Acute bronchitis is thought to reflect an inflammatory response to infections of the
epithelium of the bronchi. Epithelial-cell desquamation and denuding of the airway
to the level of the basement membrane in association with the presence of a lymphocytic
cellular infiltrate have been demonstrated after influenza A tracheobronchitis9;
microscopical examination has shown thickening
of the bronchial and tracheal mucosa corresponding
to the inflamed areas. Such pathological
findings are consistent with reports of proximal
lower airway inflammation confined to the bronchi,
as detected by positron-emission tomography
with 18F-fluorodeoxyglucose as a tracer, in the
setting of acute bronchitis.10