Pathology of restrictive lung dieseases

Question 1

What is restrictive lung disease

Answer 1

• group of pulmonary and extra pulmonary diseases characterised by reduced lung compliance, hence decreased lung volumes.

Question 2

Features of intersitial lung disease

Answer 2

• FEV1 + FVC reduced (VC is a key marker)
• FEV1:FVC ratio normal
• V/Q imbalance when small airways affected
• reduced gas transfer ( Tco or Kco) < diffusion abnormality

Question 3

Types of restrictive lung diseases/condition

Answer 3

• Interstitial lung disease
• muscoskeletal
• pleura
• subdiaphragmatic

Question 4

Name Intersitial lung diseases

Answer 4

-diffuse alveolar damage, sarcoidosis, hypersensitivity pmeumonitis, idiopathic pulmonary fibrosis

Question 5

State Muscoskeletal conditions ( restrictive)

Answer 5

• -amytrophic lateral sclerosis, thoracoplasty, ankylosing spondylitis, kyphoscoliosis, rib fractures

Question 6

State restrictive pleural conditions

Answer 6

-pleural effusion, pneumothorax, pleural thickenings

Question 7

State subdiaphragmatic restrictive conditions

Answer 7

-obesity( prevents diaphragm descending), pregnancy

Question 8

What is the lung intersitium

Answer 8

• microscopic space that forms part of the BBB

- connective tissue found around airways + space inbetween basement membranes of alveolar walls

Question 9

Patterns of diffuse intersitial lung disease

Answer 9

Acute: Diffuse alveolar damage(DAD)

Granulomatous responses(C): Sarcoidosis, Hypersensitivity pneumonitis

Usual Intersitial pneumonitis(C): Cryptogenic fibrosing alveolitis, Idiopathic pulmonary fibrosis(IPF), Connective tissue diseases, Drugs, Asbestos, viruses

Other(C): Non-specific(NSIP), asbestos, sillicosis, COP, BOOP, cmoking related fibrosis

Question 10

What is diffuse alveolar damage?(DAD) and state the causes

Answer 10

• acute response to intersitial damage
• major trauma, chemical injury/toxic inhalation, circulating shock, drugs, infection, radiation, autoimmune disease
• can be idiopathic ( without known cause)

Question 11

Describe stages of DAD

Answer 11

-Exudative and proliferative

• protein rich oedema formed and fills alveoli, the basement membrane of alveoli also shed in alveolar lumen.
• Fibrin deposition ( formation of hyaline membrane) which is a fibrous layer that settles in alveoli preventing GE
• epithelial cells proliferation occurs
• fibroblast proliferation occurs
• widespread fibrosis in air spaces + intersitium follows
• patients may die of secondary infection/underlying cause of DAD opposed tos carring itself

Question 12

What is sarcoidosis?

Answer 12

• multisystem granulomatous disorder of unknown cause
• disease of temperature climates
• affects F>M

Question 13

Histopathology of sarcoidosis

Answer 13

• non caseous granuloma ( no necrosis)
• epitheloid + giant cell granulomas
• little lymphoid infiltrate
• variable associated fibrosis

Question 14

What organs does sarcoidosis affect?

Answer 14

• Lymph nodes
• Lung
• Spleen
• Liver
• Skin, eyes, skeletal muscle
• Bone marrow
• Salivary glands

(all arranged from most common)

Question 15

Symptoms of sarcoidosis

Answer 15

• Acute arthralgia(YA) [resolves after 2 years]
• Erythema nodosum(YA) [resolves after 2 years]
• Bilateral hilar lymphadenopathy (YA)[resolves after 2 years]
• SOB, cough, abnormal CXR[resolve/persist/progress]
• asymptomatic[resolve/persist/progress]

Question 16

Treatment of sarcoidosis

Answer 16

-corticosteroids

Question 17

Investigations of sarcoidosis

Answer 17

• Hypercalcaemia ( serum Calcium ions)
• High ACE enzyme
• hypergammaalbuinaemia(high gamma globin)
• Kveim test 60% +ve (historical int)
• Tuberculin test (historical int)

Question 18

What is hypersensitivity pneumonitis

Answer 18

• inflammation of alveoli due to exposure of organic dust

Question 19

Antigens of hypersensitivity pneumonitis

Answer 19

-thermophillic actinomycetes (Micropolyspora faeni,
Thermoactinomyces vulgaris> farmers lung)

• bird/animal proteins ( faeces, bloom)
• fungi(aspergillus)
• chemicals

Question 20

Acute presentation of Hyper sensitivity pneumonitis (extrinsic allergy alveolitis)

Answer 20

ACUTE

• fever
• dry cough
• myalgia
• chills 4-9hrs after ag exposure
• crackles, tachyopnoea, wheeze
• precipitating antibody

CHRONIC

• insidious
• malaise, SOB, cough
• low grade illness
• crackles, some wheeze

Can lead to RF as Gas transfer is low. History is important !

Question 21

Histopathology of hypersensitivity pneumonitis

Answer 21

Type 3/4 hypersensitivity reaction ( immune complexes + Th1 cells)

• soft centriacinar epitheloid granuloma
• interstitial pneumonitis
• foamy histiocytes
• bronchiolitis obliterans
• upper zone disease

Question 22

Where can intersitial pneumonitis be seen in?

Answer 22

• connective tissue diseases (sleceroderma + rheumatoid disease)
• drug reaction
• post infection
• industrial exposure( asbestos)

-most is Cryptogenic(cryptogenic fibrosing alveolitis)/idiopathic(idiopathic pulmonary fibrosis)

Question 23

What is usual intersitial pneumonitis

Answer 23

-progressive scarring of both lungs. The scarring (fibrosis) involves the supporting framework (interstitium) of the lung.

Question 24

Histopathology of UIP

Answer 24

• patchy intersitial chronic inflammation
• type 2 pneumocyte hyperplasia
• smooth muscle + vascular proliferation
• Evidence of old/recent injury - temporal + spatial heterogeneity
• proliferating fibroblastic foci

Question 25

Symptoms of idiopathic UIP, Risk factors and treatment

Answer 25

• dypsnoea, cough, basal crackles, cyanosis, clubbing
• death within 5yrs
• Restrictive PFT + GT
• pathology=UIP
• elderly >50 M>F
• CXR
• steroids

Question 26

What is seen on CXR in Idiopathic UIP?

Answer 26

• basal/posterior fibrosis with honeycombing ( complicated by peripheral adenocarcinoma)
• diffuse infiltrates, cysts, ground glass appearance of pulmonary fibrosis

Question 27

What is honeycombing of lungs?

Answer 27

is the radiological appearance seen with widespread fibrosis. Presence of small cystic spaces with irregularly thickened walls composed of fibrous tissue.