Juvenile Idiopathic Arthritis Flashcards
ddx for joint pain in children
- trauma
- biomechanical
- infection
-septic joint/osteomyelitis
-lyme disease
-gonococcus
-viral arthritis - reactive
-enteric (shigella, salmonella, campylobacter)
-acute rheumatic fever - malignancy
-leukemia
-bone tumors (malignant & benign)
classic presentation of juvenile idiopathic arthritis
*3 year old female presents with history of left knee pain and swelling
*no history of recent illness or trauma
*exam: painful, warm left knee with an effusion and limited range of motion
*no fever or rash
*unremarkable CBC and ESR, Lyme negative
*ANA positive
joint pain in children - red flags (need immediate evaluation)
*fever, systemic upset (malaise, weight loss, night sweats)
*lymphadenopathy, hepatosplenomegaly
*bone pain
*persistent night waking
*incongruence between history and exam
summary - do NOT miss infection, malignancy, NAT
ddx for joint pain in kids: Lyme arthritis
*lyme arthritis is a late finding
*usually follows erythema migrans rash earlier
*more common in older kids with 1 knee affected
ddx for joint pain in kids: acute rheumatic fever
*Jones criteria
*supporting evidence of antecedent GAS infection (elevated or rising strep antibody titers, positive throat culture or rapid strep antigen)
*major criteria: carditis, polyarthritis (usually migratory), chorea/CNS disease, erythema marginatum, subcutaneous nodules
ddx for joint pain in kids: biomechanical causes
*benign nocturnal MSK pains of childhood (growing pains)
*joint hypermobility
*overuse syndromes
*apophysitis
Beighton Hypermobility Criteria (after age 6)
- touch thumb to forearm
- hyperextend MCPs (parallel forearm)
- > 10 degree hyperextension knees
- touch pals to floor (straight knees)
- excessive hip rotation
hypermobility syndrome
*behind the knee pain
*evening pain, especially bedtime
*worse after activities
*better with rubbing
*tx: NSAIDs prior to onset of pain, PT
*if concerned for connective tissue disorder (EDS, Marfan’s), refer to genetics
ddx for joint pain in kids: rheumatologic ddx
*SLE
*juvenile dermatomyositis
*mixed connective tissue disease
*vasculitis (IgA vasculitis, Kawasaki)
*periodic fever syndromes
*Juvenile idiopathic arthritis
arthritis vs arthralgia - defined
ARTHRITIS:
*effusion (swelling) or 2+ of the following:
-limited range of motion
-pain with motion
-warmth
-tenderness
ARTHRALGIA: joint pain without objective evidence of inflammation
juvenile idiopathic arthritis (JIA) - epidemiology
*most common chronic rheumatologic condition of childhood
*affects 1 to 4 per 1000 children
juvenile idiopathic arthritis (JIA) - overview
*heterogenous group of diseases characterized by arthritis that:
-begins before age 16
-involves 1+ joint
-persists 6+ weeks
*complications of poorly controlled JIA include growth disturbances, joint contractures and destruction, and chronic pain
juvenile idiopathic arthritis (JIA) - diagnosis
*rule out other causes (diagnosis of exclusion)
*no labs are diagnostic, but can be useful for supporting dx, prognosis, monitoring therapy toxicity
*6 months to determine subtype
ANA in JIA
*antibodies against proteins in the nucleus
*no diagnostic utility in JIA
*helpful in evaluation risk of uveitis in JIA (positive ANA = increased risk of developing uveitis)
RF & CCP in JIA
*in pts with polyarticular JIA, RF+ and CCP+ can have more aggressive disease
*not diagnostic of JIA
HLA B27 in JIA
*associated with spondyloarthritis, IBD, psoriatic arthritis, and reactive arthritis
*up to 10% of general population is positive
*not diagnostic of JIA
7 categories of JIA
*younger kids:
-oligoarticular
-polyarticular, RF negative
-polyarticular, RF positive
*spondyloarthropathies:
-psoriatic
-enthesitis related
-undifferentiated
*systemic JIA
oligoarticular JIA
*1-3 year old girl, ANA+, arthritic joint (knee > ankle > fingers)
*4 or fewer arthritic joints within first 6 months of diagnosis
*next step = REFER TO OPHTHAMOLOGY (due to chance of iritis)
polyarticular, RF negative JIA
*more than 5 arthritic joints within first 6 months of diagnosis
*RF negative
*biphasic trend: 1-3 yo and adolescence
*TMJ disease
*number of affected joints tend to be less than in RF+
polyarticular, RF positive JIA
*more than 5 arthritic joints within first 6 months of diagnosis
*RF positive
*teenage females
*upper and lower extremity, large and small joints involved
*similar to adult RA
*CCP positive
enthesitis-related arthritis
*arthritis and enthesitis
OR
*arthritis plus 2 of the following:
-presence or history of inflammatory SI tenderness and/or inflammatory lumbosacral pain
-presence of HLA B27 antigen
-onset of arthritis in a male over age 6
-history of ankylosing spondylitis, ERA, sacroiliitis, with IBD, Reiter’s syndrome, or acute anterior uveitis in first-degree relative
systemic juvenile idiopathic arthritis (JIA) - epidemiology
*frequency: 10% of JIA
*occurs equally in males and females
*peak age: 1-5 years old
*arthritis (usually polyarticular)
*fever with daily high spikes for a minimum of 2 weeks
systemic juvenile idiopathic arthritis (JIA) - diagnostic criteria
-
quotidian fever (occurs daily at intervals) of at least 2 weeks duration
PLUS -
arthritis in any number of joints
AND at least one of the following:
a. evanescent rash (faint, salmon-colored, nonpruritic, macular, transient; Koebner phenomenon)
b. generalized lymphadenopathy
c. enlarged liver or spleen
d. serositis
systemic juvenile idiopathic arthritis (JIA) - labs
*elevated WBC
*anemia
*thrombocytosis
*elevated ESR and CRP
*mildly elevated LFTs
*elevated ferritin
macrophage activation syndrome - overview
*complication of systemic JIA (also seen in lupus, Kawasaki, MIS-C)
*uncontrollable activation and expansion of T cells and macrophages leading to overwhelming systemic inflammatory response
*febrile pt with known or suspected systemic JIA with high ferritin and low platelets
macrophage activation syndrome - bone marrow findings
*systemic “cytokine storm:”
-cytopenias
-liver dysfunction
-coagulopathy
-extreme hyperferritinemia
macrophage activation syndrome - treatment
*methylprednisone
*anakinra
*canakinumab
*tocilizumab
*cyclosporine
uveitis in JIA
*chronic anterior non-granulomatous inflammation affecting the iris and ciliary body
complications of JIA
*uveitis
*synechiae (asymptomatic iritis)
*TMJ disease
*joint contracture
*limb length discrepancy
