Juvenile Idiopathic Arthritis Flashcards
What is juvenile idiopathic arthritis?
Group of systemic inflammatory disorders affecting children below age of 16 years. The most commonly diagnosed rheumatic disease in children. An important cause of disability and blindness.
What’s the criteria for JIA diagnosis?
Age of onset <16years. Duration of disease > 6 weeks. Presence of arthritis - Joint swelling or 2 of the following: painful and limited joint motion, tenderness, warmth.
What are the different clinical subtypes of JIA?
Pauciarticular (4 or less joints, 55%), Polyarticular (5 or more, 25%), Systemic Onset (Still’s disease, 20%). Can be identified after 6 months.
Describe the presentation of Type 1 pauciarticular JIA
G: B = 8:1. Present with limp rather than pain. Mainly lower limb joints. Knee > ankle > hand or elbow (hip very rare). Chronic uveitis in 20% of cases. Asymptomatic in 50%. Irregular iris due to posterior synechiae (adhesions form between iris and either cornea or lens).
Describe the presentation of Type 2 pauciarticular JIA
G: B = 1:7. Limp due to lower leg affection. Mainly knee and ankle. Hip can be affected early with rapid damage requiring total hip replacement early in life; enthesitis; many have sacroiliac joints affected and may evolve AS or another spondyloarthritis. Acute iridocyclytis in 10-20% (inf of iris and ciliary body)
Describe the presentation of Type 3 pauciarticular JIA
G: B = 4:1. Chronic iridocyclitis in 10-20%. Arthritis can be very destructive. FH of psoriasis in 40% +/- nail pitting. Asymmetric upper limb and lower limb, dactylitis.
Describe the presentation of RF –ve polyarticular JIA
G: B = 9:1. Symmetrical large and small joint affection: knees, ankle, wrists, MCPJs, PIPJs, neck. Presentation: constitutional manifestations (low grade fever, malaise), hepato-splenomegaly, mild anaemia, growth abnormalities.
Describe the presentation of RF +ve polyarticular JIA
Iridocyclitis rare. Can be complicated by Sjorgen’s, Felty or vasculitis, AR, pulmonary fibrosis, AAS, CTS. Similar to adult rheumatoid arthritis but in child. Presents with constitutional manifestations (low grade fever, malaise, weight loss). Anaemia. Nodules.
Describe the presentation of systemic onset JIA (Still’s disease)
- Arthritis – 75%, within 3-12 months of onset of fever
- Fever – rise to 39.5 daily for at least 2 weeks, late in afternoon and then returns to normal/subnormal in morning
- Rash – 90%, evanescent salmon red eruption, on trunk and thighs, accompanies fever, can be brought on by scratching
- Lymph nodes – 50-75%, generalised lymphadenopathy, non-tender
- Serositis – polyserositis, pericarditis in 36%, tamponade and myocarditis rare
- Abdominal – hepatosplenomegaly, 50-75%, abdominal pain
- Pulmonary – rare, pleural effusion, pulmonary fibrosis
What is the first line treatment for JIA?
Simple pain killers. NSAIDS (are able to control disease)
What is the 2nd line therapy for JIA?
If no response to NSAIDs/joint steroid injection. Rarely needed in oligoarticular JIA.
1: Methotrexate (pharmacokinetics is age related).
2: Anti-TNF (all 3) – in methotrexate failure.
3: IL-1 R-antagonist (Anakira) in refractory systemic arthritis.
4: IL-6 antagonist (Tocilizumab) for refractory systemic disease.
Describe the use of systemic steroids
Limited use due to serious side effects. Used in systemic JIA (control pain and fever). Serious disease complications with any subtype (e.g. pericardial effusion, tamponade, vasculitis, sever auto-immune anaemia, severe eye disease). As a bridge between DMARDs. Children undergoing surgery.
What are the side effects of systemic steroids?
Risk of osteoporosis, infection, growth abnormalities.
Describe the use of local steroids
Intra-articular mainly in oligo-articular JIA. Eye disease (ANA +ve oligo-articular disease)
Describe the use of surgical treatment
Synovectomy. Reconstructive / joint replacement surgery.
