combined pulmonary fibrosis and emphysema

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Combined pulmonary fibrosis and emphysema (CPFE) is a possible new addition to a growing list of smoking-related lung disease characterized by the coexistence of usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) with emphysema in smokers.

Epidemiology

It typically occurs in male smokers . It is estimated to represent between 5-10% of cases of diffuse interstitial lung disease.

Clinical presentation

Clinical features include:

tobacco smoking
severe dyspnea
unexpected subnormal spirometry findings
severely impaired transfer capacity for carbon monoxide
hypoxemia on exercise

Pathology

Although the pathogenesis and the exact association are yet to be elucidated in larger studies, it is important to be aware of probable inherent susceptibility of some patient to pulmonary fibrosis from cigarette smoking.

Radiographic features

CT

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

centrilobular and/or paraseptal emphysema:
- often upper zone predominant
- the emphysema component may have a tendency to be more paraseptal
pulmonary fibrosis of the lower lobes: can be of UIP or NSIP pattern

Three distinct patterns have been described in recent literature :

progressive transition with diffuse emphysema (centrilobular and/or bullous) and zone of transition between bullae and honeycombing
paraseptal emphysema with predominant subpleural bullae of enlarging size at the bases
separate processes with independent areas of fibrosis and emphysema

Treatment and prognosis

Complications

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 without emphysema .

Patients may have a higher risk of developing lung cancer . Lung cancer occurring on those with CPFE may have a poorer prognosis and according to one study, the commonest type has been squamous cell lung cancer .