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, refer to parent article: scleroderma.
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
The pathogenesis of pulmonary involvement relates to separate mechanisms:
- scleroderma-related interstitial lung disease (SSc-ILD)
- scleroderma-related pulmonary arterial hypertension (SSc-PAH)
- pathogenesis is unclear but may be due to vascular endothelial injury with subsequent apoptosis, inflammation and dysregulated angiogenesis leading to arterial obliteration and narrowing from fibrosis 6
- indirect involvement
The two pathologies may co-exist. The remainder of the article discusses the former. Please refer to aspiration pneumonitis for discussion of that entity.
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 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.
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 5). Interstitial lung changes in scleroderma are 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 1-5 cm in diameter 4
- pleural effusions are usually not a feature
- CT may also show features of pulmonary hypertension and mediastinal lymphadenopathy 10-11
- four corner sign: inflammation and fibrosis involving the bilateral anterolateral upper lobes and posterosuperior lower lobes is a specific finding and differentiates it from idiopathic pulmonary fibrosis 12
- tends to be cylindrical in general
- maybe present in around 60% of patients according to one study 8
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 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 aspiration pneumonia.
On HRCT, the differential is essentially that of usual interstitial pneumonia and lower zone pulmonary fibrosis.
- 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
- 5. Kim DS, Yoo B, Lee JS et-al. The major histopathologic pattern of pulmonary fibrosis in scleroderma is nonspecific interstitial pneumonia. Sarcoidosis Vasc Diffuse Lung Dis. 2002;19 (2): 121-7. Pubmed citation
- 6. Solomon JJ, Olson AL, Fischer A et-al. Scleroderma lung disease. Eur Respir Rev. 2013;22 (127): 6-19. doi:10.1183/09059180.00005512 - Free text at pubmed - Pubmed citation
- 7. Strollo D, Goldin J. Imaging lung disease in systemic sclerosis. Curr Rheumatol Rep. 2010;12 (2): 156-61. doi:10.1007/s11926-010-0095-0 - Free text at pubmed - Pubmed citation
- 8. Andonopoulos AP, Yarmenitis S, Georgiou P et-al. Bronchiectasis in systemic sclerosis. A study using high resolution computed tomography. Clin. Exp. Rheumatol. 2001;19 (2): 187-90. Pubmed citation
- 9. Mayberry JP, Primack SL, Müller NL. Thoracic manifestations of systemic autoimmune diseases: radiographic and high-resolution CT findings. Radiographics. 2000;20 (6): 1623-35. doi:10.1148/radiographics.20.6.g00nv031623 - Pubmed citation
- 10. Farrokh D, Abbasi B, Fallah-Rastegar Y, Mirfeizi Z. The Extrapulmonary Manifestations of Systemic Sclerosis on Chest High Resolution Computed Tomography. (2015) Tanaffos. 14 (3): 193-200. Pubmed
- 11. Bhalla M, Silver RM, Shepard JA, McLoud TC. Chest CT in patients with scleroderma: prevalence of asymptomatic esophageal dilatation and mediastinal lymphadenopathy. (1993) AJR. American journal of roentgenology. 161 (2): 269-72. doi:10.2214/ajr.161.2.8333359 - Pubmed
- 12. Walkoff L, White DB, Chung JH, Asante D, Cox CW. The Four Corners Sign: A Specific Imaging Feature in Differentiating Systemic Sclerosis-related Interstitial Lung Disease From Idiopathic Pulmonary Fibrosis. (2018) Journal of thoracic imaging. 33 (3): 197-203. doi:10.1097/RTI.0000000000000319 - Pubmed