Diagnosis: Lung abscess
PA chest radiograph shows a consolidative opacity in the right upper lobe (arrow). Axial enhanced CT scan obtained 7 days later shows a right upper lobe consolidative opacity (arrows) with central cavitation, consistent with lung abscess.
Discussion
Lung parenchymal abscess is defined by central necrosis and diameter greater than 2 cm.
-
Abscesses most commonly result from aspiration or necrotizing pneumonia, and less commonly complicate infarcts or contusions.
-
In aspiration, causative organisms include mixed anaerobic and aerobic gingival flora (e.g., Bacteroides, Fusobacterium, Klebsiella, Staphylococcus, Pseudomonas). Fungi (e.g., Aspergillus, Candida) and parasites (e.g., Entamoeba) are also sometimes implicated.
Symptoms often have a subacute onset over weeks.
-
Typical, nonspecific signs and symptoms include fever, production of foul-smelling sputum, leukocytosis, and hemoptysis.
-
Elderly patients and others at risk for aspiration are more vulnerable. 70 to 80 percent of affected patients are smokers.
-
Immunocompromised patients are at greater risk.
Prognosis is poor without early diagnosis and treatment.
-
Image-guided aspiration is avoided for lesions >4 cm in the acute phase because of risk of spillover of infected contents into normal lung.
-
Treatment with antibiotics for an extended period is required; drainage is seldom needed, in contradistinction to abscesses in other organ systems.
-
Interventions are generally reserved for non-resolving abscesses or when the abscess abuts the chest wall.
The typical imaging appearance is a thick-walled cavitary lesion with surrounding consolidation, containing debris or gas–fluid levels. Abscesses are more common in dependent portions of the lung.
-
Chest radiography is the modality of choice for initial evaluation of any patient with a clinical presentation concerning for pulmonary infection.
-
Additional uses of chest x-ray in the management of pulmonary abscess include:
-
Monitoring of response to therapy
-
Detection of important complications such as pneumothorax, empyema, bronchopleural fistula, and pulmonary hemorrhage
-
Identification of additional or alternative diagnoses
-
-
CT may be needed for further diagnostic clarification in some cases, and to guide therapeutic interventions.
Abscess may sometimes be difficult to distinguish from empyema on chest x-ray or CT. Imaging findings that distinguish abscess from empyema are summarized in the following table:
| Abscess | Empyema |
|---|---|
| Intermediately thickened (4–15 mm) walls | Thin walls |
| Spherical | Lenticular |
| Surrounded by consolidation | “Split pleura” sign (CT) |
| Equal-length air-fluid levels on frontal and lateral radiographs | Different-length air fluid levels on frontal and lateral radiographs |
| Narrow interface with chest wall (CT) | Broad contact with chest wall |
| Bronchovascular markings extend to abscess | Adjacent compressed lung |
Related posts:
12 68-year-old man with left lower quadrant pain and hypotension
32 32-year-old male complaining of chest pain after upper endoscopy
28 30-year-old male presented with a palpable left testicular mass
29 19-year-old male presented with acute onset right scrotal pain
53 42-year-old female presenting with fever and back pain
66 21-year-old male with quadriplegia after diving into a shallow pond. The patient struck his head against an embankment, with his head flexed, chin against chest
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
