대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Tuberculous Empyema

Radiologic Findings

Chest PA shows well-defined soft tissue density on right lower lateral hemithorax, based pleural surface.
Pre-contrast CT (only done because of renal failure) shows lobulated contour of mass (35 HU) with obtuse angles, suggestive of pleural mass.
Multiple mediastinal lymph nodes are enlarged with homogenous density, and central necrosis is not seen.
There's a calcification on subcarinal node.
Thoracostomy was done, and some purulent fluid containing AFB was aspirated.

Brief Review

Although pleural infection may be rare, tuberculous effusion is commonly caused by rupture of a subpleural caseous focus into the pleural space.
And tuberculous pleurisy may develop at any stage of active infection.
The diagnosis of tuberculous pleurisy is difficult, usually complaining of pleuritic chest pain and non-productive cough.
And only 40% in tuberculous pleurisy, active pulmonary disease coexisted.
Pleural fluid and/or sputum cultures are positive in 30% of cases, and 50-80% with pleural biopsy and culture.
Rarely, tuberculous pleurisy progresses to become chronic tuberculous empyema, may be defined as persistent, grossly purulent pleural fluid.
Therefore, CT attenuation of empyema may be slightly increased than that of normal fluid, like this case.
Final outcome is extensive fibrothorax, thick calcified pleura.
On contrast-enhanced CT scan, the periphery of empyema may show rim-like enhancement with central low attenuation of fluid.
Mediastinal lymph nodes may show central low attenuation with peripheral rim enhancement or totally homogenous attenuation.
In case of homogenous attenuated lymph nodes, it may be difficult to differentiate from lymphoma or other metastatic lymphadenopathy.
However, small calcification within the lymph node highly suggests tuberculous origin.

References

Hulnick DH, Naidich DP, McCauley DI. Pleural tuberculosis evaluated by computed tomography. Radiology 1983;149:759-765
Neff CC, vanSonnenberg E, Lawson DW, Patton AS. CT follow-up of empyemas: pleural peels resolve after percutaneous catheter drainage. Radiology 1990;176:195-197

Keywords

Pleura, Infection, Bacterial infection,