What Histological Changes are Observed in Common Pulmonary Diseases?
Asthma In asthma, histological examination often shows airway inflammation, thickening of the basement membrane, and increased mucus production. These changes can cause airway obstruction and hyperresponsiveness, which are reflected in PFTs as reduced forced expiratory volume (FEV1) and peak expiratory flow rate (PEFR).
Chronic Obstructive Pulmonary Disease (COPD) COPD is characterized by a combination of emphysema and chronic bronchitis. Histologically, emphysema shows destruction of alveolar walls leading to enlarged air spaces, while chronic bronchitis shows increased mucus gland size and goblet cell hyperplasia. These changes result in airflow limitation, which is evident in PFTs as a reduced FEV1/FVC ratio.
Pulmonary Fibrosis Pulmonary fibrosis features excessive deposition of fibrous tissue in the lung parenchyma. Histologically, this can be seen as thickened alveolar walls and interstitial fibrosis. The restrictive pattern observed in PFTs, characterized by reduced total lung capacity (TLC) and diffusion capacity, can be attributed to these structural changes.
