Evaluation of arthritis/arthralgia
History
- Check the nature of onset – is it acute or insidious?
- Acute onset monoarticular arthritis associated with fever is septic until proved otherwise.
- Check the timing of symptoms during the day – as a general guide:
– Early morning stiffness = inflammatory.
– Post-activity pain = mechanical.
- Check duration of illness – if >6 weeks it is less likely to be reactive/postviral arthritis.
- Are there any intercurrent infections (respiratory, enteric or skin)? Postviral infections are probably the commonest cause of transient arthritis.
- Has the child been taking any medications (e.g. cefaclor)?
- What does the child, or parent, consider to be the most symptomatic site – is it in the joint, muscle, adjacent bone or a more diffuse area?
- Check for extra-articular symptoms – ensure a thorough systems review and keep the three following diagnoses in mind:
– Systemic lupus erythematosus (SLE).
– Acute lymphoblastic leukaemia (ALL).
– Inflammatory bowel disease (IBD).
- Assess whether the normal physical activities or interests have been interrupted.
- Assess the functional milieu of the patient (e.g. school progress, family and peer relationships, stress experiences).
- Check the family history for other types of inflammatory arthritis, particularly the spondyloarthropathies, autoimmune disorders and pain syndromes (e.g. fibromyalgia or other models for pain behaviour).
Examination
Observe the patient as they move about the room, looking for limitations or alterations in function, and be opportunistic when examining them.
- Examine all joints, not only the site of the presenting complaint. There may be inflammation without symptoms in juvenile idiopathic arthritis (JIA).
- Aim to localise the site of maximal discomfort (e.g. is it the joint capsule, adjacent bone or muscle belly, tendon or ligament attachments?).
- Examine for signs of systemic diseases with an articular component and extra-articular features of JIA. In particular, examine the skin, eyes, abdomen, nails and lymph nodes.
A musculoskeletal assessment should include:
- Joints: signs of inflammation such as swelling or tenderness, the range of movement and deformity.
- Entheses: bone attachment sites of ligaments/tendons (e.g. Achilles tendon).
- Tendon sheaths of fingers and toes (e.g. dactylitis in psoriasis).
- Gait: antalgic (pain) or limp, Trendelenburg’s sign.
- Muscles: tenderness, wasting or weakness, e.g. inability to toe or crouch walk (walking in a full-squat position).
- Patellar tracking pattern – does the patella move vertically on walking?
- Shoe sole and heel-wearing pattern.
- Leg length measurement.
- Spinal flexion, including Schober’s test (the measurement of the lumbosacral range should increase by at least 6 cm on maximal flexion; the starting range is between the lumbosacral junction and a point 10 cm above).
- Growth parameters.
The PGALS is an excellent screening tool for joint exammation. See Table 37.1.
Investigations
There is no single diagnostic test for JIA.
Often useful
- Full blood examination (FBE), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Normal inflammatory markers do not exclude the diagnosis.
- Synovial fluid culture – if sepsis is considered.
- Antinuclear antibody (ANA) – beware of over-interpretation as up to 20% of normal children may have a low positive ANA.
Occasionally useful
- Rheumatoid factor – in polyarticular patients, older children or if the pattern of disease appears unusual.
- HLA-B27 – if spondyloarthropathy is suspected. Remember almost 9% of the White population are positive.
- Imaging – consider plain radiograph, bone scan and ultrasound. In early arthritis, plain films usually give no more information than a careful examination. They may be useful for difficult sites such as the hip, or if there is a long history of arthritis. MRI can be occasionally useful but is not usually an appropriate initial investigation.
- Diagnostic aspirate – worthwhile if sepsis or haemarthrosis is considered, but will not necessarily differentiate between other inflammatory arthritides.
- Specific bacterial/viral studies – if the clinical picture is suggestive (e.g. ASOT, antiDNase B, Yersinia and parvovirus serology), see Postinfectious arthritis, p. 529.
Table 37.1 The Components of paediatric Gait, Arms, Legs, Spine screen (pGALS)
| SCREENING QUESTIONS |
| □ Do you have any pain or stiffness in your joints, muscles or your back? |
| □ Do you have any difficulty getting yourself dressed without any help? |
| □ Do you have any difficulty going up and down staris? |
| GAIT |
| □ Observe the child walking |
| □ ‘Walk on your tip-tones/walk on your heels’ |
| ARMS |
| □ ‘Put you hands out in front of you’ |
| □ ‘Turn your hands over and make a fist’ |
| □ ‘Pinch you index finger and thumb together’ |
| □ ‘Touch the tips of your fingers with your thumb’ □ Squeeze the metacarpophalangeal joints |
| □ ‘Put your hands together/put your hands back to back’ □ ‘Reach up and touch the sky’ |
| □ ‘Look at the ceiling’ |
| □ ‘Put your hands behind your neck’ |
| LEGS |
| □ Feel for effusion at the knee |
| □ ‘Bend and then straighten your knee’ (active movement of knees and examiner feels for crepitus) |
| □ Passive flexion (90 degrees) with internal rotation of hip |
| SPINE |
| □ ‘Open your mouth and put 3 of your (child’s own) fingers in your mouth’ |
| □ Lateral flexion of cervical spine – ‘Try and touch your shoulder with your ear’ |
| □ Observe the spine from behind |
| □ ‘Can you bend and touch your toes?’ Observe curve of the spine from side and behind |
Reproduced with permission from Foster, H.E., Kay, L.J., Friswell, M., Coady, D., Myers, A. Musculoskeletal screening examination (pGALS) for school-age children based on the adult GALS screen. Arthritis Care Research (2006) 55(5); 709–716.
Not useful
- Serum uric acid.
Causes of arthritis/arthralgia in childhood
Juvenile idiopathic arthritis (previously juvenile rheumatoid arthritis and juvenile chronic arthritis)
Assessment
- Age of onset <16 years of age.
- Minimum duration of arthritis – 6 weeks.
- Most acute non-septic arthritis is not JIA.
Disease subtypes
- Oligoarticular: affects 4 joints or fewer:
– Young, often ANA-positive females (can get asymptomatic uveitis that does not correlate with activity of arthritis – screen 3 monthly).
– Older, typically HLA-B27-positive males (who may have an evolving spondyloarthropathy).
- Polyarticular: affects 5 joints or more; rheumatoid factor positive or negative.
- Systemic: joint involvement plus fever, rash and lymphadenopathy.
It is useful to look for:
- Features suggestive of a spondyloarthropathy: enthesitis, sacroiliitis or acute uveitis.
- Nail pits/scalp rash (indicative of psoriasis).
- Rash of Still’s disease (faint urticarial-like erythema) – mostly when febrile.
- Uveitis (especially oligo-JIA patient) by slit-lamp.
- Inflammatory features, including subtle behavioural features such as withdrawal from activity, excessive irritability or sleep disruption.
Management
Depends on the clinical picture of disease severity and subtype.
Principles
- Preserve joint function.
- Control pain.
- Manage complications.
Multidisciplinary approach, including physiotherapy, occupational therapy, and psycho social support. Physical therapy is essential to maintain joint range and function. Splinting should be considered where appropriate.
Medication
- Initially NSAIDs, e.g. naproxen, indomethacin, diclofenac, piroxicam or ibuprofen.
- Then usually low-dose methotrexate to minimise joint destruction.
- Other options include corticosteroids in systemic JIA and intra-articular corticosteroid injections (used early in mono-or pauciarticular arthritis). These are usually performed under GA or procedural sedation and analgesia (e.g. nitrous oxide)
Enthesitis-related arthropathies (spondyloarthropathies)
- Uncommon (more frequent in males) with onset >10 years of age.
- HLA-B27 positive (80%), often raised inflammatory markers.
- Intermittent episodes of enthesitis (tender at tendon insertions) and low back pain/sacroiliitis.
- Acute uveitis (usually clinically evident).
- Management: NSAIDs such as naproxen; sulfasalazine in refractory cases.
Henoch–Schönlein purpura (HSP)
A small-vessel vasculitis.
Clinical features
- Most common age of onset 2–8 years.
- Evolving crops of palpable purpura – predominantly buttocks and legs.
- Abdominal pain (occasionally melaena) may precede rash.
- Large joint migratory arthritis of variable duration and severity.
- Nephritis.
- Other (e.g. oedema dorsum of the feet and hands, acute scrotal swelling and ‘bruising’, fever and fatigue).
- Exclude other causes of purpura (see chapter 23, Dermatologic conditions).
Investigations
- Full blood examination (to exclude thrombocytopenia).
- Urinalysis – haematuria/proteinuria.
- Renal function – urea/creatinine and urinary protein estimation.
Management
- Supportive – bed rest and analgesia.
- Corticosteroids – may reduce the duration of abdominal pain, but it is uncertain if they significantly affect other features.
- Refer to a specialist if renal dysfunction, hypertension or surgical complications develop.
Irritable hip (transient synovitis)
See chapter 34, Orthopaedic conditions.
Septic arthritis
See chapter 34, Orthopaedic conditions.
Kawasaki disease
See chapter 30, Infectious diseases.
Acute rheumatic fever
See chapter 30, Infectious diseases.
Reactive arthritis
Poststreptococcal reactive arthritis
- Afebrile symmetrical non-migratory poly-or pauciarticular arthritis.
- Arthritis responds slowly to NSAIDs.
- Carditis may occur and form part of a spectrum with acute rheumatic fever.
- Consider penicillin prophylaxis if carditis is present.
Postenteric reactive arthritis
- Mainly Salmonella, Shigella and Yersinia (also reported with Campylobacter and Giardia).
- It is clinically similar to the spondyloarthropathies; i.e. predominantly lower limb (including sacroiliitis), enthesitis is common and positive family history (especially if HLA-B27 positive). However, it may not present with all the classic clinical features.
- Consider Crohn’s disease or ulcerative colitis.
- Associated features – acute anterior uveitis and sterile pyuria.
- Treatment – NSAIDs: indomethacin 0.5–1.0 mg/kg (max. 75 mg) p.o. 8 hourly is often the most effective.
Postviral arthritis
- Many viral illnesses are associated with arthritis.
- It is uncertain in most situations whether it is the primary (infective) or secondary (reactive) event; e.g. Epstein–Barr virus, rubella, adenovirus, varicella (beware septic arthritis secondary to infected skin lesion), parvovirus B19 and hepatitis B.
- A transient arthritis often follows a non-specific ‘viral’ illness, the confirmation of which may be difficult and unnecessary.
- Treatment: NSAIDs probably shorten the duration.
Non-inflammatory causes of joint pain
Benign nocturnal limb pains (‘growing pains’)
- Onset at 3–7 years, often occurs in the evenings and at night.
- Well between attacks.
- Recurrent pain mainly involving the knee, calf and shin.
- No symptoms or signs of inflammation either on history or examination.
- Investigations (if carried out) are normal.
- Management involves analgesia (usually paracetamol), ibuprofen and reassurance; heat and massage/rubbing often help.
Benign hypermobility
Common, particularly in the older child/adolescent (<7 years of age all the features are normal variants).
Typical sites
- Hyperextension of the fingers parallel to the forearm.
- Apposition of the thumb to the anterior forearm.
- Hyperextension of the elbows, knees, or both >10°.
- Excessive dorsiflexion of the ankles.
- Hip flexion allowing the palms to be placed flat on ground.
Clinical features
- Pain occurs typically in the afternoon or after exercise and occurs mostly in the lower limbs.
- The child may have features of patello-femoral dysfunction.
- The child may have transient joint effusions.
- Management: symptomatic treatment and reassurance.
Complex regional pain syndrome
See chapter 4, Pain management.
Other rheumatological disorders
Maintain an index of suspicion regarding other rheumatological disorders (e.g. SLE, dermatomyositis and other connective tissue disorders).
Enquire about the following symptoms:
- Lethargy, weight loss, mouth ulcers, alopecia or frontal hair breaking.
- Recurrent fevers.
- Raynaud’s phenomenon, rashes or photosensitivity.
- Ophthalmological symptoms: red sore eyes, change in vision or dry eyes.
- Weakness.
- Consider investigating with: C3, C4, ANA, dsDNA, ENA, CK, LDH or LFT.
USEFUL RESOURCES
- www.arc.org.uk/arthinfo/emedia.asp – Arthritis research campaign with link to DVD on administration of pGALS.
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