Aryeh Fischer

The intersection of the connective tissue diseases (CTD) and the interstitial lung diseases (ILD) is complex. Although often considered as a single entity, "CTD-ILD" actually reflects a heterogeneous spectrum of diverse CTDs and a variety of patterns of interstitial pneumonia. The evaluation of patients with CTD that develop ILD, or the assessment for underlying CTD in those presenting with presumed "idiopathic" ILD can be challenging and these evaluations can be optimized by effective multidisciplinary collaboration. When a diagnosis of CTD-ILD is confirmed, careful and thorough assessments to determine extra- versus intra-thoracic disease activity, and degrees of impairment are needed. Pharmacologic intervention with immunosuppression is the mainstay of therapy for all forms of CTD-ILD, but should be reserved only for those that demonstrate clinically significant and/or progressive disease. The management of CTD-ILD is not yet evidence based and there is a desperate need for controlled trials across the spectrum of CTD-ILD. Non-pharmacologic management strategies and addressing comorbidities or aggravating factors should be part of a comprehensive treatment plan for individuals with CTD-ILD.

We sought to examine the relationship between measures of ILD severity and PH in patients with SSc. We identified 55 subjects from 12 PHAROS sites with RHC-proven PH and HRCT evidence of ILD. Subjects with PH due to left heart disease were excluded. Baseline HRCT scans were scored by a standardised system that graded severity of ILD. Summary statistics were generated for baseline characteristics. Spearman correlation and linear regression were used to examine relationships between ILD and PH severity variables. The majority of subjects were white women; nearly half had limited cutaneous SSc. Most subjects were New York Heart Association functional class II or III. Pulmonary function testing revealed moderate restriction (mean FVC 64.3 ± 17.2% predicted) with severe reduction in diffusing capacity (mean DLco 34.2 ± 13.3% predicted). RHC demonstrated mild to moderate PH (mean PAP 35 ± 9 mmHg, mean PVR 5.1 ± 3.7 WU). There was no correlation between severity of ILD (by either HRCT or PFT) and cardiac haemodynamic parameters of PH. No association between severity of ILD and cardiac haemodynamic profiles were identified in this cohort. We believe this underscores the complex nature of PH and ILD in individuals with SSc. We do suspect that some individuals with SSc-ILD will also have concomitant pulmonary vascular disease but simple assessments to grade severity of ILD - by PFT or HRCT estimates of ILD extent - are likely not enough to reliably distinguish between PAH versus PH-ILD. Further research into how to distinguish and manage these subsets is warranted.

Lung disease is a common manifestation of connective tissue disease (CTD) and is associated with significant morbidity and mortality. The evaluation of lung disease, and interstitial lung disease (ILD) in particular, in patients with CTD is complex because of the heterogeneity of the CTDs, the varied types and degrees of severity of ILD encountered, and because ILD can be identified at any point in time in these patients. Cross-disciplinary, thorough evaluations are needed when CTD patients develop ILD or when evaluating ILD patients for the presence of occult CTD. Determining that ILD is associated with an established CTD requires the exclusion of alternative etiologies, and thorough assessments of the clinical features of both the CTD and ILD. The detection of occult CTD in patients with “idiopathic” ILD requires careful attention to the demographic profile, historical clues, subtle physical examination findings, specific autoantibody positivity, radiological and histopathological features, and can be optimized by a multidisciplinary approach that includes rheumatological collaboration. Not all patients with CTD-associated ILD require pharmacological therapy, and management decisions should consider pace and severity of the disease, intra- and extrathoracic features of activity and can be optimized by cross-disciplinary collaboration.

The connective tissue diseases (CTDs) are a group of systemic disorders characterized by autoimmunity and autoimmune-mediated organ damage. The lung is a frequent target and all components of the respiratory system are at risk. Interstitial lung disease (ILD) represents a broad group of diffuse parenchymal lung injury patterns characterized by varying degrees of inflammation and fibrosis, is a common manifestation of CTD particularly common in systemic sclerosis, polymyositis/dermatomyositis, and rheumatoid arthritis, and is a leading cause of significant morbidity and mortality. The lung injury patterns of CTD-associated ILD (CTD-ILD) mirror those of idiopathic interstitial pneumonia and may arise at any time during the course of the CTD or may be the first manifestation of CTD. Patients with CTD that present with respiratory failure often present significant diagnostic dilemmas. Thorough and comprehensive assessments to exclude respiratory *infection, acute interstitial pneumonia, medication toxicity, pulmonary embolism, cardiac dysfunction, and diffuse alveolar hemorrhage are the fundamental components for the evaluation of such patients. Furthermore, patients with CTD are also at risk of acute exacerbations of underlying ILD. Acute exacerbations are manifested by subacute respiratory deterioration with worsening hypoxemia in the setting of new radiographic abnormalities. The prognosis of patients with CTD having respiratory failure is often quite poor, highlighting the need for prompt and thorough clinical assessments to determine the underlying etiology and implementation of appropriate therapeutic strategies.