pathology of restrictive lung disease Flashcards
what is The Interstitium of the Lung
The connective tissue space
around the airways and vessels
and the space between the basement membranes of the alveolar walls
should the alveolar epithelial and interstitial capillary endothelial cell basement membranes be in contact or apart?
contact
what does reduced lung compliance mean in the lungs?
stiff lungs
what does reduced gas transfer in the lungs indicate?
diffusion abnormality
what would ventilation/perfusion imbalance indicate?
when small airways affected by pathology
if a patient has restrictive lung disease, would the FEV1/FVC be lower or higher than normal?
higher
if a patient has restrictive lung disease, would the FVC be lower or higher than normal?
lower
whats the presentation of lung disease?
Discovery of Abnormal CXR
DYSPNOEA
Shortness of Breath on exertion
Shortness of Breath at rest
Respiratory Failure – Type 1
Heart Failure
what are the outcomes of parenchymal (interstitial) lung injury
acute response
chronic response
what are the outcomes of chronic response
usual interstitial pneumonitis UIP
granulomatous response
other patterns
ultimately ending up at fibrosis or end stage honeycomb
what is the acute response of interstitial lung injury?
diffuse alveolar damage
DAD
what is DAD associated with?
major trauma chemical injury/toxic inhalation circulatory shock drugs injection]auto(immune) disease radiation can be idiopathic
histological features of DADS
Protein rich oedema Fibrin Hyaline membranes Denuded basement membranes Epithelial proliferation Fibroblast proliferation Scarring - interstitium and airspaces
what are the two types of graanulomatous response?
sarcoidosis
hypersensitivity pneumonitis
what is sarcoidosis
A multisystem granulomatous disorder
of unknown aetiology
whats the histopathology of sarcoidosis?
epithelioid and giant cell granulomas
necrosis
little lymphoid infiltrate
what is the incidence of sarcoidosis in UK
3-4/100,000
what is the most likely organ involved in sarcoidosis?
lymph nodes and lung
whats the presentation of sarcoidosis
young adult
abnormal CXR- no sympt
sob, cough abnormal CXR
how do you diagnose sarcoidosis?
Clinical findings
Imaging findings
Serum Ca++ and ACE
Biopsy
what type of hypersensitivity gives you granulomatous responses?
type 4
what are the antigens of hypersensitivty pneumonitis?
Thermophilic actinomycetes Micropolyspora faeni Thermoactinomyces vulgaris Bird / Animal proteins - faeces, bloom Fungi - Aspergillus spp Chemicals Others
what is acute presentation of hypersensitivity pneumonitis?
Fever, dry cough, myalgia,
Chills 4-9 hours after Ag exposure
Crackles, tachyopnoea, wheeze
Precipitating antibody
what are the chronic presentation of hypersensitivity pneumonitis?
Insidious
Malaise, SOB, cough
Low grade illness
Crackles and some wheeze
is hypersensitivity pneumonitis type 3 or 4 mediated?
both, 3 and 4
what can cause usual interstitial pneumonitis?
idiopathic pulmonary fibrosis
connective tissue diseaases
drugs, asbestos, viruses
what type of pneumocyte hyperplasia contributes to usual interstitial pneumonitis
2
is UIP chronic or acute inflammation?
chronic
what age would you normally be to get idiopathic pulmonary fibrosis?
elderly >50
what gender gets pulmonary fibrosis more?
M>F
what do people clinically show with pulmonary fibrosis
dyspnoea, cough, basall crackles, cyanosis, clubbing
what 2 options can the bulk flow be?
laminar or turbulent
does hypoventilation increase or decrease paCO2
increase
what is the most common cause of hypoxaemia?
low V/Q (ventilation/perfusion)
does CO2 or oxygen diffuse faster?
CO2 diffuses 20 times faster than o2
why does co2 diffuse faster than o2?
greater solubility
what does diffusion impairment mean?
takes longer for blood and alveolar air to equilibriate , particulary oxygen
how long does equilibration normally takes?
0.25
how long does capillary transit time normally take?
0.75
how long does equilibration take in disease?
0.75
how can hypoxaemia be corrected?
increasing FIO2
what does increasing the FIO2 do to PAO2?
increases it
