Juvenile Idiopathic Arthritis

Question 1

Define “juvenile idiopathic arthritis”

Answer 1

Arthritis occurring in someone who is less than 16 years old that lasts for more than 6 week

Question 2

Types of JIA

Answer 2

Systemic

Polyarticular

Oligoarticular

Enthesitis-related

Juvenile psoriatic

Question 3

Clinical features of systemic JIA

Answer 3

Subtlesalmon-pink rash

High swinging fevers

Enlarged lymph nodes

Weight loss

Joint inflammation and pain

Splenomegaly

Muscle pain

Pleuritis and pericarditis

Question 4

Investigations in systemic JIA

Answer 4

Antinuclear antibodiesandrheumatoid factorsare typically negative

Raisedinflammatory markers, with raisedCRP,ESR,plateletsandserum ferritin

Question 5

Complications in systemic JIA

Answer 5

Macrophage activation syndrome(MAS), where there is severe activation of the immune system with a massive inflammatory response

Question 6

Presentation of macrophage activation syndrome

Answer 6

Acutely unwell child with disseminated intravascular coagulation (DIC), anaemia, thrombocytopenia, bleeding and a non-blanching rash

Question 7

Non-infective differentials in children with fever >5 days

Answer 7

Kawasaki disease

Still’s disease

Rheumatic fever

Leukaemia

Question 8

Define polyarticular JIA

Answer 8

Idiopathic inflammatory arthritis in 5 joints or more

Question 9

Clinical features of polyarticular JIA

Answer 9

Tends to besymmetrical

Can affect small joints of the hands and feet, as well as large joints such as the hips and knees

Minimal systemic symptoms

Can bemild fever,anaemiaandreduced growth

Systemic symptoms are mild, unlike systemic onset JIA

Question 10

Define oligoarticualr JIA

Answer 10

Involved 4 joints or less

Usually only affects a single joint (mono arthritis)

Question 11

Clinical features of oligoarticular JIA

Answer 11

Monoarthritis

Tends to affect larger joints e.g. knee or ankle

Anterior uveitis

Tend not to have any systemic symptoms

Inflammatory makers will be normal or mildly elevated

Antinuclear antibodiesare often positive

Rheumatoid factor is usually negative

Question 12

Define enthesitis-related arthritis

Answer 12

Paediatric version of theseronegative spondyloarthropathygroup of conditions that affect adults (ankylosing spondylitis,psoriatic arthritis,reactive arthritisandIBD-related arthritis)

Question 13

What is an enthesis?

Answer 13

Point at which tendon of a muscle inserts into bone

Question 14

Causes of enthesitis

Answer 14

Traumatic stress, such as through repetitive strain during sporting activities

Autoimmune inflammatory process

Question 15

Clinical features of enthesitis-related JIA

Answer 15

Consider signs and symptoms ofpsoriasis(psoriatic plaques and nail pitting) andIBD(intermitted diarrhoea and rectal bleeding)

Prone toanterior uveitis

Tender to localised palpation of theentheses

Question 16

Key areas in enthesitis-related JIA

Answer 16

Interphalangeal joints in the hand

Wrist

Over the greater trochanter on the lateral aspect of the hip

Quadriceps insertion at theanterior superior iliac spine

Quadriceps and patella tendon insertion around the patella

Base of achilles, at the calcaneus

Metatarsal heads on the base of the foot

Question 17

Define juvenile psoriatic arthritis

Answer 17

Seronegative inflammatory arthritisassociated withpsoriasis

Question 18

Investigations in juvenile psoriatic arthritis

Answer 18

Clinical diagnosis

Exclude other causes

Question 19

Clinical features of juvenile psoriatic arthritis

Answer 19

Plaques of psoriasison the skin

Nail pitting

Onycholysis

Dactylitis, inflammation of the full finger

Enthesitis

Question 20

Medical management of juvenile psoriatic arthritis

Answer 20

NSAIDs (symptom control only)

Steroids (intra-articular or oral)

Immunotherapy:
DMARDs e.g. methotrexate first line, sulfasalazine, leflunomide
Biologics e.g. TNF-a inhibitors)

Question 21

Complications of juvenile psoriatic arthritis

Answer 21

Flexion contractures (requiring physio and splints)

Joint destruction (requiring prostheses at young ages)

Growth failure (from steroids and chronic disease)

Chronic anterior uveitis (causing visual impairment)

1/3 of children with juvenile idiopathic arthritis continue to have joint pain into adulthood