Respiratory manifestations cause significant morbidity and mortality in patients with connective tissue diseases (CTDs). Not infrequently, respiratory involvement may be the presenting manifestation of CTDs. These disease features occurring in a patient with known CTD may be due to the underlying CTD, a treatment-related adverse effect such as a drug reaction, opportunistic infection, or an unrelated process. Clinical features of ILD include exertional dyspnea and/or chronic cough and inspiratory crackles
There is a relatively high prevalence of subclinical intersitial lung disease (ILD) in patients with CTDs. The frequency of ILD in rheumatoid arthritis is about 20 to 30% of patients, while ILD may occur in 20 to 50% of patients with idiopathic inflammatory myositis, 40-50% or more of patients with systemic sclerosis, 2 to 5% of patients with systemic lupus erythematosus, 20 to 60% of patients with mixed connective tissue disease, and up to 25% of patients with Sjögren’s syndrome.
The spectrum of ILD varies depending on the underlying CTD. The histologic pattern seen in the lung biopsy is usually not diagnostic of the underlying CTD, however, the histologic pattern of disease can determine the radiologic features and influences clinical presentation, response to therapy, and prognosis.
Beyond what is known about the genetics of the underlying CTD, no specific genetic associations have been identified for CTD ILD.
A few simple diagnostic procedures may address >95% of pulmonary consultation questions related to ILD in the CTDs. These include CBC with differential, pulmonary function tests with DLCO, high resolution computed tomography of the chest, and appropriate serologies. Secondary tests can include echocardiogram and bronchoscopy with bronchioalveolar lavage.
Corticosteroids and immunosuppressive/immunomodulatory therapy are commonly used in management of CTD-ILD, with variable response.
Disclosure of Interest None Declared