Restrictive Lung Disease

Set of pulmonary disorders characterized by reduced lung volumes

Aetiology

Intrinsic restrictive diseases

  • Diseases of the lung itself resulting in impaired alveolar gas exchange - type I oxygen failure
  • Examples: pneumonia, TB, interstitial lung diseases

Extrinsic restrictive diseases

  • Thoracic/extra thoracic - obesity, kypho-scoliosis, ascites, diaphragmatic palsy
  • Neuromuscular disorders e.g. motor neuron disease
  • Pleural diseases e.g. diffuse pleural thickening, mesothelioma, large pleural effusions
  • Impair alveolar ventilation (restrictive hypoventilation) - type II oxygen failure

Clinical presentation

Symptoms

  • Progressive dyspnoea +/- dry cough
  • CO2 retention - headache, confusion and lethargy

Signs

  • Finger clubbing
  • Obese/kyphosis/scoliosis
  • Fibrotic crepitations
  • Clinical signs of pleural effusions or ascites
  • Cyanosis
  • CO2 retention - flushed skin, bounding pulse, rapid breathing, premature heartbeats, muscle twitches, flapping tremor

Investigations

PFTs

  • Restrictive - FVC and FEV1 both decreased, FEV1/FVC ratio normal

Imaging

  • CXR
  • Chest CT
  • USS - pleural, abdominal

ABGs

  • Type I or II respiratory failure
  • Increased bicarbonate indicates chronic hypercapnia
  • Also decreased PaO2 (at rest or exercise)

Bloods

  • Connective tissue screen
  • Vasculitis screen
  • Eosinophilia
  • Secondary polycythemia from chronic hypoxia

Management

  • Treat underlying cause
  • Supportive - e.g. oxygen, CPAP, NIC