Rheumatology - Juvenile Idiopathic Arthritis Flashcards
What is JIA?
Autoimmune inflammation of the joints causing arthritis in children and adolescents
How is JIA diagnosed?
Arthritis without any other cause lasting more than 6 weeks in under 16s
What are the key features of JIA?
Joint pain
Swelling
Stiffness
What are the 5 different subtypes of JIA?
- Systemic JIA
- Polyarticular JIA
- Oligoarticular JIA
- Enthesitis related arthritis
- Juvenile psoriatic arthritis
How is systemic JIA also known?
Still’s disease
What are the typical features of systemic JIA?
- Subtle salmon-pink rash
- High swinging fevers
- Enlarged lymph nodes
- Weight loss
- Joint inflammation and pain
- Splenomegaly
- Muscle pain
- Pleuritis and pericarditis
What is raised in systemic JIA?
CRP
ESR
Platelets
Serum ferritin
Rheumatoid and ANA are negative
What is a key complication of systemic JIA?
Macrophage activation syndrome
Severe activation of the immune system with a large inflammatory response
How does macrophage activation syndrome present?
Presents with acutely unwell child with
- DIC
- Anaemia
- Thrombocytopenia
- Bleeding
- NBR
Life threatening
What investigation is key in macrophage activation syndrome?
Low ESR
What are the key non-infective differentials for high fevers in kids for over 5 days?
Kawasaki disease
Still’s disease
Rheumatic fever
Leukaemia
What is polyarticular JIA?
Idiopathic inflammatory arthritis in** 5 joints or more**
Symmetrical
Can affect small joints of hands and feet and large joints e.g. hips and knees
What symptoms are there in polyarticular JIA?
- Joint pain
- Joint swelling
- Joint stiffness
- Mild fever
- Anaemia
- Reduced growth
What is the difference between seronegative and seropositive in polyarthritis?
Seronegative - rheumatoid factor negative
Seropositive - rheumatoid factor positive
Polyarthritis is equivalent to rheumatoid arthritis in adults
What is oligoarticular JIA?
4 joints or less
Usually only affects a single joint - monoarthritis
Tends to affect larger joints e.g. knee or ankle
Occurs more in girls under 6
What classic feature is associated with oligoarticular JIA?
Anterior uveitis
Oligo = Ophthalm
What symptoms are there in oligoarticular JIA?
No systemic symptoms
Just joint issues
What is elevated in OJIA?
Inflammatory markers are normal or slightly elevated
ANA are often positive
Rheumatoid are negative
What is Enthesitis-Related Arthritis?
Common in boys over 6
Paediatric version of seronegative spondyloarthropathy conditions
Inflammatory arthritis in joints + enthesitis
What is enthesitis?
Inflammation at the point tendon inserts into a bone
What can cause enthesitis?
Traumatic stress by repetitive strain in sports or autoimmune inflammation
How can enthesitis be detected?
MRI scan
Unable to differentiate between stress or autoimmune
What do majority of patients with enthesitis-related arthritis have?
HLAB27 gene
What should you look for when assessing a patient with enthesitis-related arthritis?
- Psoriasis signs
- IBD signs
- Anterior uveitis
What should you do when examining a patient with enthesitis-related arthritis?
Patients will be tender to palpation of the entheses
Palpate
- IPJs
- Wrist
- Over greater trochanter on lateral hip
- Quadriceps insertion at the ASIS
- Quadriceps and patellar tendon at the patella
- Base of the Achilles
- Metatarsal heads on base of the foot
What is juvenile psoriatic arthritis?
Seronegative inflammatory arthritis associated with psoriasis
Can have symmetrical polyarthritis affecting small joints or asymmetrical arthritis affecting large joints
What signs on examination are associated with juvenile psoriatic arthritis?
- Plaques of psoriasis
- Nail pitting
- Onycholysis (separation of nail from the bed)
- Dactylitis (full finger inflammation)
- Enthesitis
How is JIA managed?
Paediatric rheumatology with a specialist MDT
Reduce inflammation in joints and minimise symptoms
- NSAIDs
- Steroids, either oral, IM or intra-articular in oligoarthritis
- DMARDs
- Biologic therapy e.g. TNFis, infliximab
