Synovitis with pitting edema as the presenting manifestation of antisynthetase syndrome

Abstract

Introduction: \\r\\nThe Anti-Synthetases Syndrome (ASS) is an autoimmune disease associating inflammatory myopathy, interstitial pneumonitis, polyarthritis, raynaud syndrome, characteristic cutaneous involvement (\\\"hands of mechanics\\\") and autoantibodies antiaminoacyl transfer RNA synthetases including anti-JO-1. On can also observe general manifestations like fever or asthenia. We report the case of a patient who presented acute oedematous polyarthritis that revealed an anti-synthetase syndrome. \\r\\n. Observation: \\r\\nThis is a 65-year-old patient with a history of hospitalization in pneumology for acute respiratory distress syndrome related to infectious hypoxemic pneumonitis, admitted in 2017 to the rheumatology department for exploration of acute polyarthritis, evolving for 1 month, affecting the elbows, knees, wrists, small joints of the hands and ankles associated with distal edema at the 4 members keeping the bucket. The patient was afebrile. On neurological examination, he had weak osteotendinous reflexes in the lower limbs without associated muscular deficit. The rest of the somatic examination was without notable abnormalities. \\r\\nIn biology, he had a biological inflammatory syndrome (CRP 37.7 mg/l), lymphopenia at 1000 El/mm3, LDH at 2 times normal and CPK at 3 times the normal. In the immunoassay, antinuclear antibodies were positive at 1/800 as well as anti-ENA, anti-JO-1. The tumor markers were negative. \\r\\n\\r\\nX-rays of the affected joints were without abnormalities. Thoraco-abdominopelvic Computed Tomography (CT) showed ventilatory disturbances of both basal pyramids with bronchiectasis and low abundance left pleural effusion. The functional respiratory explorations had objectified a restrictive syndrome. Muscle biopsy revealed a discrete perivascular inflammatory infiltrate with no type of necrosis or regeneration. Faced with these elements, the diagnosis of ASS was retained and the patient was put on corticosteroids at the dose of 1 mg/kg/day with a clear clinical-biological improvement. The patient was lost to follow-up for 5 months, then he was referred to rheumatology in a febrile state associated with a muscular deficit of the 2 scapular and pelvic belts, following the abrupt cessation of his treatment on his own. He also had a biological inflammatory syndrome (CRP 166.5 mg/l) with myolysis (CPK at 4 times normal and LDH at 3 times normal). He received 3 bols of methylprednisolone (1 gram/bolus) relayed by prednisolone at a dose of 1 mg/kg/day for one week. However, at a dose rate of 0.3 mg/kg/day, the patient relapsed and presented with fever and biological inflammatory syndrome; hence the decision to switch to cyclophosphamide as a monthly infusion at a dose of 0.7 mg/m2 body surface area combined with corticosteroid therapy at a dose of 0.3 mg/kg/day. The patient received a total of 6 courses of cyclophosphamide with a poor response to treatment. It was recommended, therefore, to put him on rituximab and while waiting for this treatment he was put on azathioprine 100 mg/day.\\r\\n\\r\\n. Conclusion: \\r\\n\\r\\nOur clinical case highlights the importance of thinking about the ASS in polyarthritis, which is also associated with interstitial lung disease. Indeed, the rapid diagnosis of this syndrome allows a good management of the patient and avoids evolving into a severe form of the disease may be life-threatening especially by pulmonary fibrosis. Similarly, it is essential to better understand the pathophysiological mechanisms of the ASS in order to implement effective therapeutics.