Differential diagnosis for RA patients with respiratory symptoms should include PFIs
January 19 2018
Invasive pulmonary fungal infections (PFIs) are well known to exist alongside, or follow on from, conditions such as TB, HIV/AIDS, cancer, transplant surgery and COPD. Less is written about common chronic conditions such as rheumatoid arthritis, which requires long-term treatment with steroids, standard disease-modifying anti-rheumatic drugs (sDMARDs), and/or biological DMARDs (bDMARDs), such as infliximab. While PFIs in RA patients are rare, the pool of patients potentially at risk is large: according to Arthritis Research UK, rheumatoid arthritis (RA) affects more than 400,000 people in the UK, and up to 20,000 of those also suffer interstitial lung disease that can confound recognition of PFIs. Therefore it is important that clinicians include PFIs in the differential diagnosis for patients with respiratory symptoms.
Unlike with transplant or chemotherapy patients, antifungal prophylaxis is generally not practical during long-term anti-RA treatment because of potential drug-drug interactions, immune reconstitution inflammatory syndrome (IRIS), or a patient’s ability to tolerate the side effects of harsh antifungal drugs.
The Italian Group for the Study and Management of the Infections in Patients with Rheumatic Diseases (ISMIR) has carried out a review of available evidence and published a set of recommendations on how to recognise and manage PFIs in RA patients.
General take-home messages: while PFIs are rare in RA patients taking DMARDs, they should still be included in the differential diagnosis for patients experiencing respiratory symptoms. High-resolution CT scans and testing of BAL fluid can be used to distinguish PFIs from more common conditions such as interstitial lung disease. Please see the full paper for the specific recommendations for each PFI.
RA occasionally also causes rheumatoid pulmonary nodules that can confound diagnosis of non-invasive fungal infections such as chronic pulmonary aspergillosis (CPA) and Aspergillus nodules. In rare cases a rheumatoid nodule can become cavitated and be colonised by fungi including Aspergillus. However, these scenarios are not covered in this scope of these recommendations.