Facial structure in the sudden infant death syndrome: case-control study

The Ogival Palate: A New Risk Marker of Sudden Unexpected Death in Infancy?

OBJECTIVE

Ogival palate (i.e., a narrow and high-arched palate) is usually described in obstructive breath disorder but has been found in infants unexpectedly deceased. We studied the association between ogival palate and sudden unexpected death in infancy (SUDI) on the basis of a computed tomography (CT) evaluation.

METHODS

We conducted a monocentric case-control study of children under 2 years of age who died of SUDI, for which a head CT scan and an autopsy were performed between 2011 and 2018. Each case was matched by sex and age (± 30 days) to two controls selected among living children in the same center who benefited from a cranio-encephalic CT scan. Four parameters of the hard palate were measured by CT: height, width, length, and sagittal angle; the height/width ratio was calculated. The presence of an ogival palate was also subjectively evaluated by the radiologists, independently from the measurements. Standardized odds ratios (OR) were calculated using conditional logistic regression models, all expressed for +1 standard deviation (SD).

RESULTS

Thirty-two deceased children were matched to 64 living control children. Mean ages were 5.0 and 5.3 months, respectively. Twenty-eight cases were considered to have died as a result of SIDS. The mean heights of the hard palate were significantly higher in the deceased children [4.1 (± 0.7) millimeters (mm)] than in the living children [3.2 (± 0.6) mm], with OR (+1SD) = 4.30 (95% confidence interval [CI], 2.04-9.06, P = 0.0001). The mean widths of the hard palate were 21.0 (± 1.9) mm and 23.2 (± 2.1) mm, respectively, with OR = 0.15 (95% CI, 0.06-0.40, P = 0.0001). The mean sagittal angles were significantly more acute in deceased children [134.5° (± 9.3)] than in living children [142.9° (± 8.1)], with OR = 0.28 (95% CI, 0.14-0.56, P = 0.0003). The mean height/width ratios were 19.8 (± 3.7) and 14.1 (± 3.3), respectively, with OR = 6.10 (95% CI, 2.50-14.9, P = 0.0001). The hard palate was subjectively considered as ogival in 59.4% (19/32) of the cases versus 12.5% (8/64) of the controls.

CONCLUSION

Radiological features of the ogival palate were strongly associated with SUDI. This observation still needs to be confirmed and the corresponding clinical features must be identified.

Gene variants associated with obstructive sleep apnea (OSA) in relation to sudden infant death syndrome (SIDS)

Background

Both obstructive sleep apnea (OSA) and (at least a fraction of) sudden infant death syndrome (SIDS) are associated with impaired respiration. For OSA, an association with several gene variants was identified. Therefore, our hypothesis is that these polymorphisms might be of relevance in SIDS as well.

Methods

Twenty-four single nucleotide polymorphisms (SNPs) in 21 candidate genes connected to OSA, were genotyped in a total of 282 SIDS cases and 374 controls. Additionally, subgroups based on factors codetermining the SIDS risk (age, sex, season, and prone position) were established and compared as well.

Results

Two of the analyzed SNPs showed nominally significant differences between SIDS and control groups: rs1042714 in ADRB2 (adrenoceptor beta 2) and rs1800541 in EDN1 (endothelin 1). In the subgroup analyses, 10 further SNPs gave significant results. Nevertheless, these associations did not survive adjustment for multiple testing.

Conclusions

Our results suggest that there might be a link between SIDS and OSA and its resulting respiratory and cardiovascular problems, albeit this predisposition might be dependent on the combination with other, hitherto unknown gene variants. These findings may encourage replication studies to get a better understanding of this connection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00414-020-02480-0.

Study of the growth and shape of the brain and cranial base during the first two years of life

Ontogeny of the cranial base and the brain integrates data on growth, maturation and ontogenetic allometry of these two systems in the course of development. The aim of our work was to study the ontogeny of the cranial base and the brain in order to understand their growth dynamic and shape changes using a traditional morphometric approach in individuals with normal (non-pathological) development.

MATERIEL AND METHOD

Forty-seven infants having been included in the unexpected infant death french protocol were analyzed. Medical imaging (CT and MRI) exams, followed by an autopsy and pathology examination allowed us to include only infants free from brain disease or pathology affecting growth.

RESULTS

Testing of measurement reliability validated 12 distances and 3 angles as well as the positioning of the landmarks that had been used to obtain the distances and the angles. No correlation between sex and the various variables studied was found. However, a correlation was observed between these variables and age, making it possible to propose a growth curve. A medium to strong correlation was found between brain variables and the bone variables of the cranial base, underlining the parallel development of the two systems.

CONCLUSION

Our study, carried out in a rigorously selected population of infants, presents a fundamental approach to the study of ontogenesis.

Pediatric sleep-disordered breathing: New evidence on its development

Sleep-disordered breathing (SDB) in children could be resolved by adenotonsillectomy (T&A). However, incomplete results are often noted post-surgery. Because of this partial resolution, long-term follow-up is needed to monitor for reoccurrence of SDB, which may be diagnosed years later through reoccurrence of complaints or in some cases, through systematic investigations. Children undergoing T&A often have small upper airways. Genetics play a role in the fetal development of the skull, the skull base, and subsequently, the size of the upper airway. In non-syndromic children, specific genetic mutations are often unrecognized early in life and affect the craniofacial growth, altering functions such as suction, mastication, swallowing, and nasal breathing. These developmental and functional changes are associated with the development of SDB. Children without genetic mutations but with impairment of the above said functions also develop SDB. When applied early in life, techniques involved in the reeducation of these functions, such as myofunctional therapy, alter the craniofacial growth and the associated SDB. This occurs as a result of the continuous interaction between cartilages, bones and muscles involved in the growth of the base of the skull and the face. Recently collected data show the impact of the early changes in craniofacial growth patterns and how these changes lead to an impairment of the developmental functions and consequent persistence of SDB. The presence of nasal disuse and mouth breathing are abnormal functions that are easily amenable to treatment. Understanding the dynamics leading to the development of SDB and recognizing factors affecting the craniofacial growth and the resulting functional impairments, allows appropriate treatment planning which may or may not include T&A. Enlargement of lymphoid tissue may actually be a consequence as opposed to a cause of these initial dysfunctions.

Death, nasomaxillary complex, and sleep in young children

This is an investigation of anatomical and sleep history risk factors that were associated with abrupt sleep-associated death in seven children with good pre-mortem history. Seven young children with abrupt deaths and information on health status, sleep history, death scene report, and autopsy performed in a specialized unit dedicated to investigation of abrupt death in young children were investigated Seven age and gender matched living children with obstructive-sleep-apnea (OSA) were compared to the findings obtained from the dead children. Two deaths results from accidents determined by the death scene and five were unexplained at the death scene. History revealed presence of chronic indicators of abnormal sleep in all cases prior death and history of an acute, often mild, rhinitis just preceding death in several. Four children, including three infants, were usually sleeping in a prone position. Autopsy demonstrated variable enlargement of upper airway soft tissues in all cases, and in all cases, there were features consistent with a narrow, small nasomaxillary complex, with or without mandibular retroposition. All children were concluded to have died of hypoxia during sleep. Our OSA children presented similar complaints and similar facial features. Anatomic risk factors for a narrow upper airway can be determined early in life, and these traits are often familial. Their presence should lead to greater attention to sleep-related complaints that may be present very early in life and indicate impairment of well been and presence of sleep disruption. Further investigation should be performed to understand the role of upper airway infection in the setting of anatomically small airway in apparently abrupt death of infants and toddlers.

Otolaryngological aspects of sudden infant death syndrome

INTRODUCTION

Sudden infant death syndrome (SIDS) is characterized by the sudden death of an apparently otherwise healthy infant, typically during sleep, and with no obvious case after a thorough post-mortem and scene death examination.

OBJECTIVE

To address the problem from the otolaryngologist's perspective, describe relevant pathologies, discuss controversies and suggest preventive measures in high-risk populations.

METHODOLOGY

A MEDLINE search and hand search were conducted to identify reports published between 1969 and 2011 in the English language on the pathophysiology of SIDS related to the head and neck organs. Search terms included SIDS (MeSH term), SIDS and pathophysiology (text words), and SIDS and autopsy (text words).

DISCUSSION

A growing number of reports suggested head and neck organs involvement in SIDS autopsies. Laryngeal, oropharyngeal, maxillofacial, otologic, cervical vascular abnormalities and infectious etiologies, were recognized and discussed.

CONCLUSIONS

Otolaryngologists should be aware of relevant pathologies, as some are treatable, if identified early enough in infancy. A proactive risk-management approach is warranted in infants presenting with certain abnormalities reviewed here.

The role of respiratory control disorders in SIDS

Although sudden death in infants resulting from cardiac arrhythmias are well documented these appear to account for no more than 5-10% of SIDS cases. Sudden respiratory failure currently is viewed as the most likely cause of death in the remainder. Accidental asphyxiation appears to have a causal role in less then 50% of deaths diagnosed as SIDS. The rest are most likely do to some form of acute respiratory failure. Although failure of autoresuscitation or failure to arouse from sleep likely contribute to the final sequence of events leading to at least some SIDS deaths, these cannot be regarded as causes of the primary respiratory failure initiating the fatal sequence. Past and current studies provide strong circumstantial evidence that obstructive sleep apnea and/or apnea of prematurity likely account for respiratory failure leading to SIDS in some or many deaths. In drawing conclusions it is well to recognize that mechanisms leading to death in SIDS are heterogeneous and therefore there is room for several plausible theories for respiratory or circulatory abnormalities contributing to SIDS.

Is there a familial association between obstructive sleep apnoea/hypopnoea and the sudden infant death syndrome?

BACKGROUND

One postulated cause of the sudden infant death syndrome (SIDS) is upper airway obstruction during sleep. Several studies have suggested that SIDS may be more common in families with obstructive sleep apnoea/hypopnoea syndrome (OSAHS), but were limited by uncertainty as to whether the deaths were due to SIDS. We have tested the hypothesis that parents of true SIDS cases have an increased frequency of apnoeas and hypopnoeas during sleep.

METHODS

The parents of 269 rigorously determined SIDS cases were invited for single night polysomnography and daytime ventilatory control measurement.

RESULTS

Parents of 198 cases were identified but 152 did not respond or declined. Fifty five parents of 34 cases were studied and matched for age, height, and weight to 55 subjects from general practice registers. There was no difference in breathing during sleep between the parents of SIDS cases (median (IQR) 5.9 (3.2, 10.7) apnoeas+hypopnoeas/h) and controls (6.7 (4.0, 12.2) apnoeas+hypopnoeas/h; p = 0.47), but the SIDS parents had lower minimum nocturnal oxygen saturation (median (IQR) 92 (89, 93)%) than controls (92 (90, 94)%; p = 0.048). There were no major differences in control of breathing when awake between SIDS parents and controls.

CONCLUSIONS

These results provide no evidence to support an association between SIDS and OSAHS. However, the minor impairment of oxygenation during sleep in SIDS parents requires further study.

Familial predisposition and cosegregation analysis of adult obstructive sleep apnea and the sudden infant death syndrome

Previous studies suggest a familial link between adult obstructive sleep apnea syndrome (OSAS) and sudden infant death syndrome (SIDS). However, most of these studies were hampered by the availability of too few cases of SIDS to draw conclusions. To examine the familial nature of this association in Iceland, hospital-based lists of all patients who were diagnosed with OSAS (n = 2,350) and SIDS (n = 58) from 1979 to 1998 were used to separately determine the familial occurrence of OSAS and SIDS and to search for evidence of cosegregation of these conditions in Icelandic families, using a nationwide genealogy database. The risk ratio for a first-degree relative of a patient with OSAS was 2.0 (1.7-2.8, 95% confidence interval). The risk ratio of the more severely affected patients with OSAS was slightly higher (2.3). Likewise, the kinship coefficient (KC) for the OSAS patient group, which determines the relatedness of the patients, was significantly larger than the mean KC of 1,000 matched control groups. Estimation of the KC for the SIDS group showed a trend toward significance when compared with control groups, but after excluding one of the half-siblings in the SIDS group from the analysis, the difference did not show any trend toward significance. Although the results of the analysis of the relatedness between all patients with OSAS and infants who died of SIDS were not significant, a trend toward significance was evident when the data were separately analyzed for the more severely affected patients with OSAS. Collectively, these results demonstrate a strong familial component in OSAS and suggest that infants who died of SIDS may have shared some of the same susceptibility factors with OSAS.

A review of the anatomy of the upper airway in early infancy and its possible relevance to SIDS

BACKGROUND

Since the danger of prone sleeping in the first 6 months of life has been publicised, there has been a dramatic and consistent reduction in the incidence of sudden infant death syndrome (SIDS). However, unexpected infant deaths and apparent life-threatening events (ALTEs) continue to occur that are clearly not associated with known epidemiological risk factors.

AIMS

To review the unique features of the anatomy and function of the upper airway of the young infant which contribute to increased vulnerability to hypoxia in this age group. We discuss the clinical identification of those infants at risk of obstruction or restriction of the upper airway and the management of the 'at risk' infant.

CONCLUSIONS

In the era after the "back to sleep" campaigns, it is likely that an increasing proportion of cases of ALTEs and SIDS will be related to obstruction or limitation of upper airway size leading to sleep hypoxia/asphyxia. This type of problem may be anticipated by evaluation and investigation of infants with signs or a clinical history consistent with possible upper respiratory tract compromise, including micrognathia.

Randomized controlled study of an oral jaw-positioning appliance for the treatment of obstructive sleep apnea in children with malocclusion

To evaluate the clinical usefulness and tolerability of an oral jaw-positioning appliance in the treatment of obstructive sleep apnea syndrome in children, we studied 32 patients (mean age, 7.1 +/- 2.6 yr; 20 males) with symptoms of obstructive sleep apnea, malocclusion, and a baseline apnea index > 1 event/h. A group of 19 subjects was randomly assigned to a 6-mo trial of an oral appliance; the remainder acted as control subjects. At baseline and after the trial all patients underwent physical examination, a standard polysomnography, and orthodontic assessment. A modified version of the Brouillette questionnaire related to obstructive sleep apnea symptoms was administered to parents before and after the trial and a clinical score was calculated. Of the 32 subjects enrolled, 4 treated subjects and 5 control subjects were lost to follow-up. Polysomnography after the trial showed that treated subjects all had significantly lower apnea index (p < 0.001) and hypopnea index values (p < 0.001) than before the trial, whereas in untreated control subjects these values remained almost unchanged. Clinical assessment before and after treatment showed that in 7 of the 14 subjects (50%) the oral appliance had reduced (a fall of at least 2 points in the respiratory score) and in 7 had resolved the main respiratory symptoms, whereas untreated patients continued to have symptoms. In conclusion, treatment of obstructive sleep apnea syndrome with an oral appliance in children with malocclusion is effective and well tolerated.

Review of risk factors for sudden infant death syndrome

Sudden infant death syndrome (SIDS) accounts for the largest number of deaths during the first year of life in developed countries. The possible causes of SIDS are numerous and, to date, there is no adequate unifying pathological explanation for SIDS. Epidemiological studies have played a key role in identifying risk factors, knowledge of which has underpinned successful preventive programmes. This review critically assesses information on the main risk factors and causal hypotheses put forward for SIDS, focusing on research published since 1994. The overall picture that emerges from this review is that affected infants are not completely normal in development, but possess some inherent weakness, which may only become obvious when the infant is subjected to stress. Initially there may be some minor impairment or delay in development of respiratory, cardiovascular or neuromuscular function. None of these is likely to be sufficient, in isolation, to cause death and, provided the infant survives the first year of life, may no longer be of any significance. However, when a compromised infant is confronted with one or more stressful situations, several of which are now clearly identified as risk factors, and from which the majority of infants would normally escape, the combination may prove fatal.

Obstructive sleep apnea in infants: relation to family history of sudden infant death syndrome, apparent life-threatening events, and obstructive sleep apnea

OBJECTIVES

Familial aggregation of obstructive sleep apnea (OSA) has been shown to be associated with sudden infant death syndrome (SIDS) and apparent life-threatening events (ALTE) in infants. We wanted to determine the incidence of OSA in infants with siblings with ALTE and SIDS referred to our sleep clinic and to ascertain whether OSA was more common in infants who have family histories of SIDS, ALTE, and OSA.

STUDY DESIGN

We studied 125 infants (mean age, 11.5 +/- 0.6 weeks) who were separated into 2 groups on the basis of their family history; polysomnographic studies were performed on each infant.

RESULTS

Twenty infants had a multiple family history of SIDS, ALTE, or OSA (group 1), whereas the other 105 infants (group 2) had only one case of SIDS or ALTE within the family and no known history of OSA. We found that 19 of 20 infants in group 1 had OSA, whereas only 31 of 105 infants in group 2 had OSA (chi-squared analysis, P <.05). The OSA recorded was more frequent in infants of group 1 than in those of group 2. Follow-up studies in some infants with OSA demonstrated a progressive decrease in OSA, which resolved between 6 and 12 months of age.

CONCLUSION

We conclude that infants of families with multiple histories of SIDS, ALTE, and OSA are more likely to have OSA than infants of families with only one case of SIDS or ALTE.