30. Pulmonary abscess
Organ: Lung
Description:
A part of the lung is whitish. Within this white part is an abscess, characterized by the cavity and a white membrane around it.
Diagnosis: Pulmonary abscess
Causes:
- Bronchial obstruction
- Lung cancer
- Foreign body aspiration
- Pneumonia
Theory:
A lung abscess is a localized collection of pus within the lung parenchyme. Around the pus is a pyogenic membrane that is impenetrable. It is made by granulation tissue, connective tissue produced by fibroblasts. Granulation tissue is produced by fibroblasts and contains capillaries and inflammatory cells.
The pyogenic membrane prevents spreading of the infection within, which is good, but also prevents antibiotics from entering the abscess, which is not good. Therefore must abscesses be drained or removed to be treated.
When there is a bronchial obstruction the patient can develop a type of pneumonia called retention pneumonia, which can result in retention abscess.
The whitish lung parenchyme on the prep is a pneumonia. The cavity in the preparation doesn’t contain pus, however the cavity is still visible. The white membrane around the cavity is the pyogenic membrane.
