REFERRAL & SAFETY-NETTING (NO DRUG THERAPY)
Juvenile Idiopathic Arthritis - StatPearls (NCBI Bookshelf NBK554605) - https://www.ncbi.nlm.nih.gov/books/NBK554605/
A joint that has been swollen for six weeks in a child under 16 is a rheumatology referral, and the six weeks is the whole definition. Primary care's job is to reach that threshold without treating the child as a series of sprains, and to exclude infection and malignancy on the way. Disease-modifying therapy is specialist-initiated.
- THE DEFINITION IS THE REFERRAL THRESHOLD - juvenile idiopathic arthritis (JIA) is a mixed group of inflammatory arthritides of unknown cause, arising in a child under 16 and running 6 weeks or more. Consider it in any child under 16 years whose arthritis has lasted at least six weeks, once the other causes of a chronic arthritis have been excluded.
- IT IS A DIAGNOSIS OF EXCLUSION, SO THE DANGEROUS MIMICS COME FIRST - because JIA is arrived at by ruling everything else out, any positive answer in the systems review has to be chased down as a possible disease in its own right. For a few swollen joints, the article's own list runs to infection in the joint or the muscle, osteomyelitis, sickle cell disease and haemophilia, injury that was not accidental, and the malignancies - a bone tumour, neuroblastoma, leukaemia, lymphoma. A child with a swollen joint and night pain, bruising or pallor is investigated for leukaemia before being labelled arthritic.
- AND FOR A FEVERISH CHILD WITH JOINTS, THE LIST IS DIFFERENT AGAIN - before systemic arthritis is accepted, exclude infection (mycoplasma, cat scratch disease, endocarditis, Lyme disease); acute rheumatic fever; PFAPA, that is periodic fever with mouth ulcers, sore throat and neck nodes; the other autoinflammatory syndromes; systemic vasculitis, meaning polyarteritis nodosa and Kawasaki disease; inflammatory bowel disease; and malignancy - leukaemia, lymphoma, neuroblastoma.
- WHAT THE JOINTS LOOK LIKE - JIA follows the usual pattern of an inflammatory joint disease: synovitis, an effusion, swelling of the soft tissue, thin bone, oedema within the bone, erosions. To that, a growing skeleton adds its own: growth at the epiphysis disturbed, a physis that fuses too soon, and limbs that end up different lengths. The wrists, the knees and the ankles are where it most typically sits.
- NO BLOOD TEST MAKES OR EXCLUDES THE DIAGNOSIS - nothing on the panel is specific, either for making the diagnosis or for judging how active the disease is. A positive rheumatoid factor or anti-CCP adds little diagnostically, though it does point to a rougher course and a worse outcome. What to send: a full blood count, ESR, CRP, antinuclear antibody, rheumatoid factor, anti-CCP antibodies, and HLA-B27.
- A NORMAL X-RAY EARLY ON MEANS NOTHING - the plain film is still where imaging starts for a painful joint, but early in JIA there is nothing on it to find. Ultrasound is the accessible next step: it shows the thickened synovium and the synovitis, which matters greatly for the diagnosis, and it can be done without sedating the child.
- WHAT PRIMARY CARE CAN OFFER WHILE THE REFERRAL IS ARRANGED - whatever the subtype, symptomatic treatment starts with a non-steroidal anti-inflammatory. The article names no individual NSAID and states no paediatric amount, so no dose is printed here; use the paediatric ibuprofen dosing already carried on the pain and fever entries.
- AND THE REST OF THE TREATMENT IS NOT A CLINIC DECISION - treating JIA takes drugs that damp inflammation and modulate the immune system, physiotherapy alongside them, and in time possibly an operation, help with nutrition, and psychosocial support. Reliance on NSAIDs has fallen away as treatment has grown more aggressive - methotrexate and the biologics.
- KEEP THE CHILD MOVING - physiotherapy works the joints through their range while loading them as little as possible, and swimming often suits that well. Moderate exercise for fitness, for suppleness and for strength is part of it.
- MACROPHAGE ACTIVATION SYNDROME IS THE ONE THAT KILLS - the most frightening complication of the lot, driven by T lymphocytes and macrophages activating and multiplying out of control. Nobody knows how often it happens in JIA, though some studies put it as high as 10% of cases. The tests it calls for are ferritin, fibrinogen, AST and triglycerides.
- THE LONG-TERM DAMAGE IF IT DRIFTS - the two seen most are legs of unequal length and a contracted joint. Others that matter: growth held back, bone mineral density below what the child's age should give, hips damaged badly enough to need replacing, and amyloidosis.
- WHICH IS WHY THE REFERRAL IS URGENT RATHER THAN ROUTINE - diagnosing and treating this quickly, and correctly, is what keeps a joint from being damaged for good and keeps it working.
- EYE INVOLVEMENT - ASK THE RHEUMATOLOGIST TO ARRANGE THE EYE REVIEW. The cached article records genetic ground shared by JIA and uveitis, naming HLADRB1:11 and HLADRB1:13 as linked to uveitis, and it reports uveitis commonest in northern and southern Europe and least common in Latin America, in Africa, in the Middle East and in Southeast Asia. It sets out no screening interval and no examination method, so no schedule is printed here; the interval comes from the specialist who takes the child on.