Background Diffuse alveolar hemorrhage (DAH) is a life-threatening though rare manifestation of systemic lupus erythematosus (SLE). Early diagnosis is difficult since the occurrence is abrupt and both symptoms and radiographic findings of diffuse lung infiltration on thoracic CT are nonspecific. Since DAH has high early mortality, it is important to find the clinical features indicating DAH among SLE patients with diffuse lung infiltration and factors influencing its outcomes.
Objectives To identify the clinical features of DAH in SLE patients compared with other causes of acute diffuse lung infiltration in SLE patients, and to determine the influencing factors of early outcome of SLE-DAH.
Methods We retrospectively collected the medical records of SLE patients, who had acute diffuse lung infiltration on thoracic CT in a single university hospital between January 2004 and August 2014. DAH was defined based on the clinical diagnosis, and we divided patients into two groups; DAH vs. non-DAH group. We compared the demographic and clinical characteristics and presenting symptoms between two groups. And then, we further analyzed the early mortality of SLE-DAH patients and factors affecting mortality in DAH patients.
Results Among the 815 SLE patients who checked thoracic CT, 47 patients with acute diffuse lung infiltration were selected for this study. Among them, 24 SLE patients (51.1%) were diagnosed as DAH, the rest of 23 patients (48.9%) formed non-DAH group; non-DAH group included various diseases such as CMV infection (n=2), pneumocystis infection (n=3), unspecified pneumonia (n=9), SLE associated lesions (n=7), and others (n=2). All of them were female and young: 29.6 years old in DAH group and 29.8 years old in non-DAH group. In the presenting symptoms, hemoptysis and dyspnea were more common in DAH group, while fever was more common in non-DAH group, though statistically not significant. In laboratory findings, hemoglobin level (8.2±0.3 vs. 10.0±0.4 g/dL, p<0.01) and C3 level (41.0±4.2 vs. 63.8±7.9, p=0.03) of DAH group were significantly lower than those of non-DAH group, while acute phase reactants and autoantibody profiles were comparable between two groups. The other factors indicating high SLE activity such as SLEDAI-2K score (11.5±1.7 vs. 10.1±1.1), C4 level (11.2±1.5 vs. 17.2±2.5), and CH50 level (12.0±3.4 vs. 25.0±4.6) were different between two groups, but these differences didn't reach statistical significance. During follow-up, 7 among 24 DAH patients died with mean duration of 27.1 days from DAH development; 6 patients died within 3 weeks from DAH development. In comparison between the survivor and the deceased, lupus nephritis was more common in the deceased (100% vs. 35.3%, p<0.01), and they had been taken more intensive treatment with plasmapheresis (71.4% vs. 17.6, p=0.02), IVIG (85.7% vs. 35.3%, p=0.07), transfusion (100% vs. 47.1%, p=0.02), or ventilator (71.4% vs. 0%, p<0.01) compared with survivors.
Conclusions Among SLE patients who had diffuse lung infiltration in thoracic CT, 51% was DAH and they tend to have lower level of hemoglobin and high SLE disease activity compared with non-DAH patients. DAH in SLE patients showed high early mortality and it was associated with comorbid condition of lupus nephritis
Disclosure of Interest None declared
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