plastic bronchitis

Plastic bronchitis

Plastic bronchitis (PB) is a disorder in which branching casts of the airways – i.e., accumulations of fluid or tissue that are molded in the shape of the airway – are expectorated. PB is not a single disease with a defined mechanism that explains the cast formation in all conditions. Examples of diseases associated with expectoration of casts, and which sometimes are labeled PB, include tuberculosis, atypical mycobacterial disease, allergic bronchopulmonary aspergillosis, and asthma. When casts are very large with many branches, an abnormal communication or leakage of lymphatic fluid into the airway is often the cause. This entity is termed lymphatic plastic bronchitis (LPB). LPB is a lymphatic flow disorder characterized by the recurrent formation of branching, rubbery bronchial casts composed primarily of proteinaceous and sometimes chylous material and lymphocytes. Lymphatic fluids deposited into the airspaces become gelatinous as they cool, forming large string cheese-like casts of the airways, which can obstruct airflow. Attempts to expectorate casts can be quite frightening, leading to fears of asphyxiation.