Chiari malformation and sleep related breathing disorders

Type one chiari malformation as a cause of central sleep apnea and hypoventilation in children

OBJECTIVES

Chiari type 1 malformation (CM1) may occasionally lead to central sleep apnea (CSA). We studied, in a large clinical cohort of pediatric CM1 patients, the effect of CM1 on breathing during sleep.

METHODS

This is a retrospective single pediatric pulmonology center study with a systematic evaluation of pediatric CM1 patients under age 18 with polysomnography (PSG) during 2008-2020. Children with syndromes were excluded. All patients had undergone head and spine magnetic resonance imaging.

RESULTS

We included 104 children with CM1 with a median age of 7 (interquartile range (IQR) 5-13) years. The median extent of tonsillar descent (TD) was 13 (IQR 10-18) mm. Syringomyelia was present in 19 children (18%). Of all children, 53 (51%) had normal PSG, 35 (34%) showed periodic breathing or central apnea and hypopnea index ≥5 h-1, and 16 (15%) displayed features of compensated central hypoventilation and end-tidal or transcutaneous carbon dioxide 99th percentile level above 50 mmHg. TD had the best predictive value for central breathing disorders. In a linear model, both age (61%) and TD (39%) predicted median breathing frequency (R = 0.33, p < 0.001).

CONCLUSIONS

Although severe CSA is a rare complication of brainstem compression in pediatric patients with CM1, short arousal-triggered episodes of periodic breathing and mild compensated central hypoventilation are common. TD shows the best but still poor prediction of the presence of a central breathing disorder. This highlights the use of PSG in patient evaluation. Posterior fossa decompression surgery effectively treats central breathing disorders.

The utility of poly(somno)graphy in evaluating children with Chiari malformation type II before and after surgical intervention: a case series

BACKGROUND

Children with Chiari Malformation type II (CM-II) have an increased risk of sleep apnoea. The aim of the study was to describe the management of patients with CM-II in relation to sleep apnoea syndrome, clinical symptoms and magnetic resonance imaging (MRI) findings.

CASE SERIES PRESENTATION

The paper reports 8 consecutive patients with CM-II followed between September 2013 and April 2017. The prevalence of sleep apnoea syndrome was high with 6 out of 8 patients having mild-to-severe sleep apnoea. Patients with severe sleep apnoea syndrome (3 patients) were treated with upper airway surgery and/or noninvasive ventilation.

CONCLUSION

Our findings highlight the importance of respiratory polygraphy in the management of patients with CM-ΙΙ. Poly(somno)graphy is recommended in the follow-up care of children with CM-II.

Impact of Spina Bifida on Sleep Quality: Current Insights

Spina bifida (SB) is one of the most common birth defects in children. The care for patients with SB continues to evolve, and there has been notable improvement in survival outcomes, degree of disability and quality of life for these children. However, patients with SB continue to remain at higher risk for sleep-related breathing disorders (SRBD), unexplained sudden death, and potential alterations in their sleep chronotype. Previous studies report on abnormalities in the spinal cord, brainstem function, and dysfunction of upper airway maintenance as the likely mechanisms behind SRBD that is commonly seen in SB. Most studies looking at prevalence of SRBD in SB have been retrospective studies. A recent prospective study identified a prevalence as high as 42% when a polysomnography (PSG) was completed on all patients regardless of symptomatology. Treatment options vary depending on the type and severity of SRBD and can range widely. Despite advances in care for patients with SB and SRBD, a subset of these patients with myelomeningocele (MMC) continue to experience sudden unexplained death. Studies continue to evaluate ways to stratify which of these patients may be at higher risk of this devastating outcome. Given that SRBD is potentially treatable, early assessment and intervention could become an integral part of a multidisciplinary treatment strategy to optimize long-term medical and neurodevelopmental outcomes for this patient population. By understanding the impact that SB may have on a patient's sleep quality, their biological chronotype and their potential of developing SRBD, a provider may help to optimize the care a patient with SB receives from birth into adulthood.

Protracted respiratory failure in a case of global spinal syringomyelia and Chiari malformation following administration of diazepam: illustrative case

BACKGROUND

Syringomyelia is defined as dilation of the spinal cord's central canal and is often precipitated by skull base herniation disorders. Although respiratory failure (RF) can be associated with skull base abnormalities due to brainstem compression, most cases occur in pediatric patients and quickly resolve. The authors report the case of an adult patient with global spinal syringomyelia and Chiari malformation who developed refractory RF after routine administration of diazepam.

OBSERVATIONS

A 31-year-old female presented with malnutrition, a 1-month history of right-sided weakness, and normal respiratory dynamics. After administration of diazepam prior to magnetic resonance imaging (MRI), she suddenly developed hypercapnic RF followed MRI and required intubation. MRI disclosed a Chiari malformation type I and syrinx extending from C1 to the conus medullaris. After decompressive surgery, her respiratory function progressively returned to baseline status, although 22 months after initial benzodiazepine administration, the patient continues to require nocturnal ventilation.

LESSONS

Administration of central nervous system depressants should be closely monitored in patients with extensive syrinx formation given the potential to exacerbate diminished central respiratory drive. Early identification of syrinx in the context of Chiari malformation and hemiplegia should prompt clinical suspicion of underlying respiratory compromise and early involvement of intensive care consultants.

The Chiari Malformations: A Bibliometric Analysis of the 100 Most Cited Articles

OBJECTIVE

The Chiari malformations present heterogeneous entities, raising many questions regarding their natural history, pathophysiology, treatment options, and prognosis. Bibliometric analyses have emerged as a method to assess the impact of articles in current clinical practice.

METHODS

The most cited articles were identified via Scopus Library by using the keywords "Chiari," "Arnold-Chiari," and "Chiari malformation." The 100 most cited articles were then assembled and analyzed in detail.

RESULTS

The top 100 articles yielded a mean of 155,28 citations per article, ranging from 87 to 896 citations, and from 1.63 to 38.96 per year. Years of publications ranged from 1950 to 2015. Oakes was the most cited author (n = 7), followed by Tubbs and Milhorat. The country with the highest cited articles was the United States (n = 63), followed by the United Kingdom (n = 6), Italy (n = 5), Spain (n = 5), Japan (n = 4), and Germany (n = 3). Neurosurgery is the journal with the most highly cited articles (n = 21), followed by Journal of Neurosurgery (n = 19). Most articles focused on Chiari malformation type I (n = 83). The topic discussed most often was imaging (n = 63), followed by the evaluation of treatment outcome (n = 58), clinical signs and symptoms (n = 57), and the role of surgery (n = 56).

CONCLUSIONS

The present bibliometric analysis provides a succinct appraisal of the most cited articles concerning Chiari malformation, allowing a deeper insight in this area and its main influential articles with their impact on current clinical practice and future research.

Impact of sleep-disordered breathing on the management of children with Chiari malformation type I

OBJECTIVES

Children with Chiari malformation type I (CM-I) have an increased risk of sleep apnea. The aim of the study was to describe the management of CM-I patients in relation to symptoms, magnetic resonance imaging (MRI) findings and sleep apnea syndrome (SAS).

METHODS

We performed a retrospective analysis of clinical charts of all 57 CM-I patients seen between September 2013 and April 2017.

RESULTS

A total of 45 patients had isolated CM-I or associated co-morbidity (CM-Iia), 5 had craniosynostosis (CM-Ics), and 7 a polymalformative syndrome (CM-Ipm). The prevalence of SAS, defined as an apnea-hypopnea index >1 event/h, was high in CM-I ranging from 50% to 80% according to the CM-I group. The prevalence of central sleep apnea (CSA) was low, with 5 (9%) patients having CSA and only 3 patients with CM-Iia having isolated CSA. A total of 17 patients (30%) had foramen magnum decompression (FMD). Neither positive symptoms of CM-I nor MRI findings alone, nor both combined were good indicators for FMD. No correlation was observed between the cerebellar tonsil descent and SAS in CM-I. But all 5 patients with CSA had a FMD. The combination of MRI findings and/or symptoms of CM-I together with moderate-to-severe SAS best discriminated patients who needed a FMD.

CONCLUSION

Our findings highlight the importance of a combined evaluation of symptoms, MRI and polygraphy results in the management of CM-I patients.

Social impairment and snoring: a unique presentation of pediatric Chiari I malformation

Symptomatic progression of Chiari malformation type 1 (CM-1) can be difficult to recognize in children because of the slow progressive nature of the disorder and highly varied neurological symptoms. We present a case of an obese 11-year-old girl seeking an evaluation of snoring. Progressive social impairment and academic difficulties were also endorsed. The past medical history was remarkable for absence seizures at an earlier age with an incidental finding of CM-1 on brain imaging. No headaches, vision changes, or swallowing dysfunction were endorsed in the acute presentation. The patient underwent a polysomnogram, which revealed the unexpected finding of severe central sleep apnea. Magnetic resonance imaging of the brain revealed further herniation of the cerebellar tonsils and a cervical syrinx, which was not present on initial imaging. Posterior fossa decompression resulted in the successful resolution of symptoms. It was postulated that the social impairment and academic problems were manifestations of CM-1. There are no current standard protocols for disease surveillance of pediatric CM-1. Annual polysomnograms may serve as a useful tool.

CITATION

Kanney ML, Spear J, Hsu DP. Social impairment and snoring: a unique presentation of pediatric Chiari I malformation. J Clin Sleep Med. 2022;18(12):2867-2870.

Sleep-disordered breathing in patients with Chiari malformation type II: a case-control study and review of the literature

STUDY OBJECTIVES

The main aim was to evaluate the prevalence of sleep-disordered breathing (SDB) in patients with Chiari II malformation (CM-II). The secondary objectives were to evaluate the association between SDB, morphological abnormalities, and neurological symptoms and to review the literature on patients with SDB and CM-II.

METHODS

The study has a cross-sectional, case-control design. Patients with CM-II (patients) were compared to control patients referred for clinical polysomnography in the Sleep Medicine Unit, matched for age and sex. All patients underwent brain and spinal cord magnetic resonance imaging, and polysomnography was conducted for all participants. A review of the literature about SDB in patients with CM-II was performed.

RESULTS

Forty patients were included (20 patients vs 20 control patients). SDB was identified in 45% of patients, a significantly higher prevalence compared to control patients. Three patients presented with purely obstructive SDB, 3 patients with purely central SDB, and 3 patients with both obstructive and central SDB. Compared with control patients, patients with CM-II showed a higher oxygen desaturation index (median: CM-II, 3.7; interquartile range, 1.6-19.5; control patients: 1.1; interquartile range, 0.3-3.2) and obstructive apnea-hypopnea index (median: CM-II, 1.5; interquartile range, 0.5-5.1; control patients, 0.1; interquartile range, 0.0-0.7). A logistic regression showed that the risk of developing SDB in patients affected by CM-II was 14.7 times higher than in the control population.

CONCLUSIONS

Our study and literature review showed a high prevalence of SDB in patients with CM-II. These patients are often asymptomatic at diagnosis, suggesting that PSG should be routinely provided in this population.

CITATION

Lazzareschi I, Curatola A, Massimi L, et al. Sleep-disordered breathing in patients with Chiari malformation type II: a case-control study and review of the literature. J Clin Sleep Med. 2022;18(9):2143-2154.

Obstructive Sleep Apnea in Underweight Children

OBJECTIVES

To determine predictors of obstructive sleep apnea (OSA) in underweight children and to describe the demographic, clinical, and polysomnographic characteristics of an ethnically diverse population of underweight children with OSA.

STUDY DESIGN

Case-control study.

SETTING

University of Texas Southwestern Medical Center and Children's Medical Center of Dallas.

METHODS

Underweight children aged 2 to 18 years who underwent a polysomnogram for suspected OSA between January 2014 and December 2020 were included. Underweight was defined as body mass index <5th percentile per Centers for Disease Control and Prevention guidelines. Children with apnea-hypopnea index <1.0 served as a control group. Univariate and multiple logistic regression analysis was used to determine the predictors of OSA. Significance was set at P < .05.

RESULTS

An overall 124 children met inclusion criteria: mean age, 6.4 years; 50% female; 44% Hispanic, 31% African American, and 18% Caucasian. A total of 83 children had OSA (apnea-hypopnea index ≥1.0). Height was negatively correlated with OSA (odds ratio, 0.94; 95% CI, 0.88-0.99; P = .02) while allergic rhinitis (odds ratio, 2.97; 95% CI, 1.24-7.08; P = .01) and tonsillar hypertrophy (odds ratio, 3.38; 95% CI, 1.42-8.02; P = .01) were predictors for the presence of OSA. No demographic or clinical characteristics were predictors for severe OSA.

CONCLUSION

Underweight children with OSA, as compared with those without OSA, are more likely to have decreased height, tonsillar hypertrophy, and allergic rhinitis. There are no predictors of severe OSA in underweight children. We recommend polysomnography for the diagnosis of OSA in symptomatic underweight children with large tonsils, especially when they have a history of allergies.

Chiari Malformation in Children

Chiari malformation type 1 (CM1) is often found incidentally. However, patients with symptoms or signs referable to CM1 or an associated syrinx will likely benefit from surgical intervention. Patients who are not symptomatic from CM1 at presentation are unlikely to become symptomatic at follow-up.

A case of hypercapnic respiratory failure

A 55-year-old man was referred to the department of respiratory disease with a polycythaemia. Underlying haematological disease was already excluded. Blood results are shown in table 1.

A systematicwork-up is important in case of hypercapnia. Pay attention to the shape of the flow–volume curve and any abnormal breathing sounds. In case of stridor, vocal cord paralysis should be suspected and, if confirmed, neurological investigations are advised.https://bit.ly/34APMi8

Central apnea and periodic breathing in children with underlying conditions

Central sleep apneas and periodic breathing are poorly described in childhood. The aim of the study was to describe the prevalence and characteristics of central sleep apnea and periodic breathing in children with associated medical conditions, and the therapeutic management. We retrospectively reviewed all poly(somno)graphies with a central apnea index ≥ 5 events per hr in children aged > 1 month performed in a paediatric sleep laboratory over a 6‐year period. Clinical data and follow‐up poly(somno)graphies were gathered. Ninety‐five out of 2,981 patients (3%) presented central sleep apnea: 40% were < 1 year, 41% aged 1–6 years, and 19% aged ≥ 6 years. Chiari malformation was the most common diagnosis (13%). Mean central apnea index was 20 ± 30 events per hr (range 5–177). Fifty‐eight (61%) children had an exclusive central pattern with < 5 obstructive events per hr. Periodic breathing was present in 79 (83%) patients, with a mean percentage of time with periodic breathing of 9 ± 16%. Among periodic breathing episodes, 40% appeared after a sigh, 8% after an obstructive event, 6% after breathing instability and 2% after bradypnea. The highest clinical apnea index and percentage of time with periodic breathing were observed in children with encephalopathy and/or epilepsy (68 ± 63 events per hr and 30 ± 34%). Clinical apnea index did not differ according to age, while periodic breathing duration was longer in children > 1 year old. Watchful waiting was performed in 22 (23%) patients with spontaneous improvement in 20. Other treatments (upper airway or neurosurgery, nocturnal oxygen therapy, continuous positive airway pressure, non‐invasive ventilation) were effective in selected patients. Central sleep apnea is rare in children and comprises heterogeneous conditions. Sleep studies are essential for the diagnosis, characterization and management of central sleep apnea.

The efficacy of neurosurgical intervention on sleep-disordered breathing in pediatric patients with Chiari malformation type I

OBJECTIVE

Chiari malformation type I (CM-I) involves the herniation of the cerebellar tonsils through the foramen magnum. CM-I is associated with both obstructive sleep apnea (OSA) and central sleep apnea (CSA) in children. The primary management of symptomatic CM-I remains surgical decompression. There is, however, a paucity of data evaluating the efficacy of decompression surgery on outcomes related to sleep-disordered breathing (SDB). The objective of this study was to evaluate SDB outcomes, specifically the need for respiratory support following decompression in pediatric patients with CM-I.

METHODS

This was a retrospective chart review of all children diagnosed with CM-I when younger than 18 years of age who had polysomnography (PSG) studies pre- and postsurgery, between January 2008 and October 2018 at the Hospital for Sick Children in Toronto. Patient demographics, symptoms, PSG data, ongoing respiratory support, and surgical notes were recorded. Differences in PSG studies obtained pre- and postsurgery were compared using the Wilcoxon test for paired samples.

RESULTS

A total of 15 children with 15 interventions met inclusion criteria with pre- and postsurgery PSG studies and were considered for statistical analysis. Of the 15 subjects included for analysis, preoperative OSA was present in 2 (13.3%), CSA in 5 (33.3%), mixed SDB (both OSA and CSA) in 4 (26.7%), and no significant SDB in 4 (26.7%). Postoperatively, OSA was present in 3 (20.0%), CSA in 4 (26.7%), mixed SDB in 0 (0%), and no significant SDB in 8 (53.3%). The presence of severe OSA decreased from 4/15 (26.7%) to 2/15 (13.3%) postoperatively, and severe CSA decreased from 5/15 (33.3%) to 2/15 (13.3%) postoperatively. Following decompression surgery, 7/15 subjects (46.7%) required positive airway pressure for management of their SDB. Overall, significant improvements were observed in a number of respiratory parameters following decompression including the following: the total apnea-hypopnea index (AHI) (17.5 ± 48.2 vs 6.1 ± 32.7 events/hour; p = 0.001), obstructive AHI (2.1 ± 16.1 vs 1.0 ± 6.6 events/hour; p = 0.005), central AHI (6.3 ± 48.9 vs 2.7 ± 33.0 events/hour; p = 0.005), and the desaturation index (16.7 ± 49.6 vs 3.8 ± 25.3; p = 0.001).

CONCLUSIONS

Although decompression surgery led to a significant reduction in obstructive and central events, many children continued to have persistent SDB and required additional positive airway pressure therapy. This information is important and relevant for anticipatory guidance around decompression surgery and the necessity for respiratory support for the management of SDB in pediatric patients with CM-I.

Obstructing Sleep Apnea in Children with Genetic Disorders-A Special Need for Early Multidisciplinary Diagnosis and Treatment

Background—Children with genetic disorders have multiple anatomical and physiological conditions that predispose them to obstructive sleep apnea syndrome (OSAS). They should have priority access to polysomnography (PSG) before establishing their therapeutic protocol. We analyzed the prevalence and the severity of OSAS in a particular group of children with genetic disorders and strengthened their need for a multidisciplinary diagnosis and adapted management. Methods—The retrospective analysis included children with genetic impairments and sleep disturbances that were referred for polysomnography. We collected respiratory parameters from sleep studies: apnea–hypopnea index (AHI), SatO₂ nadir, end-tidal CO₂, and transcutaneous CO₂. Subsequent management included non-invasive ventilation (NIV) or otorhinolaryngological (ENT) surgery of the upper airway. Results—We identified 108 patients with neuromuscular disorders or multiple congenital anomalies. OSAS was present in 87 patients (80.5%), 3 of whom received CPAP, 32 needed another form of NIV during sleep, and 15 patients were referred for ENT surgery. The post-therapeutic follow-up PSG parameters confirmed the success of the treatment. Conclusions—The upper airway obstruction diagnostics and management for children with complex genetic diseases need a multidisciplinary approach. Early detection and treatment of sleep-disordered breathing in children with genetic disorders is a priority for improving their quality of life.

The relationship between Chiari 1.5 malformation and sleep-related breathing disorders on polysomnography

OBJECTIVE

Chiari 1.5 malformation is a subgroup of the Chiari malformation in which tonsillar descent into the foramen magnum is accompanied by brainstem descent. No data exist on whether operative decompression in patients with Chiari 1.5 improves sleep-related breathing disorders (SRBDs) and whether there are radiological parameters predicting improvement.

METHODS

The authors performed a retrospective cohort study of consecutive pediatric patients with Chiari 1.5 malformation and SRBDs at the Alberta Children's Hospital. An SRBD was characterized using nocturnal polysomnography (PSG), specifically with the apnea-hypopnea index (AHI), the obstructive apnea index, and the central apnea index. Preoperative values for each of these indices were compared to those following surgical decompression. The authors also compared preoperative radiographic factors as predictors to both preoperative AHI and the change in AHI with surgery. Radiological factors included tonsillar and obex descent beneath the basion-opisthion line, the presence of syringomyelia, the frontooccipital horn ratio, the pB-C2 line, and the clivoaxial angle.

RESULTS

Seven patients (5 males, 2 females) met inclusion criteria. One patient had two surgical decompressions, each with pre- and postoperative PSG studies (n = 8). The median age was 9 years. Before surgical decompression, 75% underwent tonsillectomy/adenoidectomy. The majority (87.5%) experienced snoring/witnessed apnea preoperatively. The median tonsillar and obex descent values were 21.3 mm and 11.2 mm, respectively. The median values for the pB-C2 line and clivoaxial angle were 5.4 mm (interquartile range [IQR] 4.5 mm, 6.8 mm) and 144° (IQR 139°, 167°), respectively. There was a statistically significant change from preoperative to postoperative AHI (19.7 vs 5.1, p = 0.015) and obstructive apnea index (4.5 vs 1.0, p = 0.01). There was no significant change in the central apnea index with surgery (0.9 vs 0.3, p = 0.12). No radiological factors were statistically significant in predicting preoperative AHI and change in AHI.

CONCLUSIONS

This is the first series of pediatric patients with Chiari 1.5 with SRBDs who demonstrated a marked improvement in their PSG results postdecompression. Sleep apnea has a significant impact on learning and development in children, highlighting the urgency to recognize Chiari 1.5 as a more severe form of the Chiari I malformation.

The impact of polysomnograms and family-centred decision making in children with medical complexity

Objectives

To determine whether a change in clinical management (e.g., new tracheostomy or adenotonsillectomy) occurred following a polysomnogram (PSG) in children with medical complexity (CMC) and to explore whether families' goals of care (regarding results and treatment implications) were discussed prior to the completion of a PSG.

Methods

All CMC enrolled in a complex care program at the Hospital for Sick Children, Canada, who underwent a baseline PSG from 2009 to 2015 were identified. Exclusion criteria included (1) PSGs for ventilation titration and (2) PSGs outside the study time frame. Health records were retrospectively reviewed to determine demographics, medical histories, families' wishes, PSG results, and their impact on clinical care. Descriptive statistics were used to summarize results.

Results

Of 145 patients identified, 96 patients met inclusion criteria. Fifty (52%) were male. Median age was 3 years. Forty-eight (50%) were diagnosed with clinically significant (i.e., moderate to severe obstructive sleep apnea, central sleep apnea, and/or hypoventilation) sleep-related breathing disorders. Of those diagnosed, 9 (19%) had surgery, 25 (52%) underwent respiratory technology initiation, and 3 (6%) underwent both. In the remaining 11 (23%) patients, treatment was either considered too risky or did not align with the families' wishes. Only 3 of 96 patients had clear documentation of their families' wishes prior to PSG completion.

Conclusion

Recognizing the burden of medical tests for both the child and the health care system, a process of shared-decision making that includes clarifying a family's wishes may be prudent prior to conducting a PSG.

Management of Rare Causes of Pediatric Chronic Respiratory Failure

The need for long-term noninvasive positive pressure ventilation (NiPPV) in children with chronic respiratory failure is rapidly growing. This article reviews pediatric-specific considerations of NiPPV therapy. Indications for NiPPV therapy can be categorized by the cause of the respiratory failure: (1) upper airway obstruction, (2) musculoskeletal and/or neuromuscular disease, (3) lower respiratory tract diseases, and (4) control of breathing abnormalities. The role of NiPPV therapy in select rare conditions (spinal muscular atrophy, congenital central hypoventilation syndrome, cerebral palsy, scoliosis, and Chiari malformations) is also reviewed.

Treatment emergent obstructive sleep apnea after Chiari surgery: A case report

Patients with Chiari type I malformation may also present with sleep disordered breathing mainly central sleep apnea. Here, we report a patient with Chiari I malformation referred to our clinic because of snoring and sleep disordered breathing. He was a 28-year-old man referred to us for evaluation of snoring. An overnight polysomnography revealed central sleep apnea. On further evaluation of central sleep apnea, the patient found to have Chiari malformation type I on brain MRI. The patient developed obstructive sleep apnea after surgery for Chiari malformation. Accordingly, pap titration was performed for the patient's obstructive sleep apnea. In patients with central sleep apnea comprehensive evaluation of predisposing causes is required. Lesions of central nervous system including Chiari malformation should not be overlooked. Furthermore, after treatment of central sleep apnea follow up PSG is warranted to confirm newly emerged sleep breathing disorder such as obstructive sleep apnea.

Role of sleep study in children with Chiari malformation and sleep disordered breathing

PURPOSE

Chiari malformation incorporate numerous forms of congenital or acquired cerebellar herniation through the foramen magnum. This may lead to brain stem, high spinal cord and cranial nerve compression resulting in obstructive and central apneas. This review highlights he high prevalence of sleep-disordered breathing in this population and the importance of refering these patients for sleep studies as part of their workup.

METHODS

A review of the literature was performed through a PubMed and EMBASE search of original articles and reviews using the key words "chiari" "chiari malformation" "hindbrain herniation" "sleep disordered breathing" "obstructive sleep apnea" "central sleep apnea" "sleep study" and "foramen magnum decompression".

DISCUSSION

We highlight the pathophysiology of sleep disordered breathing in patients with Chiari malformation, how it can be diagnosed and what the treatment options are.

CONCLUSIONS

Sleep-disordered breathing is highly prevalent in patients with CM1. Clinicians caring for these patients should be aware of this and prioritise sleep diagnostic testing to allow for early diagnosis and management particularly in the presence of neurological symptoms and specific brain MRI pointers.

A Conditional Inference Tree Model for Predicting Sleep-Related Breathing Disorders in Patients With Chiari Malformation Type 1: Description and External Validation

STUDY OBJECTIVES

The aim of this study is to generate and validate supervised machine learning algorithms to detect patients with Chiari malformation (CM) 1 or 1.5 at high risk of the development of sleep-related breathing disorders (SRBD) using clinical and neuroradiological parameters.

METHODS

We prospectively included two independent datasets. A training dataset (n = 90) was used to obtain the best model, whereas a second dataset was used to validate it (n = 74). In both cohorts, the same clinical, neuroradiological, and sleep studies were carried out. We used two supervised machine learning approaches, multiple logistic regression (MLR) and the unbiased recursive partitioning technique conditional inference tree (URP-CTREE), to detect patients at high risk of SRBD. We then compared the accuracy, sensitivity, and specificity of the two prediction models.

RESULTS

Age (odds ratio [OR] 1.1 95% confidence interval [CI] 1.05-1.17), sex (OR 0.19 95% CI 0.05-0.67), CM type (OR 4.36 95% CI 1.14-18.5), and clivus length (OR 1.14 95% CI 1.01-1.31) were the significant predictor variables for a respiratory disturbance index (RDI) cutoff that was ≥ 10 events/h using MLR. The URP-CTREE model predicted that patients with CM-1 who were age 52 years or older and males with CM-1 who were older than 29 years had a high risk of SRBD. The accuracy of predicting patients with an RDI ≥ 10 events/h was similar in the two cohorts but in the URP-CTREE model, specificity was significantly greater when compared to MLR in both study groups.

CONCLUSIONS

Both MLR and URP-CTREE predictive models are useful for the diagnosis of SRBD in patients with CM. However, URP-CTREE is easier to apply and interpret in clinical practice.

A Bayesian Network Approach to Disease Subtype Discovery

Human diseases are historically categorized into groups based on the specific organ or tissue affected. Over the past two decades, advances in high-throughput genomic and proteomic technologies have generated substantial evidence demonstrating that many diseases are in fact markedly heterogeneous, comprising multiple clinically and molecularly distinct subtypes that simply share an anatomical location. Here, a Bayesian network analysis is applied to study comorbidity patterns that define disease subtypes in pediatric pulmonary hypertension. The analysis relearned established subtypes, thus validating the approach, and identified rare subtypes that are difficult to discern through clinical observations, providing impetus for deeper investigation of the disease subtypes that will enrich current disease classifications. Further advances linking disease subtypes to therapeutic response, disease outcomes, as well as the molecular profiles of individual subtypes will provide impetus for the development of more effective and targeted therapies.

Does Scoliosis Affect Sleep Breathing?

OBJECTIVE

Scoliosis, especially thoracic curves, causes poor pulmonary function. As a result, scoliosis may impair sleep breathing. The literature regarding the relationship between scoliosis and sleep breathing is sparse.

METHODS

Fifty-seven patients with adolescent idiopathic scoliosis or congenital scoliosis and 25 healthy control subjects were included. The wrist sleep monitors was used. Sleep breathing was evaluated with the following parameters: 1) Respiratory Disorders Index (pRDI), indicating mean respiratory events per hour of sleep including apnea, hypoxia, and respiratory effort-related arousal; 2) Apnea and Hypopnea Index (pAHI), expressing the number of apnea and hypopnea events per hour of sleep; and 3) mean and minimal oxygen saturation (Sao₂) during sleep.

RESULTS

No differences in age, sex distribution, and body mass index were found between the two groups. Patients with scoliosis had statistically significant higher pRDI (median, 10.10 vs. 8.65; P = 0.039) and pAHI (median, 1.60 vs. 0.72; P = 0.029) scores than the control group. The minimal SaO₂ value in patients with scoliosis was lower (median, 93% vs. 94%, respectively; P = 0.005), whereas no difference was found in the mean SaO₂ value during sleep. In patients with scoliosis, pAHI scores were higher when lying on the convex side of the thoracic curve compared with the concave side (2.34 vs. 2.28, respectively; P = 0.044), whereas no such difference was observed in the control group.

CONCLUSIONS

Patients with scoliosis have more respiratory events of apnea and hypopnea during sleep than the control group. The minimal SaO₂ value in patients with scoliosis is lower than the normal population. Sleeping on the convex side of the thoracic curve results in higher pAHI scores than on the concave side.

Sleeping chILD: Neuroendocrine cell hyperplasia of infancy and polysomnography

OBJECTIVES

Neuroendocrine cell hyperplasia of infancy (NEHI) is a children's interstitial and diffuse lung disease of unknown etiology that presents in infancy with characteristic findings of tachypnea, retractions, crackles, and hypoxemia. At the present, the mainstay of treatment is oxygen supplementation to normalize oxygen saturations and decrease work of breathing. There are characteristic pulmonary function, radiographic, and histologic findings, but polysomnography (PSG) data has not been reported. We sought to report PSG data and implications for management and treatment of NEHI patients.

METHODS

A retrospective chart review was performed under a Colorado Institutional Review Board approved protocol for which consent was waived. Informatics for Integrating Biology and the Bedside was used to query the electronic medical record at Children's Hospital Colorado for patients with both a diagnosis of NEHI and a PSG. PSG was performed for clinical reasons. Routine sleep quality and respiratory parameters were recorded and analyzed.

RESULTS

Of our 77 patients with NEHI, 14 (19%) children underwent PSG during the study period. Eight children met criteria for OSA and three met criteria for CSA. Ten patients had low oxygen saturations during a study, six had low sleep efficiency, and three had periodic limb movement disorder.

CONCLUSIONS

Patients with NEHI may have sleep related breathing disorders that contribute to disrupted sleep, including obstructive and central sleep apnea, hypoxemia, decreased sleep efficiency, and increased periodic limb movement disorder. PSG should be considered as part of NEHI management, as it may lead to recognition of clinically significant sleep-disordered breathing.

Spina bifida cystica and severe congenital bilateral talipes equinovarus in one twin of a monoamniotic pair: a case report

Background

Spina bifida and congenital talipes equinovarus (CTEV) are common congenital malformations which may occur together and increase morbidity. Monozygous twins are particularly at risk of these malformations and discordance in one type of malformation is typical. The occurrence of both spina bifida and CTEV in one twin of a monozygotic pair is rare.

Case presentation

A 22 year-old Cameroonian primigravida at 36 weeks of a twin gestation was received in our district hospital at the expulsive phase of labour on a background of sub-optimal antenatal care. A caesarean section indicated for cephalo-pelvic disproportion was performed and life monoamniotic male twins were extracted. The first twin was normal. The second twin had spina bifida cystica and severe bilateral CTEV. Routine postnatal care was ensured and at day 2 of life, the affected twin was evacuated to a tertiary hospital for proper management. He was later on reported dead from complications of hydrocephalus.

Conclusions

Spina bifida cystica with severe bilateral CTEV in one twin of a monoamniotic pair illustrates the complexity in the interplay of causal factors of these malformations even among monozygotic twins who are assumed to share similar genetic and environmental features. The occurrence and poor outcome of the malformations was probably potentiated by poor antenatal care. With postnatal diagnoses, a better outcome was difficult to secure even with prompt referral. Early prenatal diagnoses and appropriate counseling of parents are cardinal.

Adenotonsillectomy for Obstructive Sleep Apnea in Children with Complex Chronic Conditions

Objective To estimate the prevalence of persistent obstructive sleep apnea postadenotonsillectomy in children with complex chronic conditions. Study Design A retrospective cohort study. Setting The Hospital for Sick Children Sleep laboratory. Subjects Children ≤18 years of age who had moderate to severe obstructive sleep apnea and had polysomnography pre- and postadenotonsillectomy. Methods Medical and polysomnographic data were reviewed. The prevalence of persistent obstructive sleep apnea postadenotonsillectomy was determined for the following groups: no complex chronic conditions, single-system complex chronic conditions, and multisystem complex chronic conditions. Results We reviewed data of 133 (84 male) children. Their mean (standard deviation) age was 5.5 (3.8) years. The persistent obstructive sleep apnea rate postadenotonsillectomy was highest in children with multisystem complex chronic conditions (57%), intermediate in children with single-system complex chronic conditions (29%), and lowest in children without complex chronic conditions (15%), P = .0004. The odds (confidence interval) of having persistent obstructive sleep apnea postadenotonsillectomy was 7.42 (2.16-25.51) times higher in children with multisystem complex chronic conditions vs no complex chronic conditions and 3.35 (1.16-9.64) times higher in children with multisystem complex chronic conditions vs single-system complex chronic conditions. Conclusions Although adenotonsillectomy is considered first-line therapy in healthy children older than 2 years for the treatment of obstructive sleep apnea, there is a significantly greater risk of persistent obstructive sleep apnea postadenotonsillectomy in children with complex chronic conditions. Therefore, other surgical procedures or nonsurgical management may need to be considered as first-line treatment for this cohort.

Learning a Comorbidity-Driven Taxonomy of Pediatric Pulmonary Hypertension

RATIONALE

Pediatric pulmonary hypertension (PH) is a heterogeneous condition with varying natural history and therapeutic response. Precise classification of PH subtypes is, therefore, crucial for individualizing care. However, gaps remain in our understanding of the spectrum of PH in children.

OBJECTIVE

We seek to study the manifestations of PH in children and to assess the feasibility of applying a network-based approach to discern disease subtypes from comorbidity data recorded in longitudinal data sets.

METHODS AND RESULTS

A retrospective cohort study comprising 6 943 263 children (<18 years of age) enrolled in a commercial health insurance plan in the United States, between January 2010 and May 2013. A total of 1583 (0.02%) children met the criteria for PH. We identified comorbidities significantly associated with PH compared with the general population of children without PH. A Bayesian comorbidity network was constructed to model the interdependencies of these comorbidities, and network-clustering analysis was applied to derive disease subtypes comprising subgraphs of highly connected comorbid conditions. A total of 186 comorbidities were found to be significantly associated with PH. Network analysis of comorbidity patterns captured most of the major PH subtypes with known pathological basis defined by the World Health Organization and Panama classifications. The analysis further identified many subtypes documented in only a few case studies, including rare subtypes associated with several well-described genetic syndromes.

CONCLUSIONS

Application of network science to model comorbidity patterns recorded in longitudinal data sets can facilitate the discovery of disease subtypes. Our analysis relearned established subtypes, thus validating the approach, and identified rare subtypes that are difficult to discern through clinical observations, providing impetus for deeper investigation of the disease subtypes that will enrich current disease classifications.

Hypercapnic Respiratory Failure in Case of Chiari 1.5 Malformation: Case Report and Review of the Literature

Type 2 respiratory failure is defined as hypercapnia associated with hypoxia. Chiari 1.5 is known as herniation of the cerebellar tonsils along with brain stem and fourth ventricle. We report a 35-year-old male who presented with acute hypercapnic respiratory failure (Type 2), without any preexisting neurological or respiratory abnormality. Analysis of blood gases in emergency revealed a pH of 7.12, pCO₂ of 132 mmHg, and arterial oxygen tension of 118 mm Hg. He was intubated and ventilated. Magnetic resonance imaging brain revealed herniation of the cerebellar tonsils along with brain stem and fourth ventricle. The patient underwent surgery and gradually weaned off. He was mobilized and discharged on day 6. Acute respiratory failure has not been reported with Chiari 1.5 malformation. The lesson to be learned from this case is that craniospinal pathology must be looked for in a patient with hypercapnic respiratory failure.

Perspectives on neonatal and infant tracheostomy

Neonates and infants may need a tracheostomy for many different reasons, ranging from airway obstruction to a requirement for long term mechanical ventilator support. Here, we present the pathophysiology of the many congenital and acquired conditions that might be managed with a tracheostomy. Decisions about tracheostomy demand consideration of not only the benefits, but also the potential side-effects, which may differ in the short and long term and may be attributable to underlying conditions as well as the tracheostomy. Evaluation of potential advantages of tracheostomy will influence decisions about optimal timing. In many cases, an infant may 'graduate' from dependence on a tracheostomy and resume a natural airway, although some will require reconstructive airway surgery.

Surgical History of Sleep Apnea in Pediatric Patients with Chiari Type 1 Malformation

Sleep apnea represents a relative indication for posterior fossa decompression in pediatric patients with Chiari malformation type 1. Duraplasty was associated with improvement of sleep apnea in 100% of patients and dural splitting with improvement in 50% of patients. Duraplasty and dural splitting were associated with a similar reduction in tonsillar herniation on radiographic imaging of 58% (37% excluding tonsillectomy) and 35%, respectively. Longitudinal follow-up studies of patients with either neurologic deficits or severe symptoms will further elucidate the natural history of Chiari malformation type 1 and more appropriately gauge the risk-benefit tradeoff of surgical intervention.

Is MRI Necessary in the Evaluation of Pediatric Central Sleep Apnea?

OBJECTIVES

(1) To determine the prevalence of central nervous system (CNS) pathology identified on head magnetic resonance imaging (MRI) scans in children with central sleep apnea (CSA); (2) to assess the yield of MRI in evaluation of CSA; and (3) to identify factors that predict CNS pathology in children with CSA.

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary children's hospital.

SUBJECTS AND METHODS

A chart review was conducted over 12 years. Patients 6 months to 18 years of age who underwent head MRI for evaluation of CSA were included. CSA was diagnosed on polysomnogram as central apnea index >1.

RESULTS

Forty children were included in the CSA group. Twenty-two patients were male, and the mean age was 60 ± 41.5 months. The mean central apnea index was 3.8 ± 1.9, while the mean obstructive apnea hypopnea index was 3.4 (interquartile range, 0.7-3.8). Eighteen percent (7 of 40) of children with CSA had evidence of CNS pathology on MRI, with the most common finding (n = 3) being arachnoid cyst. Children with CSA who had gastroesophageal reflux disease or abnormal neurologic examinations were more likely to have CNS pathology. Other factors, such as prematurity, did not improve the yield of MRI in children with CSA.

CONCLUSIONS

While routine evaluation of children with elevated central apnea index by MRI is not indicated, providers should consider neuroimaging in children with CSA and abnormal neurologic examination findings or gastroesophageal reflux disease. Further research is necessary to identify other tests with improved diagnostic yield for evaluation of pediatric CSA.

Sleep-disordered breathing in patients with myelomeningocele

OBJECT A paucity of literature examines sleep apnea in patients with myelomeningocele, Chiari malformation Type II (CM-II), and related hydrocephalus. Even less is known about the effect of hydrocephalus treatment or CM-II decompression on sleep hygiene. This study is an exploratory analysis of sleep-disordered breathing in patients with myelomeningocele and the effects of neurosurgical treatments, in particular CM-II decompression and hydrocephalus management, on sleep organization. METHODS The authors performed a retrospective review of all patients seen in their multidisciplinary spina bifida clinic (approximately 435 patients with myelomeningocele) to evaluate polysomnographs obtained between March 1999 and July 2013. They analyzed symptoms prompting evaluation, results, and recommended interventions by using descriptive statistics. They also conducted a subset analysis of 9 children who had undergone polysomnography both before and after neurosurgical intervention. RESULTS Fifty-two patients had polysomnographs available for review. Sleep apnea was diagnosed in 81% of these patients. The most common presenting symptom was "breathing difficulties" (18 cases [43%]). Mild sleep apnea was present in 26 cases (50%), moderate in 10 (19%), and severe in 6 (12%). Among the 42 patients with abnormal sleep architecture, 30 had predominantly obstructive apneas and 12 had predominantly central apneas. The most common pulmonology-recommended intervention was adjustment of peripheral oxygen supplementation (24 cases [57%]), followed by initiation of peripheral oxygen (10 cases [24%]). In a subset analysis of 9 patients who had sleep studies before and after neurosurgical intervention, there was a trend toward a decrease in the mean number of respiratory events (from 34.8 to 15.9, p = 0.098), obstructive events (from 14.7 to 13.9, p = 0.85), and central events (from 20.1 to 2.25, p = 0.15) and in the apnea-hypopnea index (from 5.05 to 2.03, p = 0.038, not significant when corrected for multiple measures). CONCLUSIONS A large proportion of patients with myelomeningocele who had undergone polysomnography showed evidence of disordered sleep on an initial study. Furthermore, 31% of patients had moderate or severe obstructive sleep apnea. Myelomeningocele patients with an abnormal sleep structure who had undergone nonoperative treatment with peripheral oxygen supplementation showed improvement in the apnea-hypopnea index. Results in this study suggested that polysomnography in patients with myelomeningocele may present an opportunity to detect and classify sleep apnea, identify low-risk interventions, and prevent future implications of sleep-disordered breathing.

Yawning as a presenting symptom of Chiari malformation Type I: report of 2 cases

Yawning is thought to be a behavior regulated by the brainstem. Although excessive yawning has been reported in brainstem strokes, demyelination, and tumors, the cases presented here are the first reports of excessive yawning in patients with Chiari malformation Type I (CM-I). The authors believe that brainstem compression at the craniocervical junction and ensuing edema were implicated in this curious symptomatology. They describe excessive yawning as a presenting feature of CM-I in 2 adolescent females. The presentation was acute in the first case and more chronic in the second. Both patients underwent foramen magnum decompression, which resulted in complete cessation of the excessive yawning.

The association between sleep-disordered breathing and magnetic resonance imaging findings in a pediatric cohort with Chiari 1 malformation

BACKGROUND

The prevalence of sleep-disordered breathing (SDB) reported in the literature for Chiari malformation type 1 (CM1) is uniformly high (24% to 70%). In Canada, there is limited access to pediatric polysomnography (PSG). Therefore, the identification of clinical features would be invaluable for triaging these children.

OBJECTIVE

To identify demographic features, clinical symptoms/signs and radiological findings associated with SDB in a large pediatric cohort with CM1.

METHODS

A retrospective review was conducted on children with CM1 who underwent baseline PSG. Data were collected on patient demographics (age, sex, weight, height, body mass index), clinical symptoms (chart review and clinical questionnaires), diagnostic imaging of the brain and cervicothoracic spine, and medical history at the time of referral.

RESULTS

A total of 68 children were included in the review. The mean (± SD) age of the children at the time of PSG was 7.33 ± 4.01 years; 56% (n=38) were male. There was a 49% prevalence of SDB in this cohort based on the overall apnea-hypopnea index. Obstructive sleep apnea was the predominant type of SDB. Tonsillar herniation was significantly correlated with obstructive apnea-hypopnea index (r=0.24; P=0.036).

CONCLUSIONS

A direct relationship between the degree of cerebellar tonsillar herniation and obstructive sleep apnea was demonstrated. However, further prospective studies that include neurophysiological assessment are needed to further translate the central nervous system imaging findings to predict the presence of SDB.

Chiari 1 Malformation Presenting as Central Sleep Apnea during Pregnancy: A Case Report, Treatment Considerations, and Review of the Literature

Purpose: Chiari malformation (CM) type-1 frequently causes obstructive or central sleep-disordered breathing (SDB) in both adults and children, although SDB is relatively rare as a presenting manifestation in the absence of other neurological symptoms. The definitive treatment of symptomatic CM is surgical decompression. We report a case that is, to our knowledge, a novel manifestation of central sleep apnea (CSA) due to CM type-1 with severe exacerbation and initial clinical presentation during pregnancy.

Methods: Case report from tertiary care comprehensive sleep medicine center with literature review of SDB manifestations associated with CM type-1. PubMed search was conducted between January 1982 and October 2013.

Results: We report a 25-year-old woman with severe CSA initially presenting during her first pregnancy that eventually proved to be caused by CM type-1. The patient was successfully treated preoperatively by adaptive servoventilation (ASV), with effective resolution of SDB following surgical decompression, and without recurrence in a subsequent pregnancy. Our literature review found that 58% of CM patients with SDB had OSA alone, 28% had CSA alone, 8 (10%) had mixed OSA/CSA, and 6 (8%) had hypoventilation. Of CM patients presenting with SDB, 50% had OSA, 42% had CSA, 8% had mixed OSA/CSA, and 10.4% had hypoventilation. We speculate that CSA may develop in CM patients in whom brainstem compression results in excessive central chemoreflex sensitivity with consequent hypocapnic CSA.

Conclusion: Chiari malformation type-1 may present with a diversity of SDB manifestations, and timely recognition and surgical referral are necessary to prevent further neurological deficits. ASV therapy can effectively manage CSA caused by CM type-1, which may initially present during pregnancy.

[Obstructive sleep apnea-hypopnea syndrome in children: beyond adenotonsillar hypertrophy]

The prevalence of obstructive sleep apnea-hypopnea syndrome in the general childhood population is 1-2% and the most common cause is adenotonsillar hypertrophy. However, beyond adenotonsillar hypertrophy, there are other highly prevalent causes of this syndrome in children. The causes are often multifactorial and include muscular hypotonia, dentofacial abnormalities, soft tissue hypertrophy of the airway, and neurological disorders). Collaboration between different specialties involved in the care of these children is essential, given the wide variability of conditions and how frequently different factors are involved in their genesis, as well as the different treatments to be applied. We carried out a wide literature review of other causes of obstructive sleep apnea-hypopnea syndrome in children, beyond adenotonsillar hypertrophy. We organised the prevalence of this syndrome in each pathology and the reasons that cause it, as well as their interactions and management, in a consistent manner.

Chiari I malformation associated with atlanto-occipital assimilation presenting as orthopnea and cough syncope: a case report and review of literature

Although it is not uncommon for patients with Chiari I malformations to present with respiratory complaints, cough syncope is a rare presenting symptom. We report an adult patient who harbored both a Chiari I malformation and atlanto-occipital assimilation who complained of cough syncope, orthopnea, and central sleep apnea. The patient underwent decompressive craniectomy of the posterior fossa and cervical level 2 laminectomy. However, due to a possible initial underappreciation of the profound narrowing of the foramen magnum as a result of these concomitant pathologies, the patient may have had continued impaired cerebrospinal fluid flow, leading to a symptomatic pseudomeningocele and requiring a more extensive decompression that included a cervical level 3 laminectomy as well as a temporary lumbar drain. On 2-year follow-up, he has remained asymptomatic.