Children Rheum - JIA Flashcards
Another name for arthrocentesis
Joint aspiration
What is Koebners phenomenon?
Linear erythema - skin lesions - appearing on line of trauma
eg. following pruritus
What is Juvenile Idiopathic arthritis (JIA)
An umbrella term used to describe at least 7 different conditions - each representing a different form of childhood arthritis
Key features of JIA
Joint pain and swelling Diurnal variation (stiffness in morning and after periods of rest) Other rheumatic patterns of rash, fever, weakness, disease progression despite simple measures
What age of children are most commonly affected by JIA?
Preschool or early school years
What is most commonly affected joint in JIA
Knee
Can also be ankle or wrist
Rarer = small joint arthritis or axial (shoulder, hip, spine, TMJ)
What improves stiffness in JIA
Movement, warm bath or shower
How can knee joint swelling be identified in children? x4
Balloting synovial fluid
Palpating a fluid thrill on joint movement
Positive patella tap
Occasionally finding a Baker’s cyst in popliteal fossa
How can ankle joint swelling be demonstrated in children? x2
Swelling of ankle will distort contours of medial or lateral malleoli
Also on ankle dorsiflexion may not be able to see extensor tendons (may be difficult in infants or obese children)
Ways of seeing wrist arthritis in children? x2
Press palms of hands together in praying position - dorsal bulge and
Reduced range of movement - especially if asymmetrical
Signs of elbow swelling in children? x3
Swelling can usually be palpated either side of olecranon
Can also cause flexion deformity of elbow
Elbow swelling obscures posterior dimple created when elbow is fully extended
Signs of finger swelling x6
Joint margin tenderness, restricted movement, swelling, purplish discolouration, incomplete fist closure and diminished grip strength
Signs of cervical spine arthritis x2
Inability to rotate head laterally and place chin on each shoulder
Inability to extend cervical spine properly
Presentation of TMJ arthritis
Often missed
May prevent full and symmetrical opening of the mouth
Signs of sacroiliac joint involvement or enthesitis in JIA x2
Schober test - less than 6cm expansion of lumbar spine with forward bending
Tenderness of sacroiliac joints to direct palpation
Where does enthesopathy commonly affect in JIA
Achilles tendon
Other signs of systemic arthritis in JIA other than arthritis
Pink, macular, truncal rash - may be pruritic with Koebners
Lymphadenopathy
Hepatosplenomegaly
Myalgia
Arthritis might not be prominent initially
Arthritis which fit under umbrella term of JIA
Systemic arthritis Oligoarthritis Polyarthritis Psoriatic arthritis Enthesitis-related arthritis HLA-B27-related arthritis syndromes
Mechanical disorders which are DDX for JIA x3
Joint pain secondary to hypermobility
Trauma
NAI
Features of hypermobility joint pain
Younger children are generally more flexible, joints are mobile, girls>boys and black>white
May get pain after physical activity and in evenings (opposite to JIA)
Lower limbs and back
Examination shows 10-15degrees extra motion
Treat with orthotics
Infection-related disorders which are DDX for JIA x3
Reactive arthritis
Septic arthritis
Osteomyelitis
What is reactive arthritis?
Most common form of arthritis in children
Self-limited, acute and painful joint swelling following extra-articular infection
Features of septic arthritis
Almost exclusively monoarticular
Associated with “pseudoparalysis” of affected limb
Systemically ill child (high fever)
What is pseudoparalysis
Extreme pain with affected joint held rigidly in the position of maximum comfort
Treatment of septic arthritis
Joint aspiration for bacterial culture before treatment started - can also help reduce intraarticular pressure
Then antibiotics
Features of osteomyelitis
Children present with fever, bone pain and signs of toxicity
Extreme pain at sign of infection and cannot ambulate
Chronic rheumatic conditions as DDX for JIA x3
SLE
Juvenile dermatomyositis
Localised scleroderma syndromes
Typical presentation of SLE x4 features
In adolescent girl with malaise, fever and bone/joint pain
It is rare in prepubescent children
What sort of rash can be present in SLE?
Acneiform facial rash may be present along with typical malar rash (not a uniform finding)
Rash does not affect nasolabial folds
Other features of SLE found in most children x6
Hair loss Mouth sores Lymphadenopathy Organomegaly Other rashes Swollen joints
Antibody tests for SLE x5
ANAs are almost always positive
Double-stranded DNA and Sm antibodies - more specific for SLE
Antibodies to SSA (Ro) and SSB (La) and anti-cardiolipin are positive in less than 50% of paediatric SLE but associated with complications
Other haematological signs of SLE x3
Lymphopenia
Thrombocytopenia
Coombs positive anaemia
What can show on urinalysis in SLE
Proteinuria and casts - reflecting renal disease (more common in child-onset SLE than adult)
How does juvenile dermatomyositis present?
Insidiously with malaise, progressive muscle weakness and muscle pain/discomfort
What % of juvenile dermatomyositis have arthritis
20%
Dermatological features of dermatomyositis x4
Heliotrope rash (purplish discoloration and oedema of eyelids) Malar rash travelling down to nasolabial folds
Gottrons papules over MCP, elbows and knees
Cuticle hyperaemia
Serum signs of dermatomyositis
Elevated serum muscle enzymes, CPK aldolase, AST, ALT and LDH
Features of localised scleroderma syndromes
Localised disorder characterised by areas of oval or linear lesions that traverse over joints, face and trunk
Can also have frank arthritis
2 acute inflammatory DDX of JIA
HSP
Kawasaki disease
Features of HSP x5
Purpuric rash over lower legs and buttocks Cramping abdominal pain Bloody stools Haematuria Arthritis of ankles and knees
Malignant DDX of JIA x4
Acute lymphoblastic leukaemia
Neuroblastoma
Lymphoma
Primary bone malignancies (rare)
ALL presentation similar to JIA
Can present with bone pain in children and even frank arthritis
Pain over affected bone
Idiopathic pain syndromes as DDX for JIA x2
Complex regional pain syndrome
Diffuse MSK pain syndromes
Why do you do investigations in JIA
JIA is a label for children who fulfil criteria based on clinical features alone - therefore investigations to exclude other DDX
Why do you do FBC in JIA suspicion?
To look for leucopenia, Coomb’s positive anaemia and thrombocytopenia of SLE and MTCD
Also elevated WBC count and anaemic of chronic inflammation with systemic arthritis
Why do you do ESR in JIA suspicion?
ESR elevated in systemic arthritis and SLE
Normal in up to 1/2 patients with JIA and in most with dermatomyositis
Why do you do urinary catecholamines in JIA suspicion?
To exclude neuroblastoma
Why do you do Liver function tests in JIA suspicion?
To rule out dermatomyositis
Why do you do Antinuclear antibodies in JIA suspicion?
High ANAs seen in virtually all children with SLE and MCTD
Also positive ANA in oligoarthritis
Why do you do IgG in JIA suspicion?
IgG highly elevated in SLE
Why do you do Borrelia burgdorferi serology in JIA suspicion?
To rule out Lyme disease if there is a history of travel in endemic area
Why do you do synovial fluid analysis in JIA suspicion?
Mandatory if suspected septic arthritis
Why do you do radiology in JIA suspicion?
To rule out fractures, malignancy, look for joint effusions, bone dysplasia/neoplasia, avascular necrosis
Features of systemic arthritis
Prominent extra-articular features of high fever, rash, myalgia, arthralgia and irritability
Pattern of arthritis can vary from several swollen joints to widespread polyarticular pattern
Presentation age of systemic arthritis
Usually begins in early childhood - although it can occur at any age through to adulthood
Laboratory studies in systemic arthritis
High WBC count
Severe anaemia, thrombocytosis
High ESR, CRP and ferritin
Duration of systemic features in systemic arthritis?
They usually resolve after a few months but they may last indefinitely
Prognosis of systemic arthritis
Very poor, erosions of joint and loss of motion
Also severe growth delay due to treatment with steroids
What can occur with systemic arthritis?
Macrophage activation syndrome - carries a 10-15% mortality rate - IV steroids and cyclosporine may reverse rapid deterioration and DIC
What does oligo- mean?
Sparse or few
What % of JIA does oligoarthritis account for?
50%
Features of oligoarthritis?
Knee most commonly affected joint
Otherwise healthy
20% have asymptomatic anterior uveitis
Joints affected in oligoarthritis
Most commonly the knee then ankle and wrist. Hip rarely ever affected
Sex ratio of oligoarthritis
Female:Male 5:1
Features of eye problems in oligoarthritis
Chronic anterior uveitis - occurs in 20%
Clinically silent and insidiously progressive
Produces visual loss and blindness if not detected by slit lamp and treated eary
Laboratory investigations in oligoarthritis
Frequently positive ANAs but all other examinations are normal
Implications of oligoarthritis
Often localised growth disturbances - one leg longer than the other due to increased growth in the affected leg (presumbably due to chronic hyperaemia and increased blood supply to joint)
This leads to knee flexion contracture and atrophy of the muscle above the knee
Toddler with oligoarthritis will stand with affected leg bent
What is extended oligoarthritis?
1/3 of children who have less than 4 joints affected in the first 6 months go on to continue to develop arthritis in further joints afterwards
What do children with extended oligoarthritis often have
Anterior uveitis
What are the two types of polyarthritis?
Rheumatoid-negative and rheumatoid-positive
Features of rheumatoid negative polyarthritis
Usually affects preschool girls
Predominantly symmetrical arthritis of upper and lower limbs
What can happen with rheumatoid negative polyarthritis x2
Rare but important - growth restriction and chronic anterior uveitis
Prognosis of rheumatoid negative polyarthritis?
Illness lasts most of childhood and many go on to adulthood with the disease
Laboratory findings with rheumatoid negative polyarthritis
May have mild anaemia
Usually positive ANAs
ESR and CRP may be mildly elevated
What % of JIA is due to rheumatoid negative polyarthritis?
25-30%
What type of disease is rheumatoid positive polyarthritis
Similar in features and prognosis to adult RA - therefore can be called juvenile rheumatoid arthritis
Presentation age of rheumatoid positive polyarthritis
Usually in late childhood or adolescence
Gender ratio of rheumatoid positive polyarthritis
Primarily affects girls
Features of rheumatoid positive polyarthritis
Like rheumatoid arthritis
can be rapidly progressive and destructive
Rheumatoid nodules are common
Failure to thrive more frequent than in rh- polyarthritis
Laboratory findings in rheumatoid positive polyarthritis
ANAs are usually positive
Features of psoriatic arthritis in children
Arthritis may pre-date any classical skin findings by many years
Often asymmetrical arthritis, affects both small and large joints
What establishes the diagnosis of psoriatic arthritis
Family history of first degree relative with psoriasis
What can also affect children with psoriatic arthritis?
Asymptomatic uveitis - high risk of blindness if undetected
Features of enthesitis-related arthritis x3
Lower limb arthritis initially
Complicated by enthesiitis of plantar fascia, achilles tendon and around patella
Can also get uveitis but usually symptomatic with red eyes, photophobia and pain
Age and gender of children with enthesitis-related arthritis
Usually after 6 years old and boys>girls
What is enthesitis-related arthritis a precursor to?
Ankylosing spondylitis
What does treatment of arthritis in children usually start with? Details of this therapy
Usually starts with NSAIDs - used in higher doses relative to body weight than in adults because children have increased metabolism and renal excretion
Adverse effects of NSAIDs treatment in JIA
Abdominal pain, change in mood, rarely bronchospasm
Success of NSAIDs in JIA?
Majority of patients with early JIA do not respond to NSAIDs and need more aggressive treatment
What can be used for single joint involvement in JIA?
Intra-articular corticosteroids
Usually down under GA in UK
Often used in oligoarthritis
What is generally avoided treatment wise for JIA?
Systemic oral steroids because of side effects on growth and bones (avascular necrosis), and cushings
If it is needed in large pulses to control systemic disease - can also give GH to counteract growth restriction
Eg. of two slow-acting anti-rheumatic drugs used in JIA
Methotrexate and sulfasalazine
What is methotrexate effective at treating in JIA?
Effective in approx 70% of children with polyarthritis
Much less effective in systemic arthritis
When is methotrexate considered in JIA?
If disease not controlled with NSAIDs or intra-articular steroids after 4-12week trial
How long after starting can efficacy of methotrexate be determined?
1-3 months
Most common side effects of methotrexate
Nausea and mouth ulcers (ondansetron and folate)
Other side effects of methotrexate
Abdominal pain, elevated LFTs
Rarely hair loss and bone-marrow suppression
What is a possible substitute for methotrexate in JIA?
Leflunomide - same efficacy and less toxicity
When is sulfasalazine effective?
In oligoarthritis and polyarthritis - especially effective in ERA
Not much value in SA and increased risk of macrophage activated syndrome
What have revolutionised JIA treatment? 2 eg
Biologics - TNFa-antagonists
Etanercept and Infliximab
When can etanercept be used in JIA?
Children whose disease is not controlled by methotrexate or are intolerant of it
Very effective treatment
Infliximab use in JIA?
Not labelled yet for JIA use but is being increasing used as it is highly effective - used if fail etanercept
Used in combination with methotrexate to minimise risk of immune reactions
Or if uveitis
Hydroxychloroquine use in JIA?
Use in children is not supported - studies not shown to be effective
