🪟 Pulmonary Alveolar Proteinosis (PAP) 🪟
- Rare cause of insidious-onset dyspnea on exertion
- On DDx of Crazy Paving on chest CT
- Due to 👇 production/clearance of surfactant
- Rare cause of insidious-onset dyspnea on exertion
- On DDx of Crazy Paving on chest CT
- Due to 👇 production/clearance of surfactant
What is Crazy Paving?
🪟 Ground glass opacification (GGO) w/ superimposed thickening of interlobular septa & intralobular interstitium
🪟 See below for anatomy of the secondary pulmonary lobule!
🪟 Graphics by @LandsbergManual
🪟 Ground glass opacification (GGO) w/ superimposed thickening of interlobular septa & intralobular interstitium
🪟 See below for anatomy of the secondary pulmonary lobule!
🪟 Graphics by @LandsbergManual
In PAP, 👇 production/clearance of surfactant can be due to 3 categories of disease:
- 👇 GM-CSF signalling (required for macrophage clearance of surfactant)
- 👇 surfactant production (essentially, congenital diseases)
- Secondary etiologies (dust, heme-related, infxn)
- 👇 GM-CSF signalling (required for macrophage clearance of surfactant)
- 👇 surfactant production (essentially, congenital diseases)
- Secondary etiologies (dust, heme-related, infxn)
🪟 In adults, autoimmune PAP is most common (90%) & due to anti-GM-CSF antibodies. Commonly seen in 4th-5th decades, frequently in smokers.
🪟 On pathology, distal airways have characteristic PAS (+) lipoproteinaceous material with little-to-no inflammatory infiltrate.
🪟 On pathology, distal airways have characteristic PAS (+) lipoproteinaceous material with little-to-no inflammatory infiltrate.
🪟 CXR shows bilateral, symmetric, central alveolar opacities
🪟 HRCT scan of the chest shows GGOs in a predominantly homogeneous distribution +/- Crazy Paving. This eventually progresses to fibrotic lung disease, as mentioned by @jonherochung:
brown.edu
🪟 HRCT scan of the chest shows GGOs in a predominantly homogeneous distribution +/- Crazy Paving. This eventually progresses to fibrotic lung disease, as mentioned by @jonherochung:
brown.edu
References:
1) #H10" target="_blank" rel="noopener" onclick="event.stopPropagation()">uptodate.com
2) pubs.rsna.org
3) @LandsbergManual
4) brown.edu
5) rarediseases.info.nih.gov
1) #H10" target="_blank" rel="noopener" onclick="event.stopPropagation()">uptodate.com
2) pubs.rsna.org
3) @LandsbergManual
4) brown.edu
5) rarediseases.info.nih.gov
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