Path: interstitial lung diseases Flashcards
1
Q
Restrictive lung diseases
A
- Characterized by cellular fibrosis and/or inflammation of the alveolar septal wall
- The interstitial pattern share a common pathway of honeycombing fibrosis
2
Q
Idiopathic pulmonary fibrosis (IPF) 1
A
- Interstitial pneumonitis of undetermined etiology
- Grossly the lung is firm and gray, showing honeycombing fibrosis w/ a cobblestone appearance of the overlying pleural
- Mico there is the UIP (usual interstitial pneumonia) pattern: patchy involvement of the lung by fibrosing interstitial pneumonitis (geographic heterogeneity- some parts are affected and others aren’t)
3
Q
Idiopathic pulmonary fibrosis (IPF) 2
A
- There is also temporal heterogeneity: variation in the age of fibrosis w/ areas of young fibrosis (fibroblast foci- whorls of fibroblasts within the fibrosed areas) and older fibrosis
- Honeycombing (mostly near the lobular septa): destruction of alveoli w/ formation of cystic spaces lined by bronchiolar epithelium
- Usually in UIP there is extensive interstitial fibrosis very close to normal looking lung
- Process of honeycombing: interstitial inflammation-> alveolar inflammation-> cellular proliferation-> honeycombing cysts
4
Q
Idiopathic pulmonary fibrosis (IPF) 3
A
- The UIP pattern can be seen in other disease (such as asbestos), and when there is an identifiable etiology the Dx is not IPF
- Clinical presentation: insidious dyspnea or dry cough, clubbing (hypoxemia findings), restrictive PFTs, associated w/ rheumatoid arthritis (may have ANA/RF), mostly affects lower lobes and starts more central working its way to periphery
- If in the setting of RA the Dx is not IPF, but CTD-ILD (IPF only when there is not etiology)
- RA presents like IPF and has the same UIP pattern on CT and micro
5
Q
Bronchiolitis obliterans - organizing pneumonia (BOOP AKA OP)
A
- Morphologic pattern: plugs of fibrous tissue filling bronchiolar lumens (bronchiolitis obliterans) and alveolar ducts/spaces (organizing pneumonia)
- OP in the setting of rheumatoid arthritis gives the Dx CTD-ILD (interstitial lung disease due to CTD)
- OP w/ no etiology is called cryptogenic organizing pneumonia (COP)
6
Q
Diffuse alveolar damage (DAD)
A
- Characterized by hyaline membranes, looks like eosinophilic “rope” material lining interstitium
- There is breakdown of the alveolar septum resulting in edema
- Caused by infection, shock, trauma, aspiration, noxious fumes, drugs, radiation
- DAD in setting of sepsis give the Dx ARDS
- DAD in the setting of no etiology gives the Dx AIP
- DAD + bleomycin -> DIP
7
Q
Nonspecific interstitial pneumonitis (NSIP)
A
- 2 types: cellular and fibrosing
- These are a better prognosis than IPF so its important to know which one the pt has
- In cellular type the alveolar walls are very thick, w/ fairly normal airsapces
- In fibrosis type there are some dilated airspaces and some small airspaces (due to fibrosing of the interstitium)
- NSIP w/ amiodorone: drug-induced ILD
- NSIP w/ no etiology: NSIP (better Dx than IPF)
8
Q
Hypersensitivity pneumonitis 1
A
- Inflammation of the peripheral lung resulting from hypersensitivity reaction to inhaled antigens (birds, mammals, fungi)
- There is interstitial pneumonitis w/ lymphoblastic infiltrate, and usually poorly formed interstitial and peribronchiolar granulomas (+/- giant cells) but no eosinophils (one difference w/ asthma)
- Can show a UIP pattern and/or BOOP, together w/ seasonal changes in Sx suggest hypersensitivity pneumonitis (think air conditioners, farmers)
9
Q
Hypersensitivity pneumonitis 2
A
- Tufts of organizing fibrous CT in terminal and respiratory bronchioles and alveolar ducts (organization of fibrin)
- Clinical: can be acute or chronic w/ chills and flu-like Sx starting 2-9 hrs after exposure during acute reactions
- Chronic exposure characterized by gradual onset of cough and exertional dyspnea
- CXR shows diffuse reticulonodular patter
- Often seen in farmers, tobacco growers, pigeon breeders
10
Q
Drug-induced pneumonitis
A
- Drugs can cause a wide range of different types of pneumonitis
- DAD is most often seen w/ bleomycin toxicity
- Bleomycin toxicity is worse when there is prior or concurrent radiation or chemo, older age, or high levels of inspired O2
- Sx: cough and dyspnea
- Must do biopsy to exclude infection, recurrent tumor
11
Q
Asbestosis
A
- Response to inhaled asbestos fibers
- Results from inability of macrophages to successfully phagocytose the asbestos fibers, leading to inflammatory reaction and parenchymal damage
- Pts w/ asbestosis usually got it from working in ship boilers, insulation, roofing, brake repair for >15 yrs
- Grossly, the lungs are firm, white-gray fibrous parenchyma (esp lower lobes)
- Micro there’s fibrosis around respiratory bronchioles and subsequent extension of fibrosis producing a UIP pattern
- Can see asbestos bodies, which are fibers (usually brown) w/ knobs on the end (drumstick appearance)
- CXR: pleural plaques on diaphragm, bibasilar reticular infiltrates mostly in lower lobe
- Sx: dyspnea, cough, clubbing, restrictive PFTs
12
Q
CT scans of various restrictive diseases
A
- UIP has a very distinct CT scan appearance and will not require a lung biopsy if identified
- There are sub pleural reticulations (net-like opacities that radiate from the pleura) and honeycombing, which are scattered lucent cysts (usually near pleural)
- These are usually found in lower lobes
- This is compared to NSIP, which has a ground glass appearance: very fine scattered and abundant opacities mixed w/ relatively normal lung
- Many other diseases can mimic the NSIP scan so anything that is not UIP must be biopsied
- If the UIP pattern can be identified there is no need to biopsy, but it the pattern is not UIP you MUST biopsy to get the Dx
13
Q
Rx for restrictive diseases
A
- It is important to distinguish each Dx from IPF b/c IPF will not respond to immunosuppression and has a very poor prognosis
- Most other diseases will respond to immunosuppression
