Adult Onset Still's Disease

Adult-onset Still’s disease (AOSD) is a rare immune-mediated, multisystem inflammatory disorder indicated by the “Still’s triad” of high spiking fevers, rash and arthritis (joint pain). It is frequently underdiagnosed and one of the main reasons for hospital admissions due to fever of unknown origin (FUO). The disease characteristically affects younger adults, with three quarters of the patients reporting disease onset between 16 and 35 years of age.

This syndrome was formerly thought to occur solely in children as systemic-onset juvenile idiopathic arthritis (SJIA), previously known as juvenile Still’s disease. In 1971, adult Still's disease was established for adult patients who did not meet the criteria for classic rheumatoid arthritis (RA) but displayed features similar to those described in pediatric Still’s disease. There is no known reason or cure for the disease, but there are treatments available to control the reactions and symptoms.

Symptoms

Characteristic symptoms include daily spiking fevers, evanescent (or short term) rashes, and arthritis, each occuring in about 75 to 95 percent of patients. Patients with adult Still's disease (ASD) will be affected one of three ways (though the first two might evolve into the chronic pattern):

• Monophasic (or monocyclic): the disease course lasts weeks to months, completely resolving within a year
• Intermittent: the disease appears in unpredictable episodes or flares with remissions lasting weeks to years in between
• Chronic: persistent and active, this type of ASD is most destructive to joints

Other less common, but more serious symptoms can include myalgia, inflammatory myopathy, liver abnormalities, pleuritis, pericarditis, splenomegaly, pericardial tamponade, myocarditis, pulmonary fibrosis, pleural effusions, adult respiratory distress syndrome, interstitial nephritis, subacute glomerulitis, renal amyloidosis, collapsing glomerulopathy, thrombotic thrombocytopenic purpura, pure red cell aplasia, cranial nerve palsies, seizures, aseptic meningoencephalitis, and Miller-Fisher syndrome.

Life-threatening complications such as macrophage activation syndrome may occur and need to be diagnosed and treated promptly.

Diagnosis and treatment

Diagnosis is made after:

• a thorough examination and consideration of symptoms and medical history
• the exclusion of mimickers of infectious, autoimmune or neoplastic causes
• consideration of non-specific laboratory abnormalities such as peripheral leukocytosis and elevation of serum ferritin and other acute phase reactants

The disease manifestations can change frequently and can include diverse complications, affecting multiple organ systems. Moreover, the severity of the organ involvement can vary considerably, representing a wide spectrum from the self-limited to severe. The mainstay of therapy has evolved from the traditional use of corticosteroids and oral immunosupressants such as methotrexate to the newer biologic agents targeted at specific inflammatory molecules (interleukins), such as anakinra, canakinumab, and tocilizumab. These medications are given by injection or IV infusion.