Still Disease, Adult

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

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)

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)

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