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Background Congenital high airway obstruction syndrome (CHAOS) involves the partial or complete obstruction of the fetal upper airways, usually caused by atresia or stenosis of the larynx or trachea. The obstruction of bronchial tree leads to lung distension, diaphragmatic eversion, and cardiac dysfunction, which can result in fetal death. Case A primigravid 19-year-old was diagnosed with CHAOS at 193 weeks gestation. Virtual navigation using magnetic resonance imaging (MRI) data was used to visualize the fetal airways after intrauterine endoscopic laser decompression. A perforation in the fetal larynx/trachea was identified and the diagnosis was modified to tracheal stenosis. Cesarean delivery occurred at 315 weeks using an ex utero intrapartum treatment (EXIT) procedure. The neonatology team were unable to perform intubation, suggesting a final diagnosis of tracheal atresia. The male newborn weighed 1920 g and died 1 hour later. Conclusion 3D virtual bronchoscopy is a non-invasive approach to visualizing the fetal upper airways and can be used to diagnose and manage CHAOS.

Tracheal atresia causes some secondary changes (dilated trachea, flattened/inverted diaphragm, hyperintense and hyperinflated lungs). They can be reduced if a high airway fistula is present. This study evaluated fetal MR images of tracheal atresia and the secondary changes, focusing on the presence of a fistula. We assessed fetal MR images of tracheal atresia without fistula (n=4, median 26 weeks), tracheal atresia with fistula (n=4, median 33 weeks) and controls (n=30, median 32 weeks). We evaluated airway obstruction using true-positive rate in tracheal atresia and false-positive rate in controls indicating they are likely normal variants. Tracheal diameter, craniocaudal-anteroposterior ratio of the right hemidiaphragm, lung-to-liver signal intensity ratio, and cardiothoracic ratio were compared among the three groups using the Kruskal-Wallis test followed by pairwise comparison using the Mann-Whitney U test. True-positive rate was 100% in tracheal atresia, while false-positive rate was 20% in controls. The Kruskal-Wallis test showed differences among groups in craniocaudal-anteroposterior ratio and cardiothoracic ratio (P

Tracheal agenesis is a severe congenital disorder with often an emergency presentation. There is acomplete or partial absence of the trachea below the larynx, with the presence or absence of atracheoesophageal fistula. It is a rare differential diagnosis of postnatal respiratory distress and theobstetrician or neonatologist will regularly be surprised by this malformation. The etiology ofTracheal atresia is unknown, therapeutic options are limited thus making this condition a usuallyfatal disorder. In most cases, congenital anomalies of the heart, digestive tract or GUT are present.The main signs are respiratory distress and cyanosis, inability to vocalize and impossible trachealintubation. Isolated tracheal agenesis without any malformation is very rare. Here we report a caseof a preterm neonate born at 33 weeks gestation with tracheal agenesis with no other associatedmalformation. In most cases, the seldom deformation, tracheal agenesis does not get recognizedbefore the child is born.

A term male newborn infant was apneic at birth, and endotracheal intubation was unsuccessful. He was stabilized for transport with a laryngeal mask airway. Laryngoscopy revealed tracheal atresia with intrathoracic distal tracheoesophageal fistula. A laryngeal mask airway may provide ventilation in tracheal atresia patients with a fistula.

Abnormal connections between the esophagus and low respiratory tract can result from embryological defects in foregut development. Beyond well-known malformations, including tracheo-esophageal fistula and laryngo-tracheo-esophageal cleft, rarer anomalies have also been reported, including communicating bronchopulmonary foregut malformations and tracheal atresia. Herein, we describe a case of what we have called “esophageal trachea,” which, to our knowledge, has yet to be reported. A full-term neonate was born in our institution presenting with a foregut malformation involving both the middle esophagus and the distal trachea, which were found to be longitudinally merged into a common segment, 3 cm in length, located just above the carina and consisted of esophageal tissue without cartilaginous rings. At birth, the esophagus and trachea were surgically separated via right thoracotomy, the common segment kept on the tracheal side only, creating a residual long-gap esophageal atresia. The resulting severe tracheomalacia was treated via simultaneous posterior splinting of such diseased segment using an autologous pericardium patch, as well as by anterior aortopexy. Terminal esophagostomy and gastrostomy were created at that stage due to the long distance between esophageal segments. Between ages 18 and 24 months, the patient underwent native esophageal reconstruction using a multistage traction-and-growth surgical strategy that combined Kimura extra-thoracic esophageal elongations at the upper esophagus and Foker external traction at the distal esophagus. Ten months after esophageal reconstruction, prolonged, refractory, and severe tracheomalacia was further treated via anterior external stenting using a semitubular ringed Gore-Tex® prosthesis, through simultaneous median sternotomy and tracheoscopy. Currently, 2 years after the last surgery, respiratory stabilization, and full oral feeding were stably achieved. Multidisciplinary management was crucial for assuring lifesaving procedures, correctly assessing anatomy, and planning for multiple sequential surgical approaches that aimed to restore long-term respiratory and digestive functions.

Tracheal atresia is an extremely rare condition whereby a partial or total obstruction of the trachea is seen. It is almost always lethal, with just a handful of cases that ended with a good outcome. In this study we report on a 15-week male fetus, diagnosed with hyperechogenic lungs, midline heart position and inverted diaphragm. Sonographic findings suggest congenital High Airway Obstruction Syndrome (CHAOS) An ultrasound scan and fetal MRI were not able to point out the exact obstruction level. In spite of extensive counselling, the parents opted to carry on with the pregnancy. Fetal demise was noted on a scan at 19 weeks gestation. After the elective termination of pregnancy, a post-mortem examination showed partial tracheal atresia with no other anomalies. Despite technological progress in CHAOS syndrome, a precise diagnosis and accurate prognosis remain elusive.

Described here are a series of four cases of congenital high airway obstruction in the fetus. All of the patients presented in the second trimester and all had hydrops fetalis. Three cases had bilateral hyperinflated lungs, midline shift of heart, flattening or inversion of the diaphragm, and fetal ascites. Autopsy was performed in one of these three and showed laryngeal atresia. In one fetus, there was only a unilateral huge enlargement of the lung with mediastinal shift. On autopsy, this fetus had atresia of right main bronchus. All parents had terminated the pregnancy following the prenatal diagnosis. Laryngeal atresia is an extremely rare fetal anomaly with dismal prognosis. It is important to differentiate the condition from other lesions with a more favorable prognosis, such as congenital adenomatoid malformation of the lung. Much research is needed in the future to explore the therapeutic options, including fetoscopic intervention or transplantation of stem cell-derived airways.

Background: Tracheal agenesis/atresia (TA) presents with respiratory distress at birth and subsequent difficulty in endotracheal intubation. The antenatal course is complicated by polyhydramnios and premature labor. Case report: We present a newborn baby boy with respiratory distress and unsuccessful intubation. Postmortem neck dissection revealed tracheal atresia with esophageal atresia and high tracheoesophageal fistula. Conclusion: In this variant of tracheal atresia, the coexistent esophageal atresia precluded the establishment of a functional air passage. This variant that does not fall into the any of the described categories in accepted classification systems. The lack of any distal communication makes this case inoperable and fatal.

Congenital high airway obstruction syndrome (CHAOS) is a rare life-threatening fetal condition resulting from obstruction of the upper fetal airway which may be partial or complete. Prenatal diagnosis is crucial as it usually results in stillbirth or death after delivery if unrecognized. We report a case of CHAOS that was diagnosed prenatally due to characteristic ultrasound features. We also briefly review literature in light of current management options.

Summary Background Congenital high airway obstruction syndrome (CHAOS) is a rare fetal anomaly characterized by obstruction of the higher fetal airway. This could be either complete or incomplete and is more commonly seen at the subglottic level, resulting in a spectrum of characteristic secondary features. Case Report In this case study, we report two cases of CHAOS with one showing laryngeal atresia and the other, tracheal atresia. Both these cases showed characteristic findings on a detailed, meticulous USG examination which led to this diagnosis. Conclusions Early and accurate diagnosis offers a window of opportunity for parental counseling and management using procedures such as EXIT (ex-utero intrapartum procedure). Earlier, CHAOS was thought to be incompatible with life; however, with the advent of ex-utero intrapartum procedure, a few cases of post-natal survival have been noted in the literature. In this article, we emphasize the sonographic findings found in CHAOS. Early diagnosis offers an opportunity for a intrauterine fetal intervention in potentially lethal cases.

CHAOS or Congenital High Airway Obstruction Syndrome is a blockage of the fetus’s trachea or larynx due to a number of factors including narrowing of the airway, a web-like membrane or even tracheal atresia. In the uterus, the fetal lungs constantly produce fluid and as a result of this airway blockage in the trachea, the lung fluid cannot escape out of the fetal mouth. Because of this the fetus’s lungs become distended with fluid and over distended lungs can put pressure on the heart and affect the heart’s ability to function. If the heart cannot beat effectively hydrops or congestive heart failure can occur. We present a case of CHAOS with hydrops and associated anomalies, determined prenatally at about 21 weeks by MRI in our hospital.Pulse Vol.7 January-December 2014 p.38-41

Congenital high airway obstruction syndrome (CHAOS) encompasses a heterogeneous group of pathologies leading to poor lung development and difficulty oxygenating the newborn after delivery. While previously uniformly fatal, the ex utero intrapartum therapy (EXIT) procedure has provided a method to treat these patients and provide an airway to potentiate survival. We present a patient diagnosed prenatally with CHAOS secondary to tracheal atresia complicated by severe intra-uterine growth restriction (IUGR) who was successfully delivered via an EXIT procedure at 33-weeks. Multidisciplinary care and planning is paramount.

Rationale: Tracheal atresia (TA) involves complete or partial tracheal absence below the larynx. It involves failure of complete separation of the laryngotracheal diverticulum from the foregut at the 4th gestational week. In TA, the trachea and main bronchi generally proceed in the normal caudal directions. Patient concerns: At the gestational age of 34 weeks and 6 days, a male baby weighing 2290 g was born via cesarean section. A brisk bag was used, and mask ventilation was performed, but was not effective. Intubation was attempted; however, the endotracheal tube did not advance below the vocal cord. Diagnosis: Tracheal atresia. Interventions: An emergent open neck exploration could not reveal the trachea. On computed tomography, the tracheoesophageal fistula (TEF) started from the lower esophagus just above the gastroesophageal junction. The trachea arose upward to form the main bronchus. Outcomes: His parents signed the “Do not resuscitate” form due to poor outcome. On the 23rd day of birth, the baby expired. Lessons: Our case involved TA with tracheoesophageal fistula forming between the trachea and main bronchi in a cephalic direction as detected on computed tomography. Further, the trachea arose from the gastroesophageal junction; thus, it does not belong to any Floyd classification. Herein, we report a TA case with a cephalically developed lung bud.

Congenital high airway obstruction syndrome (CHAOS) is the obstruction of the fetal upper airways, which may be partial or complete. It is usually incompatible with life. Prenatal recognition of the disease is quite important due to the recently described management options. We report here two cases of CHAOS due to tracheal atresia diagnosed by antenatal ultrasonography and fetal MRI. We also briefly review the relevant literature with the associated management options.

Tracheal defects can lead to difficulties in airway management in newborns. Tracheal atresia is a very rare entity with high mortality that presents a challenge to the anesthesiologist. We report a case of a newborn with tracheal atresia, esophageal atresia and double tracheoesophageal fistula, which ventilation, until the 6th day of life, was assured through an esophageal intubation.

Tracheal agenesis (TA) is a severe congenital disorder with often an unexpected emergency presentation. There is complete or partial absence of the trachea below the larynx, with presence or absence of a tracheoesophageal fistula (TOF). A neonate with TA is described, and another 48 cases found in literature are reviewed. Due to absence of a TOF, five cases were diagnosed prenatally because of congenital high airway obstruction syndrome (CHAOS). When a TOF is present, polyhydramnion and several other congenital malformations seen on the ultrasound examination should alert clinicians of potential tracheal problems. Prenatal magnetic resonance imaging (MRI) may provide a definitive diagnosis. Postnatal diagnosis is based on recognition of specific clinical signs in the newborn with TA: respiratory distress with breathing movement without appropriate air entry, no audible cry, and failed endotracheal intubation. Despite progress in surgical interventions, mortality remains high. Prenatal diagnosis of TA is possible, but only if a TOF is absent resulting in CHAOS. Prenatal diagnosis of polyhydramnion and other congenital malformation should alert clinicians of potential tracheal problems. Prenatal MRI may provide a definitive diagnosis.

Severe tracheal stenosis, resulting in functional atresia of the trachea is a rare congenital malformation with an estimated occurrence of two in 100,000 newborns. If no esophagotracheal fistula is present to allow for spontaneous breathing, this condition is usually fatal. We report on a male infant born at 32 weeks of gestation. The patient presented with respiratory distress immediately after delivery due to severe congenital tracheal stenosis resulting in functional atresia of the trachea. Endotracheal intubation failed and even emergency tracheotomy did not allow ventilation of the patient lungs. The patient finally succumbed to prolonged hypoxia due to functional tracheal atresia. The etiology of tracheal atresia and tracheal stenosis is still unclear, but both conditions are frequently combined with other anomalies of the VACTERL (vertebral anomalies, anal atresia, cardiovascular anomalies, tracheoesophageal fistula, esophageal atresia, renal/radial anomalies and limb defects) and TACRD (tracheal agenesis, cardiac, renal and duodenal malformations) association. Conclusion Successful treatment of severe congenital tracheal stenosis and tracheal atresia depends on either prenatal diagnosis or recognition of this condition immediately after birth to perform tracheotomy without delay. Nevertheless, despite any efforts, the therapeutical results of severe tracheal stenosis and tracheal atresia are still unsatisfactory. peerReviewed

Congenital high airway obstruction syndrome (CHAOS) is a life-threatening condition characterized by complete blockage of the fetal airways associated with hydrops. We present a case of CHAOS due to the rare cause of complete tracheal agenesis. The ex utero intrapartum therapy (EXIT) strategy was employed to allow for neck and mediastinal exploration. Thymectomy allowed dissection to the level of the carina demonstrating the confluence of dilated mainstem bronchi but no trachea and no connection to the esophagus. A 2.5 endotracheal tube was inserted into the right mainstem bronchus and secured to the left clavicle. At 3 months of age, the infant succumbed to sepsis from Enterobacter mediastinitis due to friction between the tracheostomy tube and the nasogastric tube resulting in erosion of the esophagus. Complete tracheal agenesis, as seen in this case, is consistent with the failure of normal tracheal elongation as suggested by newer theories of foregut development. This case illustrates the most severe form of tracheal atresia causing CHAOS ever salvaged by the EXIT procedure at birth. The subsequent postnatal course highlights the need for early tracheal replacement in this particularly challenging form of CHAOS.

An unusual anatomic configuration of segmental tracheal agenesis/atresia with esophageal duplication on autopsy in a fetus that demised in utero at 29 weeks is reported. The mother was scanned initially for a cardiac anomaly at 20 weeks and on follow-up scan at 27 weeks had polyhydramnios and underwent amnioreduction. The final autopsy diagnosis was vertebral, ano-rectal, cardiac, tracheoesophageal, renal, and limb malformations (VACTERL). We discuss the autopsy findings along with the embryological mechanisms and compare the configuration with Floyd's classification for tracheal agenesis. The difficulties in prenatal diagnosis are discussed.

Introduction Congenital high airway obstruction syndrome is rare fetal malformation caused by obstruction of fetal airway because of laryngeal or tracheal atresia, subglottic stenosis, laryngeal cyst or laryngeal web. This clinical condition was brought into notice first by Hedrick in the late 1900 [1]. CHAOS is usually caused by atresia or stenosis of the larynx or trachea. The true incidence of CHAOS is unknown. It is important to diagnose it antenatally as it is uniformly lethal. If the syndrome is unrecognized during the prenatal period, it usually results in stillbirth or death shortly after delivery [2]. The prenatal ultrasound findings of CHAOS include large echogenic lungs, flattened or inverted diaphragms, dilated airways distal to the obstruction, and fetal ascites and/or hydrops [3]. Here we present a rare case of CHAOS diagnosed on the antenatal scan. Case Blog A 22 year old primi-gravida was referred for routine anomaly scan at 18 weeks of gestation. There was no history of consanguinity and the family history was unremarkable. Ultrasound examination revealed a single live intrauterine fetus corresponding to a gestational age of 18 weeks. Amniotic fluid was within normal limits. Bilateral lungs were echogenic and enlarged with small heart compressed in between the lungs (Figure 1), dilated bronchi and trachea (Figure 2), mild ascites (Figure 3), and flattened diaphragm (Figure 4). Based on these findings, the diagnosis of CHAOS was made. Patient and her family members were counselled regarding the possible unfavourable outcome of the pregnancy. The patient opted for termination of pregnancy.

To evaluate prenatal magnetic resonance (MR) imaging for diagnosis of fetal chest masses and to determine if MR imaging provides information in addition to that of ultrasonography (US).Eighteen pregnant women were referred for MR imaging of possible fetal chest tumors seen at US (16 congenital cystic adenomatoid malformation [CCAM], two bronchopulmonary sequestration [BPS]). The presence, position, size, and characteristics of masses were determined and correlated with postnatal results.The MR imaging diagnoses were three cases of congenital diaphragmatic hernia, nine of CCAM, two of BPS, and one each of foregut cyst, lung atresia, tracheal atresia, and bronchial stenosis. MR imaging results were in agreement with US results in nine fetuses and in disagreement in nine. MR imaging diagnoses were confirmed at surgery or autopsy in 17 fetuses. MR imaging results led to an error in diagnosis in one fetus with BPS.Fetal chest masses had characteristic MR imaging appearances. MR imaging was accurate for distinguishing congenital diaphragmatic hernia from CCAM and was useful for less common diagnoses and determination of the origin of very large chest tumors. Prenatal diagnosis was changed in some patients owing to MR results and affected treatment and counseling of parents. MR imaging is a valuable adjunct to US for prenatal diagnosis of fetal chest masses.

A spectrum of tracheo-esophageal anomalies has been described in an adriamycin-treated model with common features to the human pattern. Tracheal agenesis was part of this spectrum. It is a rare congenital anomaly that has not been described in embryos. Virgin timed-pregnant Sprague-Dawley rats were injected with adriamycin i.p. at a dose of 2 mg/Kg on days 6‐9 of gestation (plug day 5 day 0). Fetuses were recovered at term and histologic assessment of tracheoesophageal anomalies was made. Also, embryos were removed on different gestational days and the embryology of these defects was analysed. Two out of sixty-two fetuses and nine out of 180 embryos were identified with tracheal atresia. Type III tracheal atresia was seen in the full-term fetuses with a tracheo-esophageal fistula arising from the origin of the left main bronchus. Day 13 embryos did not show normal tracheal development; instead, the lung buds developed from the ventral aspect of the foregut which continued to the stomach as a lower esophageal segment. A blind ending pouch was seen on the ventral aspect of the upper part of the foregut. The embryogenesis of tracheal atresia was similar to that of esophageal atresia except that the blind upper foregut pouch developed ventrally rather than dorsally. Anat. Rec. 252:271‐275, 1998. r 1998 Wiley-Liss, Inc.

A case of a premature infant with tracheal atresia together with an exceptional combination of congenital abnormalities that partially corresponds to the TACRD and VACTERL associations is presented. Tracheal atresia was not detectable in the prenatal ultrasound due to lacking of the typical diaphragmatic and pulmonary findings because of the esophago-tracheal fistula, and therefore the resuscitation team was not prepared for this severe airway complication. After prolonged resuscitation efforts were terminated and the newborn expired after birth. Even without typical warning signs physicians have to be aware of tracheal atresia and airway obstruction if VACTERL or TACRD associations are diagnosed.

We report a rare case of tracheal atresia, without fistula, in a 19 weeks' female fetus. The abnormality was detected by prenatal ultrasonography, which demonstrated a bilateral and uniform hyperechogenicity and enlargement of the lungs, associated with ascites and moderate oligohydramnios. We suggest that oligohydramnios may be helpful in distinguishing the upper respiratory tract obstruction from congenital cystic adenomatoid malformation of the lungs, type III. A morphometric study revealed a three-fold more dense pulmonary vasculature in comparison with two control cases of the same gestational age. The pathological finding of pulmonary and vascular hyperplasia as well as the pathophysiology of the syndrome are discussed.

Congenital high airway obstruction syndrome is a rare but life-threatening condition. Therefore, prenatal diagnosis is important. The obstruction can be due to laryngeal/tracheal atresia or external compression. While a differential diagnosis with congenital cystic adenomatoid malformation (CCAM) type III may be difficult, it is still possible with ultrasonography. In this study, we report a case of bilateral echogenic lungs with hydrops fetalis. After the prenatal diagnosis of laryngeal atresia, the couple opted to have an elective termination of pregnancy performed at 20 weeks of gestation. The diagnosis was confirmed by a complete pathological examination.

A case is reported in which qualitatively, grossly abnormal fetal breathing movements turned out to be indicative of complete tracheal atresia. Fetal breathing movements were vigorous and jerky and of large amplitude; similarly abnormal movements were observed after birth. At postmortem tracheal atresia was diagnosed, in combination with other congenital abnormalities, which pointed to a VATER-association. The combination of a VATER-association with tracheal atresia has only been reported once before. An absence of the normal Hering-Breuer reflex in this case of complete tracheal atresia, probably explains the abnormal fetal breathing pattern. This case is in line with a growing number of reports in literature in which qualitatively abnormal fetal movements were indicative of congenital malformations.

Tracheal atresia is an uncommon congenital malformation with a high mortality rate. Clinical symptoms occur suddenly after birth. The diagnosis is suspected in any infant in whom improved ventilation is obtained despite aggressive attempts at resuscitation. We describe a small gestational week 34 male newborn affected by tracheal atresia without esophageal fistula with associated fetal growth restriction, ascites and polyhydramnios. Post mortem examination revealed a diffuse cyanotic status, abdominal ascites and a low birth weight. A 3 cm tract of trachea was documented that distantly ended in a blind pouch and without tracheoesophageal fistulae and enlarged bulky lungs connected to each other by a common thin-walled bronchus. Histological examination showed a normal conformed larynx and scratchily cartilaginous disks in the proximal tract of the short trachea. Vascular space referred to small arteries and veins, thin bands of fibrous tissue and adipose tissue were detected under the blind pouch. Lung distal airspaces were lined by premature cubic epithelium separated by a broad poorly vascularized interstitium. A striking interstitial and alveolar edema was remarkable.

Treatment of congenital tracheal stenosis/atresia remains essentially unresolved. Previous models of this disease entity have been restricted to rodents and the chick. We sought to establish the principles of a large, surgical animal model of this spectrum of fetal anomalies.Fetal lambs (n = 8) underwent open surgery at 90-112 days gestation. Their cervical tracheas were encircled by a biocompatible polytetrafluoroethylene wrap, so as to extrinsically restrict their external diameter by 25%. Survivors (n = 7) were killed at different time points post-operatively before term. The manipulated tracheal segments were compared with their respective proximal portions (controls). Analyses included morphometry, histology and quantitative extracellular matrix measurements.At necropsy, the typical gross appearance of tracheal stenosis/atresia was present in all manipulated tracheal segments. Histological findings included the virtual disappearance of the membranous portion of the trachea, along with infolding, fragmentation, and/or posterior fusion of cartilaginous rings, often with disappearance of the airway mucosa. There were significant decreases in diameter (P0.001) and total collagen levels (P = 0.005) on the manipulated trachea compared with the control portions. No significant differences were observed in overall elastin or glycosaminoglycan contents. A significant time-dependent increase in elastin was noted on the control, but not the experimental side.In a surgical ovine model, controlled extrinsic compression of the fetal trachea leads to morphological and biochemical findings compatible with the congenital tracheal stenosis/atresia spectrum. This simple and easily reproducible prenatal model can be instrumental in the development of emerging therapies for these congenital anomalies.

A fetus with congenital high airway obstruction syndrome (CHAOS) due to complete tracheal atresia was referred at 31 weeks of gestation after 12 weeks of massive hydrops. The fetus was delivered by the ex utero intrapartum treatment procedure allowing sufficient time while on placental support for bronchoscopy to confirm tracheal atresia and tracheostomy to secure the airway. His postnatal course was complicated by severe capillary leak syndrome secondary to hydrops, diaphragmatic paralysis, tracheobronchial malacia, and the need for chronic ventilatory support. The infant’s tracheobronchial malacia resolved by 5 months of age and normal diaphragmatic function was restored at 9 months allowing him to be weaned from mechanical ventilation. He underwent tracheal reconstruction at 17 months of age. At follow up at 32 months of age he has a patent airway and is the first long-term survivor with CHAOS.