Laboratory Studies
If findings are positive, blood culture helps to guide antibiotic therapy in patients with pneumatocele. If sputum is available, this is a good noninvasive method to discover potential pathogens. If effusion is present, culturing pleural fluid from thoracentesis can be a direct method to identify the causative organism. Tests for bacterial antigen detection can be performed on blood, urine, and pleural fluid.
Imaging Studies
Initial chest radiography often reveals pneumonia without evidence of a pneumatocele. Parapneumonic effusion or empyema can be present. Radiographic evidence of a pneumatocele most often occurs on day 5-7 of hospitalization. Rarely, it may be visible on the initial chest radiograph. Chest radiograph findings are shown in the images below.
Usually, chest CT scanning with contrast is not necessary to diagnose a pneumatocele, but CT scanning occasionally helps to differentiate an abscess from a pneumatocele (see the image below).
Rarely, CT-guided needle aspiration of the pneumatocele can relieve compression from a large and/or tension pneumatocele.
Procedures
Percutaneous catheter drainage should only be considered for a significant tension pneumatocele or a secondarily infected pneumatocele. In these rare situations, drainage has been reported to dramatically improve the patient's cardiovascular status. [14, 15]
Histologic Findings
Pathology is not commonly observed because most pneumatoceles resolve without surgical resection. However, a few reports documented necrotic material around the pneumatocele. Cavity walls can contain organized inflammatory cells with focal collections of multinucleated giant cells. In 1972, Boisset reported the presence of air corridors between the bronchiolar lumen and the interstitial space. [7]
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Pneumonia with multiple pneumatoceles.
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Pneumonia with pneumatocele (lateral).
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Resolving pneumatocele.
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Chest CT scan of pneumonia with pneumatocele.
