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an abnormal condition in which a normal opening or tube in the body (as the urethra) is closed or absent

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/06/18 18:51:57」(JST)

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Choanal atresia is a congenital disorder where the back of the nasal passage (choana) is blocked, usually by abnormal bony or soft tissue formed during fetal development.

Presentation[edit]

It can be unilateral or bilateral.

Sometimes, a unilateral choanal atresia is not detected until much later in life because the baby manages to get along with only one nostril available for breathing.

Bilateral choanal atresia is a very serious life-threatening condition because the baby will then be unable to breathe directly after birth as babies are obligate nasal breathers (they mainly use their noses to breathe). In some cases, this may present as cyanosis while the baby is feeding, because the oral air passages are blocked by the tongue, further restricting the airway. The cyanosis may improve when the baby cries, as the oral airway is used at this time. These babies may require airway resuscitation soon after birth.

Associated conditions[edit]

Sometimes babies born with choanal atresia also have other abnormalities:

coloboma
heart defects
mental retardation
growth impairment
others (see also CHARGE syndrome)

Also any condition that causes significant depression of the nasal bridge or midface retraction can be associated with choanal atresia. Examples include the craniosynostosis syndromes such as Crouzon syndrome, Pfeiffer syndrome, and Antley-Bixler syndrome.

Diagnosis[edit]

Choanal atresia can be suspected if it is impossible to insert a nasal catheter.^[1] Also, if one notices a continuous stream of mucous draining from one or both nostrils, it could be a sign of an atresia. Another common sign is cyanosis in an infant while breast feeding, as breathing is dependent on nasal patency in this situation.^[1] Diagnosis is confirmed by radiological imaging, usually CT scan.^[1]

Risk factors[edit]

Very few risk factors for choanal atresia have been identified. While causes are unknown, both genetic and environmental triggers are suspected.^[2] One study suggests that chemicals that act as endocrine disrupters may put an unborn infant at risk. A 2012 epidemiological study looked at atrazine, a commonly used herbicide in the U.S., and found that women who lived in counties in Texas with the highest levels of this chemical being used to treat agricultural crops were 80 times more likely to give birth to infants with choanal atresia or stenosis compared to women who lived in the counties with the lowest levels.^[3] Another epidemiological report in 2010 found even higher associations between increased incidents of choanal atresia and exposure to second-hand-smoke, coffee consumption, high maternal zinc and B-12 intake and exposure to anti-infective urinary tract medications.^[4]

Treatment[edit]

Temporary alleviation can be achieved by inserting an oral airway into the mouth. However, the only definitive treatment is surgery to correct the defect by perforating the atresia to create a nasopharyngeal airway. If the blockage is caused by bone, this is drilled through and stent inserted. The patient has to have this sucked out by an air vacuum machine . And in later life as a teenager or in early twenties the hole will have to be re-drilled larger.

A stent may be inserted^[5] to keep the newly formed airway patent or repeated dilatation may be performed.^[6]

=

^ ^a ^b ^c Choanal atresia - PubMed Health
^ Choanol atresia, NIH PubMed Health, August 2011.
^ Study: Exposure to herbicide may increase risk of rare disorder - Baylor College of Medicine
^ Epidemiology of choanal atresia - the National Birth Defects Prevention Study, Vijaya Kancherla, University of Iowa, 2010.
^ Sadek SA (January 1998). "Congenital bilateral choanal atresia". Int. J. Pediatr. Otorhinolaryngol. 42 (3): 247–56. doi:10.1016/S0165-5876(97)00142-0. PMID 9466228.
^ Gosepath J, Santamaria VE, Lippert BM, Mann WJ (2007). "Forty-one cases of congenital choanal atresia over 26 years--retrospective analysis of outcome and technique". Rhinology 45 (2): 158–63. PMID 17708465.

7- A New Stent for use in Children with Choanal Atresia,The British Association for Paediatric Otorhinolaryngology Annual academic Meeting’ 8 September 2006 –Birmingham, Sanjeet Agrawal, Sarwat Sadek

UpToDate Contents

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1. 鼻の先天異常 congenital anomalies of the nose
2. 鼻閉塞の臨床症状、診断、および治療 clinical presentation diagnosis and treatment of nasal obstruction
3. 新生児におけるチアノーゼの概要 overview of cyanosis in the newborn
4. DiGeorge (22q11.2 deletion) syndrome: Clinical features and diagnosis
5. 頭蓋顔面異常を伴う症候群 syndromes with craniofacial abnormalities

English Journal

Partial trisomy 4q and partial monosomy 9p in a girl with choanal atresia and various dysmorphic findings.

Cakmak-Genc G1, Karakas-Celik S2, Dursun A2, Piskin İE3.
Gene.Gene.2015 Sep 1;568(2):211-4. doi: 10.1016/j.gene.2015.05.022. Epub 2015 May 13.
We report a new-born girl with partial trisomy of 4q28-qter and partial monosomy of 9p24-9ter. Our patient has choanal atresia, hypertelorism, wide nasal bridge, high arched palate, discrete nipples, heart defects, myoclonic seizures and various dysmorphic findings. Standard chromosomal analysis wit
PMID 25979671

Management of congenital choanal atresia: A pedodontist's role.

Niloofar F, Parvathy K, Varma BR1, Mamachan XA.
Journal of the Indian Society of Pedodontics and Preventive Dentistry.J Indian Soc Pedod Prev Dent.2015 Jul-Sep;33(3):259-61. doi: 10.4103/0970-4388.160407.
Choanal atresia is a rare cryptic congenital anomaly with developmental failure of the nasal cavity to communicate with the nasophaynx, resulting in a significant physiological and anatomical alteration of the dento-facial complex. It is considered as a life-threatening or lethal congenital malforma
PMID 26156284

Interstitial 1p32.1p32.3 deletion in a patient with multiple congenital anomalies.

Kehrer M1, Schäferhoff K1, Bonin M1,2, Jauch A3, Bevot A4, Tzschach A1,5.
American journal of medical genetics. Part A.Am J Med Genet A.2015 Jun 10. doi: 10.1002/ajmg.a.37178. [Epub ahead of print]
Interstitial deletions encompassing chromosome bands 1p32.1p32.3 are rare. Only nine unrelated patients with partially overlapping 1p32.1p32.3 deletions of variable size and position have been reported to date. We report on a 17-month-old boy with choanal atresia, hearing loss, urogenital anomalies,
PMID 26061568

Japanese Journal

鋤骨を除去したことで経過良好であった先天性後鼻孔閉鎖の１例

大塚雄一郎,岡本美孝
小児耳鼻咽喉科 35(1), 27-32, 2014
先天性奇形である先天性後鼻孔閉鎖の手術には経口蓋，経鼻中隔，経鼻，経上顎洞など様々なアプローチ法が報告されている。内視鏡導入以前には経鼻的アプローチの手術は視野と手術操作が制限されるため再狭窄が多いという欠点があった。しかし内視鏡が導入されてから経鼻的アプローチは先天性後鼻孔閉鎖の手術において第一選択となった。<br/> 内視鏡により視野と術野が拡大され，後鼻孔を大きく開放するこ …
NAID 130004992687

Endocrinological Characteristics of 25 Japanese Patients with CHARGE Syndrome

Shoji Yasuko,Ida Shinobu,Etani Yuri,Yamada Hiroyuki,Kayatani Futoshi,Suzuki Yasuhiro,Kosaki Kenjiro,Okamoto Nobuhiko
Clinical Pediatric Endocrinology 23(2), 45-51, 2014
… CHARGE syndrome is a congenital disorder caused by mutation of the chromodomain helicase DNA binding protein 7 (CHD7) gene and is characterized by multiple anomalies including ocular coloboma, heart defects, choanal atresia, retarded growth and development, genital and/or urological abnormalities, ear anomalies, and hearing loss. …
NAID 130004853599

内視鏡的治療を行った後天性後鼻孔閉鎖例

黒田優美,上條篤,高橋吾郎 [他],山本卓典,遠藤周一郎,森山元大,増山敬祐
耳鼻咽喉科臨床 105(11), 1047-1051, 2012-11-01
… We report on a case of acquired choanal atresia which arose from palatal deformation caused by syphilis that the patient had had 40 years ago. …
NAID 10031128267