Juvenile idiopathic arthritis represents a family of heterogeneous diseases characterized by chronic inflammation of synovial membranes. The clinical presentation of children with juvenile idiopathic arthritis and the utility of the laboratory in evaluating children with suspected arthritis differ significantly from adults. Juvenile idiopathic arthritis is a chronic disease; only a minority of patients “outgrow it.” Thus, the goals for physicians treating children with juvenile idiopathic arthritis are to return the child to full function and prevent disability.
Epidemiology and Incident Rates
By definition and convention, all types of juvenile idiopathic arthritis (JIA) are diagnosed prior to a child’s 16th birthday. Although the need to standardize clinical studies and trials stipulates that signs and symptoms must be present for at least 6 weeks to distinguish children with JIA from those with self-limited forms of arthritis, in most cases, the clinical presentation and physical examination of a child with chronic arthritis are apparent within a shorter time frame.
JIA is a clinically diagnosed illness without specific laboratory diagnostic criteria, the reported incidence and prevalence of which vary widely. It is important to note that JIA is a common disease and is often not recognized or diagnosed in a timely manner.1–3 Prevalence estimates based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes of “any diagnosis with significant pediatric arthritis in the USA,” for the period 2001 to 2004, were 294,000 (95% CI, 188,000–400,000), ranging from 500 in Wyoming to 38,000 children in California.4
Although the specific JIA numbers cannot easily be extracted from these estimates, it is evident that JIA, the most common chronic rheumatic condition of childhood, is more prevalent than cystic fibrosis and sickle cell disease.1
Although the overall mortality from JIA has decreased over the past 20 years to a standardized rate of 0.57, JIA often persists into adulthood and can result in significant morbidity, including limitation of joint function, leading to difficulties with employment, social interactions, and independence.5 Between 40% and 70% of young adults with JIA have ongoing disease activity, and between 10% and 46% can have chronic disabilities, including osteoporosis, depression, and poor pain control.6
Oligoarticular JIA is the most common form of JIA in North America, comprising 30% to 60% of children with JIA. It most commonly affects white girls before 5 years of age. Girls are represented three times more than boys. It is rare in blacks,7 Native Americans,8 and southern Asians.8
Polyarticular JIA is the next most common form in European and European-descended populations, comprising 5% to 30% of children with JIA. Two subtypes exist; rheumatoid factor (RF) seropositive, most commonly affecting later adolescence, and RF seronegative, with peaks in ages of onset between 1 and 4 years of age and then between 6 and 12 years of age. RF seropositive polyarticular JIA patients comprise only 5% to 10% of all JIA patients,3 and their disease course appears to parallel adult rheumatoid arthritis more than JIA.
Girls are represented three to six times more than boys in polyarticular JIA. It is also the most common type in blacks and Native Americans;7,8 these groups often experience the most severe disease with the worst prognoses. Systemic onset JIA and spondyloarthritis can have overlapping features with oligo- and polyarticular JIA and are covered in detail in other articles in this issue.
Unlike adults, children with arthritis seldom present with musculoskeletal pain as an isolated complaint. In a retrospective study of 414 children seen in a pediatric rheumatology center, McGhee et al10 found that only 17% of children with JIA verbalized pain as part of their presenting complaints. In fact, they found that only one of 111 patients referred for isolated pain was diagnosed with a rheumatic disease, leading them to conclude that musculoskeletal pain without evidence of arthritis is a strong negative predictor for diagnosing JIA. Moreover, Jones et al11 found that children presenting with musculoskeletal pain, especially nighttime pain, were significantly more likely to have leukemia than arthritis (63% vs. 17%).
In contrast, McGhee et al10 showed that the presence of joint swelling and gait disturbance/limp were highly predictive in identifying children with JIA. Children with JIA more commonly describe stiffness and a dull discomfort over the affected joint(s) that is worse in the morning. Oligoarticular JIA commonly affects large joints asymmetrically (knees and ankles), and toddlers may refuse to weight bear on affected joints after periods of rest (usually upon waking in the morning or from a nap, see Table 1).12
Table 1. International League of Associations for Rheumatology (ILAR) Criteria for JIA
Polyarticular JIA most closely mimics adult rheumatoid arthritis in that it affects large and small joints, sometimes symmetrically. Children with polyarticular JIA often present with pronounced morning stiffness and fatigue. Constitutional symptoms may also be present. On physical examination, the affected joint(s) with thickened synovium in children with JIA often feel warm and doughy, and may be associated with decreased range of motion (see Figure 1). The patient may experience pain and/or tenderness with range of motion, but the joints are not usually erythematous.
Figure 1. Left knee swelling. In oligoarticular juvenile idiopathic arthritis, although the affected joint is swollen, there is minimal tenderness and erythema.Image courtesy of Joyce S. Hui-Yuen, MD, MSc; and Lisa F. Imundo, MD. Reprinted with permission.
Clinical history and physical examination are both key to making a diagnosis of JIA (see Table 2). The laboratory markers used to evaluate musculoskeletal complaints (antinuclear antibodies [ANA], anti-cyclic citrullinated protein [CCP], and RF do not accurately predict diagnosis of JIA.13,14 Given the poor positive and negative predictive values for ANA and RF in children, neither of these assays are particularly helpful in establishing a diagnosis of JIA, although both tests can help categorize JIA and may help assess prognosis after the diagnosis has been made.
Table 2. Utility of Laboratory Markers in JIA
Up to 36% of affected children with JIA may develop uveitis, an important and potentially devastating complication of JIA. Although it can be associated with photosensitivity, it is commonly asymptomatic at onset. It is typically nongranulomatous and affects the anterior chamber of the eye (see uvea, Figure 2A). Hence, other frequently used terms for this type of eye inflammation are iritis and iridocyclitis.
Figure 2. (A) Schematic of the eye. The uvea/anterior chamber is most often affected in juvenile idiopathic arthritis. Major complications of uveitis include (B) synechiae and (C) band keratopathy. It is a routine part of each pediatric rheumatology follow-up visit to check for these complications. Screening guidelines for uveitis in juvenile idiopathic arthritis have been put forth by the American Academy of Pediatrics.16Images courtesy of National Eye Institute, National Institutes of Health. Reprinted with permission.
Diagnosis of early involvement is most sensitive with slit-lamp examination by an ophthalmologist. Anterior uveitis is most commonly diagnosed in children with oligoarticular JIA. Risk factors include serum ANA positivity (present in up to 90% of children with JIA and uveitis), female gender, and age younger than 7 years at time of onset of arthritis.15 However, although uveitis is more common in girls, when present, it is more severe in boys regardless of age or serum ANA positivity.
Although early detection and treatment of uveitis in children with JIA predict good prognosis, it may be recalcitrant to treatment and is often associated with vision loss in children with JIA. Major complications include band keratopathy, posterior synechiae, formation of cataracts, glaucoma, and abnormal intraocular pressure (including hypertension or hypotony) (see Figure 2B, 2C). It is a routine part of each examination in pediatric rheumatology clinics to check for these complications.
The screening ophthalmologic evaluation should occur within 1 month of diagnosis of JIA. If uveitis is not detected on initial screen at diagnosis of JIA, it is most likely to present within the next 4 to 7 years. In 5% of cases, it has been shown to precede joint involvement. There have also been reports of uveitis diagnosed more than 10 years after onset of arthritis, suggesting that the risk of developing uveitis can be lifelong. The American Academy of Pediatrics (AAP) has put forth guidelines for uveitis screening in JIA (see Table 3).16
Table 3. American Academy of Pediatrics Guidelines for Ophthalmologic Screening
The differential diagnoses for joint swelling and gait disturbance encompass many disease entities. For any child presenting with fever and acute limb pain, infectious causes should be considered first, and not arthritis. Septic arthritis and osteomyelitis are medical emergencies that can result in joint destruction if not recognized and treated immediately.
Similarly, for any child presenting with constant and severe bone pain that wakes the child from sleep, leukemia and other malignancies must be considered first. Table 4 provides a list of common diagnoses to consider when a child presents with joint swelling, gait disturbance, and/or musculoskeletal pain.
Table 4. Arthritis: Differential Diagnoses and Diagnostic Clues
Genetics and Immunopathogenesis
The primary pathologic event in the development of oligoarticular and polyarticular JIA is synovial membrane infiltration by monocytes, cells of the innate immune system. The exact etiology and pathogenesis of JIA remain unknown. Genetic susceptibility factors (HLA and non-HLA) appear to differ between oligoarticular and polyarticular JIA, with some overlap suggesting shared pathways in pathogenesis.17 Although a specific mechanism remains to be delineated, a panoply of immunologic abnormalities, including dysregulation of cytokines and activation of the adaptive immune system,18,19 suggest interaction between the innate and adaptive immune responses to be involved in disease pathogenesis.
Treatment and Outcome
JIA is a chronic heterogeneous disease that exposes children to prolonged and chronic inflammation and the adverse effects of long-term medications of varying potencies. Treatment of JIA is aimed at preserving joint function and limiting joint damage and erosion. The current guidelines for initiating different therapies put forth by the American College of Rheumatology summarize evidence-based advances in treatment to improve outcomes for children with JIA.20
First-line treatment of oligoarticular JIA typically includes nonsteroidal anti-inflammatory drugs (NSAIDs), which are very well-tolerated in children.21 Intra-articular corticosteroids may be very effective in children with a small number of active larger joints. Clinical improvement occurs rapidly, and with triamcinolone hexacetonide, can be sustained for many months on average after injection.22 Children refractory to these treatments and extended oligoarthritis patients will benefit from intensification of treatment.
Children with polyarticular JIA are at high risk for lifelong disease and most ultimately require more intense therapy with a disease-modifying anti-rheumatic drug (DMARD) or biologic treatment. NSAIDs and corticosteroids are mainly used as bridging therapy or as adjuncts in these patients for immediate treatment of joint inflammation while awaiting therapeutic effect from DMARD or biologic agents.
Since the 1980s, weekly methotrexate (MTX) has been the standard of care for treating children with JIA.23 New biologic therapies are now used in almost 25% of children with JIA,24 and are often added to MTX to treat severe JIA. Biologic therapies appear efficacious as first-line treatment of polyarticular JIA, but improvement in long-term outcome over standard treatment regimens remains under investigation.
Biologics used to treat JIA include the tumor necrosis factor (TNF) inhibitors etanercept, infliximab, and adalimumab, as well as abatacept, a human fusion protein that inhibits the co-stimulatory signals required for T-cell activation, and tocilizumab, an inhibitor of interleukin-6 activity.25,26 Despite a black-box warning issued in 2008 for increased incidence of lymphoma in patients on infliximab, current data remain insufficient to establish a relationship between use of anti-TNF biologics and the development of malignancies in JIA patients. In addition, patients receiving DMARD and/or biologic treatments may not receive live vaccines during length of treatment, and must wait until at least several months after the last treatment to receive a live vaccine. Moreover, pubertal girls should be counseled and provided with an effective contraceptive agent if appropriate.
Although most biologics studied to date have proved beneficial in children refractory to standard treatment, and are well-tolerated, the drawbacks include relatively high cost, the risk for infection, and the relative paucity of long-term data on their safety. There is a more detailed discussion of treatment of JIA elsewhere in this issue.
In conjunction with medications, it takes a well-coordinated multi-disciplinary team to control a child’s arthritis. The longer a child is exposed to disease activity, including chronic low-level disease activity, the higher the risk for limiting daily function. Occupational and physical therapists are an important part of a child’s care team. Special accommodations in school may be needed. Klepper27 found that children with JIA who participate in activity as recommended by physical therapists for 60 minutes at least once a week have a significant improvement in their quality of life, function, and have reduced disease severity at 8 weeks.
Treatment of chronic uveitis in children with JIA can be challenging. New onset cases may be treated with topical steroids and mydriatics.15 However, long-term topical steroid use is limited to avoid development of cataracts. Anti-metabolite and biologic therapies have also been shown to be effective in controlling chronic uveitis.
Outcome Measures and Remission
Assessment of joint damage is a critical outcome in determining treatment efficacy in children with all subtypes of JIA. Classically, radiographs of affected joints in children with JIA can demonstrate soft tissue swelling, joint space narrowing, erosion, subluxation, ankylosis, calcification, and osteoporosis (see Figure 3). However, the limitations of radiographic imaging in skeletally immature children pose a challenge for assessment of damage. As the diagnosis and treatment of all JIA subtypes is moving toward earlier detection for earlier suppression of inflammation, the role of other modalities such as ultrasound and magnetic resonance imaging (MRI) are being investigated (see Table 5).
Figure 3. (A) Anterior-posterior radiograph of the left hand. The bones are diffusely osteopenic. There is overgrowth of the epiphyses of the proximal phalanges and metacarpals. The bones of the carpus are crenulated (irregular in shape and contour) secondary to erosions and abnormal growth from long-standing hyperemia. (B) The fingers are swollen. Chronic juvenile idiopathic arthritis causes changes in bone growth and development as well as destructive erosions and loss of cartilage.Image courtesy of Joyce S. Hui-Yuen, MD, MSc; and Lisa F. Imunodo, MD. Reprinted with permission.
Table 5. Usefulness of Different Imaging Modalities
Children with JIA often have arthritis that persists into adulthood and results in significant morbidity. One critical difference between JIA and adult rheumatoid arthritis are the modalities used to determine the outcome. Adult rheumatoid arthritis disease activity and remission criteria are more clearly defined, and levels of serum inflammatory markers are a more accurate reflection of disease activity than in JIA. Most recently, Vilca et al28 found that predictors of poor outcomes included longer disease duration, negative serum ANA, more severe disability, and evidence of joint damage. This only serves to emphasize the on-going challenge in finding JIA outcome measures that will allow us to standardize therapy.
For many years, the ultimate goal of treatment for children with JIA is restoration of full function, including participation in all forms of physical activity. An evaluation of the cervical spine must be done in any child with neck arthritis prior to sports participation. Benefits and adverse effects of long-term medication exposure in JIA are being investigated in multi-national trials. Current research describing emerging paradigms of disease pathogenesis coupled with new advances in treatment and a better understanding of the long-term safety of current treatment options will help us to better understand and optimally treat children with JIA.
- Gortmaker SL, Sappenfield W. Chronic childhood disorders: prevalence and impact. Pediatr Clin North Am. 1984;31(1):3–18.
- Cuesta IA, Kerr K, Simpson P, Jarvis JN. Subspecialty referrals for pauciarticular juvenile rheumatoid arthritis. Arch Pediatr Adolesc Med. 2000;154(2):122–125.
- Manners P, Bower C. Worldwide prevalence of juvenile arthritis why does it vary so much?J Rheumatol. 2002;29(7):1520–1530.
- Sacks JJ, Helmick C, Luo YH, et al. Prevalence of and annual ambulatory health care visits for pediatric arthritis and other rheumatologic conditions in the United States in 2001–2004. Arthritis Rheum. 2007;57(8):1439–1445. doi:10.1002/art.23087 [CrossRef]
- Hashkes PJ., Wright BM, Lauer MS, et al. Mortality outcomes in pediatric rheumatology in the US. Arthritis Rheum. 2010;62(2):599–608.
- Arkela-Kautiainen M, Haapasaarij J, Kautiainen H, et al. Favourable social functioning and health related quality of life of patients with JIA in early adulthood. Ann Rheum Dis. 2005;64(6):875–880. doi:10.1136/ard.2004.026591 [CrossRef]
- Schwartz MM, Simpson P, Kerr KL, Jarvis JN. Juvenile rheumatoid arthritis in African Americans. J Rheumatol. 1997;24(9):1826–1829.
- Mauldin J, Cameron HD, Jeanotte D, Solomon G, Jarvis JN. Chronic arthritis in children and adolescents in two Indian health service user populations. BMC Musculoskeletal Disord. 2004;5:30–36. doi:10.1186/1471-2474-5-30 [CrossRef]
- Aggarwal A, Misra R. Juvenile chronic arthritis in India: is it different from that seen in Western countries?Rheumatol Int. 1994;14(2):53–56. doi:10.1007/BF00300247 [CrossRef]
- McGhee JL, Burks F, Sheckels JL, Jarvis JN. Identifying children with chronic arthritis based on chief complaints: absence of predictive value for musculoskeletal pain as an indicator of rheumatic disease in children. Pediatrics. 2002;110(2 Pt 1):354–359. doi:10.1542/peds.110.2.354 [CrossRef]
- Jones OY, Spencer CH, Bowyer SL, et al. A multicenter case-control study on predictive factors distinguishing childhood leukemia from juvenile rheumatoid arthritis. Pediatrics. 2006;117(5):e840–e844. doi:10.1542/peds.2005-1515 [CrossRef]
- Petty R, Southwood T, Manners P, et al. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. J Rheumatol. 2004;31(2):390–392.
- Eichenfield AH, Athreya BH, Doughty RA, Cebul RD. Utility of rheumatoid factor in the diagnosis of juvenile rheumatoid arthritis. Pediatrics. 1986;78(3):480–484.
- Malleson PN, Sailer M, Mackinnon MJ. Usefulness of antinuclear antibody testing to screen for rheumatic diseases. Arch Dis Child. 1997;77(4):299–304. doi:10.1136/adc.77.4.299 [CrossRef]
- Rabinovich CE. Treatment of juvenile idiopathic arthritis-associated uveitis: challenges and update. Curr Opin Rheumatol. 2011;23(5):432–436. doi:10.1097/BOR.0b013e328349c324 [CrossRef]
- Cassidy JT, Kivlin J, Lindsley C, et al. Ophthalmologic examinations in children with juvenile rheumatoid arthritis. Pediatrics. 2006;117(5):1843–1845. doi:10.1542/peds.2006-0421 [CrossRef]
- Angeles-Han S, Prahalad S. The genetics of juvenile idiopathic arthritis: what is new in 2010?Curr Rheumatol Rep. 2010;12(2):87–93. doi:10.1007/s11926-010-0087-0 [CrossRef]
- Morbach H, Wiegering V, Richl P, et al. Activated memory B cells may function as antigen-presenting cells in the joints of children with juvenile idiopathic arthritis. Arthritis Rheum. 2011;63(11):3458–3466. doi:10.1002/art.30569 [CrossRef]
- Saxena N, Aggarwal A, Misra R. Elevated concentrations of monocyte derived cytokines in synovial fluid of children with enthesitis related arthritis and polyarticular types of juvenile idiopathic arthritis. J Rheumatol. 2005;32(7):1349–1353.
- Beukelman T, Patkar N, Saag KG, et al. 2011 American College of Rheumatology recommendations for the treatment of juvenile idiopathic arthritis: initiation and safety monitoring of therapeutic agents for the treatment of arthritis and systemic features. Arthritis Care Res. 2011;63(4):465–482. doi:10.1002/acr.20460 [CrossRef]
- Ruperto N, Nikishina I, Pachanov ED, et al. A randomized, double-blind clinical trial of two doses of meloxicam compared with naproxen in children with juvenile idiopathic arthritis: short- and long-term efficacy and safety results. Arthritis Rheum. 2005;52(2):563–572. doi:10.1002/art.20860 [CrossRef]
- Eberhard A, Sison MC, Gottlieb BS, Ilowite NT. Comparison of the intraarticular effectiveness of triamcinolone hexacetonide and triamcinolone acetonide in treatment of juvenile rheumatoid arthritis. J Rheumatol. 2004;31(12):2507–2512.
- Silverman E, Mouy R, Spiege L, et al. Leflunomide or methotrexate for juvenile rheumatoid arthritis. N Engl J Med. 2005;352(16):1655–1666. doi:10.1056/NEJMoa041810 [CrossRef]
- Natter MD, Winsor JR. The Childhood Arthritis and Rheumatology Research Alliance Network Registry: demographics and characteristics of the initial one year cohort. Arthritis Rheum. 2011;63(10):S747.
- Pham T, Bachelez H, Berthelot JM, et al. TNF-alpha antagonist therapy and safety monitoring. Joint Bone Spine. 2011;78(Suppl):15–185. doi:10.1016/S1297-319X(11)70001-X [CrossRef]
- Ruperto N, Lovell DJ, Cuttica R, et al. A randomized, placebo-controlled trial of infliximab plus methotrexate for the treatment of polyarticular-course juvenile rheumatoid arthritis. Arthritis Rheum. 2007;56(9):3096–3106. doi:10.1002/art.22838 [CrossRef]
- Klepper SE. Effects of an eight-week physical conditioning program on disease signs and symptoms in children with chronic arthritis. Arthritis Care Res.1999;12(1):52–60. doi:10.1002/1529-0131(199902)12:1<52::AID-ART9>3.0.CO;2-X [CrossRef]
- Vilca I, Munitis PG, Pistorio A, et al. Predictors of poor response to methotrexate in polyarticular-course juvenile idiopathic arthritis: analysis of the PRINTO methotrexate trial. Ann Rheum Dis. 2010;69(8):1479–1483. doi:10.1136/ard.2009.120840 [CrossRef]
- Damasio MB, Malattia C, Martini A, Toma P. Synovial and inflammatory diseases in childhood: role of new imaging modalities in the assessment of patients with juvenile idiopathic arthritis. Pediatr Radiol. 2010;40(6):985–998. doi:10.1007/s00247-010-1612-z [CrossRef]
- Magni-Manzoni S, Epis O, Ravelli A, et al. Comparison of clinical versus ultrasound-determined synovitis in juvenile idiopathic arthritis. Arthritis Rheum. 2009;61(11):1497–1504. doi:10.1002/art.24823 [CrossRef]
- Gardner-Medwin JM, Killeen OG, Ryder CA, Bradshaw K, Johnson K. Magnetic resonance imaging identifies features in clinically unaffected knees predicting extension of arthritis in children with monoarthritis. J Rheumatol. 2006;33(11):2337–2343.
International League of Associations for Rheumatology (ILAR) Criteria for JIA
||Persistent; affecting no more than 4 joints throughout disease course.
Extended; affecting no more than 4 joints in the first 6 months of disease, then affecting 5 or more joints thereafter.
||Painless joint swelling, gait disturbance.
Most common in white girls 2–4 years of age.
Can have poor outcome similar to polyarticular JIA patients.
||Rheumatoid factor (RF) positive; affecting 5 or more joints during first 6 months of disease, with evidence of serum RF positivity on 2 or more tests at least 3 months apart.
Rheumatoid factor negative; affecting 5 or more joints during first 6 months of disease, serum RF remains negative.
||Very prominent morning stiffness and/or flexion contractures and fatigue, affects large and small joints symmetrically.
Most common in blacks and Native Americans.
Utility of Laboratory Markers in JIA
|Antinuclear antibody level
||Sensitive but not specific, detected in 10%–30% of healthy children.14
Not useful as diagnostic tool for JIA, but used to assess risk for uveitis after clinical diagnosis of JIA is made.
|Erythrocyte sedimentation rate
||Commonly used as marker of disease activity in adults with rheumatoid arthritis.
Not as useful in JIA because oligoarticular JIA can have normal values.
|Rheumatoid factor (RF) and anti-cyclic citrullinated protein (CCP) antibody levels
||Only a minority of children (usually older teenage girls) are RF or anti-CCP positive; however, this group has a more severe and chronic disease course.
American Academy of Pediatrics Guidelines for Ophthalmologic Screening
||Antinuclear Antibody Status
Oligo- or polyarticular arthritis, disease onset younger than 6 years of age, duration of disease less than 4 years.
|Every 3 months
Oligo- or polyarticular arthritis disease onset younger than 6 years of age, duration of disease over 4 years.
Oligo- or polyarticular arthritis, disease onset over 6 years of age, duration of disease under 4 years.
Oligo- or polyarticular arthritis, disease onset under 6 years of age, duration of disease under 4 years.
|Every 6 months
Oligo- or polyarticular arthritis, disease onset over 6 years of age, any duration of disease.
Systemic onset juvenile idiopathic arthritis.
Oligo- or polyarticular arthritis, disease onset over 6 years of age, disease duration over 4 years.
Oligo- or polyarticular arthritis, disease onset under 6 years, but disease duration now over 7 years.
|Every 12 months
Arthritis: Differential Diagnoses and Diagnostic Clues
|• Septic arthritis, osteomyelitis
Fever, acute monoarthritis, often refusal to move or bear weight due to pain.
|• Reactive arthritis
||Fever/pharyngitis/preceding viral illness, self-limiting.
|• Lyme arthritis
||Time course of onset, may not have known tick bite.
|• Acute rheumatic fever
||Migratory painful arthritis.
|• Leukemia, bone tumors, neuroblastoma
||Severe and constant pain waking child from sleep, often refuse to bear weight or walk, can be worse with activity.
|• Overuse injury, fracture
||Acute limb pain, possible limp.
|• Sickle cell anemia, hemophilia
||Dactylitis, may have bleeding into joints.
|• Juvenile idiopathic arthritis
||Onset before 16 years of age, joint swelling for more than 6 weeks, possible systemic symptoms. Joint swelling is not always accompanied by verbal complaints of pain.
|• Systemic lupus erythematosus
||Characteristic clinical syndrome.
|• Henoch Schonlein purpura, serum sickness.
||May be preceded by viral illness and/or medication (antibiotic) use.
|• Slipped capital femoral epiphysis, Legg-Calve-Perthes
||Acute hip pain (may refer to knee), may have preceding history of trauma or walk with limp.
|• Growing pains
||Intermittent nocturnal nonarticular pain, usually bilateral, diagnosis of exclusion.
|• Benign hypermobility
||Daytime pain that can wake child from sleep, can have discomfort after exercise.
|• Osteoid osteoma
||Benign bone lesion, common in long bones, dull nonradiating pain that is significantly worse at night.
Usefulness of Different Imaging Modalities
Validated assessment methods.
Use of ionizing radiation.
Not sensitive for early JIA changes in synovium at diagnosis.
Findings often of late disease/irreversible damage.
More sensitive at detecting subclinical disease (especially in small joints) than physical examination and can lead to alteration of treatment regimens.30
Can visualize several joints in one session.
Can be used to guide interventions (eg, intra-articular steroid injections).
Accessibility of joints.
Difficult to standardize.
|Magnetic resonance imaging
Very sensitive for early detection of erosive changes and subclinical synovitis to direct initiation of therapy.28
Detection of subclinical disease in magnetic resonance imaging of clinically unaffected joints may, in future, predict extension of arthritis.31
Direct visualization of cartilage and bone marrow edema not visualized by radiographs or ultrasound.
Lack of radiation.
Long examination time.
Risk for sedation in younger/uncooperative children.
Only evaluates one joint at a time.