idiopathic pulmonary fibrosis [CFA] Flashcards
define IPF
Idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis (IPF, previously termed cryptogenic fibrosing alveolitis)
=is a chronic lung condition characterised by progressive fibrosis of the interstitium of the lungs.
Whilst there are many causes of lung fibrosis (e.g. medications, connective tissue disease, asbestos) the term IPF is reserved when no underlying cause exists.
IPF is typically seen in patients aged 50-70 years and is twice as common in men.
s/s
Features
- progressive exertional dyspnoea
- bibasal crackles on auscultation
- dry cough
- clubbing
Diagnosis
- spirometry: classically a restrictive picture
- In a restrictive type of ventilatory impairment the volume of the lung is restricted, for example in pulmonary fibrosis, infiltration or by rigidity of the chest wall.
- The vital capacity is reduced and the FEV1 is also reduced in proportion. The ratio between FEV1/FVC is normal - about 0.75 - or even higher than normal.
- There is a reduction in the diffusion capacity of the lung and there is usually a low arterial pCO2.
2. impaired gas exchange: reduced transfer factor (TLCO)
3. imaging: bilateral interstitial shadowing (typically small, irregular, peripheral opacities - ‘ground-glass’ - later progressing to ‘honeycombing’) may be seen on a chest x-ray but high-resolution CT scanning is the investigation of choice and required to make a diagnosis of IPF
4. ANA positive in 30%, rheumatoid factor positive in 10% but this does not necessarily mean that the fibrosis is secondary to a connective tissue disease. Titres are usually low
Mx
Management
- pulmonary rehabilitation
- very few medications have been shown to give any benefit in IPF. There is some evidence that pirfenidone (an antifibrotic agent) may be useful in selected patients (see NICE guidelines)
- many patients will require supplementary oxygen and eventually a lung transplant
prognosis
poor, average life expectancy is around 3-4 years
