27. A new presentation of interstitial lung disease

Abstract

Introduction:Patients presenting withnewonsetinterstitial lungdisease (ILD) should be assessed for secondary, potentially treatable, causes. Some patients with rheumatic disease may present with ILD as the first manifestation of their condition. Early diagnosis and treatment of an underlying rheumatic disease can improve patient outcome. As autoimmune screening has evolved to include extended myositis and sclerodermapanels, increasingnumbers of patients with ILD are being referred forreviewbyarheumatologist.Thiscasehighlightsonesuchpatientdiagnosed with new onset ILD during an acute hospital admission but subsequentlyfoundtohaveanunderlyingconnectivetissuedisease( CTD). Casedescription:A54-year-oldpreviously fitandwellmanpresentedto the Emergency Department with a three-month history of progressively worseningshortnessofbreathanddrycough.Hedeniedanyothersymptoms, including those in keeping with a connective tissue disease (CTD). His past medical history was unremarkable. His father had a possible diagnosis of Sjö gren's syndrome and his sister had Sjö gren's syndrome withILD.Hehada20packyearsmokinghistory. Onadmission his could only walk ten meters before havingto stop due to shortness of breath. On auscultation of his chest he had fine inspiratory crepitations in the mid andlower zones. Blood tests revealed an elevated c-reactive protein (CRP) of 96 and erythrocyte sedimentation rate (ESR) of 120.Hefailed to improve with intravenous antibiotics andhisCRProse to 122. Computer tomography (HRCT) of the chest, abdomen and pelvis revealed bilateral reticulation peripherally in the mid and lower zonesand paraseptal/centrilobular emphysematous changes in the upper zones. Pulmonary function tests (PFTs) demonstrated normal spirometry but reduced gas transfer. Anti-cyclic citrullinated peptide (anti-CCP) antibodies, rheumatoid factor, anti-neutrophil cytoplasmic antibodies (ANCA) and HIV screenwere negative. Creatine kinase was normal.ANA was positive, with positive anti-Ro-52 antibodies and positive anti-PL12 onanextendedmyositispanel. Adiagnosis of anti-synthetase syndromewasmade.Hewastreatedwith three 1 gram doses of intravenous methylprednisolone on consecutive days then switched to 40mg of oral prednisolone daily. His inflammatory markers improved and he was discharged home. Monthly cyclophosphamideinfusionswerecommencedandhehasreceivedtwodosesthus far. Although subjectively the patient does not reportmuchimprovement in his breathing as yet, he attends his appointments independently and is able to walk over 50 meters without stopping. Repeat PFTs and HRCT chestarescheduled. Discussion: Patients presenting with ILD with no identifiable cause should be assessed and screened for CTDs. Evaluation should include a thorough historyandexamination, lookingforassociated conditions. ILD may be associated with rheumatoid arthritis, systemic sclerosis, polymyositis, dermatomyositis, anti-synthetase syndrome, sarcoidosis, Sjogren's syndrome, mixed connective tissue disease and systemic lupuserythematous(SLE). Pulmonary function testsmaydemonstratea restrictive pattern onspirometry, although this can be normal. Gas transfer is often reduced and a carbon monoxide transfer factor of<40% is indicative of advanced disease. Imaging,usually in theformof high-resolutionCT(HRCT),canallow assessment of the pattern of ILD and the potential for reversibility. It can oftenhelpavoidtheneedforlungbiopsy. If no clear alternative cause of ILD (eg. drugs, occupational exposure, inhaledsubstances,infection, radiation)thenphysiciansshouldconsider sending bloods to help excludes CTDs, including creatine kinase, rheumatoid factor, anti-CCP antibodies, anti-nuclear antibodies (with extendedmyositisandsclerodermapanels)andANCA,eveninasymptomatic patients. Case series have demonstrated that ILD may be the only presenting feature in a proportion of those with anti-synthetase syndrome, particularly in patients with anti-PL7 or PL-12. The classic triad of clinical features for anti-synthetase syndrome consists of ILD, myositis and arthritis (mechanic's hands). Our patient had no CTD symptoms at presentation but has gone on to develop Raynaud's and stiffness in his fingers over the last 6 months. He has not at any stage had evidence of myositis, either clinically or serologically, which is in keeping with case series of patients with ILD and PL-12 positivity reporting a proportion as being amyopathic. Particular factors that should prompt screening for anti-synthetase syndrome include female gender, middle age, clinical signssuggestiveofaCTDandanNSIPpatternonHRCT. Key learning points: Rheumatic conditions which can present with ILD include rheumatoid arthritis, systemic sclerosis, polymyositis, dermatomyositis, anti-synthetase syndrome, sarcoidosis, Sjö gren's syndrome, mixed connective tissue disease and SLE.Newly presenting ILD patients with no identifiable cause should be checked for rheumatoid factor, anti-CCP antibodies, anti-nuclear antibodies (with extended myositis and sclerodermapanel)andANCA. ILDassociatedwithanti-synthetasesyndrome,polymyositisordermatomyositis often warrants early treatment with steroid and cyclophosphamideoranotherimmunosuppressiveagentsuchasrituximab. Patient characteristics which should prompt screening for anti-synthetase syndrome with extended myositis panel testing include clinical suspicion of CTD, female gender, middle age, CTD symptoms or signs and NSIPpatternonHRCT. All patients presentingwithILDshouldhavepulmonaryfunction testsand imagingtoassessseverity ofdisease. Conflicts of interest: The authors have declared no conflicts of interest.