The patient is a 56-year-old female with a past medical history of hypertension, hyperlipidemia, and ulcerative colitis who presented with complaints of joint pains for over 30 years. Her symptoms started with pain in the back radiating down the leg which later progressed to involve her shoulders, arms, wrists, and legs. She also described occasional swelling in her ankles, nonrefreshing sleep, and joint stiffness.
Eight years before presenting to our clinic, she was given a diagnosis of chronic Lyme disease based on non-CDC-approved testing and received IV ceftriaxone. However, repeat Lyme testing with IgG and IgM antibody by our facility was negative. MRI of her tibia and fibula two years prior to presenting in our clinic had revealed marrow edema, but a biopsy of her bone marrow was normal.
Upon initial presentation to our clinic, she was felt to have inflammatory arthritis and was treated with prednisone taper starting at 40 mg daily and weaned off slowly over several months. This helped her joint pain but did not resolve her symptoms completely. She was then trialed on treatment with hydroxychloroquine, methotrexate, and pregabalin without significant improvement.
At the time of diagnosis, exam revealed raised erythematous papules and plaques consistent with urticaria. They were distributed over the neck, upper back, and some on the arms. There were no signs of palpable purpura or necrosis. On joint exam, she had tenderness and swelling on palpation of bilateral 3rd PIPs. There was also tenderness in both shoulders, elbows, forearms, pretibial regions, and ankles without any swelling, erythema, or warmth. There was no evidence of synovitis or dactylitis in the feet.
A detailed workup was performed (including ANA, ENA panel, RF, ANCA, serum protein electrophoresis and immunofixation, Lyme serology, muscle enzymes, ESR, CRP, ferritin, and cryoglobulins). She was found to have elevated inflammatory markers, with ESR 48 mm/hr, CRP 4.3 mg/dL, and ferritin 320.2 ng/mL. The electrophoresis and immunofixation revealed an IgM kappa monoclonal gammopathy. The rest of the blood work was negative. A bone survey of all long bones and a bone scan were also performed which showed diffuse osteitis and remodeling of long bones. Based on the urticarial rash, IgM kappa monoclonal gammopathy, abnormal bone remodeling, and elevated acute phase reactants, she fulfilled the Strasbourg criteria for diagnosis of Schnitzler syndrome.
She was started on anakinra 100 mg subcutaneous daily. The patient also tested quantiferon positive and was started on isoniazid and vitamin B-6 simultaneously for treatment of latent tuberculosis.
The patient noticed significant improvement in her urticarial rash within days after initiating the anakinra. Shortly after that, she also had progressive decline in her musculoskeletal pain and gradually became symptom free. The improvement was also reflected in her inflammatory markers. Her CRP dropped from 4.3 mg/dL to 0.7 mg/dL, and ESR dropped from 48 mm/hr to 4 mm/hr.