tb, lung abscess, and cystic fibrosis. tb radiographic findings in primary tb are nonspecific tends...
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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