Interstitial pneumonia as an initial manifestation in a patient with late‐onset SLE

Systemic lupus erythematosus (SLE) has the potential to affect any organ and the lungs are commonly involved later in the course of the disease. The most common pulmonary manifestation attributable to SLE is pleuritis. Parenchymal involvement includes chronic interstitial lung disease (ILD) and acute lupus pneumonitis (ALP). Pulmonary involvements except pleural effusion are uncommonly manifested as an initial presentation of SLE. SLE usually develops over 50 years of age in a small subset ranging from 3–18% of cases.1 These patients frequently show a more insidious onset with non-specific clinical features and less common occurrence of severe manifestations. Thus, diagnosis of late-onset SLE is often delayed and established after more extensive investigations. A 70-year-old Japanese man had productive cough and pain in the chest and back, in the middle of December 2011. Then, he had bilateral swelling and painful purpura of fingers and toes. He had a history of membranous nephropathy, Hashimoto's thyroiditis and idiopathic thrombocytopenia at 55 years old. He had been treated with prednisolone for 2 years and 4 months; after then he had maintained remission. He had a history of normal pressure hydrocephalus at 64 years old. He was admitted to our hospital on January 27, 2012. On admission, his vital signs were body temperature 36.2°C, heart rate 87/min, blood pressure 115/66 mmHg, oxygen saturation by pulse oximetry (SpO2) of 98% on air. Fine crackles were heard throughout both lungs on auscultation. His initial laboratory findings are shown in Table 1. Forced vital capacity (FVC) was 90.4% predicted and forced expiratory volume percentage in one second (FEV1.0%) was 85.4%. Urine examination revealed positive reaction of proteinuria (0.2 g/day). A thoracic high-resolution computed tomography (HRCT) scan revealed patchy infiltrates bilaterally in lower lung zones. It clearly appeared on the right side with infiltrative appearance (Fig. 1). He was diagnosed as having SLE because of arthritis, platelet depletion (72 × 109/L), hypocomplementemia (22.7 U/mL), positive anti-double-stranded DNA antibody (> 400 IU/mL) and anti-nuclear antibody titers of 1 : 320. The histological features of surgical lung biopsies showed a major pattern of nonspecific interstitial pneumonia (NSIP), along with a minor component of usual interstitial pneumonia (UIP). His symptoms improved after commencement of prednisolone (40 mg/day), proteinuria disappeared promptly, and thrombocytopenia and hypocomplementemia were gradually improved. At this time, 22 months after the diagnosis of SLE, he had no symptoms and interstitial pneumonitis is under control with a maintenance dose of 8 mg prednisolone. Pulmonary involvement occurs in up to 25% of patients with SLE.2 Pleural disease is the most frequent respiratory manifestation (30–59%) due to SLE. On the other hand, lung involvement is identified in 3% at the onset of SLE, and develops in an additional 7% over the period of observation.3 The onset of the symptoms of ILD is insidious in most cases, but may appear after one or more episodes of acute lupus pneumonitis.4 The histological pattern usually observed in ILD with SLE is that of NSIP. Because of different treatments and prognoses for NSIP and UIP, accurate diagnosis for these two diseases is critical.5 However, the differential diagnosis between them is hard for both clinicians and pathologists,6 especially between NSIP fibrotic pattern (NSIP-F) and UIP. In addition, cryptogenic organizing pneumonia (COP, formerly known as bronchiolitis obliterans organizing pneumonia: BOOP) has been reported in several patients with SLE.7-11 The current approach to the diagnosis of ILD is based on clinical, radiological and pathological data. Surgical lung biopsy is the most sensitive method for collecting accurate pathological data; however, this procedure is performed in less than 15% of patients.12 An accurate diagnosis of the histopathological subtype of ILD is important to guide prognosis and management. There are only a few reports on pathological investigation of ILD with SLE. To our knowledge, there are 11 cases of SLE complicated with ILD, including ours (Table 2).7-9, 11, 13-15 COP7-11 was the most frequently reported in seven cases, and lymphocytic interstitial pneumonia (LIP),13 acute fibrinous and organizing pneumonia (AFOP)14 and desquamative interstitial pneumonitis (DIP)15 were reported, one in each case. It was reported that ILD with SLE is highly associated with the presence of anti-SS-A (Ro) antibodies, and 82% of patients (9/11) with lupus pneumonitis had anti-SS-A (Ro) antibodies.16 However, in the patients in Table 2, anti-SS-A antibody was positive in only one patient.13 ILD was the initial manifestation of SLE in five cases (45%), including our case.8, 10, 11 Prognosis seems to be favorable since 10 out of 11 cases (91%) displayed improvement. PSL 60 mg CPA 100 mg PSL 50 mg AZP 150 mg The clinical course of late-onset SLE is considered mild, rarely characterized by the occurrence of severe manifestations, such as renal or neuropsychiatric involvement. By contrast, serositis, lung involvement and secondary Sjögren's syndrome are more frequently detected in elderly lupus patients.1 The pooled analysis of the literature data showed significant decline of the female/male sex ratio observed with aging in SLE (4.4 in the late-onset group vs. 10.6 in the early-onset group). This probably reflects the relationship between SLE and estrogen status. The present report describes an unusual case of ILD in a patient with late-onset SLE. Clinicians should consider a surgical lung biopsy in patients with ILD. Further study is necessary to clarify the pathogenesis, clinical characteristics and prognosis of ILD associated with SLE. More attention to the pulmonary manifestations of late-onset SLE is warranted.