- Pathology of Restrictive Lung Disease Flashcards
<p>What is the interstitium of the lung?</p>
<p>Connective tissue space around the airways and vessels and the space between the basement membranes of the alveolar walls</p>
<p>What is the connective tissue space around the airways and vessels called?</p>
<p>Interstitium of the lung</p>
<p>How are alveolar epithelial (pneumocytes) and interstitial capillary endothelial cell basement membranes in normal alveolar walls?</p>
<p>In direct contact</p>
<p>What does restrictive lung disease show?</p>
<p>Reduced lung compliance (stiff lungs)</p>
<p>Low FEV1and low FVC but same FEV1/FVC ratio</p>
<p>Reduced gas transfer</p>
<p>Ventilation/perfusion mismatch</p>
What does the spirometry of restrictive lung disease look like ?
<p>What is the presentation of restrictive lung disease?</p>
<p>Abnormal chest X-ray</p>
<p>Dyspnoea (on exertion and rest))</p>
<p>Respiratory failure (type 1)</p>
<p>Heart failure</p>
<p>What is dyspnoea?</p>
<p>Difficult breathing</p>
<p>What is difficult breathing called?</p>
<p>Dyspnoea</p>
<p>What is the difference in chest X-rays between:</p>
<p>Emphysema<br></br>Normal<br></br>Restrictive lung disease</p>
<p>Emphysema can see all ribs</p>
<p>Normal can see 10 ribs</p>
<p>Restrictive lung disease can see less than 10</p>
<p>What is restrictive lung disease also known as?</p>
<p>Interstitial lung disease</p>
<p>What is the pathway leading to restrictive lung disease?</p>
<p>1) Lung injury</p>
<p>2) Leads to chronic response</p>
<p>3) One of usual interstitial pneumonitis (UIP), granulomatous response, or other pattens leads to</p>
<p>4) Fibrosis or end stage honeycomb lung</p>
<p>What does the acute response to lung injury lead to?</p>
<p>Diffuse alveolar damage</p>
<p>What is diffuse alveolar damage associated with?</p>
<p>Major trauma</p>
<p>Chemical injury/toxic inhalation</p>
<p>Circulatory shock</p>
<p>Drugs</p>
<p>Infection</p>
<p>Autoimmune disease</p>
<p>Radiation</p>
<p>Idiopathic</p>
<p>What does idiopathic mean?</p>
<p>No known cause</p>
<p>What is no known cause called?</p>
<p>Idiopathic</p>
<p>What does the extend of diffuse alveolar damage depend on?</p>
<p>How many days the injury lasts for</p>
<p>What does DADS stand up for?</p>
<p>Diffuse alveolar damage</p>
<p>What are the histological features of acute alveolar damage?</p>
<p>Protein rich oedema</p>
<p>Fibrin</p>
<p>Hyaline membranes</p>
<p>Denuded basement membranes</p>
<p>Epithelial proliferation</p>
<p>Fibroblast proliferation</p>
<p>Scarring</p>
<p>Why do granulomatous responses to chronic inflammation lead to fibrosis or end stage honeycomb lung?</p>
<p>Sarcoidosis</p>
<p>Hypersensitivity pneumonitis</p>
<p>What is sarcoidosis?</p>
<p>Multisystem granulomatous disorder of unknown aetiology</p>
<p>What is a multisystem granulomatous disorder of known aetiology?</p>
<p>Sarcoidosis</p>
<p>What is the histopathology of sarcoidosis?</p>
<p>Epitheloid and giant cell granulomas</p>
<p>Necrosis/caseation very unusual</p>
<p>Little lymphoid infiltrate</p>
<p>Variable associated fibrosis</p>
<p>What is a granulomas?</p>
<p>Structure formed during inflammation that is found in many diseases, being a collection of macrophages</p>
<p>What is a structure formed during inflammation that is composed of a collection of macrophages?</p>
<p>Granulomas</p>
What is the purpose of a granulomas?
Wall of a substance that cannot be destroyed
What is used to wall of a substance that cannot be destroyed?
Granulomas
Who does sarcoidosis commonly affect?
Young adults
Does sarcoidosis affect more males or females?
Females
What is the prevalence of sarcoidosis?
3-4/100,000 in UK
Where is sarcoidosis often common?
Temperate climates
What organs are involved in sarcoidosis?
Lymph nodes
Lung
Spleen
Liver
Skin, eyes, skeletal muscle
Bone marrow
Salivary glands
What are the most common organs involved in sarcoidosis?
Lymph nodes (100% of cases)
Lung (90% of cases)
Spleen (75% of cases)
What are typical presentations of sarcoidosis?
Young adult (acute arthralgia, erythema nodosum, bilateral hilar lymphadenopathy)
Incidental abnormal chest X-ray (no symptoms)
Shortness of breath, cough, and abnormal X-ray
What is acute arthralgia?
Joint pain
What is joint pain called?
Acute arthralgia
What is erythema nodosum?
Swollen fat under the skin that causes red bumps
What is swollen fat under the skin that causes red bumps called?
Erthema nodosum
What is bilateral hilar lymphadenopathy?
Bilateral enlargement of the lymph nodes of pulmonary hila
What is bilateral enlargement of the lymph nodes of pulmonary hila called?
Bilateral hilar lymphadenopathy
How long does it take for most presentations of sarcoidosis to resolve?
2 years
What are the possible outcomes of sarcoidosis after 2 years?
Resolve
Persist
Progress
What does the diagnosis of sarcoidosis involve?
Clinical findings
Imaging findings
Serum calcium and angiotenis converting enzyme (ACE)
Biopsy
What does ACE stand for?
Angiotenis converting enzyme
What is hypersensitive pneumonitis?
Lung becomes inflammed due to an allergic reaction
What is it called when the lung becomes inflammed due to an allergic reaction?
Hypersensitive pneumonitis
What are possible antigens for hypersensitive pneumonitis?
Thermophillic actinomycetes
Bird/animal proteins (faeces)
Fungi (aspergillus species)
Chemicals
What are the acute presentations of hypersensitive pneumonitis?
Fever, dry cough, myalgia
Chills 4-9 hours after antigen exposure
Crackles, tachyopnoea, wheeze
Precipitating antibody
What is myalgia?
Pain in a muscle or group of muscles
What is pain in a muscle or group of muscles called?
Myalgia
What is tachypnoea?
Abnormally rapid breathing
What is abnormally rapid breathing called?
Tachypnoea
What are chronic presentations of hypersensitive pneumonitis?
Insidious
Malaise
Shortness of breath
Cough
Low grade illness
Crackles and some wheeze
What is insidious?
Comes on slowly and does not have obvious symptoms at first
What is something that comes in slowly and does not have obvious symptoms at first called?
Insidious
What is malaise?
General feeling of illness or discomfort
What is the general feeling of illness or discomfort called?
Malaise
What can hypersentive pneumonitis lead to?
Respiratory failure due to gas transfer bing low
What is the immune reaction of hypersensitive pneumonitis mediated by?
Type III and IV hypersensitive reaction
What is the histopathology of hypersensitive pneumonitis?
Soft centriacinar epitheloid granulomata
Foamy histocytes
Bronchiolitis obliterans
Upper zone disease
What are foamy histocytes?
Histocytes that are laden with lipid
What are histocytes that are laden with lipid called?
Foamy histocytes
What is bronchiolitis obliterans?
Disease results in obstruction of the small airways due to inflammation
What does UIP stand up for?
Usual interstitial pneumonitis
What is usual interstitial pneumonitis?
Form of lung disease characterised by progressive scarring of both lungs
What is a form of lung disease characterised by progressive scarring of both lungs?
Usual interstitial pneumonitis (UIP)
What may usual interstitial pneumonitis be seen in?
Connective tissue diseases
Drug reaction
Post infection
Industrial exposure (asbestos)
What are examples of connective tissue diseases that can cause usual interstitial pneumonitis (UIP)?
Scleroderma
Rheutamoid
What are most interstitial pneumonitis?
Cryptogenic or idiopathic
What does cryptogenic mean?
Disease of obscure or uncertain origin
What is a disease of obscure or uncertain called?
Cryptogenic
What is the histology of usual interstitial pneumonitis?
Patchy interstitial chronic inflammation
Type II pneumocyte hyperplasia
Smooth muscle and vascular proliferation
Proliferating fibroblastic foci
What is a hyperplasia?
Enlargement of an organ or tissue caused by an increase in the reproductive rate of its cells, of an initial stage in the development of cancer
What is the enlargement of an organ or tissue caused by an increase in the reproductive rate of its cells called?
Hyperplasia
What does normal pulmonary gas exchange look like?
Bulk flow
Beyond terminal bronchiole is diffusion
Blood-air barrier
Haemoglobin affinity for oxygen means blood leaving the capillary bed is 98% saturated for FIO2 of only 0.21
CO2 is very soluble and rapidly equilbrates between blood and air
What are the different kinds of bulk flow?
Laminar
Turbulent
What does bulk flow depend on?
Pressure difference
What occurs beyond the terminal bronchiole?
Diffusion
Why is blood 98% saturated at only 0.21 FIO2?
High affinity between haemoglobin and oxygen
What is the normal PaO2?
10.5-13.5kPa
What is the normal PaCO2?
4.8-6kPa
What are the 2 kinds of respiratory failure?
Type 1 (PaO2 < 8kPa)
Type 2 (PaCO2 > 6.5kPa)
What are the 4 abnormal states associated with hypoxaemia?
Alveolar hypoventilation
Shunt
Ventilation/perfusion imbalance
Diffustion impairment
What does hypoventilation do to partial pressure values?
Increases PACO2 so increases PaCO2
Increase in PACO2 decreases PAO2
Causes PaO2 to fall
What is a fall in PaO2 due to alveolar hypoventilation fixed by?
Increasing FIO2
What is shunt?
Blood passes from right to left side of the heart without contacting ventilated alveoli
How large is a shunt normally?
2-4%
What diseases cause a shunt?
AV malformation
Congenital heart disease
Pulmonary disease
How does a large shunt respond to increasing FIO2?
Poorly as blood leaving normal lung is already 98% saturated
What is the size of a normal breath?
4L/min
What is the size of cardiac output?
5L/min
What is the normal V/Q?
0.8
What is the most common cause of hypoxaemia?
Low V/Q
What does a low V/Q in only some alveoli arise due to?
Local alveolar hypoventilation due to some focal disease
How do you treat a low V/Q?
Increase FIO2
What does gas flow through a membrane depend on?
Thickness and surface area of the membrane and the gas pressure across it
How does the speed of CO2 diffusion compare to oxygen?
20 times faster due to greater solubility
What do diseases imparing gas diffusion not change?
CO2 levels
What does diffusion impairment mean?
It takes longer for blood and alveolar air to equilbrate, particularly for oxygen
How long does equilbrium of gas exchange normally take?
0.25s
What is the capillary transit time normally?
0.75s
What may occur when disease causes equilbrium to be closer to 0.75s?
PaO2 is maintained at rest but serious fall may occur during exercise
How can hypoxaemia due to diffusion impairment be corrected?
Increasing FIO2
What is hypoxaemia?
Abnormally low concentration of oxygen in the blood
What is an abnormally low concentration of oxygen in the blood called?
Hypoxaemia
