Associations among upper airway structure, body position, and obesity in skeletal Class I male patients with obstructive sleep apnea

Association among craniofacial morphology, ethnicity, and risk of pediatric sleep-related breathing disorders: A multicenter study

INTRODUCTION

Craniofacial morphology and ethnicity may be risk factors for sleep-related breathing disorder (SRBD) in children but have not yet been assessed in an international multicenter study. The objectives of this study were to assess the association among craniofacial features, self-reported ethnicity, and risk of SRBD in children undergoing orthodontic treatment.

METHODS

Children aged 5-18 years who presented for orthodontic evaluation were enrolled in the United States, South Africa, South Korea, Saudi Arabia, and Japan. The risk of SRBD was defined as answering ≥0.33 positive responses to the Pediatric Sleep Questionnaire. Craniofacial features included measurements in sagittal and vertical dimensions to evaluate the cranial base, maxillomandibular and dental relationships, and nasopharyngeal airway dimensions. Logistic regression was performed to assess the association among craniofacial features, ethnicity, age, body mass index, and risk of SRBD.

RESULTS

Data were obtained from 602 patients from 5 sites. A total of 76 patients (12.6%) had a risk of SRBD. The mean age was 12.5 years. Male gender (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.0-3.4; P = 0.041), Middle Eastern ethnicity (OR, 10.2; 95% CI, 4.1-25.4; P = 0.001), body mass index (OR, 1.1; 95% CI, 1.04-1.10; P = 0.001), gonial angle (OR, 0.91; 95% CI, 0.85-0.98; P = 0.011), and inferiorly positioned hyoid (OR, 1.1; 95% CI, 1.0-1.2; P = 0.002) were significantly associated with the risk of SRBD.

CONCLUSIONS

In an ambidirectional cohort study across 5 sites, male gender, Middle Eastern ethnicity, body mass index, gonial angle, and inferiorly positioned hyoid were associated with the risk of SRBD in children undergoing orthodontic treatment.

Airway Analysis in Skeletal Class I and Class II Subjects with Different Growth Patterns: A 2D Cephalometric Study

OBJECTIVE

A two-dimensional cephalometric study was carried out to assess the airway among individuals with Class I and Class II skeletal base.

MATERIALS AND METHODS

Class II subjects were further categorized into horizontal and vertical growers and average growth patterns to check the possible relationship between the facial skeleton and pharyngeal airway. Lateral cephalograms of 150 subjects were obtained using standard protocol in natural head position (NHP). Nasopharyngeal and oropharyngeal linear, and angular and nasopharyngeal area measurements were obtained using standardized tracing technique. Analysis of variance (ANOVA), level of significance, and post hoc Turkey's test were performed to assess the correlation between skeletal pattern of the individual and airway dimension. Gender discrimination was assessed using independent sample t test.

RESULTS

In linear measurements, significant differences were observed among upper pharynx (0.039), adenoid tissue 1 (0.036), and adenoid tissue 2 (0.01). In angular measurements, differences were observed with angle of nasopharynx (0.008). The nasopharyngeal area measurements were also associated with significant difference (0.038) with Class II vertical growers less than those with Class I average and Class II horizontal groups.

CONCLUSION

Class II vertical growers had significantly reduced nasopharyngeal airways.

Treatment of snoring with positional therapy in patients with positional obstructive sleep apnea syndrome

Position therapy plays a role in treating snoring and obstructive sleep apnea syndrome (OSAS). The purpose of this study was to investigate whether position therapy using a head-positioning pillow (HPP) could reduce snoring sounds in patients with mild-to-moderate positional OSAS, taking into account the potential confounding effects of body weight. A total of 25 adults with positional OSAS (apnea-hypopnea index [AHI]_supine:AHI_non-supine ≥ 2) were prospectively enrolled. Patients were asked to use their own pillows at home during the first night (N₀), and the HPP during the second (N₁) and third (N₂) nights. The primary outcome measures included the subjective snoring severity (SS, measured on a visual analogue scale ranging from 0 to 10) and the objective snoring index (SI, expressed as the number of snoring events per hour measured on an acoustic analytical program). Both endpoints were recorded over three consecutive nights. From N₀ to N₂, the median SS and SI values in the entire study cohort decreased significantly from 5.0 to 4.0 and from 218.0 events/h to 115.0 events/h, respectively. In the subgroup of overweight patients, SS showed a significant improvement, whereas SI did not. Both SS and SI were found to be significantly improved in normal-weight patients.

Importance of cephalographs in diagnosis of patients with sleep apnea

Introduction:

Obstructive sleep apnea (OSA) is considered to be a potentially life threatening disorder, which is characterized by repeated collapse of the upper airway during sleep with cessation of breathing. The cephalometric method despite being a static, two-dimensional evaluation of dynamic three-dimensional structures of the head and neck is useful in diagnosing patients with OSA, as they have shown that significant differences exist between asymptomatic controls and patients with OSA.

Aims and Objectives:

This study is designed to compare and validate the craniofacial morphology in patients with OSA using lateral cephalometry in both upright and supine position.

Materials and Methods:

Sixty subjects participated in the study of which 30 were patients with OSA diagnosed by questionnaire and 30 were healthy control group with age range of 25–45 years.

Results:

The study group demonstrated an increased ANB, mandibular plane angles (GoGn-SN), lower anterior facial height which are statistically significant with a significant P < 0.05. Significant decrease in posterior airway space, increased soft palate length, tongue length, and thickness suggesting reduced airway space in supine posture.

Conclusion:

Evaluation of craniofacial morphology in OSA patients using lateral cephalometry helps in recognizing the morphological changes induced by altered sleep pattern and for appropriate treatment planning.

Airway changes in obstructive sleep apnoea patients associated with a supine versus an upright position examined using cone beam computed tomography

OBJECTIVE

This study aimed to describe total volume and cross-sectional area measurement changes in obstructive sleep apnoea patients associated with a supine versus an upright position.

METHOD

A retrospective chart review of patients who underwent cone beam computed tomography in upright and supine positions was performed, and the images were analysed.

RESULTS

Five obstructive sleep apnoea patients (all male) underwent both upright and supine cone beam computed tomography imaging. Mean age was 35.0 ± 9.3 years, mean body mass index was 28.1 ± 2.7 kg/m2 and mean apnoea-hypopnoea index was 39.3 ± 23.0 per hour. The airway was smaller when patients were in a supine compared with an upright position, as reflected by decreases in the following airway measurements: total volume; posterior nasal spine, uvula tip, retrolingual and tongue base (not significant) cross-sectional areas; and site of the minimum cross-sectional area (of the overall airway). Total airway volume decreased by 32.6 per cent and cross-sectional area measurements decreased between 32.3 and 75.9 per cent when patients were in a supine position.

CONCLUSION

In this case series, the airway of obstructive sleep apnoea patients was significantly smaller when patients were in a supine compared with an upright position.

Pharyngeal airway space, hyoid bone position, and head posture after bimaxillary orthognathic surgery in Class III patients: long-term evaluation

OBJECTIVE

(1) To determine the effect of bimaxillary orthognathic surgery on pharyngeal airway, hyoid bone, and craniocervical posture in Class III bimaxillary surgery patients. (2) To evaluate short-term and long-term results. (3) To compare short- and long-term values.

MATERIALS AND METHODS

Twenty-six Class III adult patients treated with bimaxillary surgery were included in the study. Cephalometric records were taken before treatment (T1), before surgery (T2), and 5 months (T3), 1.4 years (T4), 3 years (T5), and 5 years (T6) postsurgery.

RESULTS

No significant differences were identified in craniocervical angulation between time intervals. There was a significant superior movement of hyoid bone at postsurgery (T3; P < .05); however, adaptation occurred to the normal position in the long term. A nonsignificant decrease occurred at the oropharyngeal middle pharyngeal distance parameter; however, this was compensated with a significant increase between T5 and T6 (P < .001). A significant decrease was observed in the hypopharyngeal Go-P parameter between T3 and T1 (P < .01), but it recovered with a nonsignificant increase in the long term. A significant increase in nasopharyngeal area was observed between T3 and T1 (P < .05). The hypopharyngeal area significantly increased between T5 and T6, and PNS-R significantly increased between T3 and T1 (P < .05).

CONCLUSION

The pharyngeal areas adversely affected after surgery recover at long-term follow-up; thus, adaptation occurs after bimaxillary surgery.

Features of lateral cephalograms associated with difficult laryngoscopy in Japanese children undergoing oral and maxillofacial surgery

BACKGROUND

Difficult laryngoscopy and tracheal intubation are occasionally encountered in children with congenital anomalies or micrognathia. However, no study has elucidated anatomical etiology in relation to craniofacial development.

METHODS

Two hundred ten patients aged 8 months-18 years were analyzed. We analyzed the lateral cephalograms of: (i) eight patients in whom laryngoscopy was anticipated as difficult before anesthesia and who were unable to be intubated by direct laryngoscopy and needed fiberoptic bronchoscopy (group A); (ii) 11 patients in whom laryngoscopy was anticipated as difficult before anesthesia but who were able to be intubated by direct laryngoscopy (group B); and (iii) 191 patients in whom laryngoscopy was anticipated as easy before anesthesia and was actually found to be easy (group C). Eight cephalometric parameters were measured and age-parameter relationships were plotted. Logistic regression analysis was performed to characterize group A children for each of the cephalometric variables.

RESULTS

Apparently insufficient growth of the mandible was observed in the group A children. Furthermore, the group A children of aged <4 years had undeveloped maxilla, longer mandibular plane-hyoid distances (≥1.3 cm), and deeper depth of the oropharynx; those of aged ≥4 years showed increased inclination of the mandible (sella-nasion plane to mandibular plane angle of ≥46.5°).

CONCLUSIONS

Difficult laryngoscopy and tracheal intubation are expected in children aged <4 years with lower-positioned hyoid bone caused by caudal larynx as well as undeveloped maxilla and mandible, and in those aged ≥4 years with increased inclination of the mandible as well as undeveloped mandible.

Supine position related obstructive sleep apnea in adults: pathogenesis and treatment

The most striking feature of obstructive respiratory events is that they are at their most severe and frequent in the supine sleeping position: indeed, more than half of all obstructive sleep apnea (OSA) patients can be classified as supine related OSA. Existing evidence points to supine related OSA being attributable to unfavorable airway geometry, reduced lung volume, and an inability of airway dilator muscles to adequately compensate as the airway collapses. The role of arousal threshold and ventilatory control instability in the supine position has however yet to be defined. Crucially, few physiological studies have examined patients in the lateral and supine positions, so there is little information to elucidate how breathing stability is affected by sleep posture. The mechanisms of supine related OSA can be overcome by the use of continuous positive airway pressure. There are conflicting data on the utility of oral appliances, while the effectiveness of weight loss and nasal expiratory resistance remains unclear. Avoidance of the supine posture is efficacious, but long term compliance data and well powered randomized controlled trials are lacking. The treatment of supine related OSA remains largely ignored in major clinical guidelines. Supine OSA is the dominant phenotype of the OSA syndrome. This review explains why the supine position so favors upper airway collapse and presents the available data on the management of patients with supine related OSA.

Pharyngeal airway space, hyoid bone position and head posture after orthognathic surgery in Class III patients

OBJECTIVE

To determine the effect of orthognathic surgery on pharyngeal airway in Class III patients and to (1) compare the results of different surgical techniques, (2) determine the change at the position of the hyoid bone, and (3) evaluate the craniocervical posture changes related to pharyngeal airway change.

MATERIALS AND METHODS

Forty-eight Class III adult patients were included in the study to assess airway space after orthognathic surgery. Nine patients were treated with maxillary advancement, seven patients were treated with mandibular set back, and 32 patients were treated with bimaxillary surgery. Cephalometric records were taken before treatment, after surgery, and about 1 year after surgery (at the end of the treatment).

RESULTS

No differences were determined at the position of hyoid bone and craniocervical posture. Nasopharyngeal area was significantly increased in all groups (P < .05). Oropharyngeal area and SPSS and IPS parameters were significantly decreased after mandibular set back operation (P < .05). In bimaxillary and maxillary advancement groups, PPS parameter was significantly increased (P < .01), and IPS parameter was significantly decreased (P < .05). No differences were detected at oropharyngeal and hypopharyngeal areas in bimaxillary and maxillary advancement groups.

CONCLUSION

Different surgical procedures have different effects on pharyngeal airway space.

The role of malocclusion in non-obese patients with obstructive sleep apnea syndrome

OBJECTIVE

The maxillofacial characteristics of patients with obstructive sleep apnea syndrome (OSAS) have previously been analyzed using standard cephalometric analysis. Malocclusion influences the occurrence of sleep apnea, but the pathology of malocclusion in OSAS has not yet been fully investigated. Therefore, we investigated malocclusion in patients with OSAS using cephalometric and dental analysis.

METHODS

Cephalometric and dental analyses were performed to evaluate malocclusion in 97 male patients with OSAS (49.7+/-11.7 years). The number of apnea and hypopnea episodes per hour (apnea-hypopnea index: AHI) was determined by standard polysomnography.

RESULTS

The overall prevalence of severe overjet (the horizontal distance between the upper and lower incisors of >or=6 mm) was 43.3%. AHI was significantly correlated with body mass index (BMI) in obese OSAS patients (r=0.385, p=0.010), whereas it was significantly correlated with overjet in non-obese OSAS patients (BMI<25 kg/m2) (r=0.313, p=0.022). Multiple regression analysis revealed that BMI was the significant factor contributing to increased AHI in all patients, and overjet was in non-obese OSAS patients. There were no significant differences between non-obese and obese OSAS patients in the angle of protrusion of the superior alveolar base (SNA) or in the angle of protrusion between the superior and inferior alveolar bases (ANB). The angle of protrusion of the inferior alveolar base (SNB) was significantly smaller in non-obese than in obese OSAS patients.

CONCLUSION

We have shown that overjet was associated with the severity of OSAS in non-obese patients. Our findings suggest that malocclusion may play an important role in the development of sleep apnea/hypopnea.

Weight loss as a treatment for obstructive sleep apnoea

Obesity is a major health problem in well-developed societies. It is frequently associated with metabolic, cardiovascular and psychological comorbid conditions. Besides, it is known that obesity constitutes a risk factor for obstructive sleep apnoea (OSA). Weight loss has been evaluated as a treatment for OSA. We reviewed the nature of the link between obesity and OSA as well as the conservative and surgical therapeutic approaches of obesity. We consider the effectiveness of weight loss alone or combined with other modalities of treatment in OSA. We conclude that although weight loss is important and can facilitate the treatment of OSA, it can rarely cure it without being associated to classical techniques, such as nasal continuous positive airway pressure (nCPAP).

A comparison of responders and nonresponders to oral appliance therapy for the treatment of obstructive sleep apnea

INTRODUCTION

This retrospective study compared cephalometric variables between responders and nonresponders to a titratable oral appliance (OA) in a group of subjects matched for sex, pretreatment age, and body mass index (BMI).

METHODS

Nine nonresponders as defined by an improvement in the apnea hypopnea index (AHI; <20%) and their individually matched responders were selected for this study. The difference in age for each matched pair was +/-5 years, and, for BMI, the difference was +/-15%. The pretreatment AHI was matched to the same category (moderate, >15 to < or =30; severe I, >30 to < or =45; and severe II, >45 AHI).

RESULTS

Middle and inferior airway space and oropharyngeal airway cross-sectional area were significantly larger in the nonresponders. Position of the mandible relative to the cervical spine was the only significant skeletal variable and was larger in nonresponders. Changes in BMI between the groups were statistically significant; the averages were a 2.9% increase in the nonresponders and a 0.5% decrease in responders. The wider airway in nonresponders might reflect an enhanced neuromuscular compensation while awake. The weight gain in nonresponders was relatively small, but it might have reduced the effectiveness of the OA.

CONCLUSION

When treating OSA patients with OA therapy, clinicians should pay particular attention to airway size and weight changes.

Relationship between head posture and hyoid position in adult females and males

AIM

The aim of this study was to investigate head posture and hyoid bone position using cephalometric radiographs of adults.

MATERIAL AND METHODS

The material consisted of 76 cephalometric films (38 each male/female) taken at the natural head posture. The individuals were over 18 years of age, had parents of Turkish origin, an acceptable face structure, ideal dental occlusion, and an ANB angle of 1-5 degrees; the dentitions were complete except the third molars and there were no visual, hearing, breathing or swallowing disorders. In addition, the subjects had not undergone orthodontic treatment or orthognathic surgery, had no burns, injuries, or scars in the head and neck regions. In order to determine the natural head position, the subjects were asked to stand in a relaxed manner (the self-balance position), and this position was transferred to the cephalostat by means of a fluid level device. The differences among sexes were investigated by means of Student's t-test, carried out using SPSS (Windows 7.5).

RESULTS

It was found that there were no sex variations in head position. The linear measurements regarding the position of hyoid bone showed statistically significant differences with respect to sex. However, hyoid bone position was higher and more posterior in females, while natural head position was not affected by sex.

Effects of maxillary distraction osteogenesis on the upper-airway size and nasal resistance in subjects with cleft lip and palate

OBJECTIVES

To investigate the short- and long-term effects of maxillary distraction osteogenesis (DOG) on the upper-airway size and nasal resistance in nine patients with cleft lip and palate (CLP).

STUDY DESIGN

Changes in the upper-airway size were measured by using lateral cephalometric radiographs taken immediately before and after DOG, and 1 year later. Nasal resistance was measured with a rhinomanometer. An analysis of variance was used to establish statistical significance. Spearman correlation coefficient was used to evaluate the relationship between changes in the cross-sectional area of the upper airway and nasal resistance in association with DOG.

RESULTS

Immediately after DOG, the anteroposterior dimension of the superior part of the upper airway was significantly increased (p < 0.01) and nasal resistance was significantly decreased (p < 0.05). Moreover, the cross-sectional area of the total upper airway was significantly increased (p < 0.01). There was a significant correlation between the increase in the upper-airway cross-sectional area and the reduction in nasal resistance (p < 0.05). The upper-airway size was significantly augmented (p < 0.05) and nasal resistance was significantly reduced (p < 0.05) at 1 year after DOG compared with immediately before DOG.

CONCLUSION

An increase in the upper-airway size and a reduction in nasal resistance occurred after maxillary DOG in patients with CLP, and these changes were stable after 1 year.

Postural cephalometric analysis and nasal resistance in sleep-disordered breathing

OBJECTIVES

The study was designed to compare upright and supine cephalometric measurements in snorers and to evaluate the effects of mandibular position and nasal resistance on pharyngeal dimensions. Anthropometric, rhinomanometric, and cephalometric measurements were used to investigate predictors of apnea-hypopnea index.

STUDY DESIGN

Prospective, cross-sectional.

METHODS

Forty consecutive habitually snoring men waiting for nasal surgery (mean age, 44 y; mean body mass index, 28 kg/m2) underwent an overnight polysomnographic, anterior rhinomanometric, and cephalometric analysis in upright and supine positions.

RESULTS

Nasal resistance correlated positively with minimal pharyngeal airspace at the level of tongue. The opening of jaws after voluntary relaxation of the mandibular position on lying down correlated with decrease in pharyngeal airway measurements at both velopharyngeal and tongue-base levels. In stepwise multiple regression analysis the overall patient model explained 68% of the variation in apnea-hypopnea index with body mass index as the largest predictor. In the nonobese patients, the model explained 86% of variation in apnea-hypopnea index with change in anteroposterior position of the lower jaw in upright and supine measurements and combined nasal resistance after mucosal decongestion as independent determinants. In selected skeletal subtypes the models predicted 83%, 79%, 61%, and 90% of the variation in apnea-hypopnea index.

CONCLUSIONS

In the nonobese patients nasal resistance and change in mandibular position on lying down were found to be independent contributing factors to the apnea-hypopnea index. Further research on supine cephalometry and relaxed mandibular position may improve prediction of sleep-disordered breathing in snorers.

Frontal and Lateral Cephalometry in Patients With Sleep-Disordered Breathing

OBJECTIVES/HYPOTHESIS

The traditional lateral-view cephalometric analysis is limited because it provides only two-dimensional analysis of the three-dimensional craniofacial structure. The objectives were to analyze lateral and frontal cephalometric radiographs in a series of normal patients and those with varying degrees of sleep-disordered breathing and to define the degrees of narrowing or other unfavorable anatomical changes that might differentiate the patients with sleep-disordered breathing from normal subjects.

STUDY DESIGN

A prospective study of 100 adult patients with sleep-disordered breathing and 60 age-matched normal subjects.

METHODS

An analysis of the lateral and frontal cephalometric measurements was performed to assess velopharyngeal anatomical features. A comparison was made between the patients' polysomnographic and cephalometric analyses.

RESULTS

The compromised cephalometric parameters that may be found in patients with sleep-disordered breathing include acute skull-base and bony nasopharynx angles, inferior hyoid position, thickening of the velum, reduced retrovelar posterior air space along with thickening of the velum, thickening of the posterior pharyngeal wall, and narrowing of the velopharyngeal lumen. Worsening of sleep-disordered breathing was generally associated with increased numbers of compromised cephalometric parameters. As body mass index increases, there is reduced velopharyngeal width, the velum thickness is increased, and the posterior pharyngeal wall thickness is increased.

CONCLUSIONS

Sleep-disordered breathing is associated with statistically significant changes in a number of cephalometric measurements. Frontal cephalometric analysis adds further information regarding the anatomical assessment of patients with upper airway obstruction, enhancing the traditional lateral cephalometric view.

Differential diagnosis of obstructive sleep apnea syndrome patients and snorers using cephalograms

Severe snoring is thought by many to be an early stage of obstructive sleep apnea syndrome (OSAS), but the anatomical relation between snoring and OSAS, if any, has remained unclear. To compare the morphology of the airway between snorers and OSAS patients for possible similarities, we conducted a cephalometric analysis of Japanese OSAS patients (n=10), habitual snorers (n=10), and non-snoring controls (n=50). There was no significant difference in SNB (the angle formed by the sella, nasion and point B) between OSAS patients and the control subjects. Obstructive sleep apnea syndrome patients tended to have an anteriorly positioned maxilla, and an anteroposterior misalignment between the maxilla and mandible. There was also a tendency toward skeletal openbite. Both OSAS patients and snorers had large tongues and large soft palates, thus causing constriction of the airway with resultant smaller airway diameter and smaller airway surface area. Significant differences between OSAS patients and snorers were found in thickness and length of soft palate surface area, and thickness, length, and position of the hyoid bone. These results suggest that cephalographic measurements may be of considerable use in determining the seriousness of a patient's condition.

Does caffeine confound relationships among adrenergic tone, blood pressure and sleep apnoea?

The purpose of this study was to determine whether caffeine consumption confounds the relationship among adrenergic tone, as measured by urinary norepinephrine (NE), blood pressure (BP) and obstructive sleep apnoea (OSA). Data were analysed using correlation and regression analysis, analysis of covariance and t-tests. Subjects included normotensives and hypertensives with and without OSA: 38 men, 23 women, aged 30-60 y; 100-150% of ideal body weight; without other major illness. Patients were studied using polysomnography, caffeine consumption was assessed, 24-h urinary NE levels were examined and ambulatory BP was recorded. Patients with OSA (N=27) reported significantly greater caffeine consumption than those without OSA (N=34) (295 vs. 103 mg, P=0.010), but caffeine was not significantly correlated with their ambulatory BP. In contrast, NE excretion correlated with caffeine consumption (r=0.24, P=0.041), apnoea severity (r=0.65, P < 0.001) and BP (r=0.34, P < 0.005). Significant OSA-NE and BP-NE relationships remained even after controlling for caffeine consumption. Patients with OSA consumed nearly three times the amount of caffeine as patients without OSA. While caffeine partially explains the increased adrenergic tone in patients with OSA and the relationship between BP and NE, it does not appear to contribute significantly to the relationship between OSA and elevated BP.

Dental considerations in upper airway sleep disorders: A review of the literature

STATEMENT OF PROBLEM

Upper airway sleep disorders are becoming recognized as common medical concerns. Multiple treatment options have been advocated, including the use of dental devices. Dental practitioners are being asked by the medical profession to become a part of the treatment team. This may be a challenging task because of the large number of dental devices available, rapid advancement in the understanding of this disease, and numerous publications.

PURPOSE

This article reviews the anatomic features and etiologic factors of upper airway sleep disorders and medical and dental treatment options.

METHODS

The literature review was conducted with an accepted literature research tool, PubMed, developed by the National Library of Medicine. Key words searched included "obstructive sleep apnea," "sleep apnea," "sleep disorders," and "snoring".

CONCLUSION

Dental devices are indicated in snoring and mild-to-moderate obstructive sleep apnea patients after medical evaluation and referral.

Sudden unexpected death in epilepsy (SUDEP): a clinical perspective and a search for risk factors

OBJECTIVES

To examine the risk factors and their relative importance and possible role in sudden unexpected death in epilepsy (SUDEP).

METHODS

The study was conducted as a retrospective analysis of deaths in an outpatient population of a tertiary referral centre, based on clinical and pathological data.

RESULTS

Of a total of 140 deaths, 61 (44%) had not been to postmortem and were excluded, 37 (26%) had a verified cause of death and formed the non-SUDEP group, and 42 (30%) were classified as SUDEP. In the SUDEP group there was pulmonary oedema in 62%, signs of preceding seizures in 67%, no visible seizures in three of six observed deaths. A high seizure frequency prevailed in SUDEP as well as non-SUDEP. Sixty per cent of deaths were sleep related. Various other circumstances were temporally associated with death. The prone position at death was seen in 71% of the SUDEP patients; possible interpretations are discussed. Supposedly subtherapeutic serum concentrations of one or more antiepileptic drugs were found in 57% of those with reported serum concentrations. Alcohol was not a factor in the material, whereas hyponatraemia was seen in two cases.

CONCLUSIONS

Most cases of SUDEP are preceded by seizures; their presence, frequency, type, aetiology, tractability, and the use of antiepileptic drugs are factors in the demise. No common risk factor, present in all cases of SUDEP, could be found, suggesting the probability of multiple mechanisms behind SUDEP.