A client is diagnosed with early pneumococcal pneumonia. What does the nurse recognize occurs during the first stage of pneumococcal pneumonia?

Pneumococcal pneumonia classically progresses through four stages. The first stage is called congestion or engorgement, during which the affected alveoli become filled with a protein-rich edema fluid that contains numerous Streptococcus pneumoniae organisms along with increasing numbers of red blood cells. This flooding of the alveolar spaces represents the lung's initial inflammatory response to bacterial invasion — the capillaries become engorged and leak fluid and organisms into the alveolar space. The second stage is red hepatization, during which the lung takes on a liver-like consistency as massive numbers of polymorphonuclear leukocytes (PMNs), red blood cells, and fibrin fill the alveoli. The third stage is gray hepatization, in which macrophages begin to arrive and phagocytose the fragmented PMNs, red blood cells, and debris — this corresponds to the answer describing macrophage activity. The fourth stage is resolution, during which the alveolar exudate is removed and lung tissue is revitalized. Therefore, the arrival of macrophages describes stage three, alveolar exudate removal and revitalization of lung tissue describe stage four, making the protein-rich edema fluid with organisms and red blood cells the correct description of the first stage.