Rheumatological disease in a child: Juvenile idiopathic arthritis Flashcards
Define juvenile idiopathic arthritis.
Juvenile idiopathic arthritis is a group of chronic arthropathies of childhood.
What are the seven subtypes suggested by the international league of Associations for Rehumatology (ILAR)?
Systemic (sJIA)
Oligoarticular
Polyarticular (RF positive)
Polyarticular (RF negative)
Enthesitis-related arthritis (ERA)
Psoriatic arthritis
Undifferentiated
Define systemic juvenila idiopathic arthritis.
> 1 joint with or preceded by fever lasting for > 3 days with > 1 of:
- Rash
- Generalized lymphadenopathy
- Hepatomegaly
- Splenomegaly
- Serositis
Define oligoarticular juvenile idiopathic arthritis.
< 4 joints affected in first 6 months of disease:
- Persistent: Followed by <4 joint involvement
- Extended: Followed by >4 joint involvement
Define polyarticular juvenile idiopathic arthritis (RF neg + RF pos).
> 4 joints affected during first 6 months
Define enthesitis-related arthritis (ERA).
Arthritis and enthesitis (inflammation at insertion of tendon, ligament, joint capsule or fascia to bone) or > 2 features of enthesitis:
- Sacroiliac joint/lumbosacral pain
- HLA-B27 positive
- Male onset > 6 years
- Acute anterior uveitis (first-degree relative)
- Reiter syndrome (acute reactive arthritis following gastroenteritis/STI)
Define psoriatic juvenile idiopathic arthritis.
Arthritis with psoriasis or > 2 features of psoriasis:
- Dactylitis
- Nail pitting/onycholysis
- Psoriasis in first-degree relative
Define undifferentiated juvenile idiopathic arthritis.
No category or > 2 of the categories previously
Explain the aetiology of juvenile idiopathic arthritis.
An aberrant immune/inflammatory response. Activated T cells (Th1 proinflammatory cytokines), humoral immunity (ANA or RF) and innate immunity (in particular neutrophils) all have evidence to support being involved in the pathogenesis of different subtypes of JIA. HLA subtypes have been linked to all classified subtypes.
What are associations of juvenile idiopathic arthritis?
Bacterial or viral infection
Malignancy
Vasculitis
Connective tissue disease.
Septic arthritis is an important differential in single joint involvement.
What is the pathophysiology of juvenile idiopathic arthritis?
All subtypes of JIA are characterised by persistent joint swelling caused by an accumulation of synovial fluid and thickening of the synovial lining.
Summarise the epidemiology of juvenile idiopathic arthritis.
JIA is the most common chronic rheymatic disease in children.
In developed countries the prevalence is 16- 150/100,000. sJIA comprises 10-20% of all JIA.
What are symptoms of juvenile idiopathic arthritis?
General: Acute joint swelling, pain, warmth and stiffness; typically, worse in the morning and improves with activity; may later present with reduced range of movement, overgrowth or contractures. Children often do not complain of pain and instead tend to stop using the affected joint.
sJIA: Usually symmetrical, polyarticular and associated with severe myalgia, abdominal pain, daily high temperature spike with associated rash.
What are the signs of juvenile idiopathic arthritis?
Paediatric Gait Arms Legs Spine (pGALS) system has been validated as a screening tool for the musculoskeletal system in children.
What are appropriate investigations for juvenile idiopathic arthritis?
- FBC
- Markers of inflammation (ESR, CRP, ferritin)
- RF
- ANA
- HLA-type
- Slit lamp examination (anterior uveitis)
- X-ray
- USS
- MRI of joints
