Sleep-related breathing disorders in infants with spina bifida repaired prenatally and postnatally

STUDY OBJECTIVES

Advances in prenatal repair of myelomeningocele (MMC) have improved outcomes involving different organ systems. There is limited data on respiratory outcomes following prenatal surgical repair. We hypothesize there is no difference in respiratory outcomes between spina bifida (SB) patients who have undergone prenatal versus postnatal repair.

METHODS

We performed a retrospective study of 46 infants <1 year with SB seen at Children's Hospital Los Angeles from 2004-2022. Demographic data, timing of closure, neonatal course, Chiari II malformation (CIIM), ventriculoperitoneal shunt (VPS), polysomnography (PSG) results, and need for supplemental oxygen were collected. Unpaired t-test and Chi-square Test were used to analyze results.

RESULTS

31/46 had prenatal repair of MMC; average age at repair was 27 weeks post-conception (PCA). Average age at postnatal repair was 37 PCA. There was no difference in age at PSG. There was no difference in CIIM presence (p=0.61). 60% of patients with postnatal repair and 23% in the prenatal group underwent VPS placement (p=0.01).

There was no difference in PSG findings between the two groups: CAI (p=0.11), OAHI (p=0.64), average SpO2 baseline (p=0.91), average SpO2 nadir (p=0.17), average PETCO2 baseline (p=0.87), and average PETCO2 maximum (p=0.54). There were no significant differences in the proportion of patients on supplemental O2 (p=0.25), CSA or OSA between groups.

CONCLUSIONS

Patients with SB who've undergone closure of neural tube defect have persistent central apneas, obstructive apneas, and significant hypoxemia. There were no differences in the frequency or severity of sleep-disordered breathing in those with prenatal repair versus postnatal repair.

Elevated transaminases in congenital central hypoventilation syndrome

Patients with CCHS who also have Hirschsprung disease, elevated or low BMI, or pulmonary hypertension may be predisposed to elevated transaminases and may need periodic follow-up of their hepatic function https://bit.ly/3uW7AUG.

When to panic about a panic attack: A challenging case of hypersensitivity pneumonitis

The COVID-19 pandemic has created diagnostic difficulties with the increase in mental health illnesses that often present with nonspecific symptoms, like hypersensitivity pneumonitis. Hypersensitivity pneumonitis is a complex syndrome of varying triggers, onset, severity, and clinical manifestations that can be challenging to diagnose in many cases. Typical symptoms are nonspecific and can be attributed to other entities. There are no pediatric guidelines, which contributes to diagnostic difficulties and delays in treatment. It is particularly important to avoid diagnostic biases, have an index of suspicion for hypersensitivity pneumonitis, and to develop pediatric guidelines as outcomes are excellent when diagnosed and treated promptly. This article discusses hypersensitivity pneumonitis with a focus on the causes, pathogenesis, diagnostic approach, outcomes, and prognosis while using a case to illustrate the diagnostic difficulties worsened by the COVID-19 pandemic.

Obstructive sleep apnea as a presentation of congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome is a rare disorder due to a mutation in the PHOX2B gene, characterized by a failure in autonomic control of breathing with diminished or absent response to hypoxia and hypercapnia, which is most pronounced during sleep. Most patients present from birth with central apneas and hypoventilation, or later in the setting of a physiologic stress. Recent literature in mice with a Phox2b27Ala/+ mutation suggests a predisposition to obstructive apneas likely due to hypoglossal dysgenesis. We report on three patients with obstructive sleep apneas with absent or mild hypoventilation. Our cases propose that obstructive apneas can be the primary presentation in patients who subsequently develop the classic phenotype of congenital central hypoventilation syndrome and emphasize their close monitoring and surveillance.

CITATION

Kagan O, Zhang C, McElyea C, Keens TG, Davidson Ward SL, Perez IA. Obstructive sleep apnea as a presentation of congenital central hypoventilation syndrome. J Clin Sleep Med. 2023;19(9):1697-1700.

Transitional care and clinical management of adolescents, young adults, and suspected new adult patients with congenital central hypoventilation syndrome

PURPOSE

With contemporaneous advances in congenital central hypoventilation syndrome (CCHS), recognition, confirmatory diagnostics with PHOX2B genetic testing, and conservative management to reduce the risk of early morbidity and mortality, the prevalence of identified adolescents and young adults with CCHS and later-onset (LO-) CCHS has increased. Accordingly, there is heightened awareness and need for transitional care of these patients from pediatric medicine into a multidisciplinary adult medical team. Hence, this review summarizes key clinical and management considerations for patients with CCHS and LO-CCHS and emphasizes topics of particular importance for this demographic.

METHODS

We performed a systematic review of literature on diagnostics, pathophysiology, and clinical management in CCHS and LO-CCHS, and supplemented the review with anecdotal but extensive experiences from large academic pediatric centers with expertise in CCHS.

RESULTS

We summarized our findings topically for an overview of the medical care in CCHS and LO-CCHS specifically applicable to adolescents and adults. Care topics include genetic and embryologic basis of the disease, clinical presentation, management, variability in autonomic nervous system dysfunction, and clarity regarding transitional care with unique considerations such as living independently, family planning, exposure to anesthesia, and alcohol and drug use.

CONCLUSIONS

While a lack of experience and evidence exists in the care of adults with CCHS and LO-CCHS, a review of the relevant literature and expert consensus provides guidance for transitional care areas.

Congenital central hypoventilation syndrome without hypoventilation: is it congenital central hypoventilation syndrome?

Congenital central hypoventilation syndrome (CCHS) is a rare condition caused by pathogenic variants of the PHOX2B gene. There have been case reports describing variable phenotypes and mutations of the PHOX2B gene, not commonly tested for, that may challenge the classic definition of CCHS. We report on 3 family members with a rare heterozygous deletion encompassing the entire PHOX2B gene with variable phenotypes, including sleep-disordered breathing and autonomic nervous system involvement, but an unexpected lack of alveolar hypoventilation, which is usually a defining feature of CCHS. Our cases highlight the dilemmas in making a diagnosis of CCHS and emphasize the need for expanded genetic testing, including for PHOX2B gene deletion. More patients with variable phenotypes of CCHS may be identified through comprehensive genetic testing and warrant surveillance as they are still at risk for high-risk complications of CCHS.

CITATION

Wo LL, Itani R, Keens TG, Marachelian A, Ji J, Perez IA. Congenital central hypoventilation syndrome without hypoventilation: is it congenital central hypoventilation syndrome? J Clin Sleep Med. 2023;19(6):1161-1164.

Does acute flaccid myelitis cause respiratory failure in children?

INTRODUCTION

Acute flaccid myelitis (AFM) is a rare disease that affects spinal cord gray matter, results in acute flaccid weakness of one or more limbs and predominantly involves the cervical spinal cord, which places patients at higher risk for respiratory failure. Our study aims to describe respiratory failure in pediatric AFM patients with emphasis on the need for assisted ventilation and respiratory nerve involvement from an acute and long-term perspective.

MATERIALS AND METHODS

We reviewed the medical records of patients diagnosed with AFM seen in a multidisciplinary clinic for persistent limb weakness between 2016 and 2020.

RESULTS

We studied 54 patients, 35% were female. The median age of patients at illness onset was 5 years (range 7 months-19 years). The median age of patients at the time of study was 8.5 years (range 2-20 years). Eleven patients (20%) required assisted ventilation for acute respiratory failure. Of those that experienced acute respiratory failure, 81% developed chronic respiratory failure. Fifty-six percent of patients with chronic respiratory failure were able to wean off assisted ventilation by 1 year. All patients that experienced unilateral diaphragm impairment with AFM onset experienced acute and chronic respiratory failure.

DISCUSSION

Many patients with AFM may experience respiratory compromise and develop chronic respiratory failure. However, most of these patients can be weaned off ventilatory support by 1 year from illness onset. Most children with unilateral diaphragm impairment can sustain adequate ventilation without the need for long-term ventilatory support.

An unusual cause of diaphragm pacer failure in congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome is a rare genetic disorder affecting ventilatory response to hypercapnia and/or hypoxemia. We describe a case of diaphragm pacing (DP) failure in a 38-year-old woman with congenital central hypoventilation syndrome who used DP as ventilatory support only during sleep for 24 years. Diagnostic evaluation began with examination of external DP equipment, but adjustment did not elicit adequate diaphragm contractions. Clinical evaluation and transtelephonic monitoring showed absent function of the right pacer and diminished function of the left pacer. The patient had surgical exploration of her internal DP components. The operation revealed that the right pacer receiver had significant circumferential calcium accumulation. After replacement of the receivers in subcutaneous pockets closer to the skin surface, robust diaphragm contractions bilaterally occurred with stimulation. This case suggests DP failure can result from development of calcification and increased distance from the skin surface to the receivers due to weight gain.

CITATION

Kwon A, Lodge M, McComb JG, et al. An unusual cause of diaphragm pacer failure in congenital central hypoventilation syndrome. J Clin Sleep Med. 2022;18(3):949-952.

Children with Congenital Central Hypoventilation Syndrome Do Not Wake up to Ventilator Alarms

PURPOSE

Congenital Central Hypoventilation Syndrome (CCHS) requires lifelong ventilatory support during sleep. Subjects with CCHS are vulnerable to sleep disturbances associated with treatments, monitoring alarms, and care they receive. We hypothesized that sleep would be disrupted in patients  with CCHS due to ventilatory support and other treatments at night.

METHODS

An anonymous survey of patients with CCHS, age up to 17 years was conducted through REDCAP. Subjects were recruited in person, by flyer, email, and social media. Data collected included demographics, PHOX2B genotype, ventilatory support, treatments, nursing, and sleep parameters.

RESULTS

We received 23 responses (35% female, 8.1 years ± 5.6). PHOX2B genotypes were 20/24 PARM (2), 20/25 PARM (4), 20/26 PARM (2), 20/27 PARM (9), ≥ 20/28 PARM (2), and NPARM (2). Two subjects did not indicate the PHOX2B genotype. 13/23 were ventilated by PPV via tracheostomy, 7 by NIPPV, 2 by diaphragm pacing, and 1 did not indicate. Additional treatments received at night included suctioning (9), aerosol (1), G-tube feeding (2), and none (11). Only 9 received nursing at night. 13 used pulse oximetry for monitoring, and 9 used both pulse oximetry and end tidal CO₂ monitor. 17/23 rarely woke up due to ventilator or monitor alarms. 11/23 usually or sometimes woke up at least once a night; only 2/11 woke up due to alarms. 5/17 who rarely woke up to the alarms had night nursing.

CONCLUSION

Most subjects with CCHS did not awaken to ventilator or monitoring alarms and a majority of these patients did not have nighttime nursing. (Mathur et al. in Sleep 43(Supplement_1):A333, 2020).

Variable phenotypes in congenital central hypoventilation syndrome with PHOX2B nonpolyalanine repeat mutations

STUDY OBJECTIVES

Congenital central hypoventilation syndrome (CCHS) is a rare disorder affecting the autonomic nervous system that is caused by variants in the PHOX2B gene. About 10% of patients with CCHS have nonpolyalanine repeat mutations (NPARM) that are associated with severe phenotypes requiring continuous assisted ventilation, Hirschsprung's disease, and increased neural crest tumor risk. However, some patients with NPARMs have milder phenotypes. Our objective was to describe the phenotypes in patients with CCHS PHOX2B NPARM.

METHODS

Retrospective case series of patients with CCHS PHOX2B NPARM was conducted at two children's hospitals to evaluate their phenotypes.

RESULTS

We identified eight patients with CCHS PHOX2B NPARM aged 3-31 years. Seven patients were diagnosed in infancy and one patient at two years of age. All patients presented with respiratory depression in the first two months of life. Only one patient was identified with a severe phenotype requiring continuous assisted ventilation, Hirschsprung's disease, and a neural crest tumor, that was resected. Five patients required positive pressure ventilation via tracheostomy only during sleep and two patients required oxygen only during sleep. Four patients had Hirschsprung's disease and one patient had a cardiac pacemaker due to a bradyarrhythmia. None of the patients had echocardiographic abnormalities.

CONCLUSIONS

Patients with CCHS PHOX2B NPARM can have variable phenotypes emphasizing the importance of implementing a plan of care that is individualized for each patient. The type of NPARM and its respective location on the PHOX2B gene may play a critical role in the severity of phenotypes displayed by each patient.

Hirschsprung disease and other gastrointestinal motility disorders in patients with CCHS

Congenital central hypoventilation syndrome (CCHS) is an autonomic nervous system dysfunction due to PHOX2B gene mutation. Little is known about gastrointestinal motility disorders in CCHS patients. This study aims to describe the spectrum of gastrointestinal motility disorders in CCHS and provide PHOX2B genotype-phenotype correlation with Hirschsprung Disease (HD). We reviewed the records of 72 CCHS patients seen at Children's Hospital Los Angeles from 1999 to 2019. Data collected included demographics, PHOX2B genotype, ventilator dependence, medical and surgical history, and gastrointestinal motility studies. Of the 72 patients, 31% had HD, 50% females, and 60% had 20/27 PARM. Rectosigmoid HD formed 73% of the cases whereas long segment (up to splenic flexure involvement) forms represented 23%. Four patients had total colonic aganglionosis, including one patient with 20/25 PARM genotype. One HD patient was identified with colonic myopathy in the residual segment. One patient was found to have achalasia type 1.Conclusion: Nearly one third of our CCHS patients had HD. Although most had 20/27 PARM, 2 patients had 20/25 PARM. Thus, CCHS patients with constipation are at risk for HD regardless of genotype. Colonic myopathy may coexist in treated HD with refractory constipation. Achalasia may occur in patients with CCHS. What is Known: • Patients with CCHS have motility disorders and present with esophageal dysmotility and constipation as a manifestation of their autonomic nervous system dysfunction. • About 20% of patients with CCHS have Hirschsprung disease and previously described to be associated with NPARM and 20/27 PARM genotype. What is New: • Thirty-one percent of CCHS patients in our series have Hirschsprung disease (HD). • HD, including the more severe total colonic aganglionosis was found in a patient with 20/25 PARM genotype suggesting that CCHS patients with constipation should be screened for HD regardless of genotype.

Pregnancy in congenital central hypoventilation syndrome

BACKGROUND

Congenital central hypoventilation syndrome is a rare genetic disorder of autonomic regulation of breathing resulting from mutations in the paired-like homeobox gene. Individuals with congenital central hypoventilation syndrome demonstrate an absent or diminished physiological response to hypercapnia and hypoxia that is most severe during sleep and depend on mechanical ventilation to maintain normal gas exchange. Increased disease awareness and availability of paired-like homeobox gene testing has improved congenital central hypoventilation syndrome morbidity and mortality, and patients are now living into adulthood. During pregnancy, delivery, and the postpartum period, women with congenital central hypoventilation syndrome are vulnerable to developing respiratory insufficiency. Currently, there is no standardized approach to monitoring ventilatory status and anticipating the need for changes to existing ventilatory support for women with congenital central hypoventilation syndrome during pregnancy, labor, and delivery.

OBJECTIVE

This study aimed to characterize current practices for monitoring ventilatory status and managing ventilatory needs in women with congenital central hypoventilation syndrome during pregnancy; identify specific circumstances through which ventilation may be compromised during pregnancy, delivery, and postpartum; evaluate utilization of prenatal congenital central hypoventilation syndrome testing; and report any adverse pregnancy outcomes.

STUDY DESIGN

We conducted an anonymous cross-sectional survey of women with congenital central hypoventilation syndrome with current or prior pregnancy. The 26-item electronic questionnaire included questions on congenital central hypoventilation syndrome genotype; number and outcome of pregnancies; use of mechanical ventilation; and issues with or adjustments made to ventilation during pregnancy, delivery, and the postpartum period.

RESULTS

We received 10 responses. Three patients were not diagnosed with congenital central hypoventilation syndrome until after pregnancy and delivery. The 7 patients with a preexisting congenital central hypoventilation syndrome diagnosis reported information on 10 total pregnancies. At baseline, patients relied on various types of ventilatory support including positive pressure ventilation via tracheostomy, bilevel noninvasive positive pressure ventilation, and diaphragm pacing by phrenic nerve stimulation. Polysomnography for objective assessment of nocturnal ventilation was not consistently utilized. Changes to baseline ventilatory support were required during 3 out of 10 pregnancies. In addition, 2 patients using diaphragm pacing reported discomfort with pacing during the third trimester or after cesarean delivery, prompting discontinuation of diaphragm pacing. In 1 instance, discontinuation of diaphragm pacing and lack of recognition of need for an alternative support method led to respiratory arrest and need for emergent resuscitation. All patients who were offered prenatal congenital central hypoventilation syndrome testing chose to undergo testing. Of note, 9 out of 10 pregnancies were carried successfully to term and 5 infants were diagnosed with congenital central hypoventilation syndrome.

CONCLUSION

Women with congenital central hypoventilation syndrome may experience issues maintaining adequate ventilation during pregnancy, necessitating an adjustment of ventilator settings or use of an alternative type of ventilation. Objective assessment of nocturnal ventilation by means of polysomnography is an important part of congenital central hypoventilation syndrome pregnancy care to optimize maintenance of adequate gas exchange. Patients who rely on diaphragm pacing may experience discomfort with pacing during the later stages of pregnancy and after cesarean delivery. Anticipatory guidance and contingency planning for changing ventilatory needs should be discussed early in pregnancy. Prenatal congenital central hypoventilation syndrome testing should be offered to pregnant patients with congenital central hypoventilation syndrome to inform delivery decisions and prepare for the provision of advanced neonatal care.

Correction to: Life-threatening cardiac arrhythmias in congenital central hypoventilation syndrome

The publisher regrets that in the original published version of this article, one of the author's name was incorrectly presented as "Yaniv Bar Cohen". The correct presentation should have been "Yaniv Bar-Cohen" and is now presented correctly in this article.

0887 Diaphragm Pacer Malfunctions Requiring Surgical Repair in CCHS Patients

Introduction

Congenital Central Hypoventilation Syndrome (CCHS) is a genetic disorder that results in the loss of autonomic ventilatory control, and patients require ventilatory support during sleep or both sleep and wakefulness. One method of ventilatory support is diaphragm pacing (DP), where electrodes surgically placed on the phrenic nerve are connected to subcutaneously implanted receivers that communicate with external antennas and transmitter. There are limited data on the frequency of DP malfunctions that require surgical revision.

Methods

We reviewed the records of 24 CCHS patients ventilated by DP followed at CHLA from 1990-2019. Records were examined for demographics, PHOX2B mutation, pacing duration/day, date and type of malfunctions, age and time since implantation at malfunction occurrence, and repair success rate.

Results

All 24 patients had thoracoscopic electrode placement. 17/24 (71%) of patients used DP while asleep; 3/24 (13%) during wakefulness only. 4/24 (17%) were not currently using their pacers. 10/24 (42%) patients required at least one surgical intervention (Age at implantation 9 ± 4.6 (SD) years; age at malfunction 12.5 ± 7.4 years). The average time from pacer implantation to malfunction was 3.8 ± 3.5 years. Malfunctions included defective receivers (6), insulation leaks (1), defective electrodes (4), and hardware infection (1). Of 12 unique component repairs, 6/12 (50%) involved changing receivers, 1/12 (8%) involved repairing an insulation leak, 4/12 (33%) involved replacing the electrodes and receivers, and 1/12 (8%) involved hardware extraction. Of the 12 malfunctions, 10 (83%) had successful surgical revision. 2/12 (17%) repairs were not attempted. While awaiting surgical revision, patients were successfully ventilated by unilateral DP.

Conclusion

Nearly half of CCHS patients on DP experienced malfunctions within 11 years of implantation. The most common DP repair was receiver replacement. Patients who are waiting for repair often successfully ventilate while pacing unilaterally.

Support

None

0874 Patients with Congenital Central Hypoventilation Syndrome Do Not Wake Up to Ventilator Alarms

Introduction

Congenital Central Hypoventilation Syndrome (CCHS) requires lifelong ventilatory support during sleep. CCHS patients are vulnerable to sleep disturbances associated with treatments, monitoring alarms, and care they receive. We hypothesized that sleep would be disrupted in CCHS patient’s due to ventilatory support and other treatments at night.

Methods

An anonymous survey of CCHS patients aged 0-17 years was conducted through REDCAP. Patients were recruited in person, by flyer, email, and social media. Data collected included demographics, PHOX2B genotype, ventilatory support, treatments, nursing, and sleep parameters.

Results

We received 22 responses (27% Female, 8.1 years ± 5.7). PHOX2B genotypes were 20/27 PARM (8), 20/26 PARM (2), 20/24 PARM (2), 20/25 PARM (4), ≥ 20/28 PARM (2), and 2 NPARM (2). Two respondents did not indicate the PHOX2B genotype. 13/22 were ventilated by PPV via tracheostomy, 7/22 by BPAP, and 2/22 by diaphragm pacing. Additional treatments received at night included suctioning (8), aerosol (1), G-tube feeding (2), and none (11). Only 9 received nursing at night. 13 used pulse oximetry for monitoring, and 9 used both pulse oximetry and end tidal CO2 monitor. 16/22 rarely woke up due to ventilator or monitor alarms. 15/22 slept within 20 minutes after going to bed. Sleep latency was not affected by mode of ventilation. 11/22 reported night waking ≥ 2 nights/week and 10/22 returned to sleep without help after night waking. 6/7 BPAP dependent patients reported low frequency of night waking (0-1 time/week). Of the PPV + trach group, 7/13 reported high frequency of night wakings, mostly 5-7 times/week.

Conclusion

Most CCHS patients do not awaken in response to ventilator alarms. Sleep is rarely disrupted by nursing or feeding intervention. We speculate that CCHS patients contemplating to live independently should be tested to see if they awaken in response to ventilator alarms.

Support

None

Life-threatening cardiac arrhythmias in congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS) patients are at risk for life-threatening cardiac arrhythmias, and presentation is dependent on their PHOX2B gene mutation. We describe the presentation of life-threatening arrhythmias in our cohort of CCHS patients. We reviewed the records of 72 CCHS patients seen at CHLA from 2004 to 2018. Data collected included demographics, PHOX2B genotype, ventilatory support, clinical symptoms, ambulatory cardiac monitoring results, and presence of cardiac pacemaker. Sixteen of 72 patients had evidence of potential life-threatening cardiac arrhythmias. PHOX2B genotypes were 20/25 polyalanine repeat expansion mutation (PARM), 20/26 PARM, 20/27 PARM, 20/32 PARM, and c.245C > T non-polyalanine repeat mutation. 11/16 patients were ventilated during sleep only. Symptoms included syncope, dizziness, chest pain, tingling in the left arm, and palpitations. 15/16 patients had recorded ambulatory cardiac monitoring. 5/16 patients were symptomatic without significant sinus pauses. 12/16 patients had implantation of cardiac pacemakers. 9/12 had significant sinus pauses on ambulatory monitoring, and 7/12 patients were symptomatic.Conclusion: CCHS patients have potential life-threatening arrhythmias requiring cardiac pacemaker implantation. Many of these patients are symptomatic with significant sinus pauses on ambulatory monitoring. However, some symptomatic patients with no significant pauses on ambulatory monitoring may still require cardiac pacemaker implantation.What is Known:• CCHS patients are at risk for life-threatening sinus pauses and require cardiac pacemaker implantation.What is New:• CCHS patients regardless of PHOX2B genotype are at risk for significant sinus pauses. Many CCHS patients with significant sinus pause on ambulatory cardiac monitoring are symptomatic and most present with syncope. Some symptomatic patients do not have significant sinus pauses but may still require cardiac pacemaker implantation.

Positional impairment of gas exchange during diaphragm pacing alleviated by increasing amplitude settings in congenital central hypoventilation syndrome

None

Diaphragm pacing (DP) by phrenic nerve stimulation is a modality of chronic ventilatory support in individuals with congenital central hypoventilation syndrome (CCHS). We report a 9-year-old girl with CCHS who uses DP without tracheostomy during sleep. Her parents report hypoxemia and hypercapnia related to positional changes of the body during sleep requiring frequent adjustment of pacer settings. Overnight polysomnography was performed to titrate DP settings that showed adequate gas exchange in the supine position, but intermittent hypoxemia and hypercapnia were noted in the left decubitus position without obstructive sleep apnea occurring. Subsequently, the DP amplitude settings were increased during polysomnography, thereby identifying and treating positional hypoxemia and hypercapnia in various body positions. Our case emphasizes the importance of polysomnography in children with CCHS using DP to monitor for sleep-disordered breathing and titration of DP settings to achieve optimal oxygenation and ventilation with different body positions during sleep.

Assessing the effects of sleep on neurocognitive performance and injury rate in adolescent athletes using actigraphy

The National Sleep Foundation recommends that adolescents (age 14-17 years) sleep 8 to 10 hours per night. Sleep loss is associated with cognitive dysfunction, decreased reaction time, and poorer athletic performance. This study evaluated the effects of sleep on sports injury rate and academic and cognitive performance. Seventeen high school track and field athletes (7 males, 10 females, mean age 15.9 years) wore an actigraph device for 10 weeks and performed a computerized neurocognitive assessment. Overall, 900 nights of nocturnal sleep data were analysed. Total minutes in bed averaged 501 minutes (8 hours and 21 minutes) and total sleep time averaged 378 minutes (6 hours and 18 minutes). Statistically significant correlations were observed between mean total sleep time and age-adjusted scores for the neurocognitive domains of episodic memory (p = .03) and fluid cognition (p = .03). Sleep loss in student-athletes may result in greater cognitive difficulties and impair academic abilities in the classroom.

Association between REM sleep and obstructive sleep apnea in obese and overweight adolescents

PURPOSE

Overweight and obese children have demonstrated reduced rapid eye movement (REM) sleep, affecting energy balance regulation and predisposition to weight gain. Obstructive sleep apnea (OSA) is a known cause of decreased REM sleep. The purpose of this study is to examine the association between the percentage of REM sleep, BMI z-score, and OSA severity in overweight and obese adolescents.

METHODS

We performed a cross-sectional study of 92 (43% female) overweight and obese adolescents (13-17 years old) who underwent overnight polysomnography (PSG) at Children's Hospital Los Angeles between 2010 and 2017.

RESULTS

The average Body Mass Index (BMI) z-score was 2.27 ± 0.47, with 71% having BMI z-score ≥ 2. REM% during PSG was 15.6 ± 6.8, and obstructive apnea-hypopnea index was 17.1 ± 24.3. The distribution across categories of OSA severity was 27% none (≤ 1.5 events/h), 24% mild (> 1.5-5 events/h), 8% moderate (> 5-10 events/h), and 41% severe (> 10 events/h). REM% was not associated with BMI z-score, either on univariate or multivariate regression with adjustment for age, gender, and apnea-hypopnea index (AHI). When subdivided into OSA categories, a 1-unit increase in BMI z-score was associated with a 5.96 (p = 0.03) increase in REM% in mild OSA and an 8.86 (p = 0.02) decrease in REM% in severe OSA. There was no association between BMI z-score and REM% in none and moderate OSA.

CONCLUSION

Among overweight and obese adolescents, BMI z-score was associated with decreased REM% in severe OSA and unexpectedly increased REM% in mild OSA, but there was no association in none or moderate OSA.

Adult With PHOX2B Mutation and Late-Onset Congenital Central Hypoventilation Syndrome

ABSTRACT

PHOX2B 20/27 polyalanine repeat mutation (PARM) in patients with congenital central hypoventilation syndrome (CCHS) is generally associated with full-time ventilator dependence, Hirschsprung disease, and increased risk for cardiac asystole. We follow a 14-year-old boy with CCHS PHOX2B 20/27 PARM who is full-time ventilator dependent via tracheostomy and has Hirschsprung disease. His mother, age 52 years, has a history of prolonged recovery from anesthesia and an elevated serum bicarbonate level of 45 mEq/L discovered on routine blood chemistry. PHOX2B gene mutation analysis was performed and showed an identical 20/27 PARM, diagnostic of CCHS. Late-onset CCHS has been reported in those with 20/24, 20/25 PHOX2B PARM, and in nonpolyalanine repeat mutations. This is the first report of a patient with PHOX2B 20/27 PARM with a mild phenotype diagnosed during adulthood. This unusual presentation supports the screening for PHOX2B mutations in parents of children with CCHS.

The genetics of congenital central hypoventilation syndrome: clinical implications

Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder of the autonomic nervous system (ANS) and respiratory control. This disorder, formerly referred to as Ondine’s curse, is due to a mutation in the PHOX2B gene that affects the development of the neural crest cells. CCHS has an autosomal dominant pattern of inheritance. Majority of the patients have a polyalanine repeat mutation (PARM) of the PHOX2B, while a small group has non-PARM (NPARM). Knowledge of the patient’s PHOX2B gene mutation helps predict a patient’s clinical presentation and outcome and aids in anticipatory management of the respiratory and ANS dysfunction.

Obstructive Sleep Apnea in Patients With Congenital Central Hypoventilation Syndrome Ventilated by Diaphragm Pacing Without Tracheostomy

STUDY OBJECTIVES

To determine presence of obstructive sleep apnea (OSA) in patients with congenital central hypoventilation syndrome (CCHS) ventilated by diaphragm pacing (DP) without tracheostomy, and to determine if OSA can be improved by DP setting changes.

METHODS

We reviewed polysomnography (PSG) results of 15 patients with CCHS from October 2001 to April 2014, age 15.4 ± 7.8 years, body mass index 22.0 ± 6.0 kg/m², and 60% female.

RESULTS

Of the 22 PSG results obtained for the 15 patients with CCHS, 9 were performed with tracheostomy capped, and 13 were performed after patients underwent decannulation. OSA was present on 6 of 9 tests in patients with tracheostomy capped, including 3 patients with immediate, severe OSA necessitating that the studies be completed with tracheostomy uncapped. OSA was present on 2 of 13 tests in patients in whom decannulation had been performed. Hypoventilation was seen on only one test without OSA. On 2 of 5 tests showing OSA, OSA improved by decreasing DP amplitude settings; apnea-hypopnea index decreased from 11.1 ± 2.5 to 1.8 ± 2.5 events/h; PETCO₂ decreased from 57.5 ± 3.5 to 38.5 ± 0.7 torr; SpO₂ increased from 76.5 ± 0.7% to 93.0 ± 7.1%. OSA improved in one patient with slight increase in respiratory rate. Settings were manipulated in 4 tests showing OSA; no changes were attempted in the remaining study. One patient was placed on bilevel positive airway pressure with temporary suspension of DP. Age (P < .119), previous adenotonsillectomy (P < .211), and body mass index (P < .112) did not significantly contribute to OSA.

CONCLUSIONS

OSA occurs in patients with CCHS ventilated by DP. However, decreasing DP amplitude settings can lessen upper airway obstruction without compromising gas exchange.

Three-Generation Family With Congenital Central Hypoventilation Syndrome and Novel PHOX2B Gene Non-Polyalanine Repeat Mutation

ABSTRACT

PHOX2B non-polyalanine repeat mutation (NPARM) in patients with congenital central hypoventilation syndrome (CCHS) is generally considered to be associated with full-time ventilator dependence and severe autonomic nervous system dysfunction. We report a three-generation family with four individuals possessing a novel PHOX2B NPARM (c.245C > T) with variable phenotypes. This mutation was inherited in an autosomal dominant pattern with variable penetrance. The affected family members with CCHS have a milder phenotype than is typically expected with a NPARM. Two family members are ventilator dependent only during sleep and do not have Hirschsprung disease or neural crest tumors. One family member was asymptomatic until systemic hypertension developed during adulthood and another family member remains asymptomatic as an adult. Our findings emphasize the importance of monitoring adults with a PHOX2B NPARM who are considered asymptomatic in childhood.

Congenital central hypoventilation syndrome: diagnostic and management challenges

Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder with failure of central control of breathing and of the autonomic nervous system function due to a mutation in the paired-like homeobox 2B (PHOX2B) gene. Affected patients have absent or negligible ventilatory sensitivity to hypercapnia and hypoxemia, and they do not exhibit signs of respiratory distress when challenged with hypercarbia or hypoxia. The diagnosis of CCHS must be confirmed with PHOX2B gene mutation. Generally, the PHOX2B mutation genotype can aid in anticipating the severity of the phenotype. They require ventilatory support for life. Home assisted ventilation options include positive pressure ventilation via tracheostomy, noninvasive positive pressure ventilation, and diaphragm pacing via phrenic nerve stimulation, but each strategy has its associated limitations and challenges. Since all the clinical manifestations of CCHS may not manifest at birth, periodic monitoring and early intervention are necessary to prevent complications and improve outcome. Life-threatening arrhythmias can manifest at different ages and a normal cardiac monitoring study does not exclude future occurrences leading to the dilemma of timing and frequency of cardiac rhythm monitoring and treatment. Given the rare incidence of CCHS, most health care professionals are not experienced with managing CCHS patients, particularly those with diaphragm pacers. With early diagnosis and advances in home mechanical ventilation and monitoring strategies, many CCHS children are surviving into adulthood presenting new challenges in their care.

Disorders of Sleep and Ventilatory Control in Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is an imprinted genetic disorder conferred by loss of paternal gene expression from chromosome 15q11.2-q13. Individuals with PWS have impairments in ventilatory control and are predisposed toward sleep disordered breathing due to a combination of characteristic craniofacial features, obesity, hypotonia, and hypothalamic dysfunction. Children with PWS progress from failure to thrive during infancy to hyperphagia and morbid obesity during later childhood and onward. Similarly, the phenotype of sleep disordered breathing in PWS patients also evolves over time from predominantly central sleep apnea in infants to obstructive sleep apnea (OSA) in older children. Behavioral difficulties are common and may make establishing effective therapy with continuous positive airway pressure (CPAP) more challenging when OSA persists after adenotonsillectomy. Excessive daytime sleepiness (EDS) is also common in patients with PWS and may continue after OSA is effectively treated. We describe here the characteristic ventilatory control deficits, sleep disordered breathing, and excessive daytime sleepiness seen in individuals with PWS. We review respiratory issues that may contribute to sudden death events in PWS patients during sleep and wakefulness. We also discuss therapeutic options for treating sleep disordered breathing including adenotonsillectomy, weight loss, and CPAP. Lastly, we discuss the benefits and safety considerations related to growth hormone therapy.

Thoracoscopic placement of phrenic nerve pacers for diaphragm pacing in congenital central hypoventilation syndrome

PURPOSE

Congenital central hypoventilation syndrome (CCHS), or Ondine's curse, is a rare disorder affecting central respiratory drive. Patients with this disorder fail to ventilate adequately and require lifelong ventilatory support. Diaphragm pacing is a form of ventilatory support which can improve mobility and/or remove the tracheostomy from CCHS patients. Little is known about complications and long-term outcomes of this procedure.

METHODS

A single-center retrospective review was performed of CCHS patients undergoing placement of phrenic nerve electrodes for diaphragm pacing between 2000 and 2012. Data abstracted from the medical record included operation duration, ventilation method, number of trocars required, and postoperative and pacing outcomes.

RESULTS

Charts of eighteen patients were reviewed. Mean surgical time was 3.3±0.7 hours. In all cases except one, three trocars were utilized for each hemithorax, with no conversions to open procedures. Five patients (27.8%) experienced postoperative complications. The mean ICU stay was 4.3±0.5 days, and the mean hospital stay is 5.7±0.3days. Eleven patients (61.1%) achieved their daily goal pacing times within the follow-up period.

CONCLUSIONS

Thoracoscopic placement of phrenic nerve electrodes for diaphragmatic pacing is a safe and effective treatment modality for CCHS. Observed complications were temporary, and the majority of patients were able to achieve pacing goals.