Interstitial lung disease: are we missing formes frustes of connective tissue disease?

Abstract

Patients with connective tissue disease (CTD) may encompass a variety of respiratory manifestations, including: pleural disease; pulmonary hypertension; bronchial or bronchiolar disease; interstitial pneumonia; restrictive lung disease secondary to musculo-skeletal changes; and iatrogenic drug-induced lung disease. Patients also have an increased risk of opportunistic infections, often favoured by corticosteroids and/or immunosuppressive or immunomodulatory therapy 1, 2. The respective frequency of manifestations, their clinical and radiological presentations, response to treatment, and outcome are dependent on the underlying CTD. Rheumatoid arthritis may be responsible for a broad spectrum of manifestations, including: pleural effusion; chronic interstitial pneumonia; lung rheumatoid nodules; bronchiectasis; obstructive ventilatory defect due to constrictive bronchiolitis; laryngeal involvement; and opportunistic infections, such as mycobacterial infections facilitated by anti-tumour necrosis factor-α treatments. Systemic sclerosis may be commonly associated with chronic interstitial pneumonia (especially in patients with diffuse systemic sclerosis and anti-topoisomerase-1 antibodies), or pulmonary arterial hypertension (most frequently, but not exclusively, in patients with limited systemic sclerosis with anti-centromere antibodies), with both contributing to the unfavourable prognosis of the disease 3. Although less frequent among CTDs than rheumatoid arthritis and systemic sclerosis, the spectrum of idiopathic inflammatory myopathy (including dermatomyositis, polymyositis, and amyopathic dermatomyositis) may give rise to a variety of respiratory manifestations, which represent a common cause of death in these patients. These include interstitial lung disease (ILD), aspiration pneumonia, ventilatory failure secondary to diaphragmatic dysfunction 4, and rarely, acute respiratory distress syndrome, pleural effusion, pneumothorax, pulmonary hypertension 5, diffuse alveolar haemorrhage, and dyspnoea due to dermatopolymyositis-related cardiac disease 2, 6. In addition, some manifestations may be the consequence of treatment, such as drug-induced pneumonitis and opportunistic infections. First described in 1986 7, the high frequency of pneumomediastinum in dermatomyositis has been better appreciated more recently 8. The association of ILD and …