Juvenile idiopathic arthritis Flashcards
What is Juvenile Idiopathic Arthritis?
- This is a group of systemic inflammatory disorders affecting children under the age of 16.
- Most common;y diagnosed rheumatic disease in children.
- An important cause of disability and blindness.
Generally, outline the aetiology and pathogenesis of JIA.
- JIA is an auto-immune disease.
- It has a multifactorial aetiopathogenesis that is different to that of adult rheumatoid arthritis.
- Strong subset-specific genetic markers may affect the immune response.
What is the criteria for diagnosis of Juvenile Idiopathic Arthritis?
- Age of Onset - under 16
- Duration of disease - greater than 6 weeks.
- Presence of arthritis
- Joint swelling; or 2 of the following
- Painful of limited joint movement
- Tenderness
- Warmth
- Joint swelling; or 2 of the following
After how long can the clinical subtypes of JIA be identified.
What are the subtypes of JIA.
What is the benefit of knowing these subtypes?
- After 6 months the clinical subtypes can be identified.
The clinical subtypes are:
- Pauarticular
- Polyarticular
- Systemic Onset
Knowing the subtypes is beneficial because it helps suspect:
- The natural history
- Complications
- Prognosis
- Preferred treatment strategies
Outline Pauarticular JIA?
JIA affecting 4 or less joints.
There are 3 different subtypes.
- Type 1
- Type 2
- Type 3
Outline Type 1 Pauarticular JIA in terms of:
- Epidemiology
- Presentation
- Affects areas
- Other associated areas/implications.
Epidemiology
- Most common pauarticular subtype
- Appears before 5y/o, with peak incidence between 1-3 y/o.
- Girls > Boys (8:1)
Presentation
- Limp, rather than pain.
- No constitutional manifestations (group of symptoms that can affect many different systems of the body)
Affected areas
- Mainly lower limb joints
- Knee > Ankle > Hand or Elbow (hip very rare)
Other associated areas/implications
- Chronic uveitis (inflammation of the uvea — the middle layer of the eye that consists of the iris, ciliary body and choroid.)
- 20% of cases (95% if female Less than 2y/o)
- Asymptomatic in 50%
- Irregular iris due to posterior synechiae (where the iris adheres to the lens)
- +ve ANA (antinuclear antibodies) in 40-75%
Outline type 2 Pauciarticular JIA, in terms of:
- Epidemiology
- Presentation
- Affected areas
- Associated features/issues
Epidemiology
- 15% of pauciarticular JIA
- After 8/9 years of age
- Boys > Girls (7:1)
Presentation
- Limp due to Lower Limb being affected
- Constitutional rare
Affected areas
- Mainly knee and ankle joints.
- Hip can be affected early & rapidly accumulate damage
- Leads to hip replacement early in life
- Enthesistis - inflammation of area when ligament/tendon attach to bone.
- May affected sacroiliac joints - can evolve to AnkSpon or spondyloarthritis
Associated features/issues
- Acute iridocyclitis in 10-20% - inflammation of the iris and of the ciliary body.
- If HLA-B27 + back involved = Juvenile Ankylosing spondylitis.
Outline Type 3 puaciarticular JIA in terms of:
- Epidemiology
- Presentation
- Other clinical features
Epidemiology
- Occurs at any age in childhood.
- Girls > Boys (4:1)
Presentation
- Constitutional involvement rare
- Asymmetric Upper Limb and Lower Limb arthritis
- Dactylitis - inflammation of an entire digit (a finger or toe)
Other clinical features
Arthritis can be very destructive
- Family history of psoriasis in 40%
- +/- nail pitting
- These patients may develop psoriasis later in life
- Chronic iridocyclitis in 10-20%.
What is the link between presenting with Pauarticular JIA and later Polyarticular JIA?
- 30% of these presenting with pauciarticular JIA can go on to more severe polyarticular course.
Outline Polyarticular JIA.
This JIA affects 5 or more joints, and can be subdivide into:
- Rhematoid Factor - Neg.
- Rheumatoid Factor - Pos.
Outline Polyarticualr RF- JIA in terms of:
- Epidemiology
- Presentation
Epidemiology
- Any age affected, often early
- Girls > Boys (9:1)
Presentation
- Constitutional manifestations (low grade fever, malaise)
- Hepato-splenomegaly
- Mild anemia
- Growth abnormalities
- Symmetric large and small joints affection: knees, wrists, ankles, MCPs, PIPs, neck
- Iridocyclitis rare.
Outline Polyarticualr RF+ JIA in terms of:
- Epidemiology
- Presentation
- Other Clinical Features
Epidemiology
- Age: late childhood (teens, 12-16 years)
- Girls: boys = 7:1
Presentation
- Constitutional manifestations (low grade fever, malaise, weight loss)
- Anemia
- Nodules.
Other Clinical Features
- Can be complicated by sjogren’s, Felty or vasculitis, AR, pulmonary fibrosis, AAS, CTS.
- Similar to adult RA but in a child
- Erosions in x ray occur early
What is Systemic Onset JIA known as?
Still’s Disease
- Least common JIA - but most serious short and long term morbidity and mortality.
In term of Still’s Disease/Systemic Onset JIA, outline:
- Extra-articular features
- Fever
- Rash
- Lymph Nodes
- Abdominal
- Serositis - inflammation of a serous membrane.
- Pulmonary
- Arthritis
This is a long car
Extra-articular features
- These define the disease - start early and dissapear after 2-5 years.
-
Fever
- Rise to 39.5 daily for at least 2wks
- RIse in afternoon/evening - normal/subnormal in morning.
- Child looks toxic w/ fever and chills, but normal when fever goes.
-
Rash
- 90%
- Evanescent salmon red eruption, on trunk and thighs
- Accompanies fever
- Can be brought on by scratching. (+ve Koebner’s phenomenon)
-
Lymph Nodes
- 50-75%
- Generalised non-tender lymphadenopathy
-
Abdominal
- Hepatosplenomegaly
- Abdominal pain
- +/- transaminases
-
Serositis - inflammation of a serous membrane.
- Polyserositis
- Percarditic in 36%
- Tamponade and myocarditis.
-
Pulmonary
- Rare
- Pleural effusion
- Pulmonary fibrosis
-
Fever
Arthritis
- 75%
- Within 3-12 moonths of onset of fever
- Wrists, knees, ankles, cervical spine, hips and TMJ.
What is the 1st Line Management of JIA?
- Simple pain killers
- NSAIDs:
- Difference between adults and children half life
- Can control disease
- Doses
- Same compounds only
