The child with joint pain in primary care

Abstract

Joint pains are a common reason for children to present to primary care. The differential diagnosis is large including some diseases that do not primarily affect the musculoskeletal system. Although the cause for many patients will be benign and self-resolving, in rare cases the diagnosis is associated with long-term morbidity and mortality if not detected early and appropriately treated. These include primary and secondary malignancies, septic arthritis, osteomyelitis, inflammatory arthritis, slipped upper femoral epiphysis (SUFE) and non-accidental injury. We highlight the importance of a thorough history and directed yet comprehensive examination. A diagnostic algorithm is provided to direct primary care physicians' clinical assessment and investigation with the evidence base where available. In many cases, tests are not required, but if there is suspicion of malignancy, infection or inflammatory conditions, laboratory tests including full blood count, blood film, erythrocyte sedimentation rate, C-reactive protein and lactate dehydrogenase help to support or exclude the diagnosis. Autoimmune tests, such as antinuclear antibodies and rheumatoid factor, have no diagnostic role in juvenile idiopathic arthritis; therefore, we advise against any form of ‘rheumatological/autoimmune disease screen’ in primary care. Imaging does have a place in the diagnosis of joint pains in children, with plain radiographs being most appropriate for suspected fractures and SUFE, whilst ultrasound is better for the detection of inflammatory or infective effusions. The appropriate referral of children to paediatric rheumatologists, oncologists, orthopaedic surgeons and the emergency department are discussed.

Introduction

Musculoskeletal (MSK) symptoms are a common presentation of children to primary care and emergency departments. Painful joints and/or limping are presenting features of a wide range of conditions, many of which do not primarily affect the MSK system. Appropriate management requires targeted history taking and directed yet comprehensive examination to narrow the differential diagnosis before selection of investigations. A practical approach considers the differentials filtered by the age of the child, pattern of joint involvement and chronicity of symptoms. We will also highlight ‘red flags’ pointing to serious conditions that may rarely be seen in primary care.

The overall prevalence of MSK pain during childhood has been estimated to be 25–50% [1], [2], *[3]. In many cases, this is benign and self-resolving; therefore, it is not brought to medical attention. However, epidemiological surveys have highlighted that MSK complaints are a common presentation to primary care representing around 7% of all paediatric attendances [4], and they are the third leading reason for primary care presentation among adolescents in the USA [5]. In one study, MSK symptoms also represented 3% of paediatric day-case non-elective admissions [6]. A retrospective study in a paediatric primary care clinic in Spain identified the prevalence of MSK pain increasing with age from 2.4 to 5.7% at age 3 years to 27.5–36% at age 14 [7]. The most common presentations were knee arthralgias, other joint arthralgias (ankles, wrists and small joints of the fingers) and soft tissue (muscles, ligaments and tendons) pain comprising 65% of complaints across all age groups. Hip pain was reported significantly more frequently in the preschool-age group, whereas heel and back pain was more common among adolescents.

In this review, we will provide a guide to differential diagnosis through comprehensive and targeted history taking and examination leading the reader to appropriate investigation and referral to secondary care.