Lobar Pneumonia is the most deadly variant of pneumonia. It infects the entire lobe of the lung. It is categorised into four stages:
Congestion: The first stage is marked by the spread of infection in one of the lobes. This stage usually lasts for a day. Lungs become red and inflamed by this stage.
Red hepatization: This stage lasts for a few days. By this stage, alveoli are unable to filter oxygen and other gases into the blood. Fibrous tissue accumulates around the alveoli, and the lungs become firm and dry.
Grey hepatization: This stage appears a couple of days after the second stage. The spread of fibrous tissue increases and RBCs are destroyed. This leads to greying or discolouration of tissues of the lung.
Resolution: This is the recovery phase of lobar pneumonia. By this stage, immune cells and enzymes start creating defence mechanisms against the infection, fibrous tissues start dissolving, and alveoli start regaining functionality.