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 4.
For a discussion of scleroderma in general, please refer to parent article : scleroderma.
The pathogenesis of pulmonary involvement relates to to separate mechanisms :
- usual interstitial pneumonia (UIP) : histologically indistinguishable from rheumatoid lung and idiopathic pulmonary fibrosis (IPF)
- secondary lung injury due to aspiration pneumonitits secondary to oesophageal involvement : see gastrointestinal manifestations of scleroderma
The two pathologies may co-exist. The remainder of the article discusses the former. Please refer to aspiration pneumonitis for discussion of that entity.
In patients who are symptomatic due to pulmonary involvement, respiratory function tests typically demonstrate a restriction pattern, consisting of 4:
- diminished lung volumes
- preserved flow rates
- low diffusion capacity
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 4:
- dilated oesophagus
- eggshell calcification of mediastinal nodes
- pleural effusions are uncommon
- enlargement of cardiac silhouette and pulmonary arteries due to scleroderma induced pulmonary vascular disease may also be evident.
On HRCT, scleroderma may appear in a usual interstitial pneumonitis (UIP) or non specific interstitial pneumonitis (NSIP) pattern. Interstitial lung changes in scleroderma are generally less extensive and less coarse than those with idiopathic pulmonary fibrosis (IPF) 3 with most patients only show a limited portion of lung involvement (less than 10% in half of cases) 1.
- early stages may show ground glass changes
- later stages may show honeycombing and evidence of lung volume loss
- lung bases and sub-pleural regions typically involved 4
- cysts may be present measuring 1 - 5cm in diameter 4
- pleural effusions are usually not a feature
A dilated oesophagus is not an uncommon finding.
Treatment and prognosis
Pulmonary involvement is incurable but a number of compounds may improve or halt progression. These include cyclophosphamide, glucocorticoids or N-acetylcysteine, although the data is inconclusive 5.
- pulmonary arterial hypertension is seen in up to 50% of patients, and may develop without evidence of interstitial fibrosis 2,4
- higher incidence of lung cancer, particularly bronchoalveolar carcinoma 4
- rupture of pulmonary cysts resulting in a pneumothorax 4
The cause of death is often from an aspiration pneumonia.
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 oesophagus.
Pleural effusions are distinctly uncommon in scleroderma, and would favour the diagnosis or either rheumatoid lung or SLE 4.
- 1. Wells AU. High-resolution computed tomography and scleroderma lung disease. Rheumatology (Oxford). 2008;47 Suppl 5 (Supplement 5): v59-61. doi:10.1093/rheumatology/ken271 - Pubmed citation
- 2. Stratton RJ, Pompon L, Coghlan JG et-al. Soluble thrombomodulin concentration is raised in scleroderma associated pulmonary hypertension. Ann. Rheum. Dis. 2000;59 (2): 132-4. doi:10.1136/ard.59.2.132 - Free text at pubmed - Pubmed citation
- 3. Desai SR, Veeraraghavan S, Hansell DM et-al. CT features of lung disease in patients with systemic sclerosis: comparison with idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia. Radiology. 2004;232 (2): 560-7. doi:10.1148/radiol.2322031223 - Pubmed citation
- 4. Brant WE, Helms CA. Fundamentals of diagnostic radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781761352. Read it at Google Books - Find it at Amazon
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Scleroderma - pulmonary features||✗|