Leg aches, or growing pains, are idiopathic, benign discomfort of extremities, which occur in 15–30% of children. The pains are most common in girls, usually occur at night, and primarily affect the lower limbs. The condition produces no functional disability or objective signs and resolves spontaneously without residua. The cause is unknown. Undocumented speculation on cause includes genetic, functional, or structural (hypermobility) etiology. Leg aches follow headaches and stomach aches as the most common sites of pain during childhood.
The differential diagnosis of leg aches includes most of the painful conditions involving the musculoskeletal system in child. The diagnosis is made by exclusion.
History The pain from leg aches is typically vague, poorly localized, bilateral, nocturnal, and seldom alters activity. This condition does not affect gait or general health. A history of long duration is most consistent with the diagnosis of leg aches. This long duration is helpful in separating out more serious problems, which over a period of time will usually produce objective findings.
Screening examination Does the child appear systemically ill? Is deformity or stiffness present? Does the child limp?
Tenderness Systematically palpate the limbs and trunk for tenderness.
Joint motion Is joint motion guarded or restricted? Check for symmetry of medial rotation of hips.
Night pain may also be due to a tumor, such as ostoid osteoma, osteogenic, or Ewing sarcomas. Tumor pain is more localized, often associated with a soft mass, progressive, and usually occurs later in childhood than growing pains.
Management of Leg Aches
If the history is atypical for leg aches, or signs are found on examination, imaging and laboratory studies are required. If the findings are negative, a presumptive diagnosis of growing pains or leg aches is made. Provide symptomatic treatment with heat and an analgesic. Reassure the family about the benign, self-limited course of the condition, but advise them that if the clinical features change, the child should be reevaluated.