Case Presentation:

A 73‐year‐old male with HTN presented with 1 month of bilateral UE throbbing pain in his upper arms followed by his hands. This was associated with swelling ascending up from his hands to forearms. This limited bilateral arm elevation and fist formation. He denied any fevers, rash, weight loss, leg symptoms, neck pain, face swelling, visual changes, or jaw claudication. Symptoms persisted although statins were discontinued, and NSAIDS provided only temporary relief. On exam, he was afebrile with normal, nonlender temporal artery pulsations. Upper extremities showed bilateral pitting edema of hands and forearm, synovitis of wrist and hand joints, along with tenderness over biceps, triceps tendons, and distal forearm. Shoulder abduction was limited to 15 degrees bilaterally with no other gross motor deficits. Labs revealed normal CBC and CMP except an Hb of 10.5. ESR 41, CRP 4.8, normal CK and TSH, and negative ANA, ANCA. RA factor, and CCP Ab. Hand x‐rays did not show any erosions. MRI cervical spine revealed mild spondylosis with normal cord morphology. Ultrasound venous duplex was negative for DVT in the upper extremities. EMG revealed no evidence of a generalized myopathy. Rheumatology was consulted. Having ruled out myopathy and neurovascular and spinal etiologies, a clinical diagnosis of remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome was made. Steroids were started, and the patient responded well with decreasing pain and swelling.

Discussion:

RS3PE syndrome is a subset of the seronegative symmetrical polyarthritides. The proposed diagnostic criteria include bilateral pitting edema of hands, sudden onsei of polyarthritis, age more than 50 years, and seronegativity. It is associated with HLA B7 and HLA A2 hapbtypes anc hasa male predominance (M:F 2:1). Tenosynovitis of both flexor and extensor tendons at Ihe wrist is the hallmark of RS3PE and is responsible for the edema of subculaneous and peritendinous soft tissue. Labs reveal discrete inflammatory anemia and raised inflammatory markers, and x‐rays show soft tissue swelling but no erosions. The patients with idiopathic RS3PE syndrome show an excellent response to steroids as compared to RS3PE associated with neoplasia. If patients show a poor response to steroids, it may be a paraneoplastic manifestation, and looking for underlying malignancy is recommended. The main differential is polymyalgia rheumatica (PMR), which is more common in females and rarely presents with pitting edema. However some authors opine that because of the similarities of demographic, clinical, and MRI findings between RS3PE and PMR, these conditions may be part of the same disease, and the presence of distal edema seems to indicate a better prognosis.

Conclusions:

RS3PE is a close mimicker of PMR, differentiated only by the presence of bilateral upper‐extremity edema. Awareness of this condition can help offer a better prognosis to affected patients because it is more responsive to steroids.

Author Disclosure:

R. Bahuva, none; A. Satra, none; S. Kandpal, none; M. Patel, none.