4- overview of restrictive lung disease

Question 1

what is restrictive lung disease?

Answer 1

group of lung disorders characterised by reduced lung volume and impaired expansion of lung volume. can be intrinsic or extrinsic (depending on what cause is)
- disease of lung itself

Question 2

what is common type of intrinsic restrictive lung disease?

Answer 2

interstitial lung disease (ILD)

Question 3

what is ILD?

Answer 3

interstitial lung disease = big spectrum group of lung diseases characterized by inflammation and scarring (fibrotic) of the lung’s interstitial tissue, which surrounds the air sacs (alveoli) and small blood vessels

Question 4

what is common cause of ILD?

Answer 4

idiopathic pulmonary fibrosis (IPF) = characterised by irreversible fibrolytic and causes shrinkage of lung through scarring which can also prevent exchange

Question 5

what are components of ILD diagnosis?

Answer 5

history, examination, pulmonary function tests and radiological assessment

Question 6

what are important sub types of interstitial lung disease, ILD (which is a type of intrinsic restrictive lung disease)?

Answer 6

IPF = idiopathic pulmonary fibrosis
COP = cryptogenic organising pneumonia (associated with things like rheumatoid arthritis)
NSIP = inflammatory type ILD which can happen seperately but commonly associated with connective tissue diseases
RB-ILD = respiratory bronchiolitis interstitial lung disease = seen exclusively in smokers (common inflammatory ILD)

Question 7

what should you think about when granulomatous?

Answer 7

think sarcoidosis, HP, TB

granulomatous ILDs = associated with sarcoidosis and hypersensitive pneumonitis

Question 8

what is restrictive pattern on pulmonary function test?

Answer 8

• decreased FEV1 & FVC, but normal/increased ratio (70% is normal)
• decreased DLCO = a test to measure efficiency of gas exchange, patient inhales very small amount of carbon monoxide (<80% predicted is abnormal = worse efficiency)

Question 9

why is gas exchange impaired in ILD (interstitial lung disease)?

Answer 9

impaired alveolar walls = impaired gas exchange

*more advanced stages = physical effect on FVC, means decreased PaO2 and normal PaCO2 (type 1 respiratory disease)

Question 10

what can affect diffusion capacity (DLCO)?

Answer 10

• anaemia
• emphysema (alveolar damage)
• ILD’s
• pulmonary oedema
• large volume pulmonary embolisms →can affect blood flow

Question 11

why is it helpful to monitor DLCO?

Answer 11

to monitor treatment response in ILD (more sensitive than FVC)

Question 12

what are extrinsic problems that can result in restriction?

Answer 12

• obesity e.g. can also cause sleep apnoea, diaphragmatic palsy
• neuromuscular disorders e.g. motor neuron disease or myasthenia gravis
• pleural diseases e.g. Diffuse pleural thickening; mesothelioma; large pleural effusions

Question 13

what is pathophysiology of restrictive hypoventilation?

Answer 13

Hypoventilation means impaired alveolar ventilation which means a rise in paCO2 and reduced paO2

Question 14

how does neuromuscular conditions help cause restrictive hypoventilation?

Answer 14

reduces power of muscles involved in respiration

Question 15

how does obesity/kyphoscoliosis cause restrictive hypoventilation?

Answer 15

by reducing chest wall compliance

Question 16

what is obstructive sleep apnoea?

Answer 16

sleep disorder characterised by repetitive episodes of partial or complete obstruction of upper airway during sleep

Question 17

what is obesity hypoventilation syndrome?

Answer 17

condition characterized by obesity and chronic hypoventilation during wakefulness, leading to elevated levels of carbon dioxide (hypercapnia) and decreased levels of oxygen (hypoxemia) in the blood

Question 18

what are clinical features of restrictive lung disease?

Answer 18

• finger clubbing - growth in nail bed due to hypoxia
• obese; kyphosis; scoliosis
• fibrotic crepitations = characteristic sound like velcro, persistent basal crepitation think about ILD or bronchiectasis
• clinical signs of pleural effusions or ascites
• cyanosis

Question 19

what are symptoms of CO2 retaining?

Answer 19

flushed skin, bounding pulse, rapid breathing, premature heart beats, muscle twitches, flapping tremor

Question 20

what is asbestosis?

Answer 20

pulmonary fibrosis caused by asbestos

Question 21

what are investigations for restrictive lung disease?

Answer 21

• measure with PFT’s (to check for type 1 resp failure), can do exercise desaturation
• chest x-ray
• blood test - can pick up pigeon serum IgG, this causes reaction if gets into lung i think? serum precipitants done with hypersensitivity

Question 22

what is non-pharmacological treatment of ILD?

Answer 22

• weight management
• smoking cessation
• remove trigger e.g. drug, bird etc

Question 23

what is medical therapy treatment for ILD?

Answer 23

• anti-inflammatory /immunosuppressive drugs (steroids 1st line, usually prednisolone +/- rituximab etc)
• antifibrotic drugs (pirfenidone or nintedanib) = only 2 of these type
• Treat neuromuscular disease (Pyridostigmine in MG)

Question 24

what is treatment for restrictive lung disease?

Answer 24

= mostly obesity related lung diseases

• CPAP (continuous positive airways pressure) - mostly for obstructive sleep apnoea progresses, enough but also need NIV a lot. not used in ILD
• Non-invasive ventilation (NIV) = ventilatory support for neuromuscular weakness; kyphoscoliosis