Croup pathophysiology

Associate Editor-In-Chief: Ujjwal Rastogi, MBBS [mailto:urastogi@perfuse.org]

Overview
The viral infection that causes croup leads to swelling of the larynx, trachea, and large bronchi due to infiltration of white blood cells (especially histiocytes, lymphocytes, plasma cells, and neutrophils). Swelling produces airway obstruction which, when significant, leads to dramatically increased work of breathing and the characteristic turbulent, noisy airflow known as stridor.