MSK - Juvenile idiopathic arthritis Flashcards
1
Q
Definition
A
Juvenile idiopathic arthritis (JIA) is a group of chronic inflammatory arthritides of unknown cause, affecting children under the age of 16.
2
Q
Types of JIA
A
- Oligoarticular JIA
- Polyarticular JIA (RH-factor negative)
- Polyarticular JIA (RH-factor positive)
- Enthesitis-related arthritis
- Psoriatic JIA
- Systemic JIA (formely Still’s disease)
- Undifferentiated JIA
3
Q
Oligoarticular JIA
A
- Most common type (50% of JIA)
- Mildest form (affects 4 or fewer joints)
- Commonly affected joints include knees and ankles
- Associated with chronic uveitis
4
Q
Polyarticular JIA (rheumatoid factor-negative)
A
- Next most common type
- Affects 5 (+) joints in the first 5 months
- Similar joints affected to those in rheumatoid arthritis
- Rheumatoid factor negative
- Some association with chronic uveitis
5
Q
Polyarticular JIA (rheumatoid factor-positive)
A
- Occurs in pre-teen and adolescent females.
- Affects 5 or more joints in the first 5 months
- Similar joints affected to those in rheumatoid arthritis
- Rheumatoid factor positive
6
Q
Enthesitis-related arthritis
A
- Arthritis, occurring in the hips, knees, ankles and feet
- Enthesitis (inflammation of the insertion of the ligament or tendon to the bone), occurring in the knees, heels and plantar region of the feet
- More common in boys, unlike other JIA types
- Associated with acute anterior uveitis
7
Q
Psoriatic JIA
A
Associated with psoriasis, which usually precedes the arthritis but may occur years later.
8
Q
Systemic JIA (formerly Still’s disease)
A
- Arthritis is preceded by a fever and rash
- Classical “salmon-pink” rash
- In severe forms, inflammation can affect the spleen, liver, pleura and pericardium
Affects males and females equally
9
Q
Undifferentiated JIA
A
- Clinical features do not fit into any of the above categories
- Clinical features may fit into multiple categories
10
Q
Epidemiology
A
- JIA = MC chronic rheumatic disease in children.
- Female predominance : in most subtypes, except for enthesitis-related arthritis
- Genetic predisposition: HLA associations vary by subtype
- Possible triggers:
= infections,
= environmental factors
11
Q
Signs
A
- Joint swelling
- Joint warmth
- Limited range of movement in affected joints
- Limited (if lower limb joints are affected)
- Salmon-pink rash (Systemic JIA only):
= discrete
= macules of different sizes
= occurs with a rash which migrates across the trunk and proximal extremities
12
Q
Symptoms
A
- Joint pain
- Joint stiffness (in the morning)
- Fatigue
- Fatigue (systemic JIA only)
13
Q
Diagnosis
A
- ESR/CRP: elevated (esp systemic JIA)
- Rheumatoid factor: type of PA JIA
- HLA B27: assosciated with undifferentiated, enthesitis-related + psoriatic JIA types
- Joint X-ray: joint space narrowing, erosions + bony ankylosis
- Joint USS: visualise joint effusions, synovial thickening + bone erosions
14
Q
Treatment FIRST LINE
A
- Intra-articular corticosteroids: all patients + 3-6 monthly assessment
- IV corticosteroids: Short-term use = control severe symptoms or in cases of systemic JIA
- METHOTREXATE: DMARD = slow disease progression and prevent joint damage.
= Avoided if presence of sacro-ilitis or macrophage activation syndrome (MAS). - NSAIDs: IBUPROFEN used to reduce inflammation and alleviate pain
- Physiotherapy and occupational therapy
15
Q
Treatment SECOND LINE
A
- Etanercept: Anti-TNF antibody = first biological agent choice,
= unless presence of sacro-ilitis or macrophage activation syndrome (MAS)
= Should be avoided in those with uveitis. - Anakinra: Interleukin-1 (IL-1) receptor antagonist is offered to those with macrophage activation syndrome.
- Tocilizumab: Anti-interleukin-6 receptor antibody is offered to those with systemic JIA (Still’s disease) or those who have not tolerated anakinra.
