What describes the pathophysiology of pneumonia?

The pathophysiology of pneumonia is characterized primarily by inflammation and consolidation of lung tissue as a response to infection. When pathogens, such as bacteria, viruses, or fungi, invade the lung parenchyma, the body mounts an immune response that leads to the accumulation of inflammatory cells and fluid in the alveoli. This process results in the consolidation of lung tissue, meaning that the normally air-filled spaces become filled with this fluid and immune cells.

This inflammation can impair gas exchange, as the fluid-filled alveoli cannot effectively transfer oxygen and carbon dioxide. Symptoms often associated with pneumonia include cough, fever, difficulty breathing, and chest discomfort, which arise as the body attempts to clear the infection and recover from the inflammation.

In contrast, the other options describe different respiratory conditions. Constriction of airways leading to reduced airflow pertains to asthma or chronic obstructive pulmonary disease, while infection of the pleura surrounding the lungs refers to pleuritis or pneumonia that has spread to the pleural space. Lastly, obstruction of air passages by foreign objects typically relates to choking incidents and is not a characteristic of pneumonia. Thus, the primary hallmark of pneumonia is indeed the inflammation and consolidation of lung tissue due to infection.