Disorders of the Respiratory Tract in Children

Abstract

Atelectasis describes an incomplete expansion of lung tissue, which may be congenital or acquired. Congenital atelectasis is due to incomplete expansion of the lungs, including primary and secondary congenital atelectasis, whereas the most common causes of later atelectasis are loss of air in lung tissue previously expanded or collapse of a lung or lung tissue. Several pulmonary and extrapulmonary conditions may cause atelectasis. Occlusion of the bronchial lumen is the most common cause and may be due to airways inflammation and mucous plug, to increased viscosity of the bronchial mucus and to foreign bodies, among other causes. In occlusion of the bronchial lumen, the air of the occluded lung tissue has gradually been absorbed by the perfusing blood. Atelectasis may also occur during anesthesia. The middle right lobe is often the location of atelectasis caused by pulmonary infections as bronchiolitis or airways inflammation during asthma and is often called middle-lobe syndrome. Atelectasis may occur without clinical signs; plain chest radiography at end-inspiration is important for diagnosis. Multislice computed tomography may point to the diagnosis when plain x-rays do not suffice, and magnetic resonance imaging is well suited for the diagnosis and follow-up of atelectasis. Bronchography combined with diagnostic and therapeutic bronchoscopy may be diagnostic in selected cases. Chest physiotherapy is often the first-line treatment, but its efficacy is not yet proven. Middle-lobe atelectasis has been associated with positive bacterial cultures; in such cases antibiotic treatment may be tried. Bronchoalveolar saline lavage with or without direct instillation of dornase alfa has been tried on rare occasions, and lobectomy has been tried in cases of persistent right-middle-lobe and left-lower-lobe syndrome not responding to intensive medical therapy. Stent placement has been tried in carefully selected patients, with biodegradable stents offering a new alternative.