How many stages does lobar pneumonia progress through?

Lobar pneumonia is typically divided into four stages: congestion and edema stage, red hepatization stage, gray hepatization stage, and resolution stage. The specific classification is as follows:

1. Congestion and Edema Stage

The first stage is the congestion and edema phase, which usually occurs within 1 to 2 days after disease onset. Patients commonly present with high fever and chills, accompanied by serous exudate. Chest imaging reveals patchy, poorly defined shadows.

2. Red Hepatization Stage

The second stage is the red hepatization phase, typically appearing around 4 to 5 days after onset. During this stage, cyanosis or hypoxia may develop, characterized by extensive red blood cell exudation.

3. Gray Hepatization Stage

The third stage is the gray hepatization phase, usually occurring about 5 to 6 days after onset. Rust-colored sputum gradually changes into mucopurulent sputum. The main features include massive fibrin exudation along with numerous neutrophils.

4. Resolution Stage

The fourth stage is the resolution phase, generally beginning approximately 7 days after onset and sometimes lasting up to two weeks. During this period, body temperature decreases and symptoms gradually improve, with macrophages becoming predominant.

Lobar pneumonia is a typical bacterial pneumonia, most commonly caused by Streptococcus pneumoniae. It tends to involve an entire lobe or segment of the lung and presents with prominent clinical symptoms. Therefore, treatment primarily focuses on controlling pulmonary infection, requiring comprehensive management, usually centered on antimicrobial drug therapy supplemented by symptomatic treatments. In daily life, during outbreaks of respiratory infections such as influenza—especially in winter and spring—it is advisable for patients to avoid crowded places as much as possible.