FM Radiology Case - Cavitary Disease Flashcards
Define a cavity in the lung.
Air-containing space surrounded by a wall
What are the elements of a systematic evaluation for cavitary lung disease?
- Number
- Location
- Wall thickness
- Lining of the wall
- Contents
- Other associated findings
What are the two general etiologies leading to multiple cavities?
Hematogeous etiology and bronchogenous etiology
DDx - hematogenous etiology of multiple cavities on lung x-ray?
Metastases, septic emboli, vasculitis
DDx - bronchogenous etiology of multiple cavities on lung x-ray?
Aspiration abscess, TB, coccidiomycosis, bronchiectasis
DDx - single cavities on lung x-ray?
Primary lung cancer, post-traumatic lung cyst, many other diseases
Aspiration lung abscesses are in dependent locations based on the position when the patient aspirated. 85% of aspiration lung abscesses are located in what locations?
Superior segment of lower lobes, axillary sub-segment of anterior and posterior segments of RUL
When can aspiration lung abscesses be ruled out?
When the cavity is located in the apical segment of upper lobes
Where does TB classically occur?
Apical segments of lower and upper lobes
DDx - thick-walled (>5mm cavities)
Aspiration lung abscess, necrotizing pneumonia, squamous cell cancer, blastomycosis, Wegener’s granulomatosis
DDx - thin-walled (<1mm cavities)
M. kansasii, coccidiomycosis, open negative TB, blebs, congenital cysts, metastatic cavitating squamous cell carcinoma from larynx or cervix
DDx - irregular, nodular, shaggy lining of the wall
Lung abscess, necrotizing pneumonia, cavitating primary cancer
DDx - contents - air fluid level
Lung abscess, cavitating primary lung cancer, active bleeding in the cavity
DDx - contents - fungal ball
Aspergillosis
Associated features seen with lung cancer?
Ipsilateral lymph nodes, lytic bone lesion
Associated feature seen with fungal ball?
Adjacent thickening of the pleura
Lesions that evolve?
Infected bullae, aspergilloma, subacute necrotizing asgerillosis, bleeding from Rasmussen’s aneurysm in a tuberculous cavity
Why does aspiration lung abscess occur in the superior segment of lower lobes?
Gravity dependent phenomenon; location of aspiration depends on the position of patient at the time of aspiration. If the patient is supine on their back, the first dependent entry is into the superior segment of lower lobe. If the patient is in right lateral decubitus position, it is the axillary sub-segments of RUL. If you are in supine position with face down, aspiration into lungs does not occur. Hence it is very unusual to encounter aspiration lung abscesses in anterior segments.
What is the process for determining the etiology of a cavity?
- Single or multiple?
If single: location, wall thickness, associated findings
If multiple: vascular or bronchial?
Vascular - sharp contrast with the rest of the lungs
Bronchial - when there is fuzziness around the cavity
