What is Choanal Atresia?
Choanal atresia is a birth defect where the openings between the nose and the back of the throat, known as the nasal choanae, get blocked by soft tissue, bone, or both. This happens when the nasal passages don’t fully open during development in the womb. If it only happens on one side, it can lead to a discharge from the affected nostril. If it happens on both sides, it can prevent the newborn from being able to breathe, because newborns are built to breathe through their noses. When it results in breathing difficulty, it’s an immediate emergency that ear, nose, and throat doctors need to address.
What Causes Choanal Atresia?
The nasal passages, also known as choanae, are developed between the third and seventh weeks of being an embryo. This is done through a process where a vertical skin-like layer between the smell-sensitive area and the roof of the mouth (also called the stomodeum) ruptures or breaks.
Researchers have proposed several theories to explain how choanal atresia, a congenital disorder characterized by a blockage in the back of the nasal passage, forms. These include:
– Persistence of the buccopharyngeal membrane: This means that a certain membrane in the embryo did not vanish as it normally should.
– Persistence of the nasobuccal membrane of Hochstetter: Similarly, this is when another membrane in the embryo lingers instead of disappearing.
– Incomplete absorption of the nasopharyngeal mesoderm: Here, a certain tissue in the embryo did not fully integrate.
– Misdirection of neural crest cell migration: This implies that certain important cells did not move to the right places.
Scientists have been linking these theories to studies on molecules and genes to further understand the causes of choanal atresia.
Risk Factors and Frequency for Choanal Atresia
This birth defect occurs in between 1 in 5,000 and 1 in 8,000 live births. It’s more likely to affect only one side of the body, rather than both (60% vs. 40%). It also occurs more often in females than in males, with a ratio of 2:1.
Signs and Symptoms of Choanal Atresia
Choanal atresia is a condition where the passageway between the nose and throat is blocked. How this affects a person can differ quite a lot, mainly depending on whether one or both passageways are blocked.
When both passageways are blocked in new-borns, it can intermittently lead to trouble breathing, which gets worse when they are resting and better when they are crying. This is known as paradoxical cyanosis. Infants with this condition may also display feeding difficulties, including choking while feeding because they can’t breathe and eat at the same time.
On the other hand, if only one passageway is blocked, it rarely causes breathing troubles in newborns. But, it’s most often noticed with symptoms like repeated nasal discharge from the affected nostril or past occurrences of chronic sinusitis. In some cases, it may not even be properly diagnosed until adulthood due to these less specific symptoms.
Besides these, choanal atresia can sometimes exist alongside other conditions. One of the more common ones is CHARGE syndrome, which features a range of problems including issues with the eye (coloboma), heart disease, growth and mental development issues, underdevelopment of sexual organs, and ear anomalies.
- Difficulty breathing in resting and crying infants (bilateral choanal atresia)
- Choking during feeding (bilateral choanal atresia)
- Repeated nasal discharge (unilateral choanal atresia)
- Past occurrences of chronic sinusitis (unilateral choanal atresia)
- Possible link with CHARGE syndrome: Coloboma, heart disease, growth and mental developmental issues, underdevelopment of sexual organs, and ear anomalies
Testing for Choanal Atresia
Immediately after a baby is born, it’s important to check their health. Doctors might suspect a condition called choanal atresia if the baby has trouble breathing through their nose. To check this, a tiny mirror is placed under the baby’s nostril to see if it fogs up with breath. Additionally, a tiny flexible tube is carefully passed through the nostril to the baby’s mouth.
These tests can suggest the possibility of choanal atresia, but it’s crucial to get a definitive diagnosis. For this, a doctor can use a tool called a nasal endoscope. This is a flexible, lighted tube inserted into the newborn’s nose. It allows the doctor to see whether there is any blockage in the nasal passage. Before using the nasal endoscope, the doctor prepares the baby by cleaning out their nose and suctioning out any mucus.
To confirm the diagnosis, a CT scan (a type of X-ray that provides detailed pictures of the inside of the body) is run to specifically look at the blockage. This scan not only confirms the presence of choanal atresia but also shows all the small details, like how big the blockage is and whether there is a bone involved in the blockage.
The CT scan is also useful in ruling out other conditions that may look like choanal atresia but are actually different issues. For example, the baby’s nasal bone may be narrow (a condition called pyriform aperture stenosis), there could be cysts in the tear duct (nasolacrimal duct cysts), the nasal tissue could be abnormally large (turbinate hypertrophy), the baby’s nasal septum may be dislocated or deviated, or there could be a growth or tumor in the nose (antrochoanal polyp or nasal neoplasm).
Treatment Options for Choanal Atresia
Choanal atresia is a condition where the back of a person’s nasal passage is blocked, typically by abnormal bony or soft tissue. The primary treatment for this condition is surgery. The aim of the surgery is to clear this blockage (restore choanal patency), minimize impact on the patient’s facial development, limit invasiveness, and reduce the chances of the condition returning.
In cases where only one side of the nasal passage is blocked (unilateral choanal atresia), surgery may not be urgently needed. It can usually be postponed until the child is older and their facial structure is more similar to that of an adult. However, it’s important to keep an eye out for any signs of breathing problems. Using nasal saline sprays can help to keep the nasal passage clear.
If a baby is born with both sides of their nasal passage blocked (bilateral choanal atresia) and they’re struggling to breathe, immediate action would be necessary. A tube could be placed in their windpipe (endotracheal intubation) to help them breathe. Alternatively, a special device (McGovern nipple) could be used to maintain an adequate airway.
There are several different surgical techniques that can be used to treat choanal atresia. Until recently, the most common approach was through the roof of the mouth (transpalatal). But with advancements in technology and experience, surgeon’s nowadays prefer an approach through the nose (endoscopic endonasal approach). This is because it provides better results and fewer surgical complications than traditional procedures.
After surgery, some surgeons use a supportive device (choanal stenting) or a medication called mitomycin C to prevent the blockage from coming back. However, the overall benefit of using these methods after choanal atresia surgery is still a topic of debate as there’s no clear evidence to prove their effectiveness.
What else can Choanal Atresia be?
Here’s a list of medical conditions that could be related to nose or nasal problems:
- Antrochoanal polyp (a non-cancerous nasal growth)
- Chordoma (a rare type of bone cancer)
- Deviated nasal septum (uneven partition between nostrils)
- Dislocated nasal septum (the partition between the nostrils is pushed out of position)
- Hematoma (an abnormal collection of blood outside of a blood vessel)
- Isolated piriform aperture stenosis (narrowing of the nostril’s opening)
- Nasal dermoid (a type of cyst that forms at the base of the nose)
- Nasolacrimal duct cyst (a blockage in the tear ducts)
- Septal dislocation (misalignment of the nasal septum)
- Turbinate hypertrophy (enlargement of the structures within the nose)