TB, Lung Abscess, and Cystic Fibrosis

TB

• Radiographic findings in primary TB are Nonspecific

• Tends to like the lower lung zones• Cavitation is not as common in primary TB

as in reactivation TB• However lymphadenopathy is a common

finding in primary TB and uncommon in reactivation TB

TB

• Patchy left lower lobe opacity

• Looks like pneumonia

TB

• Right upper and lower lobe consolidation

• Right pleural effusion

TB

• Cavitary right upper lobe lesion

• Right paratracheal lymphadenopathy

• Right middle lobe infiltrate

• Notice the ipsilateral lymphadenopathy

TB

• Thick walled cavity with satellite nodules

• Smooth inner wall

TB

• Focal right middle lobe infiltrate

• Nodular like infiltrate• Endobronchial spread

of TB• Adjacent areas of lung

are infected by bronchial secretions

TB

• Radiographic findings usually present 2 years after initial infection

• Infiltrates usually like the apical and posterior segments of upper lobes and superior segment of lower lobes

TB

• CT scan through the upper chest shows a thick walled cavity with an air fluid level and surrounding infiltrate

• Cavities result from caseous necrosis

TB

• Complications of TB cavities

• Mycetoma “fungus ball”

• Rasmussen Aneurysm which is weakening of bronchial artery adjacent to a cavitary lesion

Rasmussen Aneurysm

TB

• Bilateral lung nodules resulting from endobronchial spread of TB

• Right upper lobe cavity

Miliary TB

• Right paratracheal lymphadenopathy

• Bilateral tiny uniform nodules

• Diffuse pattern of nodules is due to hematogenous spread

Miliary TB

TB Key Points

• Imaging findings of primary TB are nonspecific

• Primary TB differentiated from bacterial pneumonia by the presence of lymphadenopathy

• Reactivation TB recognized by fibrocavitary disease and a history of prior exposure

TB Key Points

• Inactive disease cannot be established without prior films

• Primary TB tends to affect the lower lung zones while reactivation TB tends to affect the upper lung zones

Pneumococcal PNA

• Complications• Lung necrosis• Abscess formation• Often need clinical

history to distinguish from TB

Lung Abscess

• Air fluid level within a large cavity

• Can communicate with the pleura resulting in an empyema

Lung Abscess

Lung Abscess

• 54 year old male with cough and foul smelling sputum

• Cavity within the superior segment of the left lower lobe

• Common site for aspiration

Lung Abscess

• Irregular cavity• Typically more

posterior• Often has an air/fluid

level within it• Often has surrounding

infiltrate

Lung Abscess

• Cavity with air fluid level and foul smelling sputum

• Anaerobic organisms often the cause of abscesses from aspiration

Lung Abscess Key Points

• Typical radiographic appearance is an irregular cavity with an air fluid level

• Lung abscesses from aspiration often occur in the posterior segments of upper lobes or superior segments of lower lobes

• The wall thickness of lung abscesses progresses from thick to thin and irregular to well circumscribed

Cystic Fibrosis

• Abnormal sodium/chloride transport in exocrine tissues

• Results in thick viscous mucus• Obstructs airways resulting in repeat

infections and colonization• Airways dilate and cysts form from air

trapping• Scarring from the repeated infections

Cystic Fibrosis

• Hyperinflation• Upper lobe

bronchiectasis• Tram tracking