A 60-year-old woman was admitted to the Emergency Department (ED) of our hospital for cough, shortness of breath, chills, and myalgia. There was no sputum. She was a tourist from Japan and had come to Korea three days earlier. The patient had been in good health until the past week, when she developed a fever and headache. In response, she took acetaminophen for 3 days. She had no history of smoking and was not on any continuous therapy. On arrival to the ED, the patient's body temperature was 37.8℃, blood pressure 130/74 mm Hg, pulse rate 82 beats per minute, respiratory rate 24 breaths per minute, and oxygen saturation 86% while breathing ambient air. Crackles were heard at the base of lungs. Respiratory failure was confirmed by the arterial blood gas: PO
2 51 mm Hg, PCO
2 32 mm Hg, and pH 7.52. The white blood cell count was 7,500/µL (neutrophils, 80%; lymphocytes, 12%; monocytes, 5%) and a hemoglobin value of 13.0 g/dL. C-reactive protein was increased to 12.7 mg/dL (normal, 0-0.8 mg/dL). Procalcitonin was <0.05 ng/mL (normal, <0.05 ng/mL). Chest radiography (
Figure 1B) showed bilateral infiltrates in both lower fields. The patient was admitted to the Respiratory Department, where she received antibiotics (intravenous levofloxacin plus piperacillin-tazobactam plus oral clarithromycin) and oxygen. Further blood tests were conducted, which showed elevations of creatinine kinase (448 IU/L), lactate dehydrogenase (596 IU/L), aspartate aminotransferase (144 IU/L), and alanine aminotransferase (128 IU/L). On the second day of hospitalization, the patient's respiratory failure worsened, and she was transferred to the intensive care unit, where endotracheal intubation and mechanical ventilation were performed. As she progressed to respiratory failure (
Figure 1C), we thought she had severe community-acquired pneumonia, and we administered hydrocortisone intravenously (100 mg then 50 mg every 6 hours) for 3 days. After 4 days on the ventilator (
Figure 1D), we removed the endotracheal tube. However, two days later, the patient's body temperature was 39℃, her respiratory rate was 35 breaths per minute, and she complained of general weakness and dyspnea. Due to the development of ARDS (
Figure 1E), we re-intubated the patient and began mechanical ventilation again. We thought her condition may be ventilator-associated pneumonia, and changed antibiotics from levofloxacin plus piperacillin-tazobactam to meropenem plus vancomycin. However, the patient's high fever persisted and her chest radiography worsened. On the eighth day of hospitalization, there was still no improvement and the microbiological evaluation provided no evidence for bacterial, fungal, or viral infection under repeated endotracheal aspiration cultures and protected bronchial washing culture. We suspected inflammatory myopathy with ILD due to the increased muscle and liver enzyme values. Especially, creatinine kinase was elevated to >2,000 IU/L. Thus, we checked specific markers for connective tissue diseases. In addition, we reviewed her past medical history from her daughter. Before admission, the patient had suffered from frequent oral ulcers and eye dryness for several weeks. Two months ago, she underwent chest radiography (
Figure 1A) at a Japanese hospital and the results were normal. One week before she arrived in Korea, she underwent a blood test due to multiple arthralgias, which showed a high value of lactate dehydrogenase (422 IU/L). While we screened for the specific markers for inflammatory myopathy, an empirical therapy with high-dose corticosteroids was started (intravenous pulses of 125 mg every 6 hours for one day tapered 60 mg/day). The therapy led to a significant improvement of PaO
2/FIO
2 ratio, and enabled to wean the patient from mechanical ventilation on the 11th day after intubation. On the 13th day of hospitalization, laboratory results revealed positive anti-Jo-1 antibody with 6.4 index (normal range, <1.0 index), aldolase with 22.9 U/L (normal range, 0-7.6 U/L), and anti-Ro (SSA) antibody with >240 U/mL (normal range, <10 U/mL). Rheumatoid factor, antinuclear antibody, anti-La (SSB) antibody, anti-centromere antibody, anti-Scl-70 antibody, anti-ds-DNA antibody, anti-ribonucleoprotein antibody, and anti-Sm antibody were all negative. On high-resolution computed tomography (HRCT) (
Figure 2) after extubation, there were still irregular diffuse ground-glass opacity in both upper lungs and irregular patchy consolidation on both lower lungs without honeycombing. Although a histologic diagnosis was not made, we provisionally diagnosed the patient with ARDS as the initial clinical manifestation of an anti-Jo-1 antibody-positive antisynthetase syndrome. After 25 days of hospitalization (
Figure 1F), the patient was discharged without oxygen.
Figure 3 shows the whole course of laboratory values, clinical course, and treatments.