CASE PRESENTATION
The patient was an 80-year-old Japanese man. During the month before admission, he experienced progressive dysphagia and muscle weakness in the lower extremities. Because of difficulty with walking, he sought medical attention at the hospital. He had a 60-year history of smoking 10 cigarettes per day and infrequent hospital visits and was not currently on any medication. The patient had no history of Raynaud phenomenon.
On admission, the patient’s temperature was 37.3°C, and no other abnormalities were detected in his vital signs. Indurated edema was observed in both lower legs, and a purple color change was observed in the second to fifth fingers of the left hand (Fig. 1–A). Although muscle atrophy was not evident because of edematous changes, the patient experienced generalized muscle pain in the bilateral thighs. The strength in the upper extremities was assessed as a Muscle Strength Testing (MMT) score of 4, while the iliopsoas and quadriceps muscles were graded as an MMT score of 2.
Blood test findings revealed elevated levels of muscle enzymes (creatine kinase [CK], 7,930 U/L and C-reactive protein [CRP], 2.0 mg/dL), an erythrocyte sedimentation rate (ESR) of 16 mm/h, and an elevated inflammatory response. Results were negative for antinuclear antibodies, rheumatoid factor (RF), myeloperoxidase-anti-neutrophil cytoplasmic antibodies (MPO-ANCA), proteinase-3-anti-neutrophil cytoplasmic antibodies (PR3-ANCA), anti-Scl-70, U1RNP, centromere, Jo-1, PL-12, anti-melanoma differentiation-associated gene-5 (MDA5), and anti-transcriptional intermediary factor 1-γ (TIF1-γ), and for MI-2, Ku, PM-SCL75, PM-SCL100, SRP, PL-7, EJ, and OJ. However, Ro-52 (EUROLINE Myositis Profile 3; EUROIMMUN Medizinische Labordiagnostika AG, Lubeck, Germany) demonstrated a strong positive result (3+). During the patient’s hospitalization, further testing using immunoprecipitation was conducted at another institute’s laboratory, and the patient was strongly positive for anti-OJ antibodies.
Contrast-enhanced magnetic resonance imaging (MRI) revealed a contrast effect in muscle electromyography, and positron emission tomography-computed tomography also showed extensive soft tissue accumulation despite normal blood glucose levels (Fig. 2A and B). Muscle biopsy findings were consistent with myositis, which led to a diagnosis of anti-ARS antibody syndrome. Chest CT upon admission indicated chronic obstructive pulmonary disease and mild interstitial pneumonia; however, no malignancy was detected. MRI of the head showed no abnormality.
After admission, the color of the patient’s fingers changed from purple to black, indicating necrosis (Fig. 1B). Contrast-enhanced CT images showed no signs of vascular stenosis or obstruction. Intravenous heparin sodium (10,000 U/day), prostaglandins (limaprost alfadex 30 μg/day), tocopherol nicotinate 600 mg/day, and warming agents for a week, the progression of the finger necrosis did not stop.
On day 10 of hospitalization, the patient’s respiratory status deteriorated, necessitating ventilator management. Worsening interstitial pneumonia was treated with a methylprednisolone pulse of 1,000 mg for 3 days and post-therapy prednisolone (PSL; 60 mg [1 g/kg]). Following initiation of treatment, his respiratory condition rapidly improved, and he was weaned off the ventilator within approximately 10 days. Close examination revealed no exacerbation of interstitial pneumonia or changes in Krebs von den Lungen 6 (KL-6; 216 U/mL) or surfactant protein-D (SP-D; 65 ng/mL). This was attributed to improved carbon dioxide (CO2) narcosis. After the first day of PSL pulse administration, a purple transition zone appeared in the necrotic area of the fingers, which subsequently ceased expanding (Fig. 1C).
The patient experienced repeated episodes of aspiration pneumonia owing to dysphagia; however, over time, both swallowing ability and lower limb muscle strength gradually improved. On day 40 of hospitalization, the MMT score of the lower limbs recovered to 3–4, and CK levels were normal. Additionally, the CRP level and ESR had substantially decreased. Furthermore, the progression of finger necrosis had ceased. By day 70 of hospitalization, all MMT scores had improved to 5, indicating complete recovery of muscle strength. Swallowing function had also improved to the state before the disease onset, leading to the patient’s discharge from the hospital. Although the necrotic areas of the fingers became narrower and drier after pulse therapy, necrosis did not progress (Fig. 1D).