AB0331 PULMONARY INVOLVEMENT IN A SINGLE CENTER COHORT OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS
Authors: N. Senkal, E. Kiyan, E. Kocasoy-Orhan, A. Demir, M. Aydogan, Y. Yalçinkaya, A. Gul, M. Inanc, M. L. Ocal, B. Artim-Esen
Journal: Annals of the Rheumatic Diseases (2021)

Background: The prevalence of SLE pulmonary involvement varies depending on several factors, including diagnostic methods [1]. Objectives: We aimed to determine the frequency of involvement with different diagnostic methods in a single center cohort. Methods: 300 SLE patients were included. Chest x-ray (CXR), lung spirometry, carbonmonoxide diffusion test (DLCOc) and echocardiography were performed. High resolution thorax computed tomography (HRCT) was done for a definite diagnosis of interstitial lung disease (ILD) whilst diagram electromyography (EMG), ultrasonography (USG) and magnetic resonance imaging (MR) were utilized to diagnose shrinking lung syndrome (SLS). Results: The mean age and follow-up time were 43 and 11,5 years respectively. Of 300 patients, 16% had ILD, 6,7% had pulmonary hypertension (PHT), 3% had SLS, 0,3% had pulmonary infarction. At the start of the study, patients’ records showed that 4% had ILD, 5% PHT, 0,3% SLS and 0,3% pulmonary infarction. The median age, mean duration of disease and follow-up time were significantly higher and longer in patients with ILD compared to patients without (p&lt;0.05). Forced expiratory volume (FEV1), forced vital capacity (FVC), DLCOc and total lung capacity (TLC) were significantly lower in patients with ILD and with SLS (p&lt;0,001). Patients with ILD had significantly higher frequency of arthritis, serositis, Raynaud myositis and anti-Scl70 positivity. Avascular necrosis, diabetes and malignancy were significantly more frequent in those patients. All patients with suspected SLS undergone diagram EMG, USG and MR. Out of 10 suspected cases, in 6 EMG, in 5 USG and in 9 MR was compatible with SLS diagnosis. 5 patients had 3 of the diagnostic methods positive to diagnose SLS. Muscle atrophy and weakness, avascular necrosis were more frequent in this group of patients (p&lt;0.05). There were more patients treated with mycophenolate mofetil (MMF) and cyclophosphamide in the SLS group whilst more with MMF in the ILD group. Significantly higher frequency of patients had stopped using hydroxychloroquine (HCQ) in the ILD group (p=0,04). Conclusion: Interstitial lung disease is common in patients with SLE and considerable number of patients have SLS [2]. Spirometry, DLCOc and CXR are simple but valuable to diagnose pulmonary involvement in SLE patients. Diaphragm MR, USG and EMG are complementary methods for definite diagnosis in SLS [2]. Considering the significant difference of prevalence between the start and the end of the study, one of the possibbilities is the underrecognition of SLE pulmonary disease due to its being part of a multisystemic presentation. Higher usage of immunosuppressives in these patients may support a multisystemic active disease. Although drug effect is another concern, it is hard to establish a causal relationship due to the study’s cross-sectional design. HCQ may have a role in ILD prevention. References: [1]Keane MP, Lynch JP. Pleuropulmonary manifestations of systemic lupus erythematosus. Thorax 2000;55:159-166. [2]Singh R, Huang W, Menon Y, Espinoza LR. Shrinking lung syndrome in systemic lupus erythematosus and Sjogren’s syndrome. J Clin Rheumatol. 2002 Dec;8(6):340-5. Table 1. Spirometry; DLCO; diaphragm EMG, USG and MRI results of patients with SLS. Patient/ Age/ Sex 1/ 44/ F 2/ 57/ F 3/ 39/ F 4/ 38/ M 5/ 23/ F 6/ 60/ F 7/ 58/ F 8/ 37/ F 9/ 66/ F 10/ 28/ F FEV1 (%) 47 65 59 63 67 62 71 53 70 39 FVC (%) 56 73 59 62 79 70 72 55 62 37 DLCO (%) 45 50 44 65 53 55 47 65 62 45 TLC (%) 61 71 65 66 78 64 54 63 62 45 USG deep inspiration (L) 4,70 4,74 2,59 3,01 3,06 3,06 5,73 4,17 2,12 1,59 USG deep inspiration (R) 3,72 1,98 2,26 2,24 2,77 2,17 4,67 2,83 4,62 2,49 USG diaphragm thickness (L) 4,82 3,00 2,48 2,84 2,55 1,59 2,09 3,18 1,62 1,44 USG diaphragm thickness R(R) 1,23 1,04 1,84 1,80 2,19 1,31 1,79 1,97 2,08 1,63 MR high side R R R R R R R L L MR height difference 4,92 6,19 2,87 2,64 1,67 2,45 1,73 0,95 0,78 EMG resting AMP (R) 0,2 0,3 0,6 0,5 0,6 0,4 0,1 0,8 0,9 0,7 EMG resting LAT (R) 7 6,4 7,1 6 6,7 8 6,15 4,75 6 5,8 EMG resting AMP (L) 0,4 0,5 0,8 0,7 1,2 0,6 0,3 1,2 0,5 0,5 EMG resting LAT (L) 6,35 5,75 6,85 5,6 6,05 6 6 4,35 5,2 6,15 Disclosure of Interests: None declared