Adult Onset Stills Disease
What is Adult Onset Stills Disease?
Adult onset stills disease (AOSD) is a rare acquired autoinflammatory disease. It is characterised by fever and signs and symptoms of inflammation in the body that are not due to infection or autoimmune causes. They are acquired, meaning they are not passed down in families in genes. The disease affects adults, but a similar presentation occurs in children, this is called systemic juvenile idiopathic arthritis (SJIA).
The course of the disease is variable, some people experience one single episode of inflammation, and others get chronic episodic inflammation. AOSD occurs equally in males and females and usually occurs around the age of 16-40.
Causes of Adult Onset Stills Disease
Adult onset still disease is an autoinflammatory disease. The immune system usually produces inflammation in response to trauma and infection. In the case of AOSD, unregulated activation of inflammation occurs which damages the body. The disease is not autoimmune, meaning that there are no proteins called antibodies produced, the immune system reaction that is triggered is more primitive and innate.
The exact cause of the over activation of inflammation is still unknown, although there is a suggestion of infections triggering the disease.
Symptoms of Adult Onset Stills Disease
- Often variable during the day, usually rising in the afternoon or evening
- Loss of appetite
- Sore throat, mouth ulcers
- Skin rash
- Salmon pink over the trunk, arms and legs
- Joint pain and swelling
- Muscle pain (myalgia)
- Swollen lymph nodes in the neck
- Pericarditis- inflammation of the heart lining causing chest pain
- Pleuritis- inflammation of the lung lining, often leading to fluid build up around the lung (pleural effusion) resulting in chest pain and shortness of breath
- Interstitial lung disease- scarring in the lung leading to cough and breathlessness
- Peritonitis- inflammation of the abdominal wall lining causing pain
- Colitis- inflammation of the bowel lining leading to diarrhoea, nausea and vomiting
- Enlarged liver or spleen
- Macrophage activation syndrome
- A life threatening complication with high blood ferritin levels, low white blood cells, clotting abnormalities and deranged liver function
- Usually triggered by a viral infection
How do we diagnose Adult Onset Stills Disease?
A thorough history and examination is carried out by your doctor, AOSD is diagnosed when other causes are excluded. Other investigations are listed below:
- Blood tests
- Inflammatory markers CRP and ESR will be raised
- Ferritin is also raised in inflammation
- Routine bloods for full blood counts, clotting, liver and kidney function
- Autoimmune screen including ANA and RF to rule out other causes
- X rays and MRI scans are often used to look at the joints
- CT scans can be used to rule out other diagnoses.
Management is based on the severity of symptoms; the main treatments from first line are listed below:
- If life threatening features are present or the symptoms are uncontrolled with the above treatments biological medications are used such as tocilizumab or anakinra.
Blood markers for inflammation including ferritin and blood cell counts measure the efficacy of treatment.
AOSD usually follows one of 3 patterns:
- Self limiting- remission achieved within a year
- Intermittent flares- recurrent flares of fevers and rash, often with addition of joint symptoms
- Chronic- persistent active disease with predominantly joint problems
Versus Arthritis: http://www.versusarthritis.org