pulmonary manifestations of scleroderma

Pulmonary manifestations of scleroderma are demonstrated histologically in 90% of patients with scleroderma. It is a leading cause of mortality and at autopsy. The lung is reportedly involved in close to 100% of cases. However, only 25% of patients will present with respiratory symptoms or demonstrate abnormalities on CT .

For a discussion of scleroderma in general, refer to parent article: scleroderma.

Clinical presentation

In patients who are symptomatic due to pulmonary involvement, respiratory function tests typically demonstrate a restriction pattern, consisting of :

  • diminished lung volumes
  • preserved flow rates
  • low diffusion capacity

Pathology

The pathogenesis of pulmonary involvement relates to separate mechanisms:

The two pathologies may co-exist. The remainder of the article discusses the former. Please refer to aspiration pneumonitis for discussion of that entity.

Radiographic features

Plain radiograph

Chest radiographs are insensitive to early changes and may appear normal despite respiratory function test abnormalities. Eventually, changes of pulmonary fibrosis become evident. Additional features include :

  • dilated esophagus
  • eggshell calcification of mediastinal nodes
  • pleural effusions are uncommon
  • enlargement of the cardiac silhouette and pulmonary arteries due to scleroderma induced pulmonary vascular disease may also be evident. 
CT

On HRCT, scleroderma may appear in either a usual interstitial pneumonitis (UIP) or non-specific interstitial pneumonitis (NSIP) pattern (the latter is considered more common). Interstitial lung changes in scleroderma are less extensive and less coarse than those with idiopathic pulmonary fibrosis (IPF)  with most patients only show a limited portion of lung involvement (less than 10% in half of cases) .

A dilated esophagus is not an uncommon finding.

Treatment and prognosis

Pulmonary involvement is incurable but some compounds may improve or halt progression. These include cyclophosphamide, glucocorticoids or N-acetylcysteine, although the data is inconclusive .

Complications include:

The cause of death is often from aspiration pneumonia.

Differential diagnosis

On HRCT, the differential is essentially that of usual interstitial pneumonia and lower zone pulmonary fibrosis.

A helpful clue to the diagnosis on CT is the presence of a dilated esophagus.
Pleural effusions are distinctly uncommon in scleroderma and would favor the diagnosis of either rheumatoid lung or SLE .

See also