Congenital Lung Abnormalities

CONGENITAL PULMONARY AIRWAY MALFORMATION
Congenital pulmonary airway malformation are a heterogenous group of cystic and non cystic lung lesion that largely result from early airway maldevelopment. Congenital pulmonary airway malformation may communicate with the proximal airways. although this communicationis abnormal. Most of them derive their blood supply from the pulmonary artery and drain via pulmonary veins, with the exception of hybrid lesions, which can have a systemic blood supply.
A fast growing congenital pulmonary airway malformation may cause mediastinal shift and subsequent development of polyhydramnions and hydros. It well established  that indicators of a poor prognosis include large lesions, bilateral lung involvement and hydrops.
If not recognized antenatally, congenital pulmonary airway malformation are usually discovered between the neonatal period and 2 years of age, manifestating as respiratory difficulty or infection. Symptomatic infants who are diagnosed postnatally   are treated with surgical resection, which generally  consists of lobectomy or segmental resection.

CONGENITAL LOBAR OVERINFLATION
Congenital lobar overinflation also referred to as congenital lobar emphysema, is characterized by progressiive lobar overexpansion, usually with compression of the remaining (ipsilateral) lung. The underlying cause can be secondary to an intrinsic cartilaginous abnormality with resultant weak or absent bronchial cartilage,  extrinsic compression of an airway (eg, by a large pulmonary artery or a bronchogenic cyst). In either case, the collapsed airway can act as one-way valve, resulting in air trapping. Although the alveoli expand, the alveolar walls remain intact, therefore, the term emohysema is technically inaccurate.
Although most patients with congenital lobar overinflation present in the neonatal period, typically with respiratory distress, congenital lobar overinflation can be detected in utero by ultrasonography and magnetic resonance imaging.

BRONCHIAL ATRESIA
Bronchial atresia is a rare anomally resulting from focal obliterasion of a segmental, subsegmental or lobar bronchus. The bronchi distal to the stenosis are dilated and filled with mucus, with mild hyperinflation of the adjacent lung due to collateral air drift. In bronchial atresia, the airway is occluded rather than narrowed, consequently, there is no ball-valve effect as seen in congenital lobar overinflation.  Hence, the lobe or segment does not become nearly as hyperinflated as with congenital lobar overinflation. This may be the reason why congenital lobar overinflation manifest in the neonatal periods, whereas bronchial atresia is usually found incidently in adults.

BRONCHOGENIC CYSTS
Bronchogenic cysts are part of the spectrum of foregut duplication cysts and are  developmental lesion resulting from abnormal ventral budding of the tracheobronchial tree, probably  occuring between the 26th and 40th days of fetal life. They are mostly situated in the mediastinum, typically near the carina. Less commonly, they may occur within the lung parenchyma, pleura or diaphragm
Most bronchogenic cysts are found incidentally. In  infants, symptoms are generally caused by compression of the trachea or bronchii and esophagus, leading to wheezing, stridor, dyspnea and dysphagia. Intraparenchymal cysts may manifest with recurrent infection. Symptomatic cysts are generally resected surgycally.