Contents
Definition
Systemic juvenile arthritis / systemic JIA is also called Still's disease in children and is characterized by high fever peaks over time, without infection. Varying bright-red rash that accompanies the fever peaks and arthritis in the course is common. The disease has common features with them periodic fever syndrome (autoinflammatory diseases), but is considered a form of juvenile arthritis (juvenile idiopathic arthritis, JIA) together with oligoarticular-, polyarticular og encephalitis-related juvenile arthritis.
Occurrence
Systemic childhood arthritis accounts for 10% of all JIAs and occurs as frequently among girls as boys, most often among young children aged 2 - 4 years, but all age groups can be attacked. There is also an adult form (Adult Stills disease).
Symptoms
Fever peaks. Daily fever peaks of more than 39 degrees and duration over at least 2 weeks (without effect of any antibiotic regimens). Children are often very involved during the fever. Normal body temperature between episodes of fever ("spiking fever"), even without antipyretic drugs.
Rash. A pink ("salmon-red colored") rash may follow the fever peaks.
Lymph nodes. Enlarged (swollen) lymph nodes, large liver and spleen occur.
Joint inflammation (arthritis) in one or more joints (knees, wrists, ankles, fingers, neck or hips) is common gradually in the course of the disease. With early, effective treatment, arthritis can be avoided.
Other. Some children get inflammation in pericardium (pericarditis), the lung (pleuritis) or Abdominal peritoneum (peritonitis) without the presence of bacteria or other infection.
Examinations
Medical history maps current symptoms (see above). Symptom onset and age at onset. Fever course: fever peaks replaced by normal values without the use of antipyretic drugs. Volatile rash (erythema) and arthritis in the course. Signs of infection and other causes of fever (differential diagnoses) are also requested.
Clinical examined systematically according to routines for children. Body temperature is measured, skin, joints, lymph nodes, spleen, liver, heart, lungs are examined. The number of affected joints with localization is noted.
Blood tests. Inflammation tests (CRP, SR) are elevated. Also increased white blood cell count (leukocytes) up to 20-30.000 / mm3 is not uncommon. Also high ferritin expected. Blood cultures are taken in case of high fever if there is a suspicion of infection and unclear diagnosis. Immunological tests / antibody not expected to knock out.
Joint fluid. In case of unclear diagnosis with arthritis, examination of synovial fluid can rule out infection by microscopy, culture and PCR examinations.
Imaging. Assessment of the lungs with X-rays can rule out signs of disease in the lungs. At ultrasound, joints, heart (echocardiography) and pleura can be assessed.
Tissue sample (biopsy). In case of unclear diagnosis, bone marrow examination may be relevant.
Macrophage Activation Syndrome (MAS)
Macrophage Activation Syndrome (MAS) is a serious complication that occurs in approx. 10% of children with systemic JIA. Triggering is often a viral infection, especially Epstein-Barr virus (EBV). Symptoms of MAS are persistent high fever with poor general condition, affected brain function, large liver and spleen, swollen lymph nodes. Typical changes in blood tests are increase in liver enzymes (ALT, AST, LD), most often above 2-3 x upper reference ranges, triglycerides (fats), ferritin (most often> 1500), but lower lowering reaction (SR), but often moderately above reference area.
Similar conditions / differential diagnoses in systemic JIA
At the onset of the disease, no definite diagnosis is possible. One must exclude other forms of juvenile arthritis. bacterial or viral infection, malignancy (leukemia) and other rheumatic diseases (Kawasaki disease, Rheumatic fever). In case of possible exposure must also malaria assessed.
Treatment of systemic JIA
Against symptoms it is common to give NSAIDs such as naproxen or ibuprofen, but these are rarely sufficient. There is usually a need for more efficient, biological drugs in the form of interleukin-1 inhibitors such as anakinra (Kineret), canakinumab (Ilaris) or IL-6 inhibitors (tocilizumab). These have an almost immediate good effect on most people. The need for prednisolone (a cortisone) or methotrexate, which was widely used in the past, is then small. If MAS is suspected (see above), close monitoring is required, and is often supplemented with glucocorticoids in high doses intravenously.
Prognosis
Healing treatment is not available, but in many cases the disease stops by itself. Some have only a period of active illness, while others have recurrent episodes (duration of illness from a few weeks to many years). A less typical course is characterized by chronic arthritis (arthritis) which is then treated as wood oligoarticular or polyarticular child joints.
Literature
Children with rheumatic disease, BINDEVEVSSYKDOMMER.no
