Restrictive (Interstitial) Lung Diseases Flashcards
What is interstitium?
The connective tissue space
around the airways and vessels
and the space between the basement membranes of the alveolar walls
Describe the relationship between the normal alveolar wall and most of the alveolar epithelial (pneumocyte) & interstitial capillary endothelial cell basement membranes
They are in direct contact
What is the material which impedes the elasticity of the alveoli (reducing compliance)?
Collagen
What are the characteristics of Restrictive – Diffuse - Interstitial Lung Disease?
•Reduced Lung Compliance
- Stiff Lungs
•Low FEV1 & Low FVC but FEV1/FVC normal ratio
•
•Reduced Gas Transfer (Tco or Kco)
-Diffusion abnormality
•Ventilation/Perfusion Imbalance
When small airways affected by pathology
Is there airflow limitation in restrictive lung disease?
NO
What are the clinical presentations for restrictive lung disease?
Which one is Normal? Emphysema? Interstitial Lung Disease?
What are the outcomes of Parenchymal (Interstitial) Lung Injury?
Acute inflammation (can develop into chronic response in rare circumstances) or Chronic inflammation
What are the three outcomes of Chronic response?
Which Chronic restrictive disease is most likely to develop end - stage honeycomb lung?
Usual Interstitial Pneumonitis
What does DAD stand for?
Difuse alveolar damage
What is DAD asociated with?
What are the exudative stages of DADS?
Edema and Hyaline membranes
Edema - Vessels become massively leaky - moreso than in a normal response
Hyaline membranes - lots of proteins
What are the proliferative stages of DADS?
What are the histological features of DADS?
What is the commonest interstitial lung disease that you will encounter?
Sarcoidosis
Apart from sarcoidosis what is the other granulomatous respnse?
Hypersensitivity pneumonitis
What is the histopathology of sarcoidosis?
Why is sarcoidosis called multisystem?
Involves many organs
Do most patients with sarcoidosis reach end stage fibrotic lung disease?
No ???
What is the presentation of sarcoidosis?
What is the diagnosis of sarcoidosis?
What is ACE?
A converting enzyme, converts angiotensin 1 to angiotensin 2.
Angiotensin II helps increase blood pressure by causing small blood vessels in the body to tighten or narrow.
Doctors most often use the ACE level test to monitor a disease called sarcoidosis. This condition causes inflammatory cells called granulomas to form in the body, leading to organ inflammation.
The granulomas associated with sarcoidosis increase the amount of ACE in the blood.
What are the hypersensitivity pneumonitis antiges?
What is the accute presentation for Hypersensitivity Pneumonitis?
What is the chronic presentation of Hypersensitivity pneumonitis?
What type of hypersensitivity causes Hypersensitivity Pneumonitis?
•Immune complex mediated combined Type III and Type IV Hypersensitivity reaction
Describe the granulomata in Hypersensitivity Pneumonitits
•Soft centriacinar epithelioid granulomata, causing interstitial pneumonitis
Hypersensitivty pneumonitis is said to cause Bronchiolitis obliterans, what does this mean?
Inflammatory obstruction of bronchioles, these bronchioles become damaged and ingflamed by chemical particles or respiratory infections. Features extensive scarring that blocks airways.
What are the causes of Usual interstitial pneumonitis?
Connective tissue diseases - •scleroderma and rheumatoid disease
Drugs
Asbestos
Viruses
Idiopathic/cryptogenic reasons
What is cryptogenic fibrosing alveolitis?
Old fashioned name for UIP
Describe the interstitium of UIP?
Patchy chronic inflammatino
Type 2 pneumocytes hyperplasia
Smooth muscle and vascular proliferation
Proliferating fibroblastic foci
What are Proliferating Fibroblastic Foci?
Nodules of fibrous tissue in the walls of the alveoli, reflect the severity of the disease
Who usually suffers from Idiopathic Pulmonary Fibrosis?
What is the pathology of Idiopathic Pulmonary Fibrosis?
UIP
What is the clinical presentation of Idiopathic Pulmonary Fibrosis?
What is the prognosis for Idiopathic Pulmonary Fibrosis?
Usually dead within 5 years
What will you see in the ches X-ray for someone with Idiopathic Pulmonary Fibrosis?
•CXR : Basal/Posterior, Diffuse infiltrates, Cysts, ‘ Ground Glass ’
What is UIP Basal and posterior fibrosis with honeycombing often complicated with?
Peripheral adenocarcinoma
Describe the airway flow in interstitial lung disease
Normal air flow, diffusion is altered
What is normal PaO2 and PaCO2?
What is type 1 and type 2 respiration failure?
What are the 4 abnormal states associated with Abnormal pulmonary gas exchange?
Alveolar hypoventilation
Shunt
Ventilation / Perfusion Imbalance
Diffusion Impairment
What is the resut of alveolar hypoventilation on PACO2 and PAO2 ?
Hypoventilation increases the PACO2 and therefore decreases PaCO2
Increased PACO2 takes up space in the alveoli and therefore causes PAO2 and PaO2 to fall
How can you correct a fall in PaO2 due to hypoventilation?
Raising the FIO2
What is the commones cause of hypoxaemia clinically?
V/Q mismatch
Why is normal V/Q ration 0.8?
•Normally breath 4 l/min. CO is 5 l/min so normal V/Q is 4/5 or 0.8
How can you treat hypoxaemia due to low V/Q?
Increase in FIO2
Will Interstitial lung disease affect CO2 levels?
Not usally becuase CO2 diffuses 20 times faster than O2
How does diffusion impairment affect diffusing speed of oxygen?
•Diffusion impairment means it takes LONGER for blood and alveolar air to equilibrate, particularly for oxygen
What is equilibration time for patients with diffusino impairment?
May take as long as 0.75 seconds - the same time as capillary transit time. Normally the equillibration takes 0.25 seconds.
Why does diffusion impairment result in a fall in Pa O2 during exercise?
Capillary transit time decreases during exercise, less time for equillibration.
Why don’t we have 100% haemoglobin saturation?
Because we have a 2-4% shunt
When do we see a pathological shunt?
Alveolar ventilatino malformations, congenital heart disease and pulmonary disease
Does large shunt respond well to increase in FIO2?
No, blood leaving normal sections of the lung is already 98% saturated
