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Pain
Pain is the major symptom of children with JIA [ 34 ]. Several studies have shown that
pain is more prevalent in JIA than previously recognized and that a sizeable percent-
age of patients continues to report pain long after disease onset [ 35 ]. High levels of
pain limit physical activities, disrupt school attendance, and contribute to psychoso-
cial distress. These issues make reduction of pain a key goal of treatment [ 36 ].
The physician global rating of overall disease activity, the parent global rating of
the child’s overall well-being, and the parent rating of the intensity of child’s pain
on VAS are important quantitative measures used to assess the disease status in
children with JIA. The 10 cm horizontal line VAS is traditionally used to make these
assessments. However, as for the PGA, it has been suggested that the 21-numbered
circle VAS may increase the precision of patient assessment [ 29 ].
Only a few studies of medications in JIA have reported their effi cacy in control-
ling pain [ 37 , 38 ]. This paucity of data might be partly due to the lack of inclusion
of pain in the traditional outcome end points used in therapeutic studies in JIA,
including the JIA ACR response criteria, the criteria for inactive disease and clinical
remission or minimal disease activity, and the Juvenile Arthritis Disease Activity
Score (JADAS) [ 11 ]. The impact of pain is presumed to be incorporated, at least in
part, in the parent’s or child’s global rating of overall well-being. Furthermore, pain
is known to be affected by many non-disease-related factors, which makes it an
imperfect measure of disease activity. However, pain perception in children with
chronic arthritis is multifactorial, and results from the integration of biological pro-
cesses, psychological aspects, and sociocultural contexts [ 34 ]. Assessment of pain
should, therefore, address its impact on a broad range of factors, including physical,
social, and school activities; family and peer interactions; cognitive functioning;
emotional distress; mood; behavior; and pain-coping strategies [ 35 ]. These issues
make it clear that a reliable appraisal of pain in children with JIA requires the use of
well-validated and developmentally based pediatric pain-assessment tools that can
capture the multifaceted character of the pain experience.
Functional Ability
Functional ability/disability status or physical functioning are broad summary state-
ments with respect to the effect of a disease on the patient’s ability to carry out usual
tasks, such as the activities of daily living [ 14 ]. The assessment of physical function
is a fundamental component of the clinical evaluation of children with JIA.
Together with PGA, physical functioning assessment is also included among the
ACR core outcome variables for JIA [ 16 ] (Table 8.2 ).
A. Consolaro et al.