Segmental atelectasis refers to the collapse of a specific segment
of the lung, leading to reduced or absent air within that area. It
occurs when a segmental bronchus becomes obstructed, often due
to mucus plugs, tumors, foreign bodies, or inflammation, which
prevents air from reaching the alveoli in that segment. The affected
lung tissue then collapses as the trapped air is absorbed, resulting
in a loss of lung volume. Symptoms can include shortness of
breath, cough, and chest discomfort, but segmental atelectasis may
also be asymptomatic and found incidentally on imaging. Diagnosis
is made through chest X-rays or CT scans, where the collapsed
segment appears as an area of increased density with volume loss,
often accompanied by signs like displacement of fissures or
crowding of vascular structures. Treatment depends on the
underlying cause and may involve bronchoscopy to clear
obstructions, physiotherapy to improve lung expansion, or other
interventions to restore normal airflow.