Choanal atresia is a congenital disorder where the back of the nasal passage (choana) is blocked, usually by abnormal bony or soft tissue (membranous) due to failed hole development of the nasal fossae during prenatal development. It causes persistent rhinorrhea, and with bilateral choanal atresia and obstructed airway that can cause cyanosis and hypoxia. Choanal atresia is diagnosed based on the inability to place a nasal catheter, and radiology results (particularly CT scans). Treatment involves maintaining an open airway, and may involve surgery to reopen the airway, potentially with a stent. Choanal atresia is a fairly rare condition, affecting between 1 in 7,000 to 1 in 5,000 live births. Presentation
Choanal atresia can be unilateral or bilateral. A unilateral choanal atresia may not be detected until much later in life because the baby manages to get along with only one nostril available for breathing. Symptoms are minor, including persistent rhinorrhea (mainly normal mucus) and chronic sinusitis. Bilateral choanal atresia is a life-threatening condition because the baby will 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. Cyanosis may improve when the baby cries, as the oral airway is used. These babies may require airway resuscitation soon after birth. Associated conditions
Choanal atresia is associated with a higher risk of other airway problems, including:

tracheomalacia. laryngomalacia.
Tobacco smoking cessation is strongly recommended since tobacco smoke exposure can worsen fibrosis. Severe cases of fibrothorax may require supportive mechanical ventilation if the affected person is unable to breathe adequately on their own.In cases of fibrothorax caused by medication, it is recommended that the offending medications be stopped. Ergot alkaloid medications, which can worsen pleural fibrosis, are typically avoided. Cases of fibrothorax attributable to medication typically stop worsening if the provoking medication is stopped. In some situations, medication-induced fibrothorax improves after stopping the causative medication but fibrothorax usually does not completely resolve.Watchful waiting is appropriate for milder cases of fibrothorax in certain situations. Fibrothorax caused by tuberculosis, empyema, or haemothorax often improves spontaneously 3–6 months after the precipitating illness. Corticosteroids are commonly used to treat fibrothorax but are not well-supported by available evidence. Surgical
In severe cases of fibrothorax that are compromising a persons ability to breathe, the scar tissue (fibrous peel) causing fibrothorax can be surgically removed using a technique called decortication. However, surgical decortication is an invasive procedure which carries the risk of complications including a small risk of death, and is therefore generally only considered if severe symptoms are present and have been for many months. Surgical decortication is generally considered for people with fibrothoraces that are severe, causing significant shortness of breath, and have otherwise relatively healthy lungs since this enhances the likelihood of a better outcome. Surgical removal of the pleura (pleurectomy) may be performed in refractory cases, as often happens when asbestosis is the cause.