Still Disease, Adult

Key Features

• A systemic form of juvenile chronic arthritis; this rare syndrome also occurs in adults

• Most adults are in their 20s or 30s; onset after age 60 is rare

• High spiking fevers are much more prominent, especially at the outset, than arthritis

• The course of adult Still disease can be monophasic, intermittent, or chronic

• Macrophage activation syndrome is a life-threatening complication; it can manifest as

  • Fever

  • Splenomegaly

  • Either thrombocytopenia or neutropenia, or both

  • Hypertriglyceridemia

  • Hypofibrinogenemia

  • Marked elevation of serum ferritin

  • Elevated soluble CD25

  • Depressed natural killer cell activity

  • Hemophagocytosis in bone marrow, spleen, and lymph nodes

Clinical Findings

• Fever

  • Often with daily spikes to 40°C

  • Associated with sweats and chills and then plunging to normal or several degrees below normal in the absence of antipyretics

• Sore throat is common initial complaint

• An evanescent salmon-colored nonpruritic rash

  • Characteristic

  • Appears chiefly on the chest and abdomen

  • Can be missed since it often appears only with the fever spike

• Lymphadenopathy

• Pericardial effusions

• Joint symptoms

  • Mild or absent in the beginning

  • However, a destructive arthritis, especially of the wrists, may develop months later

• Differential diagnosis

  • Familial Mediterranean fever

  • TNF receptor-1 associated periodic syndrome

  • Schnitzler syndrome (intermittent bone pain, urticarial rash, and fever associated with a monoclonal gammopathy)

Diagnosis

• Anemia and leukocytosis, with white blood counts sometimes exceeding 40,000/mcL

• Serum ferritin levels are often strikingly elevated (> 3000 mg/mL or 6741 pmol/L)

Treatment

• About half of the patients respond to nonsteroidal anti-inflammatory drugs

• Half of patients require prednisone, sometimes in doses > 60 mg/day orally

• For patients with refractory disease,

  • Targeting IL-1 with anakinra or canakinumab or

  • Targeting IL-6 with tocilizumab can be effective