What are the other Names for this Condition? (Also known as/Synonyms)

• Adult Still’s Disease
• AOSD (Adult-Onset Still’s Disease)
• Wissler-Fanconi Syndrome

What is Adult-Onset Still’s Disease? (Definition/Background Information)

• Adult-Onset Still’s Disease (AOSD) is a rare condition that may affect several parts of the body. It is considered to be an auto-inflammatory condition that affects young and middle-aged adults
• The condition is marked by a set of 3 characteristic symptoms consisting of high fevers, joint pain, and salmon-colored rashes on the skin. The symptoms may ‘come and go’, meaning that some individuals may remain without symptoms for many months or even years
• It is reported that Adult-Onset Still’s Disease can progress in the following 3 diverse ways:
  • Monophasic AOSD: The symptoms are present for a period lasting less than 1 year  
  • Intermittent AOSD: The affected individual experiences multiple flare-ups, with periods of full remission in between each episode (remaining symptom-free for over 3 months)
  • Chronic AOSD: The disease is permanent and there are no periods of remission 
• The complications of Adult-Onset Still’s Disease include the involvement and inflammation of many vital organs in the body, including the heart, kidney, and lungs, causing associated signs and symptoms
• Adult-Onset Still’s Disease is treated symptomatically, since it is presently an incurable condition. Often, a combination of medications (including steroid therapy, if necessary) may be recommended by the healthcare provider. The medication Canakinumab offers dramatic relief
• The prognosis of Adult-Onset Still’s Disease depends on the severity of the signs and symptoms and may be assessed on a case-by-case manner. Individuals showing involvement of the vital organs may have poorer prognosis

Who gets Adult-Onset Still’s Disease? (Age and Sex Distribution)

• A bimodal distribution pattern is observed for Adult-Onset Still’s Disease. Most cases are observed in the 15-25 years’ and 36-46 years’ age group. The condition may occur at any age in adults
• Both males and females are equally affected
• All racial and ethnic groups may be at risk and no specific predilection is noted
• An incidence of 1.6 new cases per million population is reported; and, the prevalence of AOSD is about 15 cases per million population

What are the Risk Factors for Adult-Onset Still’s Disease? (Predisposing Factors)

• No specific risk factors for Adult-Onset Still’s Disease have been observed. The condition is not likely to be hereditary (meaning a family history has not been reported)
• Young and middle-aged adults have the highest risk for AOSD, among all other age groups

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Adult-Onset Still’s Disease? (Etiology)

There is no known definitive cause for Adult-Onset Still’s Disease.

• It is thought to be triggered by a viral or bacterial infection, causing an abnormal immune response in the body. Such infections may include Lyme disease and infectious mononucleosis
• No particular infection has been found to consistently result in Adult-Onset Still’s Disease
• Some researchers consider it to be an adult form of systemic juvenile inflammatory arthritis (JIA)
• Adult-Onset Still’s Disease is linked to many HLA types often linked to autoimmune and autoinflammatory diseases

What are the Signs and Symptoms of Adult-Onset Still’s Disease?

The key signs and symptoms of Adult-Onset Still’s Disease including the following:

• High fever; the fevers are usually high-spiking fevers, typically seen during late afternoons or early evenings
• Joint pain: Joints may be achy, swollen, and stiff (especially knees, wrists, ankles, elbows, hands, and shoulders). The characteristic site of chronic arthritis is the carpal (wrist) bones. It leads to decreased mobility of the wrist
• Salmon-colored skin rash (usually on the chest and back) that may come and go with the fever; the rashes are bumpy or flat and non-itchy

The other signs and symptoms may include:

• Muscle pain, that may come and go with the fever
• Sore throat
• Swollen lymph nodes (lymphadenopathy), especially in the neck region
• In some cases, enlarged liver or spleen (hepatomegaly or splenomegaly respectively)
• Inflamed lining of the heart or lungs (pericarditis or pleuritis respectively)
• Symptoms and complications are directly related to inflammation of affected body parts

The signs and symptoms of AOSD can vary from one individual to another.

• Some individuals may have a single episode of signs and symptoms and the condition may never recur
• In some, the symptoms come and go. In some of these individuals, the condition may be asymptomatic between episodes, for months to years sometimes
• Also, because of the variability in the symptoms, the condition may go undiagnosed in some individuals

How is Adult-Onset Still’s Disease Diagnosed?

Adult-Onset Still’s Disease is a diagnosis of exclusion. It is diagnosed by ruling out all other conditions with similar signs and symptoms. The following tests and exams may be considered to diagnose AOSD:

• Complete physical examination and assessment of medical history
• X-rays may be taken to examine the condition of the affected joints
• CT scans may be performed to look for enlarged organs throughout the abdomen
• Abdominal ultrasounds may also be performed to look for the organs that are involved/affected
• Echocardiogram and CT scan of chest may be undertaken, to detect any heart/lung abnormalities
• Several additional blood tests may be taken:
  • Complete blood count may show elevated white blood cell levels and low red blood cell levels
  • C-reactive protein levels are usually elevated in the presence of inflammation
  • Estimated sedimentation rate (ESR) is usually high in the presence of inflammation
  • Antinuclear antibodies (ANA) and rheumatic factor tests are known to be negative
  • Fibrinogen levels may be abnormal
  • Ferritin levels may be abnormal
• Liver function tests may show signs of liver inflammation

The Yamaguchi criteria are helpful in diagnosing Adult-Onset Still’s Disease. According to this system, there are many major and minor criteria, as outlined below. Any individual having 5 of the criteria below, of which 2 are major, may be diagnosed as having AOSD.

Major criteria:

• Fever of 39 deg. C for at least 1 week
• Joint pain for at least 2 weeks
• Non-itchy salmon-colored skin rashes during episodes of fever
• Increased white blood cell (WBC) count with increase in neutrophils and bands (the immature type of neutrophils)

Minor criteria:

• Sore throat
• Enlarged lymph nodes (lymphadenopathy)
• Enlarged liver or spleen (hepatomegaly or splenomegaly)
• Abnormal liver function test
• Negative rheumatoid factor and negative ANA blood tests

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Adult-Onset Still’s Disease?

The major complications of Adult-Onset Still’s Disease often result from chronic inflammation. The complications of AOSD may include:

• The signs and symptoms may become chronic in about 50% of the affected individuals
• Joint inflammation for extended periods of time can lead to permanent joint damage
• Some individuals, who have recurring symptoms, can develop chronic arthritis
• Sometimes, the inflammation can affect major organs such as the heart, lungs, and kidneys causing severe complications
  • Organ inflammation can affect the covering around the heart or the heart muscle itself. This can result in pericarditis, myocarditis, or pericardial effusion
  • Inflammation of the pleura may cause excess fluid to buildup in the fluid-filled space around the lungs (pleural effusion)
• AOSD can cause aseptic meningitis, which is a non-infectious inflammation of the lining of the brain
• Sensorineural hearing loss
• Taking steroids for extended periods of time can increase the risk of diabetes and osteoporosis
• Canakinumab side effects include increased susceptibility to some infections

How is Adult-Onset Still’s Disease Treated?

There is no cure for Adult-Onset Still’s Disease, and often symptomatic treatment is provided. The treatment measures may include:

• The treatment may involve a variety of drugs; the healthcare provider may determine a suitable combination of drugs for each patient that works best for them, in order to modulate the abnormal immune response
• This may include non-steroidal anti-inflammatory drugs (NSAIDs) including aspirin and ibuprofen (OTC pain medications)
• In severe cases where NSAIDs do not work, steroid therapy may be recommended
• Canakinumab is FDA-approved for use in Adult-Onset Still’s Disease. The response of the disease is usually rapid
• If the condition is chronic and symptoms worsen, immune-suppressing drugs may be prescribed

Other medications and treatment measures may be prescribed/considered, when the heart, lung, or kidney is involved.

How can Adult-Onset Still’s Disease be Prevented?

Currently, it is not possible to prevent Adult-Onset Still’s Disease. However, the condition may be managed through appropriate medications.

What is the Prognosis of Adult-Onset Still’s Disease? (Outcomes/Resolutions)

The prognosis of Adult-Onset Still’s Disease may be assessed on a case-by-case basis.

• Individuals with mild symptoms have better prognosis than those with severe symptoms
• Involvement of the heart, lungs, brain, or kidney may portray poorer outcomes
• Even though, patients with chronic AOSD are often known to remain functional

Additional and Relevant Useful Information for Adult-Onset Still’s Disease:

When in children, Still’s disease is known as juvenile idiopathic inflammatory arthritis.