Interstitial lung disease

Question 1

interstitium

Answer 1

bits of the lung between the alveoli
very thin layer in normal health
alveoli bordered by type I and type II pneumocytes, separated by a thin layer of connective tissue

Question 2

ILD investigations

Answer 2

CXR:
reticular-nodular shadowing
small, stiff, white lungs on xray

‘velcro’ crackles - ask the patient to cough, and then listen again and make sure the crackles remain
TLCO and KCO (correcting for size of the lungs) will be decreased
type I respiratory failure - pO2 >8kPa on air at sea level, normal or low pCO2

investigate with a high resolution CT scan, which is the gold standard radiology

Question 3

often misdiagnosed

Answer 3

can be mistaken for more common disease, such as:
cardiac failure
asthma
COPD
pneumonia
bronchiectasis

Question 4

Interstitial lung disease (ILD)

Answer 4

idiopathic pulmonary fibrosis
ie must therefore be able to exclude other ILD such as:
sarcoidosis
hypersensitivity pneumonitis
pneumoconiosis
connective tissue disease (RA, scelroderma)
drugs (eg methotrexate)

Question 5

high resolution CT

Answer 5

slices lungs into very thin (1mm) sections to show the fibrosis

Question 6

treatment ILD

Answer 6

nothing
supportive
pirfenidone/nintedinab - anti-fibrotic drugs that slow progression of disease. only 2 licensed in the world for ILD
clinical trials
transplant

Question 7

central cyanosis

Answer 7

look under tongue

lips are a sign of peripheral cyanosis

Question 8

crackles

Answer 8

fine = fibrosis
dry cough
restrictive physiology

coarse = bronchiectasis
wet, productive cough
obstructive physiology

Question 9

sarcoidosis

Answer 9

90% will have involvement of the lung or mediastinal lymph nodes
often found by chance after CXR shows bilateral hilar lymphadenopathy. will show up on CT scan
use HRCT as gold standard
also seen in the right paratracheal region
in a small minority can lead to progressive pulmonary fibrosis

not a histological diagnosis, used to suggest sarcoid along with the rest of the history

Question 10

bilateral hilar lymphadenopathy

Answer 10

4 important possible causes:
sarcoid
TB
lymphoma
carcinoma

biopsy using endobronchial USS

Question 11

treatment of sarcoid

Answer 11

often resolves

if needed use steroids

Question 12

hypersensitivity pneumonitis (HP)

Answer 12

aka extrinsic allergic alveolitis
allergic reaction to something inhaled
environmental/occupational Hx vital
ask about birds, feather pillows, farming etc

present with cough, SOB, fever, weight loss
might have crackles, and also wheeze and squeaks - HOP also affects the bronchioles, not just the interstitium

CXR - as with ILD
HRCT - expiratory scan, will show mosaicism. black areas are abnormal, as they represent trapped air

treatment:
avoid the antigen
steroids - esp if they present in respiratory failure, to dampen the immune response