Parenchymal Lung Diseases and Sarcoidosis Flashcards
Pulmonary Interstitium
Components
- BM of endothelial & epithelial cells
- Collagen fibers
- Elastic tissue
- Proteoglycans
- Fibroblasts
- Mast cells
- Few lymphocytes and monocytes
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/442/930/a_image_thumb.png?1600627560)
Diffuse Parenchymal Lung Diseases (DPLD)
Overview
Diffuse and predominantly chronic changes of the pulmonary CT.
- Affects most peripheral and delicate interstitium in alveolar walls
-
Diseases share clinical signs, sx, radiographic ∆, and pathophysiologic ∆
- ± Intra-alveolar component
- Freq. overlap in histologic features
- Many have unknown etiologies
- Accounts for 15% of noninfectious pulmonary diseases
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/442/529/a_image_thumb.jpg?1600629211)
DPLD
Known Etiologies
- Environmental
- Asbestos
- Silica
- Fumes
- Gases
- Ionizing radiation
- Sequela of ARDS
- Drugs
- Busulfan
- Bleomycin
DPLD
Pathogenesis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/444/296/a_image_thumb.jpg?1600628847)
DPLD
Clinical Features
See clinical and pulmonary functional changes of restrictive disease:
- Dyspnea & tachypnea ⇒ eventual cyanosis without wheezing
- ↓ Oxygen diffusing capacity
- ↓ Lung volumes
- ↓ Compliance
- Pulmonary HTN
- Cor pulmonale
DPLD
Radiographic Features
Diffuse infiltration by small nodules or shadows
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/443/790/a_image_thumb.png?1600627445)
DPLD
Morphology
Similar histologic appearance in late stages:
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/444/224/a_image_thumb.jpg?1600629226)
Honeycomb lung or end-stage lung
Diffuse Parenchymal Lung Diseases
Types
- Idiopathic Pulmonary Fibrosis
- Non-specific Interstitial PNA
- Desquamative Interstitial PNA
- Acute Interstitial PNA
- Cryptogenic Organizing PNA
- aka Bronchiolitis Obliterans with Organizing PNA (BOOP)
Idiopathic Pulmonary Fibrosis
Epidemiology
- Age > 60 years
- 7-16 cases/100k
- ♂ > ♀
- 75% former or current smokers
- Rare familial cases
- Poor prognosis ⇒ 5 year survival rate 50%
Idiopathic Pulmonary Fibrosis
Possible Causes
- Alveolitis ⇒ Fibrosis
- Repeated cycles of alveolitis provoked by unknown agent
- Direct fibrosis
- Aberrant wound healing with fibroblastic proliferation
- Peripheral location ⇒ effect of gravity or aspiration
IPF
Histology
Termed “Usual Interstitial Pneumonia” (UIP)
Pathological definition
Patchy fibrosis most prominent in subpleural region
Temporal heterogeneity ⇒ alternating zones of inflammation, active fibrosis, scarring, honeycomb and normal lung
Usually affects lower lobes.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/447/296/a_image_thumb.jpg?1600630327)
IPF
Radiology
Generally lower lobe and peripheral interstitial changes.
Central lung and upper lobe sparing typical.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/447/715/a_image_thumb.jpeg?1600630208)
IPF
Treatment
- No proven therapy
- Poor response to corticosteroids & combo therapy
- Clinical trials ongoing
- Anti-fibrotic drugs ⇒ some slowing of progression
-
Supportive care
- Pulmonary rehab
- Vaccines
- Nutrition
- Cough control
- Only definitive therapy is lung transplant
Non-specific Interstitial Pneumonia (NSIP)
Epidemiology
- Associations ⇒ HIV, CT diseases, drugs
- Onset 5th and 6th decades
- Earlier than IPF
- Insidious onset
- No male/female predominance
NSIP
Histology
Cellular and fibrosing patterns
Temporal uniformity ⇒ suggests that NSIP is not due to recurrent sequential bouts of alveolitis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/449/070/a_image_thumb.jpg?1600630899)
NSIP
Radiology
CXR not necessarily able to differentiate NSIP from IPF.
CT can show a ground glass appearance (alveolar pattern)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/450/317/a_image_thumb.png?1600631794)
NSIP
Treatment
- Steroids and other immune modulators may be helpful
- Treat underlying rheumatologic disease if present
- Outcomes extremely variable
Diffuse Interstitial Pneumonia (DIP)
Epidemiology
“Desquamative Interstitial Pneumonia”
-
Exclusively in smokers
- Usually heavy 30+ pack years
- Onset in 4th and 5th decade
- More common in men
- 8% of total IPF cases
DIP
Histology
- Airspaces ⇒ many Mφ with brown pigment (yellow star)
- Alveolar septae thickened with lymphocytic infiltrate
- Prominent pneumocytes (arrow)
- Mild interstitial fibrosis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/450/076/a_image_thumb.jpg?1600632174)
DIP
Radiology
More lower lobe involvement.
Ground glass appearance on CT
Milder changes compared to others.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/450/442/a_image_thumb.png?1600632244)
DIP
Treatment
- Quit smoking
- Steroids if needed
- Generally a good prognosis
Cryptogenic Organizing Pneumonia (COP)
Overview
“Bronchiolitis Obliterans Organizing Pneumonia” (BOOP)
- Etiology unknown
- Often linked to viral, drug, or cardiovascular disease
- Idiopathic
- Pt presents with subacute cough and SOB
- Onset 5th decade most commonly
COP
Histology
- Polypoid plugs of loose organizing CT within airspaces
- Do not see interstitial fibrosis or honeycomb lung
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/450/976/a_image_thumb.jpg?1600632611)
COP
Radiology
Subpleural or peribronchial patchy areas of airspace consolidation.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/451/453/a_image_thumb.png?1600632837)
COP
Treatment
Responds well to several months of steroids.
Acute Interstitial Pneumonia (AIP)
Pathophysiology
“Hamman-Rich Syndrome”
- Pathologic features of ARDS appears acutely in pt without known triggers
- Fulminant presentation
- Rapid progressive clinical course
- Average age 50-55 y/o
- Not smoking related
AIP
Histology / Pathology
Termed diffuse alveolar damage (DAD)
- ↑ Pulmonary vascular permeability
- Interstitial inflammation
- Epithelial cell death
- See hyaline membranes lining alveolar spaces
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/452/369/a_image_thumb.jpg?1600633432)
AIP
Radiology
Diffuse, bilateral alveolar infiltrates.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/452/667/a_image_thumb.png?1600633761)
Interstitial Lung Disease
Clinical Approach
- History
- Age
- Fhx
- Drugs, CT diseases, dust exposure, Beryllium, World Trade Center, etc.
- Physical exam
- CXR
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/453/024/a_image_thumb.png?1600634099)
DPLD
Summary Table
![](https://s3.amazonaws.com/brainscape-prod/system/cm/321/453/724/a_image_thumb.jpg?1600634511)
Sarcoidosis
Definition
Need all 3 of the following:
- Compatible clinical symptoms
- Evidence of non-caseating granulomas
- Rule out other causes of granuloma