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Flashcards in 4 - Juvenile Idiopathic Arthritis Deck (22):

What is the second most common chronic disease in childhood?

Juvenile Idiopathic Arthritis (second only to asthma)



Requires one of the below:
Joint swelling or effusion
Limited range of motion of the joint
Heat over the joint
Redness over the joint

Pain in the joint is not sufficient to call it arthritic. Without the others, it is arthralgia.


Juvenile Idiopathic Arthritis - Criteria

Less than 16 years old at the onset
Persistent arthritis in one or more joint for more than 6 weeks
Exclude other forms of arthritis

JIA is distinct and a different disease from RA


Classifications of Juvenile Idiopathic Arthritis

Systemic JIA (10 - 20%) - has fever and rash, sometimes no arthritis
Pauci-articular (40 - 60%) - fewer than 5 joints involved
Polyarthritis RF (-) (20 - 25%) - More than 5 joints
Polyarthritis RF (+) (5 - 10%) - More than 5 joints, probably have adult RA, but are below the cutoff for age
Enthesitis-related arthritis (10 - 15%) - insertion of tendon or ligament into the bone, arthritis at the insertion site
Psoriatic arthritis (5%)
Undifferentiated (5%)

Lumped together in peds, but really they respond to different treatments, and they are DIFFERENT DISEASES gurl


Juvenile Idiopathic Arthritis - Etiology

Unknown and multifactorial

Activated T cells and macrophages are involved in pathogenesis
In some types, autoantibodies are elevated such as ANA and RF
Elevated levels of cytokines are present such as IL-1, IL-6 & TNF-α


ANA positivity

Some JIAs are ANA positive
Rheumatoid Arthritis typically is not.


JIA - Innate immune system

Uncontrolled activation of PMN is present in poly-articular disease

Genetic polymorphisms of the IL-1 B genes are associated with susceptibility to systemic JIA

Increased NK cells are present in systemic JIA


JIA - Adaptive immune system

Polyclonal B-Cell activation is reflected in the hypergammaglobulinemia present in JIA

Complement is activated and associated with activity of the disease

Activated T cells are increased in the pauci and poly-articular disease

CD4+ T cells are the predominant infiltrating cell in the inflamed synovium


JIA - Presentation

Insidious onset
Minimal pain
Morning stiffness and walk with a limp, sometimes have to have their parents carry them around for half an hour in the morning
Change in function and in activity level

Knee is the most common joint involved
PIP joint involved in psoriatic arthritis


Pauci-articular JIA

Fewer than 5 joints
Peak incidence at 2 years old
Female/male 5:1
No systemic disease
Associated with uveitis
ANA positivity 80%


Polyarthritis (JIA)

Over 5 joints involved
Peak at 2 years old
Female/male 3:1
Often unremitting
10% RF positive, 40% ANA positive
Guarded prognosis - more severe, tends to become chronic


Systemic JIA

Variable number of joints involved, or no joints at all
Any age, throughout childhood (can spill into adulthood)
Female/male 1:1
50% unremitting and destructive
Very rare autoantibodies or uveitis
Now known to be auto-inflammatory and dependent on EITHER IL-1 or IL-6, not both. Auto-inflammatory, not autoimmune, because it's due to one specific cytokine.

Salmon fleeting rash (mild red, not itchy, transient at the height of the fever, usually central)


JIA - Differential of Excluded Diseases

Mechanical traumatic (Patello-femoral syndrome, SCFE, Osgood-Schlatters)
Infectious (Lyme)
Hematologic or oncologic
Other rheumatologic diseases
Inflammatory conditions (FMF, IBD)
Chronic pain syndromes


Specific to childhood arthritis

Delayed growth, particularly height
Delayed puberty
Localized growth disturbances from accelerated growth
Significant TMJ involvement

Localized growth failure (eg second digit)


If a kid has ANA positive JIA

Send them to the ophthalmologist every 3 months if you don't want them to go damn blind.


Helpful laboratory tests (not specific, but helpful)

CBC (Anemia, thrombocytosis)
Acute phase response (ESR, CRP, Ferritin)

Other labs to be done once diagnosis of arthritis is made (NEVER as screening tests):
X-rays are rarely helpful at diagnosis. Can exclude trauma and junk.
Synovial fluid to rule out septic arthritis


JIA - Non-pharmacologic management

Activity and exercise
Physical and occupational therapy
Diet and sleep


Occupational and Physical Therapy to JIA

Finger splinting (with kyoot rings)
Wrist splinting


JIA - Pharmacologic Treatment

Joint injection
Disease modifying agents - Sulfasalazine, methotrexate, azathioprine, hydroxychloroquine, leflunamide
Biologics - TNF inhibitors, IL-1 inhibitors, IL-6 inhibitors, CTLA-4 inhibitors
Small molecule kinase inhibitors


JIA - Predictors of outcome

Initial articular severity score
Early hand involvement (worse)
Ana negativity or RA positivity (worse)
Male sex (worse)


JIA - Death rate

Usually in systemic disease and related to infection


JIA- Morbidity

Outcome based on disease subtype classification after 6 months of activity
70% have a satisfactory outcome without serious disability
5% have a relapse in adulthood
20% continue into adulthood with moderate to severe disabilities