restrictive (interstitial) lung diseases

Question 1

what is the interstitium of the lung?

Answer 1

The connective tissue space

around the airways and vessels and the space between the basement membranes of the alveolar walls

Question 2

are interstitial lung diseases usually unilateral or bilateral?

Answer 2

bilateral

Question 3

is pulmonary oedema a restrictive lung disease?

Answer 3

no, however it does cause restriction

Question 4

what happens to the interstitium in restrictive lung diseases?

Answer 4

it becomes thicker so the capillaries and pneumocytes no longer as close together. This is causes buy a build up of a substance in the interstitium, usually fibrous tissue.

Question 5

what happens to compliance in restrictive lung disease?

Answer 5

it is reduced

Question 6

what happens to FEV1 in restrictive lung disease?

Answer 6

it is reduced

Question 7

what happens to FVC in restrictive lung disease?

Answer 7

it is reduced

Question 8

what happens to the FEV1/FVC ratio in restrictive lung disease?

Answer 8

it remains nomal

Question 9

what happens to gas transfer in restrictive lung disease?

Answer 9

it is decreased

Question 10

why is gas transfer reduced in restrictive lung diseases?

Answer 10

the distance between alveoli and capillaries is increased as there is increases tissue in the interstitium

Question 11

why is there a V/Q imbalance in restrictive lung diseases?

Answer 11

the disease can sometimes cause small airways to be constricted

Question 12

when can a restrictive lung disease present?

Answer 12

when there is an abnormal discovery on a CXR.
dyspnoea that gets worse (SOB exertion –> SOB rest)
type 1 resp. failure
heart failure

Question 13

why do sufferers of restrictive lung disease experience type 1 respiratory failure?

Answer 13

it is much easier for carbon dioxide to diffuse across the thickened alveolar walls than it is for oxygen.

Question 14

what does an interstitial lung disease look like on a CXR?

Answer 14

lung extends <10 ribs

more lung markings because increased tissue

Question 15

what is diffuse avleolar damage associated with?

Answer 15

Major trauma
Chemical injury / toxic inhalation
Circulatory shock
Drugs 
Infection
Auto(immune) disease
Radiation
idiopathic

Question 16

what is the evolution of DADS?

Answer 16

oedema–> Hyaline membranes –>interstitial inflammation —> interstitial fibrosis

Question 17

what are the histological features of DADS?

Answer 17

protein rich oedema
fibrin
hyaline membranes
denuded basement membranes
epithelial proliferation
fibroblast proliferation
scarring-interstitium and airspaces

Question 18

what is sarcoisosis?

Answer 18

a multisystem granulomatous disoder of unknown aetiology

Question 19

what is the histopathology of sarcoidosis?

Answer 19

-epitheloid and giant cell ganulomas
-no necrosis
-little lymphoid infiltration
variable associated fibrosis

Question 20

is DADS an acute of chronic response?

Answer 20

acute

Question 21

what causes the protein rich oedema in DADS?

Answer 21

damage to the capillary walls in the lung (probably by neutophils) which causes the massive leakage of fluid and proreins

Question 22

is DADS a serious condition?

Answer 22

yes, sufferers usually end up in ITU

Question 23

what sets DADS apart from pneumonia histologically?

Answer 23

the alveoli in DADS are not filled with debris like in pneumonia

Question 24

what sets sarcoidosis apart from infections histologically?

Answer 24

the absence of tissue necrosis

Question 25

what are the presentations of sarcoidosis?

Answer 25

``` 1. -acute arthralgia (joint pain) -erythema nodosum (red bumps and patches on the skin) -bilateral hilar lymphadenopathy 2. incidental abnormal CXR w/ no symptoms 3. SOB, cough and abnormal CXR ```

Question 26

is treatment required for sarcoidosis?

Answer 26

most resolve themselves after 2 years but those that don't should be given corticosteroids

Question 27

what is used to diagnose sarcoidosis?

Answer 27

- clinical findings - image findings - serum Ca++ and ACE ( angiotensin converting enzyme) - biopsy

Question 28

what are the antigens for hypersensitivity pneumonitis?

Answer 28

mostly antigens of plant or animal origin: - Thermophilic actinomycetes - Bird / Animal proteins - faeces, bloom - Fungi - Aspergillus spp some chemicals

Question 29

what is the acute presentation of hypersensitivity pneumonitis?

Answer 29

Fever, dry cough, myalgia, Chills 4-9 hours after Ag exposure Crackles, tachyopnoea, wheeze Precipitating antibody

Question 30

what is the chronic presentation of hypersensitivity pneumonitis?

Answer 30

- Insidious - Malaise, SOB, cough - Low grade illness - Crackles and some wheeze

Question 31

what is hypersensitivity pneumonitis mediated by?

Answer 31

Type III and Type IV Hypersensitivity reaction

Question 32

what is the main histological presentation of hypersensitivity pneumonitis?

Answer 32

soft centriacinar epithelioid granulomata

Question 33

what zone of the lung does hypersensitivity pneumonitis primarly affect?

Answer 33

upper zone

Question 34

why is hypersensitivity pneumonitis more likely to occur in central acinar areas?

Answer 34

this is the area where airflow changes from laminar to diffusion

Question 35

where may UIP be seen?

Answer 35

- connective tissue diseases - in drug reaction - in post infection - in industrial exposure

Question 36

which connective tissue diseases can cause UIP?

Answer 36

scleroderma and rheumatoid disease

Question 37

what is the most common form of UIP?

Answer 37

cryptogenic or idiopathic

Question 38

what is another name for idiopathic UIP?

Answer 38

idiopathic pulmonary fibrosis

Question 39

what is another name for cryptogenic UIP?

Answer 39

cryptogenic fibrosing alveolititis

Question 40

what are the histopathological features of UIP?

Answer 40

-patchy interstitial chronic inflammation -type II pneumocyte hyperplasia -smooth muscle and vascular proliferation evidence of old and recent injury as well as a spatial variation in injury -proliferating fibroblastic foci

Question 41

what is temporal heterogeneity in UIP?

Answer 41

injury in the lungs occuring at different times

Question 42

what is spatial heterogeneity in UIP?

Answer 42

injury in lungs in different areas

Question 43

who does idiopathic pulmonary fibrosis normally affect?

Answer 43

elderly >50 and M>F

Question 44

what are the clinical signs of idiopathic pulmonary fibrosis?

Answer 44

dyspnoea, cough, basal crackles, cyanosis, clubbing

Question 45

what is the prognosis of idiopathic pulmonary fibrosis?

Answer 45

most die within 5 years

Question 46

what treatments are available for idiopathic pulmonary fibrosis?

Answer 46

steroidal therapy, | anti-angiogenesis treatment, (largely uneffective though)

Question 47

what is the appearance of idiopathic pulmonary fibrosis on a chest x-ray?

Answer 47

basal/posterior diffuse infiltrates, cysts, appears like ground glass

Question 48

which of the chronic responses is most likely to lead to end-stage honeycomb lung?

Answer 48

UIP

Question 49

which of the chronic responses is least likely to lead to end-stage honeycomb lung?

Answer 49

granulomatous response

Question 50

what are the three chronic responses to parenchymal (interstitial) lung injury?

Answer 50

- usual interstitial pneumonitis - granulomatous response - other patterns (non specific interstitial pneumonitis)

Question 51

what are the granulomatous responses to parenchymal lung injury?

Answer 51

- sarcoidosis | - hypersensitivity pneumonitis

Question 52

why do diseases caused by inhaled particulates often start at the respiratory bronchioles?

Answer 52

this is where bulk flow airflow becomes diffusion

Question 53

what are the four abnormal states associated hypoxaemia?

Answer 53

- alveolar hypoventilation - shunt - ventilation/ perfusion imbalance - diffusion impairment