Introduction

Congenital choanal atresia is due to congenital closure between the nasal cavity and pharynx. Bilateralchoanal atresia is suspected when a new born infant presents with respiratory distress and cyanosis relieved by crying.Early surgical management is indicated in bilateral cases as soon as the general condition of the infant is stabilised.

Case Report

A 2.52 kg neonate girl was born to Gravida 1 Para1 mother followingfullterm normal deliveryat St. Stephen’s Hospital, Delhi APGAR score at the time of birth was 9,9,9.Soon after birth the baby developed respiratory distress with cyanosisand her paO2 dropped to 88% at room air. A size 5French suction catheter could not be passed through the nares to nasopharynx. Baby wasimmediately resuscitated and shifted to neonatal intensive care unit.

Clinical examination of the baby revealed an active vigorous girl with intermittent cyanosis.Respiratory rate was 46-50 per minuteand chest was bilaterally clear.But the baby continued to developintermittent respiratory distress with laboured breathing, cyanosis and fall in oxygen saturation.These episodes would resolve spontaneosly with the baby turning pink on crying.Respiratory distress was precipitated whenever oral feeding was attempted. Hence orogastric feeding was started which the baby tolerated well.

Chest X-ray was normal. Routine blood investigations were done. Echocardiogram confirmed a small VSD with left to right shunt. No other abnormalities were detected on detailed systemic examination. Eyes and ears were found to be normal.With a provisional diagnosis of choanal atresia, a high resolution CT Scanof nose and pharynx was done which revealed bilateral choanal atresia with thick bony obstruction more on the left side. (Figure 1)

Mouth breathing was encouraged by a nipplesecured in mouth. Orogastrictube feeding was continued. In spite of these conservative measures, no significant improvement in spontaneousnasal breathing and oral feeding could be achieved. Hence surgical repair was planned.

Choanae were reconstructed by transnasal endoscopic approach. Intraoperativelythe diagnosis was confirmedby examination with a 0 degree 2.7mm nasal endoscope. Both choanae were found tobe completely blocked by bony atretic plates. A number 6uretheral sound could not be passed. After packing the naso pharynx, posterior septal flaps were elevated. Postero inferior part of the bony septum was removed usingotologic drill and curettes and continued until the posterior choanae were opened. Drilling was confined toposterior, medial and inferior part of the nasal cavity. Flaps were reposited anda3 number endotracheal tube fashioned as a stent was kept in both nasal cavities and secured in place.Stent wasremoved after four weeks.Nasal endoscopy four weeks after surgery revealed bilateral patent choanae with minimal oedema of the flap on left side (Figure 2 & 3).Child is under regular follow up and is able to breathe through the nose and breastfeed without any distress.

Discussion

Congenital choanal atresia is adevelopmental failure of posterior nasal cavity tocommunicate with the nasopharynx.First described in 1755 by Roederer, it has an incidence of 1 in 6000 to 8000 births(1).Obstruction may be membranous in10% or bony in 90% of cases. 65-75% is unilateral.75% of bilateral cases are associated with other anomalies (2). The most frequent anomalies being CHARGE syndrome, Down’s syndrome, and Treacher collin’s syndrome. Bilateral bony atresia was present in this baby with a small ventricular septal defect but other abnormalities were absent.

Pathophysiologyhas been attributed to persistence of the buccopharyngeal membrane, failure of bucconasal membrane of Hochstetter to rupture, medial outgrowth of the vertical and horizontal processes of the palatine bone and mesodermal adhesion formation in the choanalregion.(3)

Newborn baby is an obligate nasal breather until 4-6 weeks. Bilateral choanal atresia produces complete nasal obstruction and can leadto aspiration and asphyxiation in early life.Cycles of respiratory obstruction and cyanosis relieved by crying is suggestive of this condition.Further, these episodes get precipitated while feeding and during sleep.At this point, emergency care is by inserting an oral airway.Inability to pass a 5F catheter through the nostrils to nasopharynxwill prove the diagnosis.This can be further confirmed by a flexible nasopharyngoscopy and CT scanning. High resolution computedtomography is the investigation of choice in the diagnosis and evaluation of congenital choanalatresia (4).CT scan helps the surgeon to assess the type of atresia,thickness of atresia,other causes of nasal obstruction like amidnasal stenosis and abnormalities of the skullbase. CT scan of this baby revealed bilateral bony obstruction and was useful in planningfurther treatment.

Several procedureslike, transnasal, transplatal and trans septalapproaches have been described for the repair of choanal atresia(5).The objective of repair is to correct the anatomical abnormality and provide a good long term nasal airway with least interference to the surrounding structures.With the availability of paediatric nasal endoscopes and micro surgical drilling devices transnasal endoscopic approach has gained popularty(6,7).Nasal endoscope allows the surgeon to have excellent visualization of atretic plate while drilling. Hence operating time is shorter and the blood loss is less(8).

Postoperative stenting using silastic or portex endotracheal tubes is recommended fora minimum period of four weeks (9). Postoperative medical treatment  includes nasal decongestants,saline nasal spray  and antibiotics to deal with bacterial rhinitis.Good care of the stent and removal of granulation tissue and follow up examination with endoscopes alsoplay a major role in postoperative management.Meticulous post operative care greatly influences the success of the surgical procedure(9).

In conclusion, computed tomography is the definitive investigation in case of congenital choanal atresia.Early surgical repair is indicated in bilateral choanal atresia. Transnasalendoscpic repair provides exellent results.

References

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3. Ted L .Tewfik (Author), Arlen D. Meyers(Chief editor). Choanal atresia. emedicine.medscape.com/article/872409-overview#ao104. Accessed on 2/6/2012.
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