Ondine's curse: the origin of the myth / La maldición de Ondina: el origen del mito

ABSTRACT Central alveolar hypoventilation syndrome has been known for decades as Ondine's curse. It was named as such after a German myth. Although most of the stories resemble one another, word of mouth has led to misinterpretation of this tale among the medical community. The present paper reviews the original narrative, its characters, and how it is linked to the most relevant aspects of the disease.

RESUMEN El síndrome de hipoventilación alveolar central (por sus siglas en inglés) se conoce desde hace décadas como la maldición de Ondine. Fue nombrado como tal por un antiguo mito alemán. Aunque la mayoría de las historias se parecen, la tradición oral ha llevado a una mala interpretación de esta historia entre la comunidad médica. El presente artículo revisa la narrativa original, sus personajes y su relación con los aspectos más relevantes de la enfermedad.

Síndrome de Ondina (hipoventilación central congénita), una amenaza contra la vida al dormir / Ondina syndrome (congenital central hypoventilation) a threat against life when sleeping

RESUMEN El síndrome de Ondina, o síndrome de hipoventilación central congénita, es una enfermedad neurológica rara, donde hay fracaso en el control de la ventilación en el sistema nervioso central, llevando a la hipoxia e hipercapnia que pueden generar problemas del neurodesarrollo y, finalmente, ocasionar la muerte. Puede representar una situación muy dolorosa para los familiares de los pacientes que la padecen, despertando sentimientos difíciles de enfrentar, es por esto que es importante tener conocimiento acerca de esta condición para así impactar en la disminución de su incidencia.

SUMMARY Ondina syndrome, or congenital central hypoventilation syndrome, is a rare neurological disease in which there is a failure in the control of ventilation in the central nervous system, which leads to hypoxia and hypercapnia leading to neurodevelopmental problems and ultimately to death. It can represent a very painful situation for the family of patients who suffer from it, awakening feelings that are difficult to face. Thus, it is important to have adequate knowledge of this condition in order to have an impact on the decrease of its incidence.

Congenital central hypoventilation syndrome: a report of four cases / 中国新生儿科杂志

Objective To study the molecular genetic mechanism of congenital central hypoventilation syndrome ( CCHS).Method The clinical data and molecular genetics results of CCHS diagnosed in neonatology department from 2014 to 2016 were analyzed retrospectively.The relationship between genotypes and clinical phenotypes in patients of CCHS was analyzed , and the diagnostic thinkings , follow－up and prognosis were summarized.Result A total of 4 infants with CCHS were included in this study.Among them, 2 were boys and the other 2 were girls.They were all full－term neonates without asphyxia at birth , but they soon sufferd from dyspnea and cyanosis , required assisted ventilation.One case had difficult defecation. All 4 cases had difficulty in weaning.The respiratory rhythm became weak developed apnea and carbon dioxide retention was detected in blood gas analysis.All the 4 cases died after withdrawal of treatment.The results of molecular genetic testing were as follows.There was a 38bp heterozygous deletion mutation in exon 3 of gene PHOX2B ( e.756＿776 del21bp).Three cases were found small fragment insertion in exon 3 of gene PHOX2B, which attributed to polyalanine repeat expansion mutations (PARMs).One case belonged to type 20/27 and another 2 cases belonged to type 20/26.Conclusion The main manifestation of CCHS in the neonatal period is ventilator dependant , which can combined with megacolon and atypical autonomic nerve disorder.According to the literature, more than 95%of CCHS are caused by the PHOX2B mutation. The symptom is severe when it got a non－PARMs mutation.It′s useful to make a definite diagnosis with genetic diagnosis results , which could be helpful for treating and predicting.Only effective respiratory support and standardized follow－up system can improve the quality of life in patients of CCHS.

Characteristics of sleep apnea events in non-snoring children / 中华耳鼻咽喉头颈外科杂志

Objective@#To investigate the characteristics of sleep-related respiratory events in normal children and to provide normal polysomnographic parameters for diagnosing sleep-disordered breathing in children.@*Methods@#Normal subjects between 3 and 14 years old were enrolled from 1 July 2014 to 31 December 2015 and the subjects received overnight polysomnography at the sleep center of our hospital. They were children of our hospital employees or were recruited from the communities who did not have sleep and respiratory disorders. The children were divided into preschool group (3-5 years) and school-age group (6-14 years). Apnea index (AI), obstructive apnea index (OAI), central apnea index (CAI), and mixed apnea index (MAI) were compared between the two groups. Data for continuous variables that showed normal distribution were expressed as ±s. M(P25, P75) were used when data were not normally distributed. Continuous variables that showed normal distribution were compared by using an independent-sample t-test. Wilcoxon-test was performed when data exhibited non-normal distribution. Differences in categorical data were tested with Chi-square test. Pearson correlation test was applied for the correlation analysis. P<0.05 was considered statistically significant.@*Results@#A total of 115 normal children took part in the study including 40 in preschool group and 75 in school-age group. Children in both groups had a few sleep apnea events, most of which were central apneas, accounting for 80% and 70% of the total respiratory events respectively. Central apnea index in preschool children were significantly higher than that of school-age children (P<0.001), with median of 0.6 times/h and 0.1 times/h, respectively. Median OAI of both groups were 0.0 times/h without significant difference (P=0.748). Obstructive apnea events occurred mainly in the supine position in both groups.@*Conclusions@#Normal children may have a few apnea events in sleep that were predominantly central apnea. CAI of preschool children is significantly higher than that of school-age children. Obstructive sleep apnea is rare in normal children, and sleep apnea occurs mainly in the supine position.

Chronic intermittent hypoxia increases encoding pigment epithelium-derived factor gene expression, although not that of the protein itself, in the temporal cortex of rats, / Hipóxia intermitente crônica aumenta a expressão gênica, mas não proteica, de pigment epithelium-derived factor no córtex temporal de ratos

Objective: Obstructive sleep apnea syndrome is mainly characterized by intermittent hypoxia (IH) during sleep, being associated with several complications. Exposure to IH is the most widely used animal model of sleep apnea, short-term IH exposure resulting in cognitive and neuronal impairment. Pigment epithelium-derived factor (PEDF) is a hypoxia-sensitive factor acting as a neurotrophic, neuroprotective, and antiangiogenic agent. Our study analyzed performance on learning and cognitive tasks, as well as PEDF gene expression and PEDF protein expression in specific brain structures, in rats exposed to long-term IH. Methods: Male Wistar rats were exposed to IH (oxygen concentrations of 21-5%) for 6 weeks-the chronic IH (CIH) group-or normoxia for 6 weeks-the control group. After CIH exposure, a group of rats were allowed to recover under normoxic conditions for 2 weeks (the CIH+N group). All rats underwent the Morris water maze test for learning and memory, PEDF gene expression and PEDF protein expression in the hippocampus, frontal cortex, and temporal cortex being subsequently assessed. Results: The CIH and CIH+N groups showed increased PEDF gene expression in the temporal cortex, PEDF protein expression remaining unaltered. PEDF gene expression and PEDF protein expression remained unaltered in the frontal cortex and hippocampus. Long-term exposure to IH did not affect cognitive function. Conclusions: Long-term exposure to IH selectively increases PEDF gene expression at the transcriptional level, although only in the temporal cortex. This increase is probably a protective mechanism against IH-induced injury. .

Objetivo: A síndrome da apneia obstrutiva do sono caracteriza-se principalmente por episódios de hipóxia intermitente (HI) durante o sono e associa-se a diversas complicações. A exposição à HI é o mais usado modelo animal de apneia do sono, e protocolos de curta duração causam diversos prejuízos cognitivos e neuronais. Pigment epithelium-derived factor (PEDF, fator derivado do epitélio pigmentado) é um fator neurotrófico, neuroprotetor e antiangiogênico sensível à hipóxia celular. Nosso estudo analisou o desempenho em tarefas cognitivas e de aprendizagem, bem como a expressão do gene PEDF e da proteína PEDF em estruturas cerebrais específicas em ratos expostos a HI de longa duração. Métodos: Ratos Wistar foram expostos a HI (21-5% de oxigênio) durante 6 semanas - o grupo HI crônica (HIC) - ou a normóxia durante 6 semanas - o grupo controle. Após a exposição à HIC, um grupo de ratos foi exposto a normóxia durante 2 semanas (o grupo HIC+N). Todos os animais foram submetidos ao labirinto aquático de Morris para avaliação de memória e aprendizado; avaliou-se também a expressão do gene PEDF e da proteína PEDF no hipocampo e nos córtices frontal e temporal. Resultados: Os grupos HIC e HIC+N apresentaram um aumento de expressão do gene PEDF no córtex temporal, porém sem aumento dos níveis proteicos. A expressão do gene PEDF e da proteína PEDF manteve-se inalterada nas demais estruturas. A exposição de longa duração à HI não afetou a função cognitiva. Conclusões: A exposição de longa duração à HI aumenta seletivamente a expressão do gene PEDF ao nível transcricional, embora apenas no córtex temporal. Esse aumento é provavelmente um mecanismo de proteção contra a HI. .

Chiari malformation and central sleep apnea syndrome: efficacy of treatment with adaptive servo-ventilation / Malformação de Chiari e síndrome de apneia central do sono: eficácia do tratamento com servoventilação adaptativa

The Chiari malformation type I (CM-I) has been associated with sleep-disordered breathing, especially central sleep apnea syndrome. We report the case of a 44-year-old female with CM-I who was referred to our sleep laboratory for suspected sleep apnea. The patient had undergone decompressive surgery 3 years prior. An arterial blood gas analysis showed hypercapnia. Polysomnography showed a respiratory disturbance index of 108 events/h, and all were central apnea events. Treatment with adaptive servo-ventilation was initiated, and central apnea was resolved. This report demonstrates the efficacy of servo-ventilation in the treatment of central sleep apnea syndrome associated with alveolar hypoventilation in a CM-I patient with a history of decompressive surgery.

A malformação de Chiari tipo I (MC-I) tem sido associada a distúrbios respiratórios do sono, sobretudo à síndrome de apneia central do sono. Apresentamos o caso de uma paciente do sexo feminino de 44 anos de idade com MC-I que foi encaminhada à nossa unidade de sono por suspeita de apneia do sono. A paciente havia sido submetida a cirurgia descompressiva 3 anos antes. A gasometria arterial mostrou hipercapnia. A polissonografia revelou um índice de distúrbio respiratório de 108 eventos/h, sendo todos os eventos apneias centrais. Foi iniciado tratamento com servoventilação adaptativa e houve resolução da apneia central. Este relato demonstra a eficácia da servoventilação no tratamento da síndrome de apneia central do sono associada à hipoventilação alveolar em uma paciente com MC-I previamente submetida a cirurgia descompressiva.