Adult-Onset Still Disease (Still's Disease)

Adult-Onset Still’s Disease (AOSD) – Treatment Options

Introduction
Adult-onset Still’s disease (AOSD) is a rare systemic autoinflammatory disorder of unknown cause. It is characterized by the clinical triad of quotidian (daily) spiking fevers, evanescent salmon-pink rash, and arthritis/arthralgia, often accompanied by sore throat, lymphadenopathy, hepatosplenomegaly, and serositis. Laboratory findings typically show marked leukocytosis, elevated ferritin, and high inflammatory markers. The disease course may be monocyclic (self-limited), polycyclic (relapsing-remitting), or chronic (persistent arthritis). Management is directed by disease severity and systemic involvement, with the goals of controlling inflammation, preventing joint damage, and avoiding life-threatening complications such as macrophage activation syndrome (MAS).

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1. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• Often used as first-line therapy in mild disease with systemic symptoms.

• Provide symptomatic relief of fever and joint pain.

• Examples: naproxen, indomethacin, ibuprofen.

• Limited efficacy as monotherapy; most patients eventually require corticosteroids or DMARDs.

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2. Glucocorticoids

• Mainstay of therapy for systemic and articular manifestations.

• Prednisone/prednisolone:

  • Dose: 0.5–1 mg/kg/day orally, tapered gradually with clinical response.

• IV methylprednisolone pulses (e.g., 1 g/day for 3 days) may be required in severe flares or MAS.

• Rapidly effective for fever, rash, and inflammation, but long-term use is limited by adverse effects (osteoporosis, diabetes, infections).

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3. Conventional Disease-Modifying Anti-Rheumatic Drugs (DMARDs)

• Indicated for patients with chronic arthritis or steroid-dependent disease.

• Methotrexate (15–25 mg weekly) is the most commonly used, effective for both systemic and joint symptoms, and useful as a steroid-sparing agent.

• Alternatives: leflunomide, azathioprine, cyclosporine, cyclophosphamide in refractory disease.

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4. Biologic and Targeted Therapies

• Transformative in refractory or severe disease, especially with systemic manifestations.

• IL-1 inhibitors:

  • Anakinra (100 mg SC daily), canakinumab (monthly SC injection), rilonacept. Highly effective in systemic disease and MAS prevention.

• IL-6 inhibitors:

  • Tocilizumab (IV/SC), sarilumab (SC). Beneficial in both systemic and articular forms.

• TNF inhibitors:

  • Etanercept, infliximab, adalimumab. Less effective for systemic features; considered mainly in arthritis-predominant disease.

• JAK inhibitors (tofacitinib, baricitinib): Emerging options in refractory cases.

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5. Management of Macrophage Activation Syndrome (MAS)

• MAS is a life-threatening hyperinflammatory complication seen in AOSD.

• High-dose IV corticosteroids are the cornerstone of therapy.

• Cyclosporine or IL-1 blockade (anakinra) are often added in refractory cases.

• Aggressive supportive management in an ICU setting is essential.

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6. Supportive and Long-Term Care

• Analgesics and physical therapy to maintain joint function.

• Bone protection (calcium, vitamin D, bisphosphonates) for patients on chronic steroids.

• Vaccinations and infection prevention for immunosuppressed patients.

• Regular monitoring of blood counts, liver function, ferritin, and inflammatory markers to guide therapy.