Choanal atresia

Most cases of choanal atresia are sporadic, although familial cases suggest autosomal dominant or autosomal recessive modes of a single gene defect. Approximately one-half to two-thirds of patients with choanal atresia have associated malformations, which occur more frequently with bilateral atresia. The most common of these is the CHARGE association:

Ans. is ‘b’ i.e., Cleft lip and palate

Carbimazole causes

o Scalp or patchy hair defect o Choanal atresia

o Esophageal atresia

o Psychomotor delay

o Fetal goitre

o Minor facial anomaly

o Tracheoesophageal fistula

o Hypoplastic or absent phalanges

Ans. is ‘c’ i.e., Congenital heart disease (Cyanotic)

Ans. is ‘b’ i.e., Choanal atresia

o Bilateral choanal atresia is a very serious life-threatening condition because the baby is unable to breath directly after birth as neonates are obligate nasal breathers.

o In some cases, this may present as cyanosis while the baby is feeding because the oral air passages are blocked by the tongue.

o The cyanosis may improve when the baby cries, as the oral airway is used at this time.

o These babies may require airway resuscitation soon after birth.

Ans. is a i.e. Difficulty in breathing

• Choanal atresia is usually U/L.
• If it occurs bilaterally the neonate presents with difficulty in breathing as infant is a nose breather and does not breathe from mouth. The neonate may have asphyxia and bilateral blockage of nose that also makes suckling difficult.
• U/L atresia presents with nasal obstruction including snoring but goes unidentified till adult life.
•  Bilateral choanal atresia presents as respiratory ilistress in ne*born and requires support immediately after birth.

Choanal atresia is associated with CHARGE syndrome: Coloboma of eye, Heart defects, Choanal Atresia, Retarded growth, Genital defects and Ear defects.

Thus posterior rhinoscopy and not anterior rhinoscopy are useful in the diagnosis of choanal atresia.

Acoustic rhinometry is a new technique which evaluates nasal obstruction by analysing reflections of a sound pulse introduced via the nostrils. The technique is rapid, reproducible, non-invasive and requires minimal cooperation from the subject. A graph of nasal cross-sectional area as a function of distance from the nostril is produced, from which several area and volume estimates of the nasal cavity can be derived. The role of acoustic rhinometry in diagnosis is somewhat limited compared to nasal endoscopy, but it is useful for nasal challenge and for quantifying nasal obstruction. It is helpful in evaluating childhood nasal obstruction, as it is well tolerated by children as young as 3 years old-a group of patients to whom objective tests have hitherto been difficult to apply.

It is due to persistence of bucconasal membrane and may be unilateral or bilateral, complete or incomplete, bony (90%) or membranous (10%). Unilateral atresia is more common and may remain undiagnosed until adult life. Bilateral atresia presents with respiratory obstruction as the newborn, being a natural nose breather, does not breathe from mouth. Diagnosis of choanal atresia can be made by (i) presence of mucoid discharge in the nose, (ii) absence of air bubbles in the nasal discharge, (iii) failure to pass a catheter from nose to pharynx, (iv) putting a few drops of a dye (methylene blue) into the nose and seeing its passage into the pharynx, or (v) flexible nasal endoscopy, (vi) installing radio-opaque dye into the nose and taking a lateral film, and (vii) computed tomography (CT) scan in axial plane is more useful.

Ans. is ‘a’ i.e., Choanal atresia

Choanal atresia

• Choana, also called posterior nares, is an opening in the posterior part of each nasal cavity, through which nasal cavity communicates with nasopharynx. Choanal atresia is a congenital anomaly characterized by closure of one or both posterior nasal cavities (i.e., choana). It is due to persistence of bucconasal membrane. Approximately 60­70% of cases are unilateral and are more common on right side. Bilateral cases occurs in 20-30% of patients and 50% of these patients are associated with other congenital anomaly, i.e., CHARGE syndrome → Coloboma, Heart defects, Choanal atresia, Retraded growth, Genitourinary abnormalities and Ear defects.

Diagnosis

• Unilateral lesions go unnoticed until the child presents with persistent unilateral nasal discharge. There is absence of air bubbles in nasal discharge. A simple test for unilateral choanal atresia is to have the child attempt nose blowing with opposite nostril occluded by external pressure. Failure to detect any air movement is suspicious for complete obstruction. Bilateral choanal atresia presents as respiratory distress in newborn and requires support immediately after birth.

Ans. is `b’ i.e., Choanal atresia

Diseases with fowl smelling nasal discharge are:

Nasal myiasis

Foreign body in nose

Rhinolith

In choanal atresia there is presence of nasal discharge without air bubbles.

• Choanal atresia is an abnormality of canalization during development of the nasal passages.
• It involves bone and/or soft tissue and may result in either partial (choanal stenosis) or complete obstruction of the posterior nasal airway.
• The most widely accepted mechanism for the development of choanal atresia is the persistence of the bucconasal membrane beyond the sixth week of gestation, but abnormal migration of cephalic neural crest cells following neural tube closure also has been implicated.
• The incidence of choanal atresia is 1 in 7000 to 8000 live births. It is more common in females (2:1), more likely to be bony or cartilaginous than membranous (9:1), and more commonly unilateral and right-sided (2:1).

Ans. B.  CT SCAN

CT SCAN in choanal atresia

CT SCAN in coronal and saggital projections provides a thorough evaluation of choanal atresia and adjescent structures.

The axial views supply fundamental information including site of obstruction, composition of atretic plate and unilateral or bilateral involvement.

Thus CT SCAN is the preferred imaging modality.