Dx of exclusion; previously JRA, now JIA per Internat League of Assoc for Rheum

Includes all forms of arthritis (swelling or limitation of motion of joint w/ heat or pain) <16 yo, >6-wk duration and of unknown cause. (Pediatr Clin North Am 2005:413)

Must exclude: Infectious and postinfectious etiology, hematologic and neoplastic dz, connective tissue disease, vasculitis, and other inflammatory conditions

Most common chronic rheumatic dz in children, prevalence 16–150 per 100,000

Oligoarthritis most common in W. European countries, polyarthritis in Costa Rica, India, New Zealand, and South Africa

Occurs as frequently as juvenile DM, 4x more freq than CF & sickle cell anemia, & 10× more than ALL, hemophilia or musc dystrophy (Pediatr Rev 2006;27:e24)

Systemic arthritis: 10% of all cases of JIA

Oligoarthritis: 40% of all cases JIA; ≤4 joints during 1st 6 mo of disease

Polyarticular onset: 25% of all cases of JIA, divided into RF + and RF –

Unknown; autoimmune, possible infectious trigger. Heterog group of disorders

Genome-wide scan of kids suggests several genes, at least 1 assoc w/ HLA region

Eval is dependent on history (associated symptoms and signs) and physical exam

Systemic arthritis labs: ↑ WBC w/ ↑ PMNs, ↑ ESR, ↑ CRP, thrombocytosis, ↑ ferritin

Oligoarthritis labs: Acute phase labs nml-↑, + ANA (70%–80%; risk for iridocyclitis)

Polyarthritis lab features: RF +/- variable as above

Joint asp to r/o infxn only if appears septic. Crystal dz very rare. If WBC >100× 10³ mL (100 × 10⁹/L) and 90% polys, infxn likely. Send fluid for cx, consider Lyme PCR

Systemic arthritis: Variable course,

Oligoarthritis: Best outcomes, joint erosion more freq in pts w/ polyartic course

If w/ iridocyclitis at risk for postsynechiae, band keratopathy, cataract, and glaucoma

Polyarthritis: RF +: Progressive and diffuse involv, x-ray Δ’s early esp in hands and feet

Combo of drugs, physical and occupational Rx, and psychosocial support

Periodic x-rays of affected joints to document progression of erosive disease

NSAID’s mainstay of Rx: Avg time to sx improv 1 mo, up to 25% w/ no improv until 8–12 wk; approx 50% w/ improv to 1st NSAID, 50% w/ relief w/ next NSAID

2/3 children w/ persistently active joint dz require DMARDS or steroids. MTX most commonly prescribed w/ ∼70% responding. Biologic agents often used: Etanercept, adalimumab, infliximab. Abatacept recently approved.

Other agents, sulfasalazine, leflunomide, cyclosporine, cyclophosphamide, hydroxychloroquine, thalidomide, intraarticular steroids often helpful

Distinct from arthritis assoc w/ rheumatic fever

At least 1–2 wk btw acute strep infxn and onset of poststrep reactive arthritis

Response to aspirin and NSAIDs is poor

Modified Jones criteria usually not met and there is no evidence of carditis

Duration prolonged or recurrent and of ↑ severity and w/ tenosynovitis and renal abn

No clear definition or Rx guidelines: No consensus on prophy PCN

Most freq and least specific sx of rheumatic fever

Migratory arthritis: Usually affects large joints, lower then the upper extremities

Joint involvement early in illness, more common and severe in adol and young adults

Polyarthritis painful, but transient, inflammation lasts 2–3 d in each joint and 2-wk total

X-ray may show slight effusion but otherwise normal

Self-limited, resolves without sequelae and responds well to NSAIDs

Arthritis associated with a recent, prior, or coexisting extraarticular infection

Can refer to post infxn arthritis, urethritis, and conjunctivitis

Classic pathogens: Campylobacter, Chlamydia trach, Salmonella, Shigella, Yersinia

Bacterial antigens in synovium, trigger T-cell resp →immune-mediated synovitis

↑ rate w/ HLA B27, perhaps because HLA B27 cells allow bacteria to persist

Uncommon disorder, estimated at 0.1% prevalence; 2nd to 4th decade of life

May be underdiagnosed because of asymptomatic prior infection

Following GU infxn (male to female 9:1) or enteric infection (male to female 1:1)

Extra-articular findings include:

No established diagnostic criteria

1996 Third International Workshop on Reactive Arthritis

Routine HLA B27 screening is not helpful

Eval: X-rays of affected joints to r/o trauma, joint aspiration to r/o septic arthritis and gout, U/A to eval for urethritis, Chlamydia PCR, stool cx’s, Lyme serology, RF

NSAIDs (1st line Rx w/ 70%–75% response rate), intraarticular corticosteroids, DMARDs (2nd line for refractory arthritis)

No controlled data, but sulfasalazine, MTX, azathioprine have shown some efficacy

Antibiotics: Rx of urethritis can ↓ risk of reactive arthritis and ↓ relapse

Generally benign course w/ most pts recovering wks–mo w/ no destructive Δ’s

Worse prognosis assoc w/: gender, FHx ankylosing spondylitis, presence HLA of B27, ESR >30, Poor response to NSAIDs, onset <16 yo. (Clin Microbiol Rev 2004;17:348)

Episodic, multisystem, AI dz affecting kids & adults w/ presence of antinuclear auto-Ab’s to ds-DNA & w/ widespread vascular & connective tissue inflamm

Neonatal lupus syndrome: Passively transferred AI dz in 1%–2% of neonates born to moms w/ AI dz (SLE, Sjögren), by transplacental passage of maternal anti-Ro or anti-La Ab’s; clinically w/ congenital heart block, rash, and rarely hepatobiliary or hematologic manifestations (anemia, thrombocytopenia)

“Drug-induced lupus” syndrome: Variant form of lupus that resolves w/i days to months after w/d of drug in pt w/ no underlying immune dysfxn. Most commonly w/ hydralazine, procainamide, quinidine, isoniazid, diltiazem, isoniazid, phenytoin, alpha-methyldopa, ethosuximide, trimethadione, and minocycline.

Prevalence is 5000–10,000 children in the U.S.; median age onset 12 yo

Female predominance of 5:1 girls to boys

Incidence and severity vary: Asians, Hispanics, AA more commonly than Caucasian

Etiology is unknown

Autoreactive B and T cells → antigen-Ab complexes in circulation and deposit in tissues, such as renal glomerulus, dermal-epidermoid junction, and choroid plexus

Immune complexes activate complement system, resulting in hypocomplementemia during the active phase and presence of complement activation products

Dx based on ACR criteria used for adults

4 or more criteria must be present simultaneously or serially

W/ + ANA titers, 4 classifications exist: Classical SLE (many criteria), definite SLE (≥4 criteria), probable SLE (3 criteria), possible SLE (2 criteria present)

ARA criteria for dx of SLE from (Clin Exp Rheumatol 1994;12:83)