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.

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