Combined pulmonary fibrosis and emphysema

Last revised by Sebastian Röhrich on 17 May 2023

Combined pulmonary fibrosis and emphysema is a controversial and poorly defined entity. Smoking-related lung diseases can coexist and the combination of emphysema and fibrosis carries a high risk of pulmonary hypertension and a poor prognosis.

Combined pulmonary fibrosis and emphysema typically occurs in male smokers 3. It is estimated to represent between 5-10% of cases of diffuse interstitial lung disease.

 Clinical features include:

  • tobacco smoking

  • severe dyspnea

  • spirometry findings are relatively preserved (compared to the severe dyspnea) as the restriction from the fibrosis and emphysema counterbalance each other 16

  • severely impaired transfer capacity for carbon monoxide

  • hypoxemia on exercise

Although the pathogenesis and the exact association are yet to be elucidated in larger studies, some patients are inherently susceptible to pulmonary fibrosis from cigarette smoking. Fibrotic lung patterns such as usual interstitial pneumonia or non-specific interstitial pneumonia have been described in tobacco smokers with emphysema but the precise definition (i.e. degree of emphysema required) is yet to be established 15.

Several theories (not mutually exclusive have been proposed) 13:

  • initial fibrosis subsequently resulting in emphysema due to traction on the adjacent lung

  • gastro-esophageal reflux exacerbated by smoking with micro-aspirations triggering lung fibrosis

  • an autoimmune phenomenon

  • development pathways based on genetic factors

The presence of characteristic imaging features in the correct clinical context is very suggestive of the diagnosis. HRCT would typically show:

Three distinct patterns have been described in recent literature 6:

  • separate processes with independent areas of emphysema (upper lobe) and fibrosis (lower lobe)

  • progressive transition with diffuse emphysema (centrilobular and/or bullous) and zone of transition between bullae and honeycombing (transitional type)

  • paraseptal emphysema with predominant subpleural bullae of enlarging size at the bases (admixed type - particularly here the pattern of thick-walled cystic lesions may be seen)

When reporting CPFE it is important to communicate the pathological pattern of the ILD-component to the referring physician (e.g.: CPFE with UIP pattern) as this may guide the further diagnostic work-up and treatment.

The risk of the development of pulmonary hypertension is considered to be notably higher in those patients with CPFE than in those with idiopathic pulmonary fibrosis (IPF) without emphysema 1,2.

Patients may have a higher risk of developing lung cancer 11. Lung cancer occurring in those with combined pulmonary fibrosis and emphysema may have a poorer prognosis and according to one study, the commonest type has been squamous cell lung cancer 10.

Patients are at risk of acute exacerbation of interstitial lung disease (e.g., when receiving chemo therapy or surgery), however, the prevalence compared to IPF is varying 16.

Combined pulmonary fibrosis and emphysema (CPFE) as a distinct condition is first thought to have been termed by V. Cottin et al in 2005 4,13 .

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