Restrictive Lung Disease

Question 1

What may cause thoracic restriction?

Answer 1

Skeletal:
Vertebrae
Ribs
Muscle Weakness: Intercostal or Diaphragmatic
Abdominal Obesity/Ascites
DLPD - disease within the lungs (interstitial lung disease)

Question 2

Name the steps of RLD?

Answer 2

1. impaired alveolar gas exchange
2. alveolar barrier to O2 exchange
3. CO2 exchange unimpaired as alveolar ventilation normal
4. decreased PaO2 (decreased SaO2) normal PaCO2

Question 3

What can cause DPLD?

Answer 3

Fluid in the alveolar air spaces
Cardiac Po oedema due to raised Po venous pressure i.e. LVF
Non-Cardiac Po oedema – Normal Po venous pressure with leaky Po capillaries - due to sepsis, trauma or altitude sickness
Inflamatory Infiltrate of alveolar walls (ie Alveolitis, sarcodosis)
Consolidation of alveolar air spaces

Question 4

What are the clinical signs of DPLD?

Answer 4

Breathless on exertion
Cough but no wheeze
Finger clubbing
Inspiratory Lung crackles
Central cyanosis (if hypoxaemic)
Pulmonary fibrosis occurs as end stage response to chronic inflammation

Question 5

How is DPLD diagnosed?

Answer 5

History-eg occupation, drugs, pets, arthritis
Reduced lung volumes: decreased FEV1 decreased FVC normal ratio > 75%: Peak flow normal
Reduced gas diffusion (DLCO)
Arterial oxygen desaturation (decreased PaO2, decreased SaO2) - at rest or on exercise
Antibodies: Avian, Fungal, Auto-antibodies
Serum ACE and Ca raised in Sarcoid
Bilateral diffuse alveolar infiltrates on chest X-ray

Question 6

What is the treatment of DPLD?

Answer 6

Remove any trigger factor - dust, drug, allergen
Treat any reversible alveolitis i.e. ground glass on HRCT -immuno-suppressives

1st line treatment: Systemic steroids- i.e. oral prednisolone-ICSnot effective
2nd line treatment -oral Azathioprine [steroid sparing]