the city of Campinas, Brazil. The exclusion criteria were obesity, asthma, chronic respiratory diseases, heart disease, and neurological or orthopedic disorders. All of the participants underwent postural assessment and the six-minute walk test (6MWT), together with determination of MIP and MEP.

RESULTS

Of the 92 children in the study, 30 presented with MB and 62 presented with NB. In the MB group, the differences between those with moderate or severe FHP and those with normal head posture, in terms of the mean MIP, MEP and six-minute walk distance (6MWD), were not significant (p = 0.079, p = 0.622, and p = 0.957, respectively). In the NB group, the mean values of MIP and MEP were higher in the children with moderate FHP than in those with normal head posture (p = 0.003 and p = 0.004, respectively). The mean MIP, MEP, and 6MWD were lower in the MB group than in the NB group. Values of MIP and MEP were highest in the children with moderate FHP.

CONCLUSIONS

Respiratory biomechanics and exercise capacity were negatively affected by MB. The presence of moderate FHP acted as a compensatory mechanism in order to improve respiratory muscle function.

Regular CPAP utilization reduces nasal inflammation assessed by nasal cytology in obstructive sleep apnea syndrome

OBJECTIVES

To analyze nasal inflammation in a group of patients with obstructive sleep apnea syndrome (OSAS) by means of nasal cytology and to describe the changes induced by continuous positive air pressure (CPAP) treatment.

SUBJECTS AND METHODS

Thirty-two consecutive patients affected by OSAS (mean age 46.9 years) and 13 control subjects (mean age 49.1 years) were enrolled. Detailed clinical, laboratory, and polysomnographic studies were obtained in all participants and, in particular, nasal cytology was performed; inflammatory cells (neutrophils, eosinophils, mast cells, lymphocytes), bacteria, and spores were counted. A subgroup of 19 OSAS patients underwent regular nasal CPAP for eight weeks while the remaining 13 were noncompliant. Nasal cytology was repeated after eight weeks in all patients and controls.

RESULTS

All patients with OSAS were affected by some form of rhinopathy, mostly subclinical, which was not found to influence compliance to CPAP. Regular CPAP treatment induced a significant reduction of cell infiltration (neutrophils, eosinophils, lymphocytes, and muciparous cells), which was not seen in nontreated patients.

CONCLUSION

Nasal inflammation/infection is a very frequent finding in OSAS and can be reverted by the regular use of CPAP.

Stress-related programming of autonomic imbalance: role in allergy and asthma

Evidence linking psychological stress to allergy has grown with our increased understanding of the natural history and pathophysiology of these disorders and the neurobiology of stress vulnerability. However, the specific pathways that increase vulnerability to developing allergy and associated disorders remain to be elucidated. Autonomic nervous system functioning (autonomic balance) has been implicated in allergy for some time albeit links between autonomic balance and immune function in early development have been under studied. Starting in utero, stress may influence the programming of brain neurotransmitter systems, sympathetic and parasympathetic nervous system functioning, and the hypothalamic-pituitary-adrenal axis, which in turn may alter neural regulation of immune function. Epigenetic dysregulation of gene expression may be a fundamental mechanism for programming of early neural-immune processes.

Alterations of vasoactive intestinal polypeptide receptors in allergic rhinitis

BACKGROUND

Vasoactive intestinal peptide (VIP) is one of the parasympathetic neurotransmitters involved in the regulation of airway mucus secretion. The biological functions of VIP are mediated through two receptors (vasoactive intestinal peptide receptor type 1 [VPAC1R] and type 2 [VPAC2R]). The purpose of this study was to determine the distribution of VIP receptors and to compare the level of VIP receptor expression in the nasal mucosa of patients with allergic rhinitis and normal controls.

METHODS

Inferior turbinate mucosal samples were obtained from 20 normal subjects and 20 patients with allergic rhinitis. VPAC1R and VPAC2R mRNA was extracted from the nasal mucosa, and then a reverse-transcription-polymerase chain reaction was performed. Sections were immunostained using specific antibodies for VIP receptors. Western blot analysis was used to analyze differences in the level of expression of VPAC1R and VPAC2R protein between patients with allergic rhinitis and normal controls.

RESULTS

The level of expression of VIP receptor mRNA and protein in patients with allergic rhinitis was significantly increased compared with normal nasal mucosa. VIP receptor immunoreactivity was detected on the nasal epithelium and submucosal glands in nasal specimens from both normal controls and patients with allergic rhinitis. In the epithelium from patients with allergic rhinitis, VIP receptor immunoreactivity was strong, whereas in the nasal epithelium from normal subjects it was faint.

CONCLUSION

These results suggest that an increased expression level of VIP receptors is one possible explanation for nasal hyperresponsiveness in patients with allergic rhinitis.

A simple, innovative way to reduce rhinitis symptoms after sedation during endoscopy

BACKGROUND

Supplmental oxygen is routinely given via nasal cannula (NC) to patients undergoing moderate sedation for endoscopy. Some patients complain of profuse rhinorrhea and⁄or sneezing after the procedure, which results in additional medical costs and patient dissatisfaction.

OBJECTIVES

To determine the causal relationship between the route of oxygen delivery and troublesome nasal symptoms, and to seek possible solutions.

METHODS

Patients (n=836) were randomly assigned to one of the three following groups: the NC group (n=294), the trimmed NC (TNC) group (n=268) and the nasal mask (NM) group (n=274). All received alfentanil 12.5 μg⁄kg and midazolam 0.06 mg⁄kg, and adjunct propofol for sedation. Supplemental oxygen at a flow rate of 4 L⁄min was used in the NC and TNC groups, and 6 L⁄min in the NM group. The incidence of nasal symptoms and hypoxia were assessed.

RESULTS

The incidence of rhinitis symptoms was significantly higher in the NC group (7.1%) than in the TNC (0.4%) and NM (0%) groups (P<0.001). The incidence of hypoxia was lower in the NC group (3.1%) (P=0.040). All hypoxia events were transient (ie, less than 30 s in duration). On spirometry, the mean value of the lowest saturation of peripheral oxygen was found to be significantly lower in the NM group (96.8%) than in the NC group (97.7%) (P=0.004).

CONCLUSIONS

Trimming the NC or using NMs reduced the incidence of rhinitis symptoms; however, the incidence of hypoxia was higher. Further investigation regarding the efficiency of oxygen supplementation is warranted in the design of novel oxygen delivery devices.

Cardiac autonomic imbalance in children with allergic rhinitis

The involvement of autonomic imbalance has been reported in the pathogenesis of hypersensitivity reactions. Allergic diseases are more frequent in children and some of predisposing factors may be changed according to the increasing age, but the involvement of autonomic imbalance has not been investigated in pediatric population. In this cross-sectional, case-control study, we evaluated the autonomic system by measuring heart rate variability (HRV) in pediatric patients with allergic rhinitis. Thirty-five pediatric patients with allergic rhinitis and 36 healthy children (mean age 11 +/- 2.7, and 12 +/- 3 years, respectively) were enrolled in the study. Age and gender were not different between the groups. The diagnosis of allergic rhinitis was based on the history, symptoms, and skin prick tests. Participants with acute infection, nasal polyposis, bronchial asthma, and any other medical problems, assessed by history, physical examination and routine laboratory tests, were excluded. Twenty-four hour ambulatory electrocardiographic recordings were obtained, and the time domain and frequency domain indices of HRV were analyzed. We found significant increase in calculated HRV variables in children with allergic rhinitis compared to controls, which reflect parasympathetic tones, such as number of R-R intervals exceeding 50 ms, root mean square of successive differences between normal sinus R-R intervals, the percentage of difference between adjacent normal R-R intervals, and high frequency. These results indicate that HRV is increased, which implies sympathetic withdrawal and parasympathetic predominance. We propose that autonomic imbalance may be involved in the pathophysiology of allergic rhinitis in pediatric patients.

Histamine in allergic rhinitis

Histamine plays a major role in allergic rhinitis. In susceptible individuals, allergen induces nasal mast cell degranulation and the release of histamine into the nasal mucosa. Histamine has been detected after controlled challenges with allergen and, when administered into the nasal cavity, elicits signs and symptoms similar to those elicited by allergen. All four histamine receptors have been demonstrated in the nasal mucosa. The role of the four histamine receptors in the pathophysiology of allergic rhinitis are discussed.

Sneeze reflex: facts and fiction

Sneezing is a protective reflex, and is sometimes a sign of various medical conditions. Sneezing has been a remarkable sign throughout the history. In Asia and Europe, superstitions regarding sneezing extend through a wide range of races and countries, and it has an ominous significance. Although sneezing is a protective reflex response, little else is known about it. A sneeze (or sternutation) is expulsion of air from the lungs through the nose and mouth, most commonly caused by the irritation of the nasal mucosa. Sneezing can further be triggered through sudden exposure to bright light, a particularly full stomach and physical stimulants of the trigeminal nerve, as a result of central nervous system pathologies such as epilepsy, posterior inferior cerebellar artery syndrome or as a symptom of psychogenic pathologies. In this first comprehensive review of the sneeze reflex in the English literature, we aim to review the pathophysiology, etiology, diagnosis, treatment and complications of sneezing.

Mouth Breathing Syndrome: cervical muscles recruitment during nasal inspiration before and after respiratory and postural exercises on Swiss Ball

OBJECTIVE

This study aimed to evaluate the recruitment of cervical muscles during nasal inspiration before and after breathing and postural exercises on the Swiss Ball in children with Mouth Breathing Syndrome (MBS).

METHOD

Surface electromyography from the sternocleidomastoid (SCM), sub-occipitals and upper Trapezius muscles was recorded during nasal inspiration, before and at the end of three months of the treatment. A physical therapy program consisting in muscular stretching and strengthening exercises along with naso-diaphragmatic breathing on the Swiss Ball were carried out for body posture realignment and respiratory training. Nineteen mouth breathing children, mean age of 10.6 years, both genres, were the subjects of this study. In order to establish a comparison between the eletromyographic results (normalized values) obtained from pre and post-physical therapy program it was used the Wilcoxon non-parametric test for dependent data.

RESULTS

It was found a significant decrease (p<0.01) in the electromyographic activity during nasal inspiration in all tested muscles after treatment (11.3-3.6% in the SCM, 22.4-11.7% in the sub-occipitals and 8.9-3.1% in the upper Trapezius). At the end of the treatment, the assessed muscles reached lower activity electromyographic levels during nasal inspiration and they became closer of those in the quiet position.

CONCLUSION

The lower activity after the physical therapy program in these muscles indicates a less effort of the accessory inspiratory muscles, probably due to a better performance of diaphragm muscle with the improvement of the body posture.

Leukotriene D4 increases the excitability of capsaicin-sensitive nasal sensory nerves to electrical and chemical stimuli

BACKGROUND AND PURPOSE

Clinical studies have demonstrated significant reductions in allergen-induced nasal symptoms of atopic rhinitis subjects by CysLT1 antagonists, including neuronally mediated symptoms such as sneeze, itch and reflex hypersecretion. Here, we test the hypothesis that cysteinyl leukotrienes activate and/or alter the activity of nasal nociceptive (capsaicin-sensitive) sensory neurones.

EXPERIMENTAL APPROACH

Using retrograde tracer (DiI), we labelled guinea-pig trigeminal sensory neurones that projected fibres to the nasal mucosa. Single-neurone reverse transcriptase (RT)-PCR was used to evaluate CysLT receptor gene expression. The effect of cysteinyl leukotrienes on individual nasal sensory nerve activity was assessed in Ca2+ assays and whole-cell gramicidin-perforated patch-clamp studies.

KEY RESULTS

Nasal C-fibre neurones express CysLT1 but not CysLT2 mRNA. LTD4 and LTC4 increased intracellular [Ca2+]free in a population of capsaicin-sensitive trigeminal nerves, an effect blocked by the CysLT1 antagonist ICI198615. In current clamp mode, LTD4 had no effect on resting membrane potential. However, LTD4 significantly increased electrical excitability (action potential discharge during current pulses) threefold in capsaicin-sensitive nasal neurones, which was inhibited by CysLT1 antagonists ICI198615 and montelukast. LTD4 had no effect on electrical excitability in capsaicin-insensitive neurones. Finally, LTD4 significantly augmented histamine-induced responses in capsaicin-sensitive neurones as measured by increased action potential discharge, peak frequency and membrane depolarization.

CONCLUSIONS AND IMPLICATIONS

LTD4, likely through CysLT1 receptors, directly increases the excitability of capsaicin-sensitive guinea-pig nasal trigeminal neurones, demonstrating a novel mechanism for the actions of cysteinyl leukotrienes and potentially explains the effectiveness of CysLT1 antagonists in treating nasal allergen-induced neuronal symptoms.

Nasal conditioning after endonasal surgery in chronic rhinosinusitis with nasal polyps

BACKGROUND

Endoscopic sinus surgery (ESS) is a frequently performed operation for chronic rhinosinusitis (CRS). The aim of this study was to investigate nasal conditioning after ESS with/without septoplasty and turbinoplasty in patients with CRS with nasal polyps and to determine its relation to nasal patency and geometry.

METHODS

Twenty-one patients were enrolled into this study. Nasal conditioning, AAR, and acoustic rhinometry were measured before and 4-8 months after endonasal surgery.

RESULTS

The temperature and humidity gradient across the nose increased significantly after operation. High nasal volumes and patency were positively correlated with elevated nasal conditioning. No correlation between preoperative and postoperative changes in nasal geometry and nasal airflow with changes in conditioning values was found.

CONCLUSION

Patients with CRS with nasal polyps seem to profit from ESS with/without septoplasty and turbinoplasty because nasal conditioning is improved postoperatively. Properly performed ESS has its importance within the variety of nasal surgical procedures ensuring improved nasal function.

Autonomic dysfunction, allergy and the upper airway

PURPOSE OF REVIEW

The autonomic nervous system has been implicated in the pathophysiology of chronic upper airway inflammatory disease for decades. We discuss the most recent literature with regard to autonomic nervous system dysfunction and chronic upper airway disease.

RECENT FINDINGS

Recently, state of the art autonomic nervous system testing has demonstrated autonomic nervous system dysfunction in patients with chronic upper airway inflammatory disease. This dysfunction has been characterized as hypoadrenergic.

SUMMARY

Autonomic nervous system dysfunction likely plays a role in chronic upper airway inflammatory disease. Further investigation may lead to a better understanding of the role of autonomic nervous system dysfunction in these disorders and, hence, opportunities for novel therapeutic modalities.

Rhinitis and snoring as risk factors for hypertension in post-menopausal women

OBJECTIVE

Several studies have suggested an association between snoring and hypertension. An association between rhinitis and hypertension has been recently indicated in men but not in women. Since menopausal status is an important determinant of blood pressure, we evaluated the relationship between rhinitis, snoring and blood pressure taking into account the modifying effect of menopausal status.

DESIGN

Cross-sectional survey.

SETTINGS

Four areas of Italy: the Po river Delta, Pisa (Tuscany), Viterbo (Lazio) and Rome.

MAIN OUTCOME MEASURES

Data were collected by a questionnaire and a medical visit.

PARTICIPANTS

One thousand five hundred and fifty-four female non-smokers.

RESULTS

Systolic blood pressure (SBP) was significantly related to both occasional and habitual snoring in the overall sample. No associations were found between SBP, snoring, and rhinitis in pre-menopausal women. Both occasional and habitual snoring, but not rhinitis, were significant risk factors for increased SBP in women who stopped menstruating fewer than 11 years previously (beta=10.27 mmHg, 95% confidence interval (CI)=3.5, 17.01 and beta=9.91 mmHg, 95% CI=2.3, 17.5, respectively). However, women who had been menopausal for more than 11 years were found to have an increased SBP if they were occasional snorers (beta=8.94 mmHg 95% CI=1.2, 16.6) or habitual snorers (beta=8.01 mmHg, 95% CI=0.10, 15.9). The increase in SBP was even greater in these women when habitual snoring was associated with rhinitis (beta=11.96 mmHg, 95% CI=1.01, 22.9).

CONCLUSION

We suggest that the association of snoring with rhinitis may facilitate the development of apnea during sleep, which in post-menopausal women may increase the risk of developing hypertension.

Sneeze related area in the medulla: localisation of the human sneezing centre?

Sneezing is a rarely explored symptom in neurological practice. In the cat, a sneeze evoking centre is located in the medulla. The existence of a sneezing centre has not been confirmed in humans. A case with abnormal sneezing secondary to a strategic infarct in the right latero-medullary region is presented. A 66 year old man suddenly presented paroxysmal sneezing followed by ataxia, right sided motor and sensory symptoms, and hoarseness. The application of stimuli to the right nasal fossa did not evoke sneezing nor the wish to sneeze. The same stimuli to the contralateral nasal fossa evoked normal sneezing. The preservation of the superficial sensitivity of the nasal fossa indicates that the lesion was localised in the hypothetical human sneezing centre, very close to the spinal trigeminal tract and nucleus. This centre appears to be bilateral and functionally independent on both sides.

Role of alveolar epithelial sodium transport in high altitude pulmonary edema (HAPE)

Alveolar edema results from an imbalance between fluid filtration into the alveolar space and removal by reabsorption. Hypoxia increases filtration by raising pulmonary capillary pressure and increasing endothelial and epithelial permeability allowing fluid and blood cells to access the alveoli. Active Na-reabsorption drives the fluid reabsorption from the alveolar space, but hypoxia inhibits reabsorption by inhibition of epithelial Na-channels (ENaC) and Na/K-ATPase. A (genetically determined) low activity of alveolar reabsorption in normoxia and further inhibition by hypoxia might cause HAPE-susceptibility, since at some point the depressed reabsorption may not keep pace with increased filtration. Na-reabsorption might even prove totally inefficient in the presence of large leaks of the alveolar barrier. Alveolar Na-reabsorption has not been measured in HAPE. Nasal epithelial Na-transport has been used as surrogate marker based on similarities in subunit expression of ENaC in nasal, airway, and alveolar epithelium. At high altitude cold, dryness, and nasal infections affect the nasal potential making any extrapolation to processes at the alveolar epithelium unreliable. The variability in nasal Na- and Cl-transport reduces the usefulness of nasal potentials to diagnose HAPE-susceptibility.

Autonomic function and dysfunction of the nose and sinuses

Patients with inflammatory disorders of the upper airway exhibit varying degrees of ANS dysfunction, including the sympathetic, parasympathetic,and sensory components. Current evidence is insufficient with regard to the exact role of ANS dysfunction and its relationship to these disorders.Thus, the interaction of the ANS and sinonasal inflammation deserves further study.

Physiological aspects of high-altitude pulmonary edema

High-altitude pulmonary edema (HAPE) develops in rapidly ascending nonacclimatized healthy individuals at altitudes above 3,000 m. An excessive rise in pulmonary artery pressure (PAP) preceding edema formation is the crucial pathophysiological factor because drugs that lower PAP prevent HAPE. Measurements of nitric oxide (NO) in exhaled air, of nitrites and nitrates in bronchoalveolar lavage (BAL) fluid, and forearm NO-dependent endothelial function all point to a reduced NO availability in hypoxia as a major cause of the excessive hypoxic PAP rise in HAPE-susceptible individuals. Studies using right heart catheterization or BAL in incipient HAPE have demonstrated that edema is caused by an increased microvascular hydrostatic pressure in the presence of normal left atrial pressure, resulting in leakage of large-molecular-weight proteins and erythrocytes across the alveolarcapillary barrier in the absence of any evidence of inflammation. These studies confirm in humans that high capillary pressure induces a high-permeability-type lung edema in the absence of inflammation, a concept first introduced under the term “stress failure.” Recent studies using microspheres in swine and magnetic resonance imaging in humans strongly support the concept and primacy of nonuniform hypoxic arteriolar vasoconstriction to explain how hypoxic pulmonary vasoconstriction occurring predominantly at the arteriolar level can cause leakage. This compelling but as yet unproven mechanism predicts that edema occurs in areas of high blood flow due to lesser vasoconstriction. The combination of high flow at higher pressure results in pressures, which exceed the structural and dynamic capacity of the alveolar capillary barrier to maintain normal alveolar fluid balance.

Nasal conditioning in perennial allergic rhinitis after nasal allergen challenge

BACKGROUND

Antigen challenge in seasonal allergic rhinitis is considered to be associated with an increased ability of the nose to condition inspired air. In contrast, little is known about air conditioning after antigen challenge in perennial allergic rhinitis (PAR).

OBJECTIVE

The aims of this study were to investigate whether antigen challenge in PAR changes nasal air conditioning and to assess the relationship between nasal conditioning and nasal patency and geometry.

METHODS

Nineteen subjects with PAR were enrolled into this study. Measurement of nasal conditioning, active anterior rhinomanometry (AAR), acoustic rhinometry (AR), and clinical symptom evaluation were performed before and after nasal allergen challenge with allergen extracts from house dust mites.

RESULTS

Ten and 20 min after nasal allergen challenge, the total water content of the air measured in the nasopharynx and the water gradient across the nose were significantly higher in the nasal cavity in which the allergen extract was sprayed. The temperature on both sides of the nose increased non-significantly after nasal allergen challenge. No correlation to data obtained by AAR, AR, and clinical symptom evaluation after nasal allergen challenge was found.

CONCLUSION

We suggest that an increase in mucosal humidity due to the allergic provocation might be responsible for the increase in nasal conditioning capacity because no correlation to changes in nasal perimeter and patency was found.