ADULT STILL'S DISEASE IN A 75‐YEAR‐OLD PATIENT

Abstract

To the Editor: The majority of adult Still's disease cases tend to be in young adulthood. This disease is underdiagnosed in the elderly even with clinical and laboratory findings characteristic of adult Still's disease. In this report, a case of adult Still's disease in a 75-year-old male who presented with fever, arthritis, rash, and elevated ferritin is discussed. He is the oldest patient ever reported in North America with adult Still's disease. Although rare, adult Still's disease in advanced age needs to be considered in the evaluation of fever of unknown origin in the elderly. A 75-year-old Hispanic male presented to his internist complaining of daily fevers up to 102° and sore throat for 6 weeks. He was given two courses of azithromycin and then trimethoprim/sulfamethoxazole without benefit. The patient subsequently developed a confluent erythematous rash on the arms and torso that was intermittent and associated with his fever. He was admitted for fever of unknown origin with a worsening pruritic rash. During this hospitalization, he developed bilateral wrist, metacarpophalangeal, and proximal interphalangeal joint pain. He denied recent travel or unusual exposure. Laboratory evaluation revealed a hematocrit of 29.9, white blood cell count of 17,500, blood urea nitrogen of 35, and creatinine of 2.6, and purified protein derivative skin test and controls were anergic. Bone marrow biopsy revealed markedly hypercellular marrow suggestive of possible myeloproliferative disorder. The patient was placed on multiple antibiotics and antifungals without a decrease in the fevers. He was transferred to a university hospital for further management. Physical examination revealed a thin man with an erythematous rash on face, torso, and extremities without lymphadenopathy. The remainder of the examination revealed lung crackles at the bases and muscle weakness. Magnetic resonance imaging of both thighs and electromyograph were suggestive of myositis, but muscle biopsy and nerve conduction studies were unremarkable. Serum creatine phosphokinase (CPK) was normal, and serum aldolase was elevated. Serum ferritin was as high as 18,000 μg/L. The patient was diagnosed with adult Still's disease with myositis. He was given methylprednisolone at 1 mg/kg and intravenous immunoglobulin 400 mg/kg for 5 days with prompt resolution of fevers, arthritis, and rash. Serum ferritin, aldolase, CPK, and complement levels all returned to normal values. Corticosteroids were tapered, and 1 year later, the patient had another flare of Still's disease with high fevers, rash, and increased ferritin of 3,000 μg/L. Corticosteroids were increased, and methotrexate was added. The patient is now in clinical remission on methotrexate 20 mg per week and has been tapered off prednisone. All tests have normalized, including ferritin to 150 μg/L. Adult Still's disease is rare and of unknown etiology, usually affecting people aged 16 to 35.1 Although it is a disease of young adults, there are two case reports in the Japanese literature of adult Still's disease in the elderly.2,3 Therefore, adult Still's disease should not be overlooked in the elderly patient. Clinical manifestations of adult Still's disease are significant for arthralgia (100%), arthritis (94%), fever of 39°C or higher (97%), sore throat (92%), rash (88%), myalgia (84%), weight loss greater than 10% (76%), lymphadenopathy (63%), splenomegaly (52%), and abdominal pain (48%).4 Laboratory tests that are abnormal include an elevated erythrocyte sedimentation rate, leukocytosis, anemia, and markedly elevated ferritin levels.5 One-fifth of people with Still's disease experience long-term remission within 1 year.6 One-third of patients have a complete remission followed by one or more relapses. Relapses tend to be less severe and of shorter duration. The remaining patients have a chronic disease course.7 Approximately one-fourth of patients respond to nonsteroidal antiinflammatory drugs. Other patients may require systemic corticosteroids and disease-modifying agents such as methotrexate and biological agents that target tumor necrosis factor. Although adult Still's disease affects primarily young adults, it is a disease that can affect all ages. We have described an elderly man who was diagnosed with Still's disease after an exhaustive search for infections, malignancy, and other autoimmune diseases. Adult Still's disease tends to be overlooked in the differential diagnosis when an individual is advanced in age. It should be considered seriously at any age while examining fever of unknown origin. A patient with high, daily spiking fevers, severe myalgia, arthralgia, rash, and leukocytosis is unlikely to have anything other than adult Still's disease. Physicians should consider this diagnosis in elderly individuals with fever of unknown origin.