Flashcards in Lec 15 ARDS Path Deck (24):
Histologically what do you see with acute lung injury / ARDS?
mostly = see diffuse alveolar damage
less common = diffuse alveolar hemorrhage, acute eosinophilic pneumonia
What is acute interstitial pneumonia?
idiopathic diffuse alveolar damage
What are some common causes of ARDS?
- fulminant infection
- post trauma
- drug overdose
What is pathogenesis of diffuse alveolar damage?
- not well understood
injury related to vascular endothelium and alveoli results in excess vascular fluid and protein leakage [early]
later --> cellular necrosis, epithelial hyperplasia, inflammation, fibrosis
What is pathology of DAD?
- acute diffuse alveolar damage + necrosis of type I pneumoncytes
- exudation of protein rich fluid into alveolai that organizes into hyaline membranes
recovery = hyperplasia of type II pneumocytes and interstitial fibrosis
What are the 3 overlapping phases of DAD?
- exudative phase [days 1-7]
- proliferative/organizing [7-12]
- fibrotic phase [> 21 days]
What are gross features of lungs in ARDS?
What do you see in exudative phase of DAD [1st wk after injury]?
- interstitial and alveolar edema
- fibrin exudate
- hyaline membranes [days 3-7]
What is simple eosinophilic pneumonia? What usually causes it?
- mild self limited pulmonary infiltrates + peripheral blood eosinophilia
usually due to ascaris
What do you see in tropical eosinophilic pneumonia? What usually cause it?
high fever, wheezing, peripheral blood eosinophilia
usually 2ndary to filarial infection
What do you see in chronic eosinophilic pneumonia?
subacute illness; fever dyspnea peripheral blood eosinophilia
patchy infiltrates that resolve + reappear in same location
pt usually has asthma history
Who get chronic eosinophilic pneumonia? What causes it?
- seen in patients with asthma history
can be idiopathic or due to drug toxicity, L-tryptophan ingestion, fungus, parasites
What do you see in acute eosinophilic pneumonia?
- acute onset respiratory failure + severe hypoxemia
often have no peripheral blood eosinophilia; usually no history of asthma
What do you see clinically/histologically in eosinophilic pneumonia?
- intra-alveolar fibrin, macrophages, abundant eosinophils, eosinophil microabscesses
+/- organizing pneumonia
Eosinophilic pneumonia is sensitive to what treatment?
sensitive to steroids
How do people with acute eosinophilic pneumonia represent?
may present with respiratory failure = clinically have ARDS
What do you see histologically in acute eosinophilic pneumonia?
hyaline membranes like those in DAD but plus eosinophils
What are histo features of classic/chronic EP?
intra-alveolar fibrin and macrophages
What is organizing pneumonia?
airspace organization = loos connective tissue in alveolar seen as common manifestation of lung injury as lung attempts repair
What are some settings where you see organizing pneumonia?
- as primary porcess [OP pattern]
- as component of another process [HSP, acute pneumonia]
- secondary reaction adjacent to unrelated process [next to tumor, granuloma, abscess]
What is organizing pneumonia pattern?
specific pattern of organizing pneumonia centered around small airways
presents in subacute way with SOB and cough
What do you see histologically in OP pattern of organizing pneumonia?
- patchy bronchiolocentric organizing pneumonia
- may have fibroblastic plugs in small airway lumens
- minimal chronic inflammation in adjacent alveoli
- interveneing lung is normal
- no other significant findings
What are potential etiologics of OP pattern?
- associated wtih collagen vascular disease, drug reaction