TB, Lung Abscess, and Cystic Fibrosis

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TB, Lung Abscess, and Cystic Fibrosis
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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

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TB

• Patchy left lower lobe opacity
• Looks like pneumonia

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TB

• Right upper and lower lobe consolidation
• Right pleural effusion

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TB

• Cavitary right upper lobe lesion
• Right paratracheal lymphadenopathy
• Right middle lobe infiltrate
• Notice the ipsilateral lymphadenopathy

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TB

• Thick walled cavity with satellite nodules
• Smooth inner wall

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TB

• Focal right middle lobe infiltrate
• Nodular like infiltrate
• Endobronchial spread of TB
• Adjacent areas of lung are infected by bronchial
  secretions

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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

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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

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TB

• Complications of TB cavities
• Mycetoma fungus ball
• Rasmussen Aneurysm which is weakening of
  bronchial artery adjacent to a cavitary lesion

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Rasmussen Aneurysm
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TB

• Bilateral lung nodules resulting from
  endobronchial spread of TB
• Right upper lobe cavity

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Miliary TB

• Right paratracheal lymphadenopathy
• Bilateral tiny uniform nodules
• Diffuse pattern of nodules is due to hematogenous
  spread

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Miliary TB
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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

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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

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Pneumococcal PNA

• Complications
• Lung necrosis
• Abscess formation
• Often need clinical history to distinguish from TB

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Lung Abscess

• Air fluid level within a large cavity
• Can communicate with the pleura resulting in an
  empyema

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Lung Abscess
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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

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Lung Abscess

• Irregular cavity
• Typically more posterior
• Often has an air/fluid level within it
• Often has surrounding infiltrate

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Lung Abscess

• Cavity with air fluid level and foul smelling
  sputum
• Anaerobic organisms often the cause of abscesses
  from aspiration

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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

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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

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Cystic Fibrosis

• Hyperinflation
• Upper lobe bronchiectasis
• Tram tracking